draft-ietf-smime-esformats-04.txt   rfc3126.txt 
Internet Draft Electronic Signature Formats
Internet Draft ETSI TC-SEC (ETSI)
S/MIME Working Group D. Pinkas (Bull)
expires in six months J. Ross (Security & Standards)
Target Category: Informational N. Pope (Security & Standards)
March 2001
Electronic Signature Formats Network Working Group D. Pinkas
Request for Comments: 3126 Integris
Category: Informational J. Ross
N. Pope
Security & Standards
September 2001
Electronic Signature Formats
for long term electronic signatures for long term electronic signatures
<draft-ietf-smime-esformats-04.txt>
Status of this Memo Status of this Memo
This document is an Internet-Draft and is NOT offered in This memo provides information for the Internet community. It does
accordance with section of RFC 2026, and the author does not not specify an Internet standard of any kind. Distribution of this
provide the IETF with any rights other than to publish as an memo is unlimited.
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Abstract Abstract
The informational RFC defines the format of an electronic signature This document defines the format of an electronic signature that can
that can remain valid over long periods. This includes evidence as to remain valid over long periods. This includes evidence as to its
its validity even if the signer or verifying party later attempts to validity even if the signer or verifying party later attempts to deny
deny (i.e. repudiates, see [ISONR]) the validity of the signature. (i.e., repudiates the validity of the signature).
The format can be considered as an extension to RFC 2630 [CMS] and RFC
2634 [ESS], where, when appropriate additional signed and unsigned
attributes have been defined.
The contents of this Informational RFC is technically equivalent to
ETSI TS 101 733 V.1.2.2. The ETSI TS is under the ETSI Copyright (C).
Individual copies of this ETSI deliverable can be downloaded from
http://www.etsi.org
1. Introduction
This document is intended to cover electronic signatures for various
types of transactions, including business transactions (e.g. purchase
requisition, contract, and invoice applications) where long term
validity of such signatures is important.
Internet Draft Electronic Signature Formats
Electronic signatures can be used for any transaction between an The format can be considered as an extension to RFC 2630 and RFC
individual and a company, between two companies, between an individual 2634, where, when appropriate additional signed and unsigned
and a governmental body, etc. This document is independent of any attributes have been defined.
environment. It can be applied to any environment e.g. smart cards, GSM
SIM cards, special programs for electronic signatures etc.
An electronic signature produced in accordance with this document The contents of this Informational RFC is technically equivalent to
provides evidence that can be processed to get confidence that some ETSI TS 101 733 V.1.2.2. The ETSI TS is under the ETSI Copyright (C).
commitment has been explicitly endorsed under a signature policy, at a Individual copies of this ETSI deliverable can be downloaded from
given time, by a signer under an identifier, e.g. a name or a http://www.etsi.org
pseudonym, and optionally a role.
The European Directive on a community framework for Electronic Table of Contents
Signatures defines an electronic signature as: "data in electronic form
which is attached to or logically associated with other electronic data
and which serves as a method of authentication". An electronic
signature as used in the current document is a form of advanced
electronic signature as defined in the Directive.
The key words "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT", 1. Introduction 4
"RECOMMENDED", "MAY", and "OPTIONAL" in this document (in uppercase, 2 Overview 5
as shown) are to be interpreted as described in [RFC2119]. 2.1 Aim 5
2.2 Basis of Present Document 5
2.3 Major Parties 6
2.4 Electronic Signatures and Validation Data 7
2.5 Forms of Validation Data 8
2.6 Extended Forms of Validation Data 11
2.7 Archive Validation Data 13
2.8 Arbitration 15
2.9 Validation Process 15
2.10 Example Validation Sequence 16
2.11 Additional optional features 21
3. Data structure of an Electronic Signature 22
3.1 General Syntax 22
3.2 Data Content Type 22
3.3 Signed-data Content Type 22
3.4 SignedData Type 22
3.5 EncapsulatedContentInfo Type 23
3.6 SignerInfo Type 23
3.6.1 Message Digest Calculation Process 23
3.6.2 Message Signature Generation Process 24
3.6.3 Message Signature Verification Process 24
3.7 CMS Imported Mandatory Present Attributes 24
3.7.1 Content Type 24
3.7.2 Message Digest 24
3.7.3 Signing Time 24
3.8 Alternative Signing Certificate Attributes 24
3.8.1 ESS Signing Certificate Attribute Definition 25
3.8.2 Other Signing Certificate Attribute Definition 25
3.9 Additional Mandatory Attributes 26
3.9.1 Signature policy Identifier 26
3.10 CMS Imported Optional Attributes 28
3.10.1 Countersignature 29
3.11 ESS Imported Optional Attributes 29
3.11.1 Content Reference Attribute 29
3.11.2 Content Identifier Attribute 29
3.11.3 Content Hints Attribute 29
3.12 Additional Optional Attributes 30
3.12.1 Commitment Type Indication Attribute 30
3.12.2 Signer Location attribute 32
3.12.3 Signer Attributes attribute 33
3.12.4 Content Time-Stamp attribute 34
3.13 Support for Multiple Signatures 34
3.13.1 Independent Signatures 34
3.13.2 Embedded Signatures 34
4. Validation Data 35
4.1 Electronic Signature Time-Stamp 36
4.1.1 Signature Time-Stamp Attribute Definition 36
4.2 Complete Validation Data 37
4.2.1 Complete Certificate Refs Attribute Definition 38
4.2.2 Complete Revocation Refs Attribute Definition 38
4.3 Extended Validation Data 40
4.3.1 Certificate Values Attribute Definition 40
4.3.2 Revocation Values Attribute Definition 41
4.3.3 ES-C Time-Stamp Attribute Definition 42
4.3.4 Time-Stamped Certificates and CRLs Attribute Definition 42
4.4 Archive Validation Data 43
4.4.1 Archive Time-Stamp Attribute Definition 43
5. Security Considerations 44
5.1 Protection of Private Key 44
5.2 Choice of Algorithms 44
6. Conformance Requirements 45
6.1 Signer 45
6.2 Verifier using time-stamping 46
6.3 Verifier using secure records 46
7. References 47
8. Authors' Addresses 48
Annex A (normative): ASN.1 Definitions 49
A.1 Definitions Using X.208 (1988) ASN.1 Syntax 49
A.2 Definitions Using X.680 1997 ASN.1 Syntax 57
Annex B (informative): General Description 66
B.1 The Signature Policy 66
B.2 Signed Information 67
B.3 Components of an Electronic Signature 68
B.3.1 Reference to the Signature Policy 68
B.3.2 Commitment Type Indication 69
B.3.3 Certificate Identifier from the Signer 69
B.3.4. Role Attributes 70
B.3.4.1 Claimed Role 71
B.3.4.2 Certified Role 71
B.3.5 Signer Location 72
B.3.6 Signing Time 72
B.3.7 Content Format 73
B.4 Components of Validation Data 73
B.4.1 Revocation Status Information 73
B.4.2 CRL Information 74
B.4.3 OCSP Information 74
B.4.4 Certification Path 75
B.4.5 Time-Stamping for Long Life of Signature 76
B.4.6 Time-Stamping before CA Key Compromises 77
B.4.6.1 Time-Stamping the ES with Complete validation data 77
B.4.6.2 Time-Stamping Certificates and Revocation Information 78
B.4.7 Time-Stamping for Long Life of Signature 79
B.4.8 Reference to Additional Data 80
B.4.9 Time-Stamping for Mutual Recognition 80
B.4.10 TSA Key Compromise 81
B.5 Multiple Signatures 81
Annex C (informative): Identifiers and roles 82
C.1 Signer Name Forms 82
C.2 TSP Name Forms 82
C.3 Roles and Signer Attributes 83
Full Copyright Statement 84
TABLE OF CONTENTS 1. Introduction
1. Introduction 1 This document is intended to cover electronic signatures for various
2 Overview 4 types of transactions, including business transactions (e.g.,
2.1 Aim 4 purchase requisition, contract, and invoice applications) where long
2.2 Basis of Present Document 4 term validity of such signatures is important. This includes
2.3 Major Parties 5 evidence as to its validity even if the signer or verifying party
2.4 Electronic Signatures and Validation Data 6 later attempts to deny (i.e., repudiates, see [ISONR]) the validity
2.5 Forms of Validation Data 7 of the signature).
2.6 Extended Forms of Validation Data 10
2.7 Archive Validation Data 12
2.8 Arbitration 13
2.9 Validation Process 13
2.10 Example Validation Sequence 14
2.11 Additional optional features 19
3. Data structure of an Electronic Signature 20
3.1 General Syntax 20
3.2 Data Content Type 20
3.3 Signed-data Content Type 20
3.4 SignedData Type 20
3.5 EncapsulatedContentInfo Type 21
3.6 SignerInfo Type 21
3.6.1 Message Digest Calculation Process 21
3.6.2 Message Signature Generation Process 21
3.6.3 Message Signature Verification Process 21
3.7 CMS Imported Mandatory Present Attributes 22
3.7.1 Content Type 22
3.7.2 Message Digest 22
3.7.3 Signing Time 22
Internet Draft Electronic Signature Formats Electronic signatures can be used for any transaction between an
individual and a company, between two companies, between an
individual and a governmental body, etc. This document is
independent of any environment. It can be applied to any environment
e.g., smart cards, GSM SIM cards, special programs for electronic
signatures etc.
3.8 Alternative Signing Certificate Attributes 22 An electronic signature produced in accordance with this document
3.8.1 ESS Signing Certificate Attribute Definition 22 provides evidence that can be processed to get confidence that some
3.8.2 Other Signing Certificate Attribute Definition 23 commitment has been explicitly endorsed under a signature policy, at
3.9 Additional Mandatory Attributes 24 a given time, by a signer under an identifier, e.g., a name or a
3.9.1 Signature policy Identifier 24 pseudonym, and optionally a role.
3.10 CMS Imported Optional Attributes 26
3.10.1 Countersignature 26
3.11 ESS Imported Optional Attributes 26
3.11.1 Content Reference Attribute 27
3.11.2 Content Identifier Attribute 27
3.11.3 Content Hints Attribute 27
3.12 Additional Optional Attributes 28
3.12.1 Commitment Type Indication Attribute 28
3.12.2 Signer Location attribute 30
3.12.3 Signer Attributes attribute 31
3.12.4 Content Timestamp attribute 31
3.13 Support for Multiple Signatures 32
3.13.1 Independent Signatures 32
3.13.2 Embedded Signatures 32
4. Validation Data 32
4.1 Electronic Signature Timestamp 33
4.1.1 Signature Timestamp Attribute Definition 33
4.2 Complete Validation Data 34
4.2.1 Complete Certificate Refs Attribute Definition 35
4.2.2 Complete Revocation Refs Attribute Definition 35
4.3 Extended Validation Data 37
4.3.1 Certificate Values Attribute Definition 37
4.3.2 Revocation Values Attribute Definition 38
4.3.3 ES-C Timestamp Attribute Definition 38
4.3.4 Time-Stamped Certificates and CRLs Attribute Definition 39
4.4 Archive Validation Data 39
4.4.1 Archive Timestamp Attribute Definition 40
5. Security considerations 41
5.1 Protection of Private Key 41
5.2 Choice of Algorithms 41
6. Conformance Requirements 41
6.1 Signer 41
6.2 Verifier using timestamping 42
6.3 Verifier using secure records 42
7. References 43
8. Authors' Addresses 44
9. Full Copyright Statement 45
Annex A (normative): ASN.1 Definitions 46
A.1 Definitions Using X.208 (1988) ASN.1 Syntax 46
A.2 Definitions Using X.680 1997 ASN.1 Syntax 54
Annex B (informative): General Description 64
B.1 The Signature Policy 64
B.2 Signed Information 65
B.3 Components of an Electronic Signature 65
B.3.1 Reference to the Signature Policy 65
B.3.2 Commitment Type Indication 66
B.3.3 Certificate Identifier from the Signer 67
Internet Draft Electronic Signature Formats The European Directive on a community framework for Electronic
Signatures defines an electronic signature as: "data in electronic
form which is attached to or logically associated with other
electronic data and which serves as a method of authentication". An
electronic signature as used in the current document is a form of
advanced electronic signature as defined in the Directive.
B.3.4. Role Attributes 68 The key words "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT",
B.3.4.1 Claimed Role 68 "RECOMMENDED", "MAY", and "OPTIONAL" in this document (in uppercase,
B.3.4.2 Certified Role 68 as shown) are to be interpreted as described in [RFC2119].
B.3.5 Signer Location 69
B.3.6 Signing Time 69
B.3.7 Content Format 70
B.4 Components of Validation Data 70
B.4.1 Revocation Status Information 70
B.4.2 CRL Information 71
B.4.3 OCSP Information 72
B.4.4 Certification Path 72
B.4.5 Timestamping for Long Life of Signature 73
B.4.6 Timestamping before CA Key Compromises 74
B.4.6.1 Timestamping the ES with Complete validation data 75
B.4.6.2 Timestamping Certificates and Revocation Information 75
B.4.7 Timestamping for Long Life of Signature 76
B.4.8 Reference to Additional Data 77
B.4.9 Timestamping for Mutual Recognition 77
B.4.10 TSA Key Compromise 78
B.5 Multiple Signatures 79
Annex C (informative): Identifiers and roles 79
C.1 Signer Name Forms 79
C.2 TSP Name Forms 79
C.3 Roles and Signer Attributes 80
2 Overview 2 Overview
2.1 Aim 2.1 Aim
The aim of this document is to define an Electronic Signature (ES) that The aim of this document is to define an Electronic Signature (ES)
remains valid over long periods. This includes evidence as to its that remains valid over long periods. This includes evidence as to
validity even if the signer or verifying party later attempts to deny its validity even if the signer or verifying party later attempts to
(repudiates) the validity of the signature. deny (repudiates) the validity of the signature.
This document specifies the use of trusted service providers (e.g. This document specifies the use of trusted service providers (e.g.,
TimeStamping Authorities (TSA)), and the data that needs to be archived Time-Stamping Authorities (TSA)), and the data that needs to be
(e.g. cross certificates and revocation lists) to meet the requirements archived (e.g., cross certificates and revocation lists) to meet the
of long term electronic signatures. An electronic signature defined by requirements of long term electronic signatures. An electronic
this document can be used for arbitration in case of a dispute between signature defined by this document can be used for arbitration in
the signer and verifier, which may occur at some later time, even years case of a dispute between the signer and verifier, which may occur at
later. This document uses a signature policy, referenced by the signer, some later time, even years later. This document uses a signature
as the basis for establishing the validity of an electronic signature. policy, referenced by the signer, as the basis for establishing the
validity of an electronic signature.
2.2 Basis of Present Document 2.2 Basis of Present Document
This document is based on the use of public key cryptography to produce This document is based on the use of public key cryptography to
digital signatures, supported by public key certificates. produce digital signatures, supported by public key certificates.
A Public key certificate is a public keys of a user, together with some
other information, rendered unforgeable by encipherment with the
private key of the Certification Authority (CA) which issued it (ITU-T
Recommendation X.509 [1]).
Internet Draft Electronic Signature Formats A Public key certificate is a public keys of a user, together with
some other information, rendered unforgeable by encipherment with the
private key of the Certification Authority (CA) which issued it
(ITU-T Recommendation X.509 [1]).
This document also specifies the uses of timestamping services to prove This document also specifies the uses of time-stamping services to
the validity of a signature long after the normal lifetime of critical prove the validity of a signature long after the normal lifetime of
elements of an electronic signature and to support non-repudiation. It critical elements of an electronic signature and to support non-
also, as an option, defines the use of additional timestamps to provide repudiation. It also, as an option, defines the use of additional
very long-term protection against key compromise or weakened time-stamps to provide very long-term protection against key
algorithms. compromise or weakened algorithms.
This document builds on existing standards that are widely adopted. This document builds on existing standards that are widely adopted.
This includes: This includes:
* RFC 2459 [RFC2459] Internet X.509 Public Key Infrastructure * RFC 2459 [RFC2459] Internet X.509 Public Key Infrastructure
Certificate and CRL Profile (PKIX); Certificate and CRL Profile (PKIX);
* RFC 2630 [CMS] Crytographic Message Syntax (CMS); * RFC 2630 [CMS] Crytographic Message Syntax (CMS);
* RFC 2634 [ESS] Enhanced Security Services (ESS); * RFC 2634 [ESS] Enhanced Security Services (ESS);
* RFC 2439 [OCSP] One-line Certificate Status Protocol (OCSP); * RFC 2439 [OCSP] One-line Certificate Status Protocol (OCSP);
* ITU-T Recommendation X.509 [1] Authentication framework; * ITU-T Recommendation X.509 [1] Authentication framework;
* RFC (to be published) [TSP] PKIX Time Stamping protocol (TSP). * RFC (to be published) [TSP] PKIX Time Stamping protocol (TSP).
NOTE: See section 7 for a full set of references. NOTE: See clause 8 for a full set of references.
2.3 Major Parties 2.3 Major Parties
The following are the major parties involved in a business transaction The following are the major parties involved in a business
supported by electronic signatures as defined in this document: transaction supported by electronic signatures as defined in this
document:
* the Signer;
* the Verifier;
* the Arbitrator;
* Trusted Service Providers (TSP).
A Signer is an entity that initially creates the electronic signature. * the Signer;
When the signer digitally signs over data using the prescribed format, * the Verifier;
this represents a commitment on behalf of the signing entity to the * the Arbitrator;
data being signed. * Trusted Service Providers (TSP).
A verifier is an entity that verifies an evidence. (ISO/IEC 13888-1 A Signer is an entity that initially creates the electronic
[13]). Within the context of this document this is an entity that signature. When the signer digitally signs over data using the
validates an electronic signature. prescribed format, this represents a commitment on behalf of the
An arbitrator, is an entity which arbitrates disputes between a signer signing entity to the data being signed.
and a verifier when there is a disagreement on the validity of a
digital signature.
Trusted Service Providers (TSPs) are one or more entities that help A verifier is an entity that verifies an evidence. (ISO/IEC 13888-1
to build trust relationships between the signer and verifier. Use of [13]). Within the context of this document this is an entity that
some specific TSP services MAY be mandated by signature policy. TSP validates an electronic signature.
supporting services may provide the following information: user An arbitrator, is an entity which arbitrates disputes between a
certificates, cross-certificates, timestamping tokens, CRLs, ARLs, signer and a verifier when there is a disagreement on the validity of
OCSP responses. a digital signature.
Internet Draft Electronic Signature Formats Trusted Service Providers (TSPs) are one or more entities that help
to build trust relationships between the signer and verifier. Use of
some specific TSP services MAY be mandated by signature policy. TSP
supporting services may provide the following information: user
certificates, cross-certificates, time-stamping tokens, CRLs, ARLs,
OCSP responses.
The following TSPs are used to support the validation or The following TSPs are used to support the validation or the
the verification of electronic signatures : verification of electronic signatures:
* Certification Authorities; * Certification Authorities;
* Registration Authorities; * Registration Authorities;
* Repository Authorities (e.g. a Directory); * Repository Authorities (e.g., a Directory);
* TimeStamping Authorities; * Time-Stamping Authorities;
* One-line Certificate Status Protocol responders; * One-line Certificate Status Protocol responders;
* Attribute Authorities; * Attribute Authorities;
* Signature Policy Issuers. * Signature Policy Issuers.
Certification Authorities provide users with public key certificates. Certification Authorities provide users with public key certificates.
Registration Authorities allows the registration of entities before a Registration Authorities allows the registration of entities before a
CA generates certificates. CA generates certificates.
Repository Authorities publish CRLs issued by CAs, cross-certificates Repository Authorities publish CRLs issued by CAs, cross-certificates
(i.e. CA certificates) issued by CAs, signature policies issued by (i.e., CA certificates) issued by CAs, signature policies issued by
Signature Policy Issuers and optionally public key certificates (i.e. Signature Policy Issuers and optionally public key certificates
leaf certificates) issued by CAs. (i.e., leaf certificates) issued by CAs.
TimeStamping Authorities attest that some data was formed before a Time-Stamping Authorities attest that some data was formed before a
given trusted time. given trusted time.
One-line Certificate Status Protocol responders (OSCP responders) One-line Certificate Status Protocol responders (OSCP responders)
provide information about the status (i.e. revoked, not revoked, provide information about the status (i.e., revoked, not revoked,
unknown) of a particular certificate. unknown) of a particular certificate.
A Signature Policy Issuer issues signatures policies that define the A Signature Policy Issuer issues signatures policies that define the
technical and procedural requirements for electronic signature technical and procedural requirements for electronic signature
creation, validation and verification, in order to meet a particular creation, validation and verification, in order to meet a particular
business need. business need.
Attributes Authorities provide users with attributes linked to public Attributes Authorities provide users with attributes linked to public
key certificates key certificates
2.4 Electronic Signatures and Validation Data 2.4 Electronic Signatures and Validation Data
Validation of an electronic signature in accordance with this document Validation of an electronic signature in accordance with this
requires: document requires:
* The electronic signature; this includes:
- the signature policy;
- the signed user data;
- the digital signature;
- other signed attributes provided by the signer;
. - other unsigned attributes provided by the signer.
* Validation data which is the additional data needed to validate * The electronic signature; this includes:
the electronic signature; this includes:
- certificates references; - the signature policy;
- certificates; - the signed user data;
- the digital signature;
- other signed attributes provided by the signer;
- other unsigned attributes provided by the signer.
Internet Draft Electronic Signature Formats Validation data which is the additional data needed to validate the
electronic signature; this includes:
- revocation status information references; - certificates references;
- revocation status information; - certificates;
- time-stamps from Time Stamping Authorities (TSAs). - revocation status information references;
- revocation status information;
- time-stamps from Time Stamping Authorities (TSAs).
* The signature policy specifies the technical requirements on * The signature policy specifies the technical requirements on
signature creation and validation in order to meet a particular signature creation and validation in order to meet a particular
business need. A given legal/contractual context may recognize a business need. A given legal/contractual context may recognize
particular signature policy as meeting its requirements. a particular signature policy as meeting its requirements.
For example: a specific signature policy may be recognized by court For example: a specific signature policy may be recognized by court
of law as meeting the requirements of the European Directive for of law as meeting the requirements of the European Directive for
electronic commerce. A signature policy may be written using a formal electronic commerce. A signature policy may be written using a
notation like ASN.1 or in an informal free text form provided the formal notation like ASN.1 or in an informal free text form provided
rules of the policy are clearly identified. However, for a given the rules of the policy are clearly identified. However, for a given
signature policy there shall be one definitive form which has a unique signature policy there shall be one definitive form which has a
binary encoded value. unique binary encoded value.
Signed user data is the user's data that is signed. Signed user data is the user's data that is signed.
The Digital Signature is the digital signature applied over the The Digital Signature is the digital signature applied over the
following attributes provided by the signer: following attributes provided by the signer:
* hash of the user data (message digest); * hash of the user data (message digest);
* signature Policy Identifier; * signature Policy Identifier;
* other signed attributes * other signed attributes
The other signed attributes include any additional information which The other signed attributes include any additional information which
must be signed to conform to the signature policy or this document must be signed to conform to the signature policy or this document
(e.g. signing time). (e.g., signing time).
According to the requirements of a specific signature policy in use, According to the requirements of a specific signature policy in use,
various Validation Data shall be collected and attached to or various Validation Data shall be collected and attached to or
associated with the signature structure by the signer and/or the associated with the signature structure by the signer and/or the
verifier. The validation data includes CA certificates as well as verifier. The validation data includes CA certificates as well as
revocation status information in the form of certificate revocation revocation status information in the form of certificate revocation
lists (CRLs) or certificate status information provided by an on-line lists (CRLs) or certificate status information provided by an on-line
service. Additional data also includes timestamps and other time service. Additional data also includes time-stamps and other time
related data used to provide evidence of the timing of given events. It related data used to provide evidence of the timing of given events.
is required, as a minimum, that either the signer or verifier obtains a It is required, as a minimum, that either the signer or verifier
timestamp over the signer's signature or a secure time record of the obtains a time-stamp over the signer's signature or a secure time
electronic signature must be maintained. Such secure records must not record of the electronic signature must be maintained. Such secure
be undetectably modified and must record the time close to when the records must not be undetectably modified and must record the time
signature was first validated. close to when the signature was first validated.
2.5 Forms of Validation Data 2.5 Forms of Validation Data
An electronic signature may exist in many forms including: An electronic signature may exist in many forms including:
* the Electronic Signature (ES), which includes the digital
signature and other basic information provided by the signer;
Internet Draft Electronic Signature Formats
* the ES with Timestamp (ES-T), which adds a timestamp to the * the Electronic Signature (ES), which includes the digital
Electronic Signature, to take initial steps towards providing signature and other basic information provided by the signer;
long term validity;
* the ES with Complete validation data (ES-C), which adds to the * the ES with Time-Stamp (ES-T), which adds a time-stamp to the
ES-T references to the complete set of data supporting the Electronic Signature, to take initial steps towards providing
validity of the electronic signature (i.e. revocation status long term validity;
information).
The signer must provide at least the ES form, but in some cases may * the ES with Complete validation data (ES-C), which adds to the
decide to provide the ES-T form and in the extreme case could provide ES-T references to the complete set of data supporting the
the ES-C form. If the signer does not provide ES-T, the verifier must validity of the electronic signature (i.e., revocation status
either create the ES-T on first receipt of an electronic signature or information).
shall keep a secure time record of the ES. Either of these two
approaches provide independent evidence of the existence of
the signature at the time it was first verified which should be near
the time it was created, and so protects against later repudiation of
the existence of the signature. If the signer does not provide ES-C the
verifier must create the ES-C when the complete set of revocation and
other validation data is available.
The ES satisfies the legal requirements for electronic signatures as The signer must provide at least the ES form, but in some cases may
defined in the European Directive on electronic signatures, see Annex C decide to provide the ES-T form and in the extreme case could provide
for further discussion on relationship of this document to the the ES-C form. If the signer does not provide ES-T, the verifier
Directive. It provides basic authentication and integrity protection must either create the ES-T on first receipt of an electronic
and can be created without accessing on-line (timestamping) services. signature or shall keep a secure time record of the ES. Either of
However, without the addition of a timestamp or a secure time record these two approaches provide independent evidence of the existence of
the electronic signature does not protect against the threat that the the signature at the time it was first verified which should be near
signer later denies having created the electronic signature (i.e. does the time it was created, and so protects against later repudiation of
not provide non-repudiation of its existence). the existence of the signature. If the signer does not provide ES-C
the verifier must create the ES-C when the complete set of revocation
and other validation data is available.
The ES-T time-stamp or time record should be created close to the time The ES satisfies the legal requirements for electronic signatures as
that ES was created to provide protection against repudiation. At this defined in the European Directive on electronic signatures, see Annex
time all the data needed to complete the validation may not be C for further discussion on relationship of this document to the
available but what information is readily available may be used to Directive. It provides basic authentication and integrity protection
carry out some of the initial checks. For example, only part of the and can be created without accessing on-line (time-stamping)
revocation information may be available for verification at that point services. However, without the addition of a time-stamp or a secure
in time. Generally, the ES-C form cannot be created at the same time as time record the electronic signature does not protect against the
the ES, as it is necessary to allow time for any revocation information threat that the signer later denies having created the electronic
to be captured. Also, if a certificate is found to be temporarily signature (i.e., does not provide non-repudiation of its existence).
suspended, it will be necessary to wait until the end of the suspension
period.
The signer should only create the ES-C in situations where it was The ES-T time-stamp or time record should be created close to the
prepared to wait for a sufficient length of time after creating the ES time that ES was created to provide protection against repudiation.
form before dispatching the ES-C. This, however, has the advantage that At this time all the data needed to complete the validation may not
the verifier can be presented with the complete set of data supporting be available but what information is readily available may be used to
the validity of the ES. carry out some of the initial checks. For example, only part of the
revocation information may be available for verification at that
point in time. Generally, the ES-C form cannot be created at the
same time as the ES, as it is necessary to allow time for any
revocation information to be captured. Also, if a certificate is
found to be temporarily suspended, it will be necessary to wait until
the end of the suspension period.
Support for ES-C by the verifier is mandated (see section 6 for The signer should only create the ES-C in situations where it was
specific conformance requirements). prepared to wait for a sufficient length of time after creating the
ES form before dispatching the ES-C. This, however, has the
advantage that the verifier can be presented with the complete set of
data supporting the validity of the ES.
Internet Draft Electronic Signature Formats Support for ES-C by the verifier is mandated (see clause 6 for
specific conformance requirements).
An Electronic Signature (ES), with the additional validation data An Electronic Signature (ES), with the additional validation data
forming the ES-T and ES-C is illustrated in Figure 1: forming the ES-T and ES-C is illustrated in Figure 1:
+------------------------------------------------------------ES-C-----+ +------------------------------------------------------------ES-C-----+
|+--------------------------------------------ES-T-----+ | |+--------------------------------------------ES-T-----+ |
||+------Elect.Signature (ES)----------+ +------------+| +-----------+| ||+------Elect.Signature (ES)----------+ +------------+| +-----------+|
|||+---------+ +----------+ +---------+| |Timestamp || |Complete || |||+---------+ +----------+ +---------+| |Time-Stamp || |Complete ||
||||Signature| | Other | | Digital || |over digital|| |certificate|| ||||Signature| | Other | | Digital || |over digital|| |certificate||
||||Policy ID| | Signed | |Signature|| |signature || |and || ||||Policy ID| | Signed | |Signature|| |signature || |and ||
|||| | |Attributes| | || +------------+| |revocation || |||| | |Attributes| | || +------------+| |revocation ||
|||+---------+ +----------+ +---------+| | |references || |||+---------+ +----------+ +---------+| | |references ||
||+------------------------------------+ | +-----------+| ||+------------------------------------+ | +-----------+|
|+-----------------------------------------------------+ | |+-----------------------------------------------------+ |
+---------------------------------------------------------------------+ +---------------------------------------------------------------------+
Figure 1: Illustration of an ES, ES-T and ES-C Figure 1: Illustration of an ES, ES-T and ES-C
The verifiers conformance requirements of an ES with a timestamp of the
digital signature is defined in subsection 6.2.
The ES on its own satisfies the legal requirements for electronic The verifiers conformance requirements of an ES with a time-stamp of
signatures as defined in the European Directive on electronic the digital signature is defined in subclause 6.2.
signatures. The signers conformance requirements of an ES are defined
in subsection 6.1, and are met using a structure as indicated in figure
2:
+------Elect.Signature (ES)-----------| The ES on its own satisfies the legal requirements for electronic
|+---------+ +----------+ +---------+ | signatures as defined in the European Directive on electronic
||Signature| | Other | | Digital | | signatures. The signers conformance requirements of an ES are
||Policy ID| | Signed | |Signature| | defined in subclause 6.1, and are met using a structure as indicated
|| | |Attributes| | | | in figure 2:
|+---------+ +----------+ +---------+ |
|+-----------------------------------+|
Figure 2: Illustration of an ES +------Elect.Signature (ES)-----------|
|+---------+ +----------+ +---------+ |
||Signature| | Other | | Digital | |
||Policy ID| | Signed | |Signature| |
|| | |Attributes| | | |
|+---------+ +----------+ +---------+ |
|+-----------------------------------+|
Where there are requirements for long term signatures without Figure 2: Illustration of an ES
timestamping the digital signature, then a secure record is needed of
the time of verification in association with the electronic signature
(i.e. both must be securely recorded). In addition the certificates
and revocation information used at the time of verification should to
be recorded as indicated in figure 3 as an ES-C(bis).
Internet Draft Electronic Signature Formats Where there are requirements for long term signatures without time-
stamping the digital signature, then a secure record is needed of the
time of verification in association with the electronic signature
(i.e., both must be securely recorded). In addition the certificates
and revocation information used at the time of verification should to
be recorded as indicated in figure 3 as an ES-C(bis).
+-------------------------------------------------------ES-C-----+ +-------------------------------------------------------ES-C-----+
| | | |
| +------Elect.Signature (ES)----------+| +-----------+| | +------Elect.Signature (ES)----------+| +-----------+|
| |+---------+ +----------+ +---------+|| |Complete || | |+---------+ +----------+ +---------+|| |Complete ||
| ||Signature| | Other | | Digital ||| |certificate|| | ||Signature| | Other | | Digital ||| |certificate||
| ||Policy ID| | Signed | |Signature||| |and || | ||Policy ID| | Signed | |Signature||| |and ||
| || | |Attributes| | ||| |revocation || | || | |Attributes| | ||| |revocation ||
| |+---------+ +----------+ +---------+|| |references || | |+---------+ +----------+ +---------+|| |references ||
| +------------------------------------+| +-----------+| | +------------------------------------+| +-----------+|
| | | |
+----------------------------------------------------------------+ +----------------------------------------------------------------+
Figure 3: Illustration of an ES-C(bis) Figure 3: Illustration of an ES-C(bis)
The verifiers conformance requirements of an ES-C(bis) is defined in The verifiers conformance requirements of an ES-C(bis) is defined in
subsection 6.3. subclause 6.3.
Note: A timestamp attached to the electronic signature or a secure time Note: A time-stamp attached to the electronic signature or a secure
record helps to protect the validity of the signature even if some of time record helps to protect the validity of the signature even if
the verification data associated with the signature become compromised some of the verification data associated with the signature become
AFTER the signature was generated. The timestamp or a secure time compromised AFTER the signature was generated. The time-stamp or a
record provides evidence that the signature was generated BEFORE the secure time record provides evidence that the signature was generated
event of compromise; hence the signature will maintain its validity BEFORE the event of compromise; hence the signature will maintain its
status. validity status.
2.6 Extended Forms of Validation Data 2.6 Extended Forms of Validation Data
The complete validation data (ES-C) described above may be extended to The complete validation data (ES-C) described above may be extended
form an ES with eXtended validation data (ES-X) to meet following to form an ES with eXtended validation data (ES-X) to meet following
additional requirements. additional requirements.
Firstly, when the verifier does not has access to,
* the signer's certificate,
* all the CA certificates that make up the full certification
path,
* all the associated revocation status information, as referenced
in the ES-C.
then the values of these certificates and revocation information may be Firstly, when the verifier does not has access to,
added to the ES-C. This form of extended validation data is called a
X-Long.
Secondly, if there is a risk that any CA keys used in the certificate * the signer's certificate,
chain may be compromised, then it is necessary to additionally * all the CA certificates that make up the full certification
timestamp the validation data by either: path,
* all the associated revocation status information, as referenced
in the ES-C.
* timestamping all the validation data as held with the ES(ES-C), then the values of these certificates and revocation information may
this eXtended validation data is called a Type 1 X-Timestamp; or be added to the ES-C. This form of extended validation data is
* timestamping individual reference data as used for complete called a X-Long.
validation.
Internet Draft Electronic Signature Formats Secondly, if there is a risk that any CA keys used in the certificate
chain may be compromised, then it is necessary to additionally time-
stamp the validation data by either:
This form of eXtended validation data is called a Type 2 X-Timestamp. * time-stamping all the validation data as held with the ES(ES-
C), this eXtended validation data is called a Type 1 X-Time-
Stamp; or
* time-stamping individual reference data as used for complete
validation.
NOTE: The advantages/drawbacks for Type 1 and Type 2 X-Timestamp are This form of eXtended validation data is called a Type 2 X-Time-
discussed in this document (see section B.4.6.) Stamp.
If all the above conditions occur then a combination of the two formats NOTE: The advantages/drawbacks for Type 1 and Type 2 X-Time-Stamp
above may be used. This form of eXtended validation data is called are discussed in this document (see clause B.4.6.)
a X-Long-Timestamped.
Support for the extended forms of validation data is optional. If all the above conditions occur then a combination of the two
formats above may be used. This form of eXtended validation data is
called a X-Long-Time-Stamped.
An Electronic Signature (ES) , with the additional validation data Support for the extended forms of validation data is optional.
forming the ES-X long is illustrated in Figure 4:
+------------------------------------------------------- ES-X Long--+ An Electronic Signature (ES) , with the additional validation data
|+--------------------------------------- EC-C --------+ | forming the ES-X long is illustrated in Figure 4:
||+---- Elect.Signature (ES)----+ +--------+| +--------+ |
|||+-------+-+-------+-+-------+| +---------+|Complete|| |Complete| |
||||Signa- | |Other | |Digital|| |Timestamp||certi- || |certi- | |
||||ture | |Signed | |Signa- || |over ||ficate || |ficate | |
||||Policy | |Attri- | |ture || |digital ||and || |and | |
||||ID | |butes | | || |signature||revoc. || |revoc. | |
|||+-------+ +-------+ +-------+| +---------+|refs || |data | |
||+-----------------------------+ +--------+| +--------+ |
|+-----------------------------------------------------+ |
+-------------------------------------------------------------------+
Figure 4: Illustration of an ES and ES-X long. +-------------------------------------------------------- ES-X Long--+
|+---------------------------------------- EC-C --------+ |
||+---- Elect.Signature (ES)----+ +--------+| +--------+ |
|||+-------+-+-------+-+-------+| +----------+|Complete|| |Complete| |
||||Signa- | |Other | |Digital|| |Time-Stamp||certi- || |certi- | |
||||ture | |Signed | |Signa- || |over ||ficate || |ficate | |
||||Policy | |Attri- | |ture || |digital ||and || |and | |
||||ID | |butes | | || |signature ||revoc. || |revoc. | |
|||+-------+ +-------+ +-------+| +----------+|refs || |data | |
||+-----------------------------+ +--------+| +--------+ |
|+------------------------------------------------------+ |
+--------------------------------------------------------------------+
An Electronic Signature (ES) , with the additional validation data Figure 4: Illustration of an ES and ES-X long.
forming the eXtended Validation Data - Type 1 is illustrated in
Figure 5:
+---------------------------------------------------------- ES-X 1 -+ An Electronic Signature (ES) , with the additional validation data
|+---------------------------------------- EC-C --------+ | forming the eXtended Validation Data - Type 1 is illustrated in
|| +---- Elect.Signature (ES)----+ +--------+| +-------+ | Figure 5:
|| |+-------+ +-------+ +-------+| +---------+|Complete|| | | |
|| ||Signa- | |Other | |Digital|| |Timestamp||certifi-|| | Time- | |
|| ||ture | |Signed | |Signa- || |over ||cate and|| | stamp | |
|| ||Policy | |Attri- | |ture || |digital ||revoc. || | over | |
|| ||ID | |butes | | || |signature||refs || | CES | |
|| |+-------+ +-------+ +-------+| +---------+| || | | |
|| +-----------------------------+ +--------+| +-------+ |
|+------------------------------------------------------+ |
+-------------------------------------------------------------------+
Figure 5: Illustration of ES with ES-X Type 1 +----------------------------------------------------------- ES-X 1 -+
|+----------------------------------------- EC-C --------+ |
|| +---- Elect.Signature (ES)----+ +--------+| +-------+ |
|| |+-------+ +-------+ +-------+| +----------+|Complete|| | | |
|| ||Signa- | |Other | |Digital|| |Time-Stamp||certifi-|| | Time- | |
|| ||ture | |Signed | |Signa- || |over ||cate and|| | stamp | |
|| ||Policy | |Attri- | |ture || |digital ||revoc. || | over | |
|| ||ID | |butes | | || |signature ||refs || | CES | |
|| |+-------+ +-------+ +-------+| +----------+| || | | |
|| +-----------------------------+ +--------+| +-------+ |
|+-------------------------------------------------------+ |
+--------------------------------------------------------------------+
Internet Draft Electronic Signature Formats Figure 5: Illustration of ES with ES-X Type 1
An Electronic Signature (ES) , with the additional validation data An Electronic Signature (ES) , with the additional validation data
forming the eXtended Validation Data - Type 2 is illustrated in forming the eXtended Validation Data - Type 2 is illustrated in
Figure 6: Figure 6:
+-------------------------------------------------------- ES-X 2 ---+ +--------------------------------------------------------- ES-X 2 ---+
|+--------------------------------------- EC-C --------+ | |+---------------------------------------- EC-C --------+ |
||+---- Elect.Signature (ES)----+ +--------+| +--------+ | ||+---- Elect.Signature (ES)----+ +--------+| +--------+ |
|||+-------+ +-------+ +-------+| +---------+|Complete|| |Times | | |||+-------+ +-------+ +-------+| +----------+|Complete|| |Times | |
||||Signa- | |Other | |Digital|| |Timestamp||certs || |Stamp | | ||||Signa- | |Other | |Digital|| |Time-Stamp||certs || |Stamp | |
||||ture | |Signed | |Signa- || |over ||and || |over | | ||||ture | |Signed | |Signa- || |over ||and || |over | |
||||Policy | |Attri- | |ture || |digital ||revoc. || |Complete| | ||||Policy | |Attri- | |ture || |digital ||revoc. || |Complete| |
||||ID | |butes | | || |signature||refs || |certs | | ||||ID | |butes | | || |signature ||refs || |certs | |
|||+-------+ +-------+ +-------+| +---------+| || |and | | |||+-------+ +-------+ +-------+| +----------+| || |and | |
||+-----------------------------+ +--------+| |revoc. | | ||+-----------------------------+ +--------+| |revoc. | |
|| | |refs | | || | |refs | |
|+-----------------------------------------------------+ +--------+ | |+------------------------------------------------------+ +--------+ |
+-------------------------------------------------------------------+ +--------------------------------------------------------------------+
Figure 6: Illustration of ES with ES-X Type 2 Figure 6: Illustration of ES with ES-X Type 2
2.7 Archive Validation Data 2.7 Archive Validation Data
Before the algorithms, keys and other cryptographic data used at the Before the algorithms, keys and other cryptographic data used at the
time the ES-C was built become weak and the cryptographic functions time the ES-C was built become weak and the cryptographic functions
become vulnerable, or the certificates supporting previous timestamps become vulnerable, or the certificates supporting previous time-
expires, the signed data, the ES-C and any additional information stamps expires, the signed data, the ES-C and any additional
(ES-X) should be timestamped. If possible this should use stronger information (ES-X) should be time-stamped. If possible this should
algorithms (or longer key lengths) than in the original timestamp. use stronger algorithms (or longer key lengths) than in the original
time-stamp.
This additional data and timestamp is called Archive Validation Data
(ES-A). The Timestamping process may be repeated every time the
protection used to timestamp a previous ES-A become weak. An ES-A
may thus bear multiple embedded time stamps.
An example of an Electronic Signature (ES), with the additional This additional data and time-stamp is called Archive Validation Data
validation data for the ES-C and ES-X forming the ES-A is illustrated (ES-A). The Time-Stamping process may be repeated every time the
in Figure 7. protection used to time-stamp a previous ES-A become weak. An ES-A
may thus bear multiple embedded time stamps.
+-------------------------------- ES-A --------- ----------+ An example of an Electronic Signature (ES), with the additional
| +-------------------- ES-A -----------------+ | validation data for the ES-C and ES-X forming the ES-A is illustrated
| | +--------- ES-X -------------- + | | in Figure 7.
| | |..............................| +-----+ | +-----+ |
| | |..............................| |Time | | |Time | |
| | |..............................| |Stamp| | |Stamp| |
| | | | +-----+ | +-----+ |
| | +----------------------------- + | |
| +-------------------------------------------+ |
+----------------------------------------------------------+
Figure 7: Illustration of ES -A +-------------------------------- ES-A --------- ----------+
| +-------------------- ES-A -----------------+ |
| | +--------- ES-X -------------- + | |
| | |..............................| +-----+ | +-----+ |
| | |..............................| |Time | | |Time | |
| | |..............................| |Stamp| | |Stamp| |
| | | | +-----+ | +-----+ |
| | +----------------------------- + | |
| +-------------------------------------------+ |
+----------------------------------------------------------+
Support for ES-A is optional. Figure 7: Illustration of ES -A
Internet Draft Electronic Signature Formats Support for ES-A is optional.
2.8 Arbitration 2.8 Arbitration
The ES-C may be used for arbitration should there be a dispute between The ES-C may be used for arbitration should there be a dispute
the signer and verifier, provided that: between the signer and verifier, provided that:
* a copy of the signature policy referenced by the signer is * a copy of the signature policy referenced by the signer is
available; available;
* the arbitrator knows where to retrieve the signer's certificate * the arbitrator knows where to retrieve the signer's certificate
(if not already present), all the cross-certificates and the (if not already present), all the cross-certificates and the
required CRLs and/or OCSPs responses referenced in the ES-C; required CRLs and/or OCSPs responses referenced in the ES-C;
* none of the issuing key from the certificate chain have ever * none of the issuing key from the certificate chain have ever
been compromised; been compromised;
* the cryptography used at the time the ES-C was built has not * the cryptography used at the time the ES-C was built has not
been broken at the time the arbitration is performed. been broken at the time the arbitration is performed.
When the second condition is not met, then the plaintiff must provide When the second condition is not met, then the plaintiff must provide
an ES-X Long. an ES-X Long.
When it is known by some external means that the third condition is When it is known by some external means that the third condition is
not met, then the plaintiff must provide an ES-X Timestamped. not met, then the plaintiff must provide an ES-X Time-Stamped.
When the two previous conditions are not met, the plaintiff must When the two previous conditions are not met, the plaintiff must
provide the two above information (i.e. an ES-X Timestamped and Long). provide the two above information (i.e., an ES-X Time-Stamped and
Long).
When the last condition is not met, the plaintiff must provide an When the last condition is not met, the plaintiff must provide an
ES-A. ES-A.
It should be noticed that a verifier may need to get two time stamps It should be noticed that a verifier may need to get two time stamps
at two different instants of time: one soon after the generation of at two different instants of time: one soon after the generation of
the ES and one soon after some grace period allowing any entity from the ES and one soon after some grace period allowing any entity from
the certification chain to declare a key compromise. the certification chain to declare a key compromise.
2.9 Validation Process 2.9 Validation Process
The Validation Process validates an electronic signature in accordance The Validation Process validates an electronic signature in
with the requirements of the signature policy. The output status of accordance with the requirements of the signature policy. The output
the validation process can be: status of the validation process can be:
* valid;
* invalid;
* incomplete verification.
A Valid response indicates that the signature has passed verification * valid;
and it complies with the signature validation policy. * invalid;
* incomplete verification.
A signature validation policy is a part of the signature policy which A Valid response indicates that the signature has passed verification
specifies the technical requirements on the signer in creating a and it complies with the signature validation policy.
signature and verifier when validating a signature.
Internet Draft Electronic Signature Formats A signature validation policy is a part of the signature policy which
specifies the technical requirements on the signer in creating a
signature and verifier when validating a signature.
An Invalid response indicates that either the signature format is An Invalid response indicates that either the signature format is
incorrect or that the digital signature value fails verification incorrect or that the digital signature value fails verification
(e.g. the integrity checks on the digital signature value fails or (e.g., the integrity checks on the digital signature value fails or
any of the certificates on which the digital signature verification any of the certificates on which the digital signature verification
depends is known to be invalid or revoked). depends is known to be invalid or revoked).
An Incomplete Validation response indicates that the format and An Incomplete Validation response indicates that the format and
digital signature verifications have not failed but there is digital signature verifications have not failed but there is
insufficient information to determine if the electronic signature insufficient information to determine if the electronic signature is
is valid under the signature policy. This can include situations valid under the signature policy. This can include situations where
where additional information, which does not effect the validity of additional information, which does not effect the validity of the
the digital signature value, may be available but is invalid. digital signature value, may be available but is invalid.
In the case of Incomplete Validation, it may be possible to request In the case of Incomplete Validation, it may be possible to request
that the electronic signature be checked again at a later date when that the electronic signature be checked again at a later date when
additional validation information might become available. Also, in the additional validation information might become available. Also, in
case of incomplete validation, additional information may be made the case of incomplete validation, additional information may be made
available to the application or user, thus allowing the application or available to the application or user, thus allowing the application
user to decide what to do with partially correct electronic signatures. or user to decide what to do with partially correct electronic
signatures.
The validation process may also output validation data : The validation process may also output validation data:
* a signature timestamp; * a signature time-stamp;
* the complete validation data; * the complete validation data;
* the archive validation data. * the archive validation data.
2.10 Example Validation Sequence 2.10 Example Validation Sequence
Figure 8, and subsequent description, describes how the validation Figure 8, and subsequent description, describes how the validation
process may build up a complete electronic signature over time. process may build up a complete electronic signature over time.
Soon after receiving the electronic signature (ES) from the signer (1),
the digital signature value may be checked, the validation process
must at least add a time-stamp (2), unless the signer has provided one
which is trusted by the verifier. The validation process may also
validate the electronic signature, as required under the identified
signature policy, using additional data (e.g. certificates, CRL, etc.)
provided by trusted service providers. If the validation process is not
complete then the output from this stage is the ES-T.
When all the additional data (e.g. the complete certificate and
revocation information) necessary to validate the electronic signature
first becomes available, then the validation process:
* obtains all the necessary additional certificate and revocation
status information;
* completes all the validation checks on the ES, using the
complete certificate and revocation information (if a timestamp
is not already present, this may be added at the same stage
combining ES-T and ES-C process);
Internet Draft Electronic Signature Formats
* records the complete certificate and revocation references (3);
* indicates the validity status to the user (4).
+---------------------------------------- ES-C ----------+ Soon after receiving the electronic signature (ES) from the signer
|+----------------------------- ES-T -------+ | (1), the digital signature value may be checked, the validation
||+--- Elect.Signature (ES) ----+ | +--------+ | process must at least add a time-stamp (2), unless the signer has
|||+-------+ +-------+ +-------+|+---------+| |Complete| | provided one which is trusted by the verifier. The validation
||||Signa- | |Other | |Digital|||Timestamp|| |certifi-| | process may also validate the electronic signature, as required under
||||ture | |Signed | |Signa- |||over || |cate and| | the identified signature policy, using additional data (e.g.,
||||Policy | |Attri- | |ture |||digital || |revoca- | | certificates, CRL, etc.) provided by trusted service providers. If
||||ID | |butes | | |||signature|| |tion | | the validation process is not complete then the output from this
|||+-------+ +-------+ +-------+|+---------+| |referen-| | stage is the ES-T.
||+------------\----------------+ ^ | |ces | |
|| \ | | +--------+ |
|| \ 1 / | ^ |
|+----------------\----------------/--------+ | |
+------------------\--------------/-------------- /------+
\ /2 ----3-----/
+----------+ | / /
| Signed |\ v / |
|User data | \ +--------------------+ +------------+
+----------+ \--->| Validation Process |---> |- Valid |
+---|--^-------|--^--+ 4 |- Invalid |
| | | | |- Validation|
v | v | | Incomplete|
+---------+ +--------+ +------------+
|Signature| |Trusted |
| Policy | |Service |
| Issuer | |Provider|
+---------+ +--------+
Figure 8: Illustration of an ES with Complete validation data (ES-C) When all the additional data (e.g., the complete certificate and
revocation information) necessary to validate the electronic
signature first becomes available, then the validation process:
Internet Draft Electronic Signature Formats * obtains all the necessary additional certificate and revocation
status information;
At the same time as the validation process creates the ES-C, the * completes all the validation checks on the ES, using the
validation process may provide and/or record the values of certificates complete certificate and revocation information (if a time-
and revocation status information used in ES-C, called the ES-X Long stamp is not already present, this may be added at the same
(5). This is illustrated in figure 9: stage combining ES-T and ES-C process);
+---------------------------------------------------- ES-X ---------+ * records the complete certificate and revocation references (3);
|+--------------------------------------- ES-C --------+ +--------+ |
||+--- Elect.Signature (ES) ----+ +--------+ | |Complete| |
|||+-------+ +-------+ +-------+|+---------+|Complete| | |certifi-| |
||||Signa- | |Other | |Digital|||Timestamp||certifi-| | |cate | |
||||ture | |Signed | |Signa- |||over ||cate and| | |and | |
||||Policy | |Attri- | |ture |||digital ||revoca- | | |revoca- | |
||||ID | |butes | | |||signature||tion | | |tion | |
|||+-------+ +---|---+ +-------+|+---------+|referen-| | |Data | |
||+--------------\--------------+ ^ |ces | | +--------+ |
|| \ | +--------+ | ^ |
|| \ 1 2/ ^ | | |
|+------------------\--------------/-----------|-------+ / |
+--------------------\------------/-----------/-------------/-------+
\ / ---3---/ /
+----------+ | / / -----------5-----/
| Signed |\ v | | /
|User data | \ +--------------------+ +-----------+
+----------+ \--->| Validation Process |---> | - Valid |
+---|--^-------|--^--+ 4 | - Invalid |
| | | | +-----------+
v | v |
+---------+ +--------+
|Signature| |Trusted |
| Policy | |Service |
| Issuer | |Provider|
+---------+ +--------+
Figure 9: Illustration ES with eXtended validation data (Long) * indicates the validity status to the user (4).
Internet Draft Electronic Signature Formats +----------------------------------------- ES-C ----------+
|+----------------------------- ES-T --------+ |
||+--- Elect.Signature (ES) ----+ | +--------+ |
|||+-------+ +-------+ +-------+|+----------+| |Complete| |
||||Signa- | |Other | |Digital|||Time-Stamp|| |certifi-| |
||||ture | |Signed | |Signa- |||over || |cate and| |
||||Policy | |Attri- | |ture |||digital || |revoca- | |
||||ID | |butes | | |||signature || |tion | |
|||+-------+ +-------+ +-------+|+----------+| |referen-| |
||+------------\----------------+ ^ | |ces | |
|| \ | | +--------+ |
|| \ 1 / | ^ |
|+----------------\----------------/---------+ | |
+------------------\--------------/--------------- /------+
\ /2 ----3------/
+----------+ | / /
| Signed |\ v / |
|User data | \ +--------------------+ +------------+
+----------+ \--->| Validation Process |---> |- Valid |
+---|--^-------|--^--+ 4 |- Invalid |
| | | | |- Validation|
v | v | | Incomplete|
+---------+ +--------+ +------------+
|Signature| |Trusted |
| Policy | |Service |
| Issuer | |Provider|
+---------+ +--------+
When the validation process creates the ES-C it may also create Figure 8: Illustration of an ES with Complete validation data (ES-C)
extended forms of validation data. A first alternative is to timestamp At the same time as the validation process creates the ES-C, the
all data forming the Type 1 X-Timestamp (6). This is illustrated in validation process may provide and/or record the values of
figure 10: certificates and revocation status information used in ES-C, called
the ES-X Long (5). This is illustrated in figure 9:
+---------------------------------------------------- ES-X -------+ +----------------------------------------------------- ES-X ---------+
|+--------------------------------------- ES-C --------+ +------+ | |+---------------------------------------- ES-C --------+ +--------+ |
||+--- Elect.Signature (ES) ----+ +--------+ | |Time- | | ||+--- Elect.Signature (ES) ----+ +--------+ | |Complete| |
|||+-------+ +-------+ +-------+|+---------+|Complete| | |stamp | | |||+-------+ +-------+ +-------+|+----------+|Complete| | |certifi-| |
||||Signa- | |Other | |Digital|||Timestamp||certifi-| | |over | | ||||Signa- | |Other | |Digital|||Time-Stamp||certifi-| | |cate | |
||||ture | |Signed | |Signa- |||over ||cate and| | |CES | | ||||ture | |Signed | |Signa- |||over ||cate and| | |and | |
||||Policy | |Attri- | |ture |||digital ||revoca- | | +------+ | ||||Policy | |Attri- | |ture |||digital ||revoca- | | |revoca- | |
||||ID | |butes | | |||signature||tion | | ^ | ||||ID | |butes | | |||signature ||tion | | |tion | |
|||+-------+ +--|----+ +-------+|+---------+|referen-| | | | |||+-------+ +---|---+ +-------+|+----------+|referen-| | |Data | |
||+-------------|---------------+ ^ |ces | | | | ||+--------------\--------------+ ^ |ces | | +--------+ |
|| | | +--------+ | | | || \ | +--------+ | ^ |
|| \ 1 2/ ^ | | | || \ 1 2/ ^ | | |
|+----------------\------------------/---------|-------+ | | |+------------------\--------------/------------|-------+ / |
+------------------\----------------/----------/-------------/----+ +--------------------\------------/------------/-------------/-------+
\ / ----3--/ / \ / ---3----/ /
+----------+ | / / --------------6---/ +----------+ | / / ------------5-----/
| Signed |\ v | | / | Signed |\ v | | /
|User data | \ +--------------------+ +-----------+ |User data | \ +--------------------+ +-----------+
+----------+ \--->| Validation Process |---> | - Valid | +----------+ \--->| Validation Process |---> | - Valid |
+---|--^-------|--^--+ 4 | - Invalid | +---|--^-------|--^--+ 4 | - Invalid |
| | | | +-----------+ | | | | +-----------+
v | v | v | v |
+---------+ +--------+ +---------+ +--------+
|Signature| |Trusted | |Signature| |Trusted |
| Policy | |Service | | Policy | |Service |
| Issuer | |Provider| | Issuer | |Provider|
+---------+ +--------+ +---------+ +--------+
Figure 10: Illustration of ES with eXtended validation data - Type 1 X- Figure 9: Illustration ES with eXtended validation data (Long)
Timestamp
Internet Draft Electronic Signature Formats When the validation process creates the ES-C it may also create
extended forms of validation data. A first alternative is to time-
stamp all data forming the Type 1 X-Time-Stamp (6). This is
illustrated in figure 10:
Another alternative is to timestamp the certificate and revocation +----------------------------------------------------- ES-X -------+
information references used to validate the electronic signature (but |+---------------------------------------- ES-C --------+ +------+ |
not the signature) (6'); this is called Type 2 X-Timestamped. This is ||+--- Elect.Signature (ES) ----+ +--------+ | |Time- | |
illustrated in figure 11: |||+-------+ +-------+ +-------+|+----------+|Complete| | |Stamp | |
||||Signa- | |Other | |Digital|||Time-Stamp||certifi-| | |over | |
||||ture | |Signed | |Signa- |||over ||cate and| | |CES | |
||||Policy | |Attri- | |ture |||digital ||revoca- | | +------+ |
||||ID | |butes | | |||signature ||tion | | ^ |
|||+-------+ +--|----+ +-------+|+----------+|referen-| | | |
||+-------------|---------------+ ^ |ces | | | |
|| | | +--------+ | | |
|| \ 1 2/ ^ | | |
|+----------------\------------------/----------|-------+ | |
+------------------\----------------/-----------/-------------/----+
\ / ----3---/ /
+----------+ | / / ---------------6---/
| Signed |\ v | | /
|User data | \ +--------------------+ +-----------+
+----------+ \--->| Validation Process |---> | - Valid |
+---|--^-------|--^--+ 4 | - Invalid |
| | | | +-----------+
v | v |
+---------+ +--------+
|Signature| |Trusted |
| Policy | |Service |
| Issuer | |Provider|
+---------+ +--------+
+---------------------------------------------------- ES-X ----------+ Figure 10: Illustration of ES with eXtended validation data -
|+--------------------------------------- ES-C --------+ +---------+ | Type 1 X-Time-Stamp
||+--- Elect.Signature (ES) ----+ +--------+ | |Timestamp| |
|||+-------+ +-------+ +-------+|+---------+|Complete| | |over | |
||||Signa- | |Other | |Digital|||Timestamp||certifi-| | |Complete | |
||||ture | |Signed | |Signa- |||over ||cate and| | |Certifi- | |
||||Policy | |Attri- | |ture |||digital ||revoc. | | |cate and | |
||||ID | |butes | | |||signature||refs | | |revoc. | |
|||+-------+ +---^---+ +-------+|+----^----++---^----+ | |refs | |
||+--------------\--------------+ | | | +---------+ |
|+----------------\------------------/----------|------+ ^ |
+----------------1-\----------------/----------/--------------|------+
\ / -----3--/ |
+----------+ | 2/ / --------------6'-----/
| Signed |\ v | | /
|User data | \ +--------------------+ +-----------+
+----------+ \--->| Validation Process |---> | - Valid |
+---|--^-------|--^--+ 4 | - Invalid |
| | | | +-----------+
v | v |
+---------+ +--------+
|Signature| |Trusted |
| Policy | |Service |
| Issuer | |Provider|
+---------+ +--------+
Figure 11: Illustration of ES with eXtended validation data - Type 2 X- Another alternative is to time-stamp the certificate and revocation
Timestamp information references used to validate the electronic signature (but
not the signature) (6'); this is called Type 2 X-Time-Stamped. This
is illustrated in figure 11:
Internet Draft Electronic Signature Formats +----------------------------------------------------- ES-X -----------+
|+---------------------------------------- ES-C --------+ +----------+ |
||+--- Elect.Signature (ES) ----+ +--------+ | |Time-Stamp| |
|||+-------+ +-------+ +-------+|+----------+|Complete| | |over | |
||||Signa- | |Other | |Digital|||Time-Stamp||certifi-| | |Complete | |
||||ture | |Signed | |Signa- |||over ||cate and| | |Certifi- | |
||||Policy | |Attri- | |ture |||digital ||revoc. | | |cate and | |
||||ID | |butes | | |||signature ||refs | | |revoc. | |
|||+-------+ +---^---+ +-------+|+----^-----++---^----+ | |refs | |
||+--------------\--------------+ | | | +----------+ |
|+----------------\------------------/-----------|------+ ^ |
+----------------1-\----------------/-----------/--------------|-------+
\ / -----3---/ |
+----------+ | 2/ / ---------------6'-----/
| Signed |\ v | | /
|User data | \ +--------------------+ +-----------+
+----------+ \--->| Validation Process |---> | - Valid |
+---|--^-------|--^--+ 4 | - Invalid |
| | | | +-----------+
v | v |
+---------+ +--------+
|Signature| |Trusted |
| Policy | |Service |
| Issuer | |Provider|
+---------+ +--------+
Before the algorithms used in any of electronic signatures become or Figure 11: Illustration of ES with eXtended validation data -
are likely, to be compromised or rendered vulnerable in the future, it Type 2 X-Time-Stamp
is necessary to timestamp the entire electronic signature, including
all the values of the validation and user data as an ES with Archive
validation data (ES-A)
An ES-A is illustrated in figure 12: Before the algorithms used in any of electronic signatures become or
are likely, to be compromised or rendered vulnerable in the future,
it is necessary to time-stamp the entire electronic signature,
including all the values of the validation and user data as an ES
with Archive validation data (ES-A)
An ES-A is illustrated in figure 12:
-------------------------------------------- ES-A --------------------+ -------------------------------------------- ES-A --------------------+
----------------------------------------------------------------+ | ----------------------------------------------------------------+ |
+------------------------------- EC-C --------++-----+ | | +------------------------------- EC-C --------++-----+ | |
| ||Time-| | | | ||Time-| | |
|+-- Elect.Signature (ES) -+ +--------+||stamp| +-------+ | |+-- Elect.Signature (ES) -+ +--------+||Stamp| +-------+ |
||+------++-------++-------|+------+|Complete|||over | Complete| | ||+------++-------++-------|+------+|Complete|||over | Complete| |
|||Signa-||Other ||Digital||Time- ||certifi-|||CES | |certi- |+----| |||Signa-||Other ||Digital||Time- ||certifi-|||CES | |certi- |+----|
|||ture ||Signed ||Signa- ||stamp ||cate and||+-----+ |ficate |Arch-| |||ture ||Signed ||Signa- ||Stamp ||cate and||+-----+ |ficate |Arch-|
|||Policy||Attri- ||ture ||over ||revoca- ||+------+ |and |ive | |||Policy||Attri- ||ture ||over ||revoca- ||+------+ |and |ive |
|||ID ||butes || ||digit.||tion |||Time- | |revoca-|Time | |||ID ||butes || ||digit.||tion |||Time- | |revoca-|Time |
||+------++---|---++-------||signa-||referen-|||stamp-| |tion |stamp| ||+------++---|---++-------||signa-||referen-|||Stamp-| |tion |stamp|
|+------------|------------+|ture ||ces |||over | |data |+----| |+------------|------------+|ture ||ces |||over | |data |+----|
| | +------++--------+|Complete\+-------+ ^ | | | +------++--------+|Complete\+-------+ ^ |
| | ^ ^ ||cert. | | | | | | ^ ^ ||cert. | | | |
+-------------|----------------|---------|----+|and rev| | | | +-------------|----------------|---------|----+|and rev| | | |
\ | / |refs. | | | | \ | / |refs. | | | |
\ | / +-------+ | | | \ | / +-------+ | | |
-----------------\-------------|-------/------------------------+ | | -----------------\-------------|-------/------------------------+ | |
+----------+ \ | / / | +----------+ \ | / / |
| Signed | \2 |3 / /--------------7-------/ | | Signed | \2 |3 / /--------------7-------/ |
|User data | \ | | / | |User data | \ | | / |
skipping to change at page 19, line 50 skipping to change at page 21, line 41
\------>| Validation Process |---> | - Valid | \------>| Validation Process |---> | - Valid |
+---|--^-------|--^--+ 4 | - Invalid | +---|--^-------|--^--+ 4 | - Invalid |
| | | | +-----------+ | | | | +-----------+
v | v | v | v |
+---------+ +--------+ +---------+ +--------+
|Signature| |Trusted | |Signature| |Trusted |
| Policy | |Service | | Policy | |Service |
| Issuer | |Provider| | Issuer | |Provider|
+---------+ +--------+ +---------+ +--------+
Figure 12: Illustration of an ES with Archive validation data (ES-A) Figure 12: Illustration of an ES with Archive validation data (ES-A)
2.11 Additional optional features of an ES 2.11 Additional optional features of an ES
This document also defines additional optional features of This document also defines additional optional features of an
an electronic signature to: electronic signature to:
* indicate a commitment type being made by the signer;
* indicate the role under which a signature was created;
* support multiple signatures.
Internet Draft Electronic Signature Formats * indicate a commitment type being made by the signer;
* indicate the role under which a signature was created;
* support multiple signatures.
3. Data structure of an Electronic Signature 3. Data structure of an Electronic Signature
This section uses and builds upon the Cryptographic Message Syntax This clause uses and builds upon the Cryptographic Message Syntax
(CMS), as defined in RFC 2630 [CMS], and Enhanced Security Services (CMS), as defined in RFC 2630 [CMS], and Enhanced Security Services
(ESS), as defined in RFC 2634 [ESS]. The overall structure (ESS), as defined in RFC 2634 [ESS]. The overall structure of
of Electronic Signature is as defined in [CMS]. The Electronic Electronic Signature is as defined in [CMS]. The Electronic
Signature (ES) uses attributes defined in [CMS], [ESS] and Signature (ES) uses attributes defined in [CMS], [ESS] and this
this document. This document defines in full the ES attributes which it document. This document defines in full the ES attributes which it
uses and are not defined elsewhere. uses and are not defined elsewhere.
The mandated set of attributes and the digital signature value is The mandated set of attributes and the digital signature value is
defined as the minimum Electronic Signature (ES) required by this defined as the minimum Electronic Signature (ES) required by this
document. A signature policy MAY mandate other signed attributes to be document. A signature policy MAY mandate other signed attributes to
present. be present.
3.1 General Syntax 3.1 General Syntax
The general syntax of the ES is as defined in [CMS]. The general syntax of the ES is as defined in [CMS].
3.2 Data Content Type 3.2 Data Content Type
The data content type of the ES is as defined in [CMS]. The data content type of the ES is as defined in [CMS].
The data content type is intended to refer to arbitrary octet strings, The data content type is intended to refer to arbitrary octet
such as ASCII text files; the interpretation is left to the strings, such as ASCII text files; the interpretation is left to the
application. Such strings need not have any internal structure application. Such strings need not have any internal structure
(although they could have their own ASN.1 definition or other (although they could have their own ASN.1 definition or other
structure). structure).
3.3 Signed-data Content Type 3.3 Signed-data Content Type
The Signed-data content type of the ES is as defined in [CMS]. The Signed-data content type of the ES is as defined in [CMS].
The signed-data content type consists of a content of any type and zero The signed-data content type consists of a content of any type and
or more signature values. Any number of signers in parallel can sign zero or more signature values. Any number of signers in parallel can
any type of content. The typical application of the signed-data content sign any type of content. The typical application of the signed-data
type represents one signer's digital signature on content of the data content type represents one signer's digital signature on content of
content type. the data content type.
To make sure that the verifier uses the right certificate, this To make sure that the verifier uses the right certificate, this
document mandates that the hash of the signers certificate is always document mandates that the hash of the signers certificate is always
included in the Signing Certificate signed attribute. included in the Signing Certificate signed attribute.
3.4 SignedData Type 3.4 SignedData Type
The syntax of the SignedData type of the ES is as defined in [CMS]. The syntax of the SignedData type of the ES is as defined in [CMS].
The fields of type SignedData have the meanings defined [CMS] except
that:
* version is the syntax version number. The value of version must The fields of type SignedData have the meanings defined [CMS] except
be 3. that:
Internet Draft Electronic Signature Formats * version is the syntax version number. The value of version
must be 3.
* The identification of signer's certificate used to create the * The identification of signer's certificate used to create the
signature is always present as a signed attribute. signature is always present as a signed attribute.
* The degenerate case where there are no signers is not valid in * The degenerate case where there are no signers is not valid in
this document. this document.
3.5 EncapsulatedContentInfo Type 3.5 EncapsulatedContentInfo Type
The syntax of the EncapsulatedContentInfo a type of the ES is as The syntax of the EncapsulatedContentInfo a type of the ES is as
defined in [CMS]. defined in [CMS].
For the purpose of long term validation as defined by this document, it For the purpose of long term validation as defined by this document,
is advisable that either the eContent is present, or the data which is it is advisable that either the eContent is present, or the data
signed is archived in such as way as to preserve the any data encoding. which is signed is archived in such as way as to preserve the any
It is important that the OCTET STRING used to generate the signature data encoding. It is important that the OCTET STRING used to generate
remains the same every time either the verifier or an arbitrator the signature remains the same every time either the verifier or an
validates the signature. arbitrator validates the signature.
The degenerate case where there are no signers is not valid in this The degenerate case where there are no signers is not valid in this
document. document.
3.6 SignerInfo Type 3.6 SignerInfo Type
The syntax of the SignerInfo a type of the ES is as defined in [CMS]. The syntax of the SignerInfo a type of the ES is as defined in [CMS].
Per-signer information is represented in the type SignerInfo. In the Per-signer information is represented in the type SignerInfo. In the
case of multiple independent signatures, there is an instance case of multiple independent signatures, there is an instance of this
of this field for each signer. field for each signer.
The fields of type SignerInfo have the meanings defined in [CMS] The fields of type SignerInfo have the meanings defined in [CMS]
except that signedAttributes must, as a minimum, contain the following except that signedAttributes must, as a minimum, contain the
attributes: following attributes:
* ContentType as defined in section 3.7.1. * ContentType as defined in clause 3.7.1.
* MessageDigest as defined in section 3.7.2. * MessageDigest as defined in clause 3.7.2.
* SigningTime as defined in section 3.7.3. * SigningTime as defined in clause 3.7.3.
* SigningCertificate as defined in section 3.8.1. * SigningCertificate as defined in clause 3.8.1.
* SignaturePolicyId as defined in section 3.9.1. * SignaturePolicyId as defined in clause 3.9.1.
3.6.1 Message Digest Calculation Process 3.6.1 Message Digest Calculation Process
The message digest calculation process is as defined in [CMS]. The message digest calculation process is as defined in [CMS].
3.6.2 Message Signature Generation Process 3.6.2 Message Signature Generation Process
The input to the digital signature generation process is as defined in The input to the digital signature generation process is as defined
[CMS]. in [CMS].
3.6.3 Message Signature Verification Process 3.6.3 Message Signature Verification Process
The procedures for CMS signed data validation are as defined in The procedures for CMS signed data validation are as defined in [CMS]
[CMS] and enhanced in this document. and enhanced in this document.
Internet Draft Electronic Signature Formats
The input to the signature verification process includes the signer's The input to the signature verification process includes the signer's
public key verified as correct using either the ESS Signing public key verified as correct using either the ESS Signing
Certificate attribute or the Other Signing Certificate attribute. Certificate attribute or the Other Signing Certificate attribute.
3.7 CMS Imported Mandatory Present Attributes 3.7 CMS Imported Mandatory Present Attributes
The following attributes MUST be present with the signed-data defined The following attributes MUST be present with the signed-data defined
by this document. The attributes are defined in [CMS]. by this document. The attributes are defined in [CMS].
3.7.1 Content Type 3.7.1 Content Type
The syntax of the content-type attribute type of the ES is as defined The syntax of the content-type attribute type of the ES is as defined
in [CMS]. in [CMS].
3.7.2 Message Digest 3.7.2 Message Digest
The syntax of the message-digest attribute type of the ES is as defined The syntax of the message-digest attribute type of the ES is as
in [CMS]. defined in [CMS].
3.7.3 Signing Time 3.7.3 Signing Time
The syntax of the message-digest attribute type of the ES is as defined The syntax of the message-digest attribute type of the ES is as
in [CMS] and further qualified by this document. defined in [CMS] and further qualified by this document.
The signing-time attribute type specifies the time at which the signer The signing-time attribute type specifies the time at which the
claims to have performed the signing process. signer claims to have performed the signing process.
This present document recommends the use of GeneralizedTime. This present document recommends the use of GeneralizedTime.
3.8 Alternative Signing Certificate Attributes 3.8 Alternative Signing Certificate Attributes
One, and only one, of the following two alternative attributes MUST be One, and only one, of the following two alternative attributes MUST
present with the signed-data defined by this document to identify the be present with the signed-data defined by this document to identify
signing certificate. Both attributes include an identifier and a hash the signing certificate. Both attributes include an identifier and a
of the signing certificate. The first, which is adopted in existing hash of the signing certificate. The first, which is adopted in
standards, may be only used with the SHA-1 hashing algorithm. The existing standards, may be only used with the SHA-1 hashing
other shall be used when other hashing algorithms are to be supported. algorithm. The other shall be used when other hashing algorithms are
to be supported.
The signing certificate attribute is designed to prevent the simple The signing certificate attribute is designed to prevent the simple
substitution and re-issue attacks, and to allow for a restricted set of substitution and re-issue attacks, and to allow for a restricted set
authorization certificates to be used in verifying a signature. of authorization certificates to be used in verifying a signature.
3.8.1 ESS Signing Certificate Attribute Definition 3.8.1 ESS Signing Certificate Attribute Definition
The syntax of the signing certificate attribute type of the ES is as The syntax of the signing certificate attribute type of the ES is as
defined in [ESS], and further qualified and profile in this document. defined in [ESS], and further qualified and profile in this document.
The ESS signing certificate attribute must be a signed attribute.
This document mandates the presence of this attribute as a signed CMS
attribute, and the sequence must not be empty. The certificate used to
verify the signature must be identified in the sequence, the Signature
Validation Policy may mandate other certificate references to be
present, that may include all the certificates up to the point of
Internet Draft Electronic Signature Formats The ESS signing certificate attribute must be a signed attribute.
trust. The encoding of the ESSCertID for this certificate must include This document mandates the presence of this attribute as a signed CMS
the issuerSerial field. attribute, and the sequence must not be empty. The certificate used
to verify the signature must be identified in the sequence, the
Signature Validation Policy may mandate other certificate references
to be present, that may include all the certificates up to the point
of trust. The encoding of the ESSCertID for this certificate must
include the issuerSerial field.
The issuerAndSerialNumber present in the SignerInfo must be The issuerAndSerialNumber present in the SignerInfo must be
consistent with issuerSerial field. The certificate identified must be consistent with issuerSerial field. The certificate identified must
used during the signature verification process. If the hash of the be used during the signature verification process. If the hash of
certificate does not match the certificate used to verify the the certificate does not match the certificate used to verify the
signature, the signature must be considered invalid. signature, the signature must be considered invalid.
The sequence of policy information field is not used in this document. The sequence of policy information field is not used in this
document.
NOTE: Where an attribute certificate is used by the signer to associate NOTE: Where an attribute certificate is used by the signer to
a role, or other attributes of the signer, with the electronic associate a role, or other attributes of the signer, with the
signature this is placed in the Signer Attribute attribute as defined electronic signature this is placed in the Signer Attribute attribute
in section 3.12.3. as defined in clause 3.12.3.
3.8.2 Other Signing Certificate Attribute Definition 3.8.2 Other Signing Certificate Attribute Definition
The following attribute is identical to the ESS SigningCertificate The following attribute is identical to the ESS SigningCertificate
defined above except that this attribute can be used with hashing defined above except that this attribute can be used with hashing
algorithms other than SHA-1. algorithms other than SHA-1.
This attribute must be used in the same manner as defined above for
the ESS SigningCertificate attribute.
The following object identifier identifies the signing certificate This attribute must be used in the same manner as defined above for
attribute: the ESS SigningCertificate attribute.
id-aa-ets-otherSigCert OBJECT IDENTIFIER ::= { iso(1) The following object identifier identifies the signing certificate
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) attribute:
smime(16) id-aa(2) 19 }
The signing certificate attribute value has the ASN.1 syntax id-aa-ets-otherSigCert OBJECT IDENTIFIER ::= { iso(1)
OtherSigningCertificate member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
smime(16) id-aa(2) 19 }
OtherSigningCertificate ::= SEQUENCE { The signing certificate attribute value has the ASN.1 syntax
certs SEQUENCE OF OtherCertID, OtherSigningCertificate
policies SEQUENCE OF PolicyInformation OPTIONAL
-- NOT USED IN THIS DOCUMENT
}
OtherCertID ::= SEQUENCE { OtherSigningCertificate ::= SEQUENCE {
otherCertHash OtherHash, certs SEQUENCE OF OtherCertID,
issuerSerial IssuerSerial OPTIONAL policies SEQUENCE OF PolicyInformation OPTIONAL
} -- NOT USED IN THIS DOCUMENT
}
OtherHash ::= CHOICE { OtherCertID ::= SEQUENCE {
sha1Hash OtherHashValue, -- This contains a SHA-1 hash otherCertHash OtherHash,
otherHash OtherHashAlgAndValue issuerSerial IssuerSerial OPTIONAL
} }
OtherHashValue ::= OCTET STRING OtherHash ::= CHOICE {
sha1Hash OtherHashValue, -- This contains a SHA-1 hash
otherHash OtherHashAlgAndValue
}
Internet Draft Electronic Signature Formats OtherHashValue ::= OCTET STRING
OtherHashAlgAndValue ::= SEQUENCE { OtherHashAlgAndValue ::= SEQUENCE {
hashAlgorithm AlgorithmIdentifier, hashAlgorithm AlgorithmIdentifier,
hashValue OtherHashValue hashValue OtherHashValue
} }
3.9 Additional Mandatory Attributes 3.9 Additional Mandatory Attributes
3.9.1 Signature policy Identifier 3.9.1 Signature policy Identifier
This document mandates that a reference to the signature policy, is This document mandates that a reference to the signature policy, is
included in the signedData, this reference is either explicitly included in the signedData, this reference is either explicitly
identified or implied by the semantics of the signed content and other identified or implied by the semantics of the signed content and
external data. A signature policy defines the rules for creation and other external data. A signature policy defines the rules for
validation of an electronic signature, is included as a signed creation and validation of an electronic signature, is included as a
attribute with every signature. The signature policy identifier must be signed attribute with every signature. The signature policy
a signed attribute. identifier must be a signed attribute.
The following object identifier identifies the signature policy
identifier attribute:
id-aa-ets-sigPolicyId OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
smime(16) id-aa(2) 15 }
Signature-policy-identifier attribute values have ASN.1 type
SignaturePolicyIdentifier.
SignaturePolicyIdentifier ::= CHOICE{ The following object identifier identifies the signature policy
SignaturePolicyId SignaturePolicyId, identifier attribute:
SignaturePolicyImplied SignaturePolicyImplied }
SignaturePolicyId ::= SEQUENCE { id-aa-ets-sigPolicyId OBJECT IDENTIFIER ::= { iso(1)
sigPolicyIdentifier SigPolicyId, member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
sigPolicyHash SigPolicyHash, smime(16) id-aa(2) 15 }
sigPolicyQualifiers SEQUENCE SIZE (1..MAX) OF
SigPolicyQualifierInfo OPTIONAL
}
SignaturePolicyImplied ::= NULL Signature-policy-identifier attribute values have ASN.1 type
SignaturePolicyIdentifier.
The presence of the NULL type indicates that the signature policy is SignaturePolicyIdentifier ::= CHOICE{
implied by the semantics of the signed data and other external data. SignaturePolicyId SignaturePolicyId,
SignaturePolicyImplied SignaturePolicyImplied }
Internet Draft Electronic Signature Formats SignaturePolicyId ::= SEQUENCE {
sigPolicyIdentifier SigPolicyId,
sigPolicyHash SigPolicyHash,
sigPolicyQualifiers SEQUENCE SIZE (1..MAX) OF
SigPolicyQualifierInfo OPTIONAL
}
The sigPolicyId field contains an object-identifier which SignaturePolicyImplied ::= NULL
uniquely identifies a specific version of the signature policy. The
syntax of this field is as follows:
SigPolicyId ::= OBJECT IDENTIFIER The presence of the NULL type indicates that the signature policy is
implied by the semantics of the signed data and other external data.
The sigPolicyHash field contains the identifier of the hash algorithm The sigPolicyId field contains an object-identifier which uniquely
and the hash of the value of the signature policy. identifies a specific version of the signature policy. The syntax of
this field is as follows:
If the signature policy is defined using a computer processable SigPolicyId ::= OBJECT IDENTIFIER
notation like ASN.1, then the hash is calculated on the value without
the outer type and length fields and the hashing algorithm must be as
specified in the field signPolicyHshAlg.
If the signature policy is defined using another structure, the type of The sigPolicyHash field contains the identifier of the hash algorithm
structure and the hashing algorithm must be either specified as part and the hash of the value of the signature policy.
of the signature policy, or indicated using a signature policy
qualifier.
SigPolicyHash ::= ETSIHashAlgAndValue If the signature policy is defined using a computer processable
notation like ASN.1, then the hash is calculated on the value without
the outer type and length fields and the hashing algorithm must be as
specified in the field signPolicyHshAlg.
A signature policy identifier may be qualified with other information If the signature policy is defined using another structure, the type
about the qualifier. The semantics and syntax of the qualifier is as of structure and the hashing algorithm must be either specified as
associated with the object-identifier in the sigPolicyQualifierId part of the signature policy, or indicated using a signature policy
field. The general syntax of this qualifier is as follows: qualifier.
SigPolicyQualifierInfo ::= SEQUENCE { SigPolicyHash ::= OtherHashAlgAndValue
sigPolicyQualifierId SigPolicyQualifierId,
sigQualifier ANY DEFINED BY sigPolicyQualifierId
}
This document specifies the following qualifiers: A signature policy identifier may be qualified with other information
about the qualifier. The semantics and syntax of the qualifier is as
associated with the object-identifier in the sigPolicyQualifierId
field. The general syntax of this qualifier is as follows:
* spuri: This contains the web URI or URL reference to the SigPolicyQualifierInfo ::= SEQUENCE {
signature policy sigPolicyQualifierId SigPolicyQualifierId,
sigQualifier ANY DEFINED BY sigPolicyQualifierId
}
This document specifies the following qualifiers:
* spUserNotice: This contains a user notice which should be * spuri: This contains the web URI or URL reference to the
displayed whenever the signature is validated. signature policy
Internet Draft Electronic Signature Formats * spUserNotice: This contains a user notice which should be
displayed whenever the signature is validated.
-- sigpolicyQualifierIds defined in this document
SigPolicyQualifierId ::= OBJECT IDENTIFIER SigPolicyQualifierId ::= OBJECT IDENTIFIER
id-spq-ets-uri OBJECT IDENTIFIER ::= { iso(1) id-spq-ets-uri OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
smime(16) id-spq(5) 1 } smime(16) id-spq(5) 1 }
SPuri ::= IA5String SPuri ::= IA5String
id-spq-ets-unotice OBJECT IDENTIFIER ::= { iso(1) id-spq-ets-unotice OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
smime(16) id-spq(5) 2 } smime(16) id-spq(5) 2 }
SPUserNotice ::= SEQUENCE { SPUserNotice ::= SEQUENCE {
noticeRef NoticeReference OPTIONAL, noticeRef NoticeReference OPTIONAL,
explicitText DisplayText OPTIONAL explicitText DisplayText OPTIONAL
} }
NoticeReference ::= SEQUENCE { NoticeReference ::= SEQUENCE {
organization DisplayText, organization DisplayText,
noticeNumbers SEQUENCE OF INTEGER noticeNumbers SEQUENCE OF INTEGER
} }
DisplayText ::= CHOICE { DisplayText ::= CHOICE {
visibleString VisibleString (SIZE (1..200)), visibleString VisibleString (SIZE (1..200)),
bmpString BMPString (SIZE (1..200)), bmpString BMPString (SIZE (1..200)),
utf8String UTF8String (SIZE (1..200)) utf8String UTF8String (SIZE (1..200))
} }
3.10 CMS Imported Optional Attributes 3.10 CMS Imported Optional Attributes
The following attributes MAY be present with the signed-data defined by The following attributes MAY be present with the signed-data defined
this document. The attributes are defined in ref [CMS] and are imported by this document. The attributes are defined in ref [CMS] and are
imported into this specification and were appropriate qualified and
into this specification and were appropriate qualified and profiling by profiling by this document.
this document.
3.10.1 Countersignature 3.10.1 Countersignature
The syntax of the countersignature attribute type of the ES is as The syntax of the countersignature attribute type of the ES is as
defined in [CMS]. The countersignature attribute must be an unsigned defined in [CMS]. The countersignature attribute must be an unsigned
attribute. attribute.
3.11 ESS Imported Optional Attributes 3.11 ESS Imported Optional Attributes
The following attributes MAY be present with the signed-data defined by The following attributes MAY be present with the signed-data defined
this document. The attributes are defined in ref [ESS] and are imported by this document. The attributes are defined in ref [ESS] and are
into this specification and were appropriate qualified and profiling imported into this specification and were appropriate qualified and
by this document. profiling by this document.
Internet Draft Electronic Signature Formats
3.11.1 Content Reference Attribute 3.11.1 Content Reference Attribute
The content reference attribute is a link from one SignedData to The content reference attribute is a link from one SignedData to
another. It may be used to link a reply to the original message to another. It may be used to link a reply to the original message to
which it refers, or to incorporate by reference one SignedData into which it refers, or to incorporate by reference one SignedData into
another. another.
The content reference attribute MUST be used as defined in [ESS]. The The content reference attribute MUST be used as defined in [ESS].
content reference MUST be a signed attribute. The content reference MUST be a signed attribute.
The syntax of the content reference attribute type of the ES is as The syntax of the content reference attribute type of the ES is as
defined in [ESS]. defined in [ESS].
3.11.2 Content Identifier Attribute 3.11.2 Content Identifier Attribute
The content identifier attribute provides an identifier for the signed The content identifier attribute provides an identifier for the
content for use when reference may be later required to that content, signed content for use when reference may be later required to that
for example in the content reference attribute in other signed data content, for example in the content reference attribute in other
sent later. signed data sent later.
The content identifier must be a signed attribute.
The syntax of the content identifier attribute type of the ES is as The content identifier must be a signed attribute.
defined in [ESS].
The minimal signedContentIdentifier should contain a concatenation of The syntax of the content identifier attribute type of the ES is as
user-specific identification information (such as a user name or public defined in [ESS].
keying material identification information), a GeneralizedTime string,
and a random number.
3.11.3 Content Hints Attribute The minimal signedContentIdentifier should contain a concatenation of
user-specific identification information (such as a user name or
public keying material identification information), a GeneralizedTime
string, and a random number.
The content hints attribute provides information that describes the 3.11.3 Content Hints Attribute
format of the signed content. It may be used by the signer to indicate
to a verifier the precise format that MUST be used to present the data
(e.g. text, voice, video) to a verifier. This attribute MUST be
present when it is mandatory to present the signed data to human users
on verification.
The syntax of the content hints attribute type of the ES is as defined The content hints attribute provides information that describes the
in ESS (RFC 2634, section 2.9 [9]). format of the signed content. It may be used by the signer to
indicate to a verifier the precise format that MUST be used to
present the data (e.g., text, voice, video) to a verifier. This
attribute MUST be present when it is mandatory to present the signed
data to human users on verification.
When used to indicate the precise format of the data to be presented to The syntax of the content hints attribute type of the ES is as
the user the following rules apply: defined in ESS (RFC 2634, section 2.9 [9]).
The contentType (defined in RFC 2630 [8]) indicates the type of the When used to indicate the precise format of the data to be presented
associated content. It is an object identifier (i.e. a unique string of to the user the following rules apply:
integers) assigned by an authority that defines the content type.
Internet Draft Electronic Signature Formats The contentType (defined in RFC 2630 [8]) indicates the type of the
associated content. It is an object identifier (i.e., a unique
string of integers) assigned by an authority that defines the content
type.
The UTF8String shall define the presentation format. The format may be The UTF8String shall define the presentation format. The format may
defined by MIME types as indicated below. be defined by MIME types as indicated below.
Note 1: The contentType can be id-data defined in CMS (RFC 2630 [8]). Note 1: The contentType can be id-data defined in CMS (RFC 2630 [8]).
The UTF8String can be used to indicate the encoding of the data, like The UTF8String can be used to indicate the encoding of the data, like
MIME type. RFC 2045 [25] provides a common structure for encoding a MIME type. RFC 2045 [25] provides a common structure for encoding a
range of electronic documents and other multi-media types, see annex B range of electronic documents and other multi-media types, see annex
for further information, a system supporting verification of electronic B for further information, a system supporting verification of
signature may present information to users in the form identified by electronic signature may present information to users in the form
the MIME type. identified by the MIME type.
id-data OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) id-data OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840)
rsadsi(113549) pkcs(1) pkcs7(7) 1 } rsadsi(113549) pkcs(1) pkcs7(7) 1 }
3.12 Additional Optional Attributes 3.12 Additional Optional Attributes
3.12.1 Commitment Type Indication Attribute 3.12.1 Commitment Type Indication Attribute
There may be situation were a signer wants to explicitly indicate to a There may be situation were a signer wants to explicitly indicate to
verifier that by signing the data, it illustrates a type of commitment a verifier that by signing the data, it illustrates a type of
on behalf of the signer. The commitmentTypeIndication attribute conveys commitment on behalf of the signer. The commitmentTypeIndication
such information. attribute conveys such information.
The commitmentTypeIndication attribute must be a signed attribute.
The commitment type may be: The commitmentTypeIndication attribute must be a signed attribute.
* defined as part of the signature policy, in which case the The commitment type may be:
commitment type has precise semantics that is defined as part of
the signature policy.
* be a registered type, in which case the commitment type has * defined as part of the signature policy, in which case the
precise semantics defined by registration, under the rules of the commitment type has precise semantics that is defined as part
registration authority. Such a registration authority may be a of the signature policy.
trading association or a legislative authority.
The signature policy specifies a set of attributes that it * be a registered type, in which case the commitment type has
"recognizes". This "recognized" set includes all those commitment types precise semantics defined by registration, under the rules of
defined as part of the signature policy as well as any externally the registration authority. Such a registration authority may
defined commitment types that the policy may choose to recognize. Only be a trading association or a legislative authority.
recognized commitment types are allowed in this field.
Internet Draft Electronic Signature Formats The signature policy specifies a set of attributes that it
"recognizes". This "recognized" set includes all those commitment
types defined as part of the signature policy as well as any
externally defined commitment types that the policy may choose to
recognize. Only recognized commitment types are allowed in this
field.
The following object identifier identifies the commitment type The following object identifier identifies the commitment type
indication attribute: indication attribute:
id-aa-ets-commitmentType OBJECT IDENTIFIER ::= { iso(1) member-body(2) id-aa-ets-commitmentType OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 16} us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 16}
Commitment-Type-Indication attribute values have ASN.1 type Commitment-Type-Indication attribute values have ASN.1 type
CommitmentTypeIndication. CommitmentTypeIndication.
CommitmentTypeIndication ::= SEQUENCE { CommitmentTypeIndication ::= SEQUENCE {
commitmentTypeId CommitmentTypeIdentifier, commitmentTypeId CommitmentTypeIdentifier,
commitmentTypeQualifier SEQUENCE SIZE (1..MAX) OF commitmentTypeQualifier SEQUENCE SIZE (1..MAX) OF
skipping to change at page 29, line 30 skipping to change at page 31, line 40
} }
CommitmentTypeIdentifier ::= OBJECT IDENTIFIER CommitmentTypeIdentifier ::= OBJECT IDENTIFIER
CommitmentTypeQualifier ::= SEQUENCE { CommitmentTypeQualifier ::= SEQUENCE {
commitmentTypeIdentifier CommitmentTypeIdentifier, commitmentTypeIdentifier CommitmentTypeIdentifier,
qualifier ANY DEFINED BY qualifier ANY DEFINED BY
commitmentTypeIdentifier commitmentTypeIdentifier
} }
The use of any qualifiers to the commitment type is outside the scope The use of any qualifiers to the commitment type is outside the scope
of this document. of this document.
The following generic commitment types are defined in this document:
id-cti-ets-proofOfOrigin OBJECT IDENTIFIER ::= { iso(1) member-
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
cti(6) 1}
id-cti-ets-proofOfReceipt OBJECT IDENTIFIER ::= { iso(1) member- The following generic commitment types are defined in this document:
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
cti(6) 2}
id-cti-ets-proofOfDelivery OBJECT IDENTIFIER ::= { iso(1) id-cti-ets-proofOfOrigin OBJECT IDENTIFIER ::= { iso(1) member-
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
smime(16) cti(6) 3} cti(6) 1}
id-cti-ets-proofOfSender OBJECT IDENTIFIER ::= { iso(1) member- id-cti-ets-proofOfReceipt OBJECT IDENTIFIER ::= { iso(1) member-
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
cti(6) 4} cti(6) 2}
id-cti-ets-proofOfDelivery OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) cti(6) 3}
id-cti-ets-proofOfApproval OBJECT IDENTIFIER ::= { iso(1) id-cti-ets-proofOfSender OBJECT IDENTIFIER ::= { iso(1) member-
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
smime(16) cti(6) 5} cti(6) 4}
id-cti-ets-proofOfCreation OBJECT IDENTIFIER ::= { iso(1) id-cti-ets-proofOfApproval OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) cti(6) 6} smime(16) cti(6) 5}
Internet Draft Electronic Signature Formats id-cti-ets-proofOfCreation OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) cti(6) 6}
These generic commitment types have the following meaning: These generic commitment types have the following meaning:
Proof of origin indicates that the signer recognizes to have created, Proof of origin indicates that the signer recognizes to have created,
approved and sent the message. approved and sent the message.
Proof of receipt indicates that signer recognizes to have received the Proof of receipt indicates that signer recognizes to have received
content of the message. the content of the message.
Proof of delivery indicates that the TSP providing that indication has Proof of delivery indicates that the TSP providing that indication
delivered a message in a local store accessible to the recipient of the has delivered a message in a local store accessible to the recipient
message. of the message.
Proof of sender indicates that the entity providing that indication has Proof of sender indicates that the entity providing that indication
sent the message (but not necessarily created it). has sent the message (but not necessarily created it).
Proof of approval indicates that the signer has approved the content of Proof of approval indicates that the signer has approved the content
the message. of the message.
Proof of creation indicates that the signer has created the message Proof of creation indicates that the signer has created the message
(but not necessarily approved, nor sent it). (but not necessarily approved, nor sent it).
3.12.2 Signer Location attribute 3.12.2 Signer Location attribute
The signer-location attribute is an attribute which specifies a The signer-location attribute is an attribute which specifies a
mnemonic for an address associated with the signer at a particular mnemonic for an address associated with the signer at a particular
geographical (e.g. city) location. The mnemonic is registered in the geographical (e.g., city) location. The mnemonic is registered in
country in which the signer is located and is used in the provision of the country in which the signer is located and is used in the
the Public Telegram Service (according to ITU-T Recommendation F.1 provision of the Public Telegram Service (according to ITU-T
[PTS]). Recommendation F.1 [PTS]).
The signer-location attribute must be a signed attribute. The signer-location attribute must be a signed attribute.
The following object identifier identifies the signer-location The following object identifier identifies the signer-location
attribute: attribute:
id-aa-ets-signerLocation OBJECT IDENTIFIER ::= { iso(1) member-body(2) id-aa-ets-signerLocation OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 17} us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 17}
Signer-location attribute values have ASN.1 type SignerLocation. Signer-location attribute values have ASN.1 type SignerLocation.
SignerLocation ::= SEQUENCE { SignerLocation ::= SEQUENCE {
-- at least one of the following must be present -- at least one of the following must be present
countryName [0] DirectoryString OPTIONAL, countryName [0] DirectoryString OPTIONAL,
-- as used to name a Country in X.500 -- as used to name a Country in X.500
localityName [1] DirectoryString OPTIONAL, localityName [1] DirectoryString OPTIONAL,
-- as used to name a locality in X.500 -- as used to name a locality in X.500
postalAdddress [2] PostalAddress OPTIONAL postalAdddress [2] PostalAddress OPTIONAL
} }
PostalAddress ::= SEQUENCE SIZE(1..6) OF DirectoryString PostalAddress ::= SEQUENCE SIZE(1..6) OF DirectoryString
Internet Draft Electronic Signature Formats
3.12.3 Signer Attributes attribute 3.12.3 Signer Attributes attribute
The signer-attributes attribute is an attribute which specifies The signer-attributes attribute is an attribute which specifies
additional attributes of the signer (e.g. role). additional attributes of the signer (e.g., role).
It may be either:
* claimed attributes of the signer; or It may be either:
* certified attributes of the signer;
The signer-attributes attribute must be a signed attribute. * claimed attributes of the signer; or
* certified attributes of the signer;
The following object identifier identifies the signer-attribute The signer-attributes attribute must be a signed attribute.
attribute:
id-aa-ets-signerAttr OBJECT IDENTIFIER ::= { iso(1) member-body(2) The following object identifier identifies the signer-attribute
us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 18} attribute:
signer-attribute attribute values have ASN.1 type SignerAttribute. id-aa-ets-signerAttr OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 18}
SignerAttribute ::= SEQUENCE OF CHOICE { signer-attribute attribute values have ASN.1 type SignerAttribute.
claimedAttributes [0] ClaimedAttributes,
certifiedAttributes [1] CertifiedAttributes
}
ClaimedAttributes ::= SEQUENCE OF Attribute SignerAttribute ::= SEQUENCE OF CHOICE {
claimedAttributes [0] ClaimedAttributes,
certifiedAttributes [1] CertifiedAttributes
}
CertifiedAttributes ::= AttributeCertificate ClaimedAttributes ::= SEQUENCE OF Attribute
-- as defined in X.509 : see section 10.3
NOTE: The claimed and certified attribute are imported from ITU-T CertifiedAttributes ::= AttributeCertificate
Recommendations X.501 [16] and ITU-T Recommendation X.509 : Draft -- as defined in X.509 : see section 10.3
Amendment on Certificate Extensions, October 1999.
3.12.4 Content Timestamp attribute NOTE: The claimed and certified attribute are imported from ITU-T
Recommendations X.501 [16] and ITU-T Recommendation X.509:Draft
Amendment on Certificate Extensions, October 1999.
The content timestamp attribute is an attribute which is the timestamp 3.12.4 Content Time-Stamp attribute
of the signed data content before it is signed.
The content timestamp attribute must be a signed attribute. The content time-stamp attribute is an attribute which is the time-
stamp of the signed data content before it is signed.
The following object identifier identifies the signer-attribute The content time-stamp attribute must be a signed attribute.
attribute:
id-aa-ets-contentTimestamp OBJECT IDENTIFIER ::= { iso(1) The following object identifier identifies the signer-attribute
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) attribute:
smime(16) id-aa(2) 20}
Content timestamp attribute values have ASN.1 type ContentTimestamp: id-aa-ets-contentTimestamp OBJECT IDENTIFIER ::= { iso(1)
ContentTimestamp::= TimeStampToken member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) id-aa(2) 20}
Internet Draft Electronic Signature Formats Content time-stamp attribute values have ASN.1 type ContentTimestamp:
ContentTimestamp::= TimeStampToken
The value of messageImprint field within TimeStampToken must be a hash The value of messageImprint field within TimeStampToken must be a
of the value of eContent field within encapContentInfo within the hash of the value of eContent field within encapContentInfo within
signedData. the signedData.
For further information and definition of TimeStampToken see [TSP]. For further information and definition of TimeStampToken see [TSP].
3.13 Support for Multiple Signatures 3.13 Support for Multiple Signatures
3.13.1 Independent Signatures 3.13.1 Independent Signatures
Multiple independent signatures are supported by independent SignerInfo Multiple independent signatures are supported by independent
from each signer. SignerInfo from each signer.
Each SignerInfo must include all the attributes required under this Each SignerInfo must include all the attributes required under this
document and must be processed independently by the verifier. document and must be processed independently by the verifier.
3.13.2 Embedded Signatures 3.13.2 Embedded Signatures
Multiple embedded signatures are supported using the counter-signature Multiple embedded signatures are supported using the counter-
unsigned attribute (see section 3.10.1). Each counter signature is signature unsigned attribute (see clause 3.10.1). Each counter
carried in Countersignature held as an unsigned attribute to the signature is carried in Countersignature held as an unsigned
SignerInfo to which the counter-signature is applied. attribute to the SignerInfo to which the counter-signature is
applied.
4. Validation Data 4. Validation Data
This section specifies the validation data structures which builds on This clause specifies the validation data structures which builds on
the electronic signature specified in section 3. This includes: the electronic signature specified in clause 3. This includes:
* Timestamp applied to the electronic signature value.
* Complete validation data which comprises the timestamp of the * Time-Stamp applied to the electronic signature value.
signature value, plus references to all the certificates and
revocation information used for full validation of the electronic
signature.
The following optional eXtended forms of validation data are also * Complete validation data which comprises the time-stamp of the
defined: signature value, plus references to all the certificates and
revocation information used for full validation of the
electronic signature.
* X-timestamp: There are two types of timestamp used in extended The following optional eXtended forms of validation data are also
validation data defined by this document. defined:
- Type 1 -Timestamp which comprises a timestamp over the ES * X-timestamp: There are two types of time-stamp used in extended
with Complete validation data (ES-C). validation data defined by this document.
- Type 2 X-Timestamp which comprises of a timestamp over the - Type 1 -Time-Stamp which comprises a time-stamp over the ES
certification path references and the revocation information with Complete validation data (ES-C).
references used to support the ES-C.
Internet Draft Electronic Signature Formats - Type 2 X-Time-Stamp which comprises of a time-stamp over the
certification path references and the revocation information
references used to support the ES-C.
* X-Long : This comprises a Complete validation data * X-Long: This comprises a Complete validation data plus
plus the actual values of all the certificates and the actual values of all the certificates and revocation
revocation information used in the ES-C. information used in the ES-C.
* X-Long-Timestamp: This comprises a Type 1 or Type 2 * X-Long-Time-Stamp: This comprises a Type 1 or Type 2 X-
X-Timestamp plus the actual values of all the Timestamp plus the actual values of all the certificates
certificates and revocation information used in the and revocation information used in the ES-C.
ES-C.
This section also specifies the data structures used in Archive This clause also specifies the data structures used in Archive
validation data: validation data:
* Archive validation data comprises a Complete validation data, * Archive validation data comprises a Complete validation data,
the certificate and revocation values (as in a X-Long the certificate and revocation values (as in a X-Long
validation data), any other existing X-timestamps, plus the validation data), any other existing X-timestamps, plus the
Signed User data and an additional archive timestamp over all Signed User data and an additional archive time-stamp over all
that data. An archive timestamp may be repeatedly applied that data. An archive time-stamp may be repeatedly applied
after long periods to maintain validity when electronic after long periods to maintain validity when electronic
signature and timestamping algorithms weaken. signature and timestamping algorithms weaken.
The additional data required to create the forms of electronic The additional data required to create the forms of electronic
signature identified above is carried as unsigned attributes signature identified above is carried as unsigned attributes
associated with an individual signature by being placed in the associated with an individual signature by being placed in the
unsignedAttrs field of SignerInfo. Thus all the attributes defined unsignedAttrs field of SignerInfo. Thus all the attributes defined
in section 4 are unsigned attributes. in clause 4 are unsigned attributes.
NOTE: Where multiple signatures are to be supported, as described in NOTE: Where multiple signatures are to be supported, as described in
section 3.13, each signature has a separate SignerInfo. Thus, each clause 3.13, each signature has a separate SignerInfo. Thus, each
signature requires its own unsigned attribute values to create ES-T, signature requires its own unsigned attribute values to create ES-T,
ES-C etc. ES-C etc.
4.1 Electronic Signature Timestamp 4.1 Electronic Signature Timestamp
An Electronic Signature with Timestamp is an Electronic Signature for An Electronic Signature with Timestamp is an Electronic Signature for
which part, but not all, of the additional data required for validation which part, but not all, of the additional data required for
is available (e.g. some certificates and revocation information is validation is available (e.g., some certificates and revocation
available but not all). information is available but not all).
The minimum structure Timestamp validation data is the Signature The minimum structure Timestamp validation data is the Signature
Timestamp Attribute as defined in section 4.1.1 over the ES signature Timestamp Attribute as defined in clause 4.1.1 over the ES signature
value. value.
4.1.1 Signature Timestamp Attribute Definition 4.1.1 Signature Timestamp Attribute Definition
The Signature Timestamp attribute is timestamp of the signature value. The Signature Timestamp attribute is timestamp of the signature
It is an unsigned attribute. Several instances of this attribute from value. It is an unsigned attribute. Several instances of this
different TSAs may occur with an electronic signature. attribute from different TSAs may occur with an electronic signature.
Internet Draft Electronic Signature Formats
The Signature Validation Policy specifies, in the The Signature Validation Policy specifies, in the
signatureTimestampDelay field of TimestampTrustConditions, a maximum signatureTimestampDelay field of TimestampTrustConditions, a maximum
acceptable time difference which is allowed between the time indicated acceptable time difference which is allowed between the time
in the signing time attribute and the time indicated by the Signature indicated in the signing time attribute and the time indicated by the
Timestamp attribute. If this delay is exceeded then the electronic Signature Timestamp attribute. If this delay is exceeded then the
signature must be considered as invalid. electronic signature must be considered as invalid.
The following object identifier identifies the Signature Timestamp The following object identifier identifies the Signature Timestamp
attribute: attribute:
id-aa-signatureTimeStampToken OBJECT IDENTIFIER ::= { iso(1) id-aa-signatureTimeStampToken OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
id-aa(2) 14} id-aa(2) 14}
The Signature timestamp attribute value has ASN.1 type The Signature timestamp attribute value has ASN.1 type
SignatureTimeStampToken. SignatureTimeStampToken.
SignatureTimeStampToken ::= TimeStampToken SignatureTimeStampToken ::= TimeStampToken
The value of messageImprint field within TimeStampToken must be a hash The value of messageImprint field within TimeStampToken must be a
of the value of signature field within SignerInfo for the signedData hash of the value of signature field within SignerInfo for the
being timestamped. signedData being timestamped.
For further information and definition of TimeStampToken see [TSP] For further information and definition of TimeStampToken see [TSP].
4.2 Complete Validation Data 4.2 Complete Validation Data
An electronic signature with complete validation data is an Electronic An electronic signature with complete validation data is an
Signature for which all the additional data required for validation Electronic Signature for which all the additional data required for
(i.e. all certificates and revocation information) is available. validation (i.e., all certificates and revocation information) is
Complete validation data (ES-C) build on the electronic signature available. Complete validation data (ES-C) build on the electronic
Timestamp as defined above. signature Time-Stamp as defined above.
The minimum structure of a Complete validation data is:
* the Signature Timestamp Attribute, as defined in section 4.1.1; The minimum structure of a Complete validation data is:
* Complete Certificate Refs, as defined in section 4.2.1;
* Complete Revocation Refs, as defined in section 4.2.2.
The Complete validation data MAY also include the following additional * the Signature Time-Stamp Attribute, as defined in clause 4.1.1;
information, forming a X-Long validation data, for use if later * Complete Certificate Refs, as defined in clause 4.2.1;
validation processes may not have access to this information: * Complete Revocation Refs, as defined in clause 4.2.2.
* Complete Certificate Values, as defined in section 4.2.3; The Complete validation data MAY also include the following
* Complete Revocation Values, as defined in section 4.2.4. additional information, forming a X-Long validation data, for use if
later validation processes may not have access to this information:
The Complete validation data MAY also include one of the following * Complete Certificate Values, as defined in clause 4.2.3;
additional attributes, forming a X-Timestamp validation data, to * Complete Revocation Values, as defined in clause 4.2.4.
provide additional protection against later CA compromise and provide
integrity of the validation data used:
* ES-C Timestamp, as defined in section 4.2.5; or The Complete validation data MAY also include one of the following
* Time-Stamped Certificates and CRLs references, as defined in additional attributes, forming a X-Time-Stamp validation data, to
section 4.2.6. provide additional protection against later CA compromise and provide
integrity of the validation data used:
Internet Draft Electronic Signature Formats * ES-C Time-Stamp, as defined in clause 4.2.5; or
* Time-Stamped Certificates and CRLs references, as defined in
clause 4.2.6.
NOTE 1: As long as the CA's are trusted such that these keys cannot NOTE 1: As long as the CA's are trusted such that these keys cannot
be compromised or the cryptography used broken, the ES-C provides long be compromised or the cryptography used broken, the ES-C provides
term proof of a valid electronic signature. long term proof of a valid electronic signature.
A valid electronic signature is an electronic signature which passes A valid electronic signature is an electronic signature which passes
validation according to a signature validation policy. validation according to a signature validation policy.
NOTE 2: The ES-C provides the following important property for long NOTE 2: The ES-C provides the following important property for long
standing signatures; that is having been found once to be valid, must standing signatures; that is having been found once to be valid, must
continue to be so months or years later. Long after the validity period continue to be so months or years later. Long after the validity
of the certificates have expired, or after the user key has been period of the certificates have expired, or after the user key has
compromised. been compromised.
4.2.1 Complete Certificate Refs Attribute Definition 4.2.1 Complete Certificate Refs Attribute Definition
The Complete Certificate Refs attribute is an unsigned attribute. It The Complete Certificate Refs attribute is an unsigned attribute. It
references the full set of CA certificates that have been used to references the full set of CA certificates that have been used to
validate a ES with Complete validation data (ES-C) up to (but not validate a ES with Complete validation data (ES-C) up to (but not
including) the signer's certificate. Only a single instance of this including) the signer's certificate. Only a single instance of this
attribute must occur with an electronic signature. attribute must occur with an electronic signature.
Note: The signer's certified is referenced in the signing certificate Note: The signer's certified is referenced in the signing certificate
attribute (see section 3.1). attribute (see clause 3.1).
id-aa-ets-certificateRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2) id-aa-ets-certificateRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 21} us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 21}
The complete certificate refs attribute value has the ASN.1 syntax The complete certificate refs attribute value has the ASN.1 syntax
CompleteCertificateRefs. CompleteCertificateRefs.
CompleteCertificateRefs ::= SEQUENCE OF OTHERCertID CompleteCertificateRefs ::= SEQUENCE OF OTHERCertID
OTHERCertID is defined in section 3.8.2. OTHERCertID is defined in clause 3.8.2.
The IssuerSerial that must be present in OTHERCertID. The certHash The IssuerSerial that must be present in OTHERCertID. The certHash
must match the hash of the certificate referenced. must match the hash of the certificate referenced.
NOTE: Copies of the certificate values may be held using the NOTE: Copies of the certificate values may be held using the
Certificate Values attribute defined in section 4.3.1. Certificate Values attribute defined in clause 4.3.1.
4.2.2 Complete Revocation Refs Attribute Definition 4.2.2 Complete Revocation Refs Attribute Definition
The Complete Revocation Refs attribute is an unsigned attribute. Only a The Complete Revocation Refs attribute is an unsigned attribute.
single instance of this attribute must occur with an electronic Only a single instance of this attribute must occur with an
signature. It references the full set of the CRL or OCSP responses that electronic signature. It references the full set of the CRL or OCSP
have been used in the validation of the signer and CA certificates responses that have been used in the validation of the signer and CA
used in ES with Complete validation data. certificates used in ES with Complete validation data.
The following object identifier identifies the CompleteRevocationRefs The following object identifier identifies the CompleteRevocationRefs
attribute: attribute:
id-aa-ets-revocationRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2) id-aa-ets-revocationRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 22} us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 22}
Internet Draft Electronic Signature Formats The complete revocation refs attribute value has the ASN.1 syntax
CompleteRevocationRefs.
The complete revocation refs attribute value has the ASN.1 syntax
CompleteRevocationRefs.
CompleteRevocationRefs ::= SEQUENCE OF CrlOcspRef
CrlOcspRef ::= SEQUENCE {
crlids [0] CRLListID OPTIONAL,
ocspids [1] OcspListID OPTIONAL,
otherRev [2] OtherRevRefs OPTIONAL
}
CompleteRevocationRefs must contain one CrlOcspRef for the signing CompleteRevocationRefs ::= SEQUENCE OF CrlOcspRef
certificate, followed by one for each OTHERCertID in the CrlOcspRef ::= SEQUENCE {
CompleteCertificateRefs attribute. The second and subsequent CrlOcspRef crlids [0] CRLListID OPTIONAL,
fields must be in the same order as the OTHERCertID to which they ocspids [1] OcspListID OPTIONAL,
relate. At least one of CRLListID or OcspListID or OtherRevRefs should otherRev [2] OtherRevRefs OPTIONAL
be present for all but the "trusted" CA of the certificate path. }
CRLListID ::= SEQUENCE { CompleteRevocationRefs must contain one CrlOcspRef for the signing
crls SEQUENCE OF CrlValidatedID} certificate, followed by one for each OTHERCertID in the
CompleteCertificateRefs attribute. The second and subsequent
CrlOcspRef fields must be in the same order as the OTHERCertID to
which they relate. At least one of CRLListID or OcspListID or
OtherRevRefs should be present for all but the "trusted" CA of the
certificate path.
CrlValidatedID ::= SEQUENCE { CRLListID ::= SEQUENCE {
crlHash ETSIHash, crls SEQUENCE OF CrlValidatedID}
crlIdentifier CrlIdentifier OPTIONAL}
CrlIdentifier ::= SEQUENCE { CrlValidatedID ::= SEQUENCE {
crlissuer Name, crlHash OtherHash,
crlIssuedTime UTCTime, crlIdentifier CrlIdentifier OPTIONAL}
crlNumber INTEGER OPTIONAL
}
OcspListID ::= SEQUENCE { CrlIdentifier ::= SEQUENCE {
ocspResponses SEQUENCE OF OcspResponsesID} crlissuer Name,
crlIssuedTime UTCTime,
crlNumber INTEGER OPTIONAL
}
OcspResponsesID ::= SEQUENCE { OcspListID ::= SEQUENCE {
ocspIdentifier OcspIdentifier, ocspResponses SEQUENCE OF OcspResponsesID}
ocspRepHash ETSIHash OPTIONAL
}
OcspIdentifier ::= SEQUENCE { OcspResponsesID ::= SEQUENCE {
ocspResponderID ResponderID, ocspIdentifier OcspIdentifier,
-- As in OCSP response data ocspRepHash OtherHash OPTIONAL
producedAt GeneralizedTime }
-- As in OCSP response data
}
When creating an crlValidatedID, the crlHash is computed over the OcspIdentifier ::= SEQUENCE {
entire DER encoded CRL including the signature. The crlIdentifier would ocspResponderID ResponderID,
normally be present unless the CRL can be inferred from other -- As in OCSP response data
information. producedAt GeneralizedTime
-- As in OCSP response data
}
Internet Draft Electronic Signature Formats When creating an crlValidatedID, the crlHash is computed over the
entire DER encoded CRL including the signature. The crlIdentifier
would normally be present unless the CRL can be inferred from other
information.
The crlIdentifier is to identify the CRL using the issuer name and the The crlIdentifier is to identify the CRL using the issuer name and
CRL issued time which must correspond to the time "thisUpdate" the CRL issued time which must correspond to the time "thisUpdate"
contained in the issued CRL. The crlListID attribute is an unsigned contained in the issued CRL. The crlListID attribute is an unsigned
attribute. In the case that the identified CRL is a Delta CRL then attribute. In the case that the identified CRL is a Delta CRL then
references to the set of CRLs to provide a complete revocation list references to the set of CRLs to provide a complete revocation list
must be included. must be included.
The OcspIdentifier is to identify the OSCP response using the issuer The OcspIdentifier is to identify the OSCP response using the issuer
name and the time of issue of the OCSP response which must correspond name and the time of issue of the OCSP response which must correspond
to the time "producedAt" contained in the issued OCSP response. Since to the time "producedAt" contained in the issued OCSP response.
it may be needed to make the difference between two OCSP responses Since it may be needed to make the difference between two OCSP
received within the same second, then the hash of the response responses received within the same second, then the hash of the
contained in the OcspResponsesID may be needed to solve the ambiguity. response contained in the OcspResponsesID may be needed to solve the
ambiguity.
NOTE: Copies of the CRL and OCSP responses values may be held using NOTE: Copies of the CRL and OCSP responses values may be held using
the Revocation Values attribute defined in section 4.3.2. the Revocation Values attribute defined in clause 4.3.2.
OtherRevRefs ::= SEQUENCE { OtherRevRefs ::= SEQUENCE {
otherRevRefType OtherRevRefType, otherRevRefType OtherRevRefType,
otherRevRefs ANY DEFINED BY otherRevRefType otherRevRefs ANY DEFINED BY otherRevRefType
} }
OtherRevRefType ::= OBJECT IDENTIFIER OtherRevRefType ::= OBJECT IDENTIFIER
The syntax and semantics of other revocation references is outside the The syntax and semantics of other revocation references is outside
scope of this document. The definition of the syntax of the other form the scope of this document. The definition of the syntax of the
of revocation information is as identified by OtherRevRefType. other form of revocation information is as identified by
OtherRevRefType.
4.3 Extended Validation Data 4.3 Extended Validation Data
4.3.1 Certificate Values Attribute Definition 4.3.1 Certificate Values Attribute Definition
The Certificate Values attribute is an unsigned attribute. Only a The Certificate Values attribute is an unsigned attribute. Only a
single instance of this attribute must occur with an electronic single instance of this attribute must occur with an electronic
signature. It holds the values of certificates referenced in the signature. It holds the values of certificates referenced in the
CompleteCertificateRefs attribute. CompleteCertificateRefs attribute.
Note: If an Attribute Certificate is used, it is not provided in this
structure but must be provided by the signer as a signer-attributes
attribute (see section 12.3).
The following object identifier identifies the CertificateValues Note: If an Attribute Certificate is used, it is not provided in this
attribute: structure but must be provided by the signer as a signer-attributes
attribute (see clause 12.3).
id-aa-ets-certValues OBJECT IDENTIFIER ::= { iso(1) member-body(2) The following object identifier identifies the CertificateValues
us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 23} attribute:
The certificate values attribute value has the ASN.1 syntax id-aa-ets-certValues OBJECT IDENTIFIER ::= { iso(1) member-body(2)
CertificateValues. us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 23}
CertificateValues ::= SEQUENCE OF Certificate The certificate values attribute value has the ASN.1 syntax
CertificateValues.
Certificate is defined in RFC2459 and ITU-T Recommendation X.509 [1]) CertificateValues ::= SEQUENCE OF Certificate
Internet Draft Electronic Signature Formats Certificate is defined in RFC2459 and ITU-T Recommendation X.509 [1])
4.3.2 Revocation Values Attribute Definition 4.3.2 Revocation Values Attribute Definition
The Revocation Values attribute is an unsigned attribute. Only a single The Revocation Values attribute is an unsigned attribute. Only a
instance of this attribute must occur with an electronic signature. It single instance of this attribute must occur with an electronic
holds the values of CRLs and OCSP referenced in the signature. It holds the values of CRLs and OCSP referenced in the
CompleteRevocationRefs attribute. CompleteRevocationRefs attribute.
The following object identifier identifies the Revocation Values
attribute:
id-aa-ets-revocationValues OBJECT IDENTIFIER ::= { iso(1) member- The following object identifier identifies the Revocation Values
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) attribute:
id-aa(2) 24}
The revocation values attribute value has the ASN.1 syntax id-aa-ets-revocationValues OBJECT IDENTIFIER ::= { iso(1) member-
RevocationValues. body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
id-aa(2) 24}
RevocationValues ::= SEQUENCE { The revocation values attribute value has the ASN.1 syntax
crlVals [0] SEQUENCE OF CertificateList OPTIONAL, RevocationValues.
ocspVals [1] SEQUENCE OF BasicOCSPResponse OPTIONAL,
otherRevVals [2] OtherRevVals
}
OtherRevVals ::= SEQUENCE { RevocationValues ::= SEQUENCE {
otherRevValType OtherRevValType, crlVals [0] SEQUENCE OF CertificateList OPTIONAL,
otherRevVals ANY DEFINED BY otherRevValType ocspVals [1] SEQUENCE OF BasicOCSPResponse OPTIONAL,
} otherRevVals [2] OtherRevVals
}
OtherRevValType ::= OBJECT IDENTIFIER OtherRevVals ::= SEQUENCE {
otherRevValType OtherRevValType,
otherRevVals ANY DEFINED BY otherRevValType
}
The syntax and semantics of the other revocation values is outside the OtherRevValType ::= OBJECT IDENTIFIER
scope of this document. The definition of the syntax of the other form
of revocation information is as identified by OtherRevRefType.
CertificateList is defined in RFC 2459 [RFC2459] and in ITU-T The syntax and semantics of the other revocation values is outside
Recommendation X.509 [X509]). the scope of this document. The definition of the syntax of the
other form of revocation information is as identified by
OtherRevRefType.
BasicOCSPResponse is defined in RFC 2560 [OCSP]. CertificateList is defined in RFC 2459 [RFC2459] and in ITU-T
Recommendation X.509 [X509]).
4.3.3 ES-C Timestamp Attribute Definition BasicOCSPResponse is defined in RFC 2560 [OCSP].
This attribute is used for the Type 1 X-Timestamped validation data. 4.3.3 ES-C Time-Stamp Attribute Definition
The ES-C Timestamp attribute is an unsigned attribute. It is timestamp
of a hash of the electronic signature and the complete validation data
(ES-C). It is a special purpose TimeStampToken Attribute which
timestamps the ES-C. Several instances instance of this attribute may
occur with an electronic signature from different TSAs.
The following object identifier identifies the ES-C Timestamp This attribute is used for the Type 1 X-Time-Stamped validation data.
attribute: The ES-C Time-Stamp attribute is an unsigned attribute. It is time-
stamp of a hash of the electronic signature and the complete
validation data (ES-C). It is a special purpose TimeStampToken
Attribute which time-stamps the ES-C. Several instances instance of
this attribute may occur with an electronic signature from different
TSAs.
id-aa-ets-escTimeStamp OBJECT IDENTIFIER ::= { iso(1) member- The following object identifier identifies the ES-C Time-Stamp
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) attribute:
id-aa(2) 25}
Internet Draft Electronic Signature Formats id-aa-ets-escTimeStamp OBJECT IDENTIFIER ::= { iso(1) member-
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
id-aa(2) 25}
The ES-C timestamp attribute value has the ASN.1 syntax The ES-C time-stamp attribute value has the ASN.1 syntax
ESCTimeStampToken. ESCTimeStampToken.
ESCTimeStampToken ::= TimeStampToken ESCTimeStampToken ::= TimeStampToken
The value of messageImprint field within TimeStampToken must be a hash The value of messageImprint field within TimeStampToken must be a
of the concatenated values (without the type or length encoding for hash of the concatenated values (without the type or length encoding
that value) of the following data objects as present in the ES with for that value) of the following data objects as present in the ES
Complete validation data (ES-C): with Complete validation data (ES-C):
* signature field within SignerInfo; * signature field within SignerInfo;
* SignatureTimeStampToken attribute; * SignatureTimeStampToken attribute;
* CompleteCertificateRefs attribute; * CompleteCertificateRefs attribute;
* CompleteRevocationRefs attribute. * CompleteRevocationRefs attribute.
For further information and definition of the Time Stamp Token see For further information and definition of the Time Stamp Token see
[TSP]. [TSP].
4.3.4 Time-Stamped Certificates and CRLs Attribute Definition 4.3.4 Time-Stamped Certificates and CRLs Attribute Definition
This attribute is used for the Type 2 X-Timestamp validation data. A This attribute is used for the Type 2 X-Time-Stamp validation data.
TimestampedCertsCRLsRef attribute is an unsigned attribute. It is a A TimestampedCertsCRLsRef attribute is an unsigned attribute. It is
list of referenced certificates and OCSP responses/CRLs which are been a list of referenced certificates and OCSP responses/CRLs which are
timestamped to protect against certain CA compromises. Its syntax is as been time-stamped to protect against certain CA compromises. Its
follows: syntax is as follows:
The following object identifier identifies the TimestampedCertsCRLsRef The following object identifier identifies the
attribute: TimestampedCertsCRLsRef attribute:
id-aa-ets-certCRLTimestamp OBJECT IDENTIFIER ::= { iso(1) member- id-aa-ets-certCRLTimestamp OBJECT IDENTIFIER ::= { iso(1) member-
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
id-aa(2) 26} id-aa(2) 26}
The attribute value has the ASN.1 syntax TimestampedCertsCRLs. The attribute value has the ASN.1 syntax TimestampedCertsCRLs.
TimestampedCertsCRLs ::= TimeStampToken TimestampedCertsCRLs ::= TimeStampToken
The value of messageImprint field within TimeStampToken must be a hash The value of messageImprint field within TimeStampToken must be a
of the concatenated values (without the type or length encoding for hash of the concatenated values (without the type or length encoding
that value) of the following data objects as present in the ES with for that value) of the following data objects as present in the ES
Complete validation data (ES-C): with Complete validation data (ES-C):
* CompleteCertificateRefs attribute; * CompleteCertificateRefs attribute;
* CompleteRevocationRefs attribute. * CompleteRevocationRefs attribute.
4.4 Archive Validation Data 4.4 Archive Validation Data
Where an electronic signature is required to last for a very long time, Where an electronic signature is required to last for a very long
and a the timestamp on an electronic signature is in danger of being time, and a the time-stamp on an electronic signature is in danger of
invalidated due to algorithm weakness or limits in the validity period being invalidated due to algorithm weakness or limits in the validity
of the TSA certificate, then it may be required to timestamp the period of the TSA certificate, then it may be required to time-stamp
the electronic signature several times. When this is required an
Internet Draft Electronic Signature Formats archive time-stamp attribute may be required. This time-stamp may be
repeatedly applied over a period of time.
electronic signature several times. When this is required an archive
timestamp attribute may be required. This timestamp may be repeatedly
applied over a period of time.
4.4.1 Archive Timestamp Attribute Definition
The Archive Timestamp attribute is timestamp of the user data and the
entire electronic signature. If the Certificate values and Revocation
Values attributes are not present these attributes must be added to
the electronic signature prior to the timestamp. The Archive Timestamp
attribute is an unsigned attribute. Several instances of this attribute
may occur with on electronic signature both over time and from
different TSAs.
The following object identifier identifies the Nested Archive Timestamp 4.4.1 Archive Time-Stamp Attribute Definition
attribute:
id-aa-ets-archiveTimestamp OBJECT IDENTIFIER ::= { iso(1) member- The Archive Time-Stamp attribute is time-stamp of the user data and
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) the entire electronic signature. If the Certificate values and
id-aa(2) 27} Revocation Values attributes are not present these attributes must be
added to the electronic signature prior to the time-stamp. The
Archive Time-Stamp attribute is an unsigned attribute. Several
instances of this attribute may occur with on electronic signature
both over time and from different TSAs.
Archive timestamp attribute values have the ASN.1 syntax The following object identifier identifies the Nested Archive Time-
ArchiveTimeStampToken Stamp attribute:
ArchiveTimeStampToken ::= TimeStampToken id-aa-ets-archiveTimestamp OBJECT IDENTIFIER ::= { iso(1) member-
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
id-aa(2) 27}
The value of messageImprint field within TimeStampToken must be a hash Archive time-stamp attribute values have the ASN.1 syntax
of the concatenated values (without the type or length encoding for ArchiveTimeStampToken
that value) of the following data objects as present in the electronic
signature:
* encapContentInfo eContent OCTET STRING; ArchiveTimeStampToken ::= TimeStampToken
* signedAttributes; The value of messageImprint field within Time-StampToken must be a
* signature field within SignerInfo; hash of the concatenated values (without the type or length encoding
* SignatureTimeStampToken attribute; for that value) of the following data objects as present in the
* CompleteCertificateRefs attribute; electronic signature:
* CompleteRevocationData attribute;
* CertificateValues attribute
(If not already present this information must be included in
the ES-A);
* RevocationValues attribute
(If not already present this information must be included in
the ES-A);
* ESCTimeStampToken attribute if present;
* TimestampedCertsCRLs attribute if present;
* any previous ArchiveTimeStampToken attributes.
For further information and definition of TimeStampToken see [TSP] * encapContentInfo eContent OCTET STRING;
* signedAttributes;
* signature field within SignerInfo;
* SignatureTimeStampToken attribute;
* CompleteCertificateRefs attribute;
* CompleteRevocationData attribute;
* CertificateValues attribute
(If not already present this information must be included in
the ES-A);
* RevocationValues attribute
(If not already present this information must be included in
the ES-A);
* ESCTimeStampToken attribute if present;
* TimestampedCertsCRLs attribute if present;
* any previous ArchiveTimeStampToken attributes.
The timestamp should be created using stronger algorithms (or longer For further information and definition of TimeStampToken see [TSP]
key lengths) than in the original electronic signatures.
Internet Draft Electronic Signature Formats The time-stamp should be created using stronger algorithms (or longer
key lengths) than in the original electronic signatures.
5. Security considerations 5. Security Considerations
5.1 Protection of Private Key 5.1 Protection of Private Key
The security of the electronic signature mechanism defined in this The security of the electronic signature mechanism defined in this
document depends on the privacy of the signer's private key. document depends on the privacy of the signer's private key.
Implementations must take steps to ensure that private keys cannot be Implementations must take steps to ensure that private keys cannot be
compromised. compromised.
5.2 Choice of Algorithms 5.2 Choice of Algorithms
Implementers should be aware that cryptographic algorithms become Implementers should be aware that cryptographic algorithms become
weaker with time. As new cryptoanalysis techniques are developed and weaker with time. As new cryptoanalysis techniques are developed and
computing performance improves, the work factor to break a particular computing performance improves, the work factor to break a particular
cryptographic algorithm will reduce. Therefore, cryptographic algorithm cryptographic algorithm will reduce. Therefore, cryptographic
implementations should be modular allowing new algorithms to be readily algorithm implementations should be modular allowing new algorithms
inserted. That is, implementers should be prepared for the set of to be readily inserted. That is, implementers should be prepared for
mandatory to implement algorithms to change over time. the set of mandatory to implement algorithms to change over time.
6. Conformance Requirements 6. Conformance Requirements
This document only defines conformance requirements up to a ES with This document only defines conformance requirements up to a ES with
Complete validation data (ES-C). This means that none of the extended Complete validation data (ES-C). This means that none of the
and archive forms of Electronic Signature (ES-X, ES-A) need to be extended and archive forms of Electronic Signature (ES-X, ES-A) need
implemented to get conformance to this standard. to be implemented to get conformance to this standard.
This document mandates support for elements of the signature policy. This document mandates support for elements of the signature policy.
6.1 Signer 6.1 Signer
A system supporting signers according to this document must, at a A system supporting signers according to this document must, at a
minimum, support generation of an electronic signature consisting of minimum, support generation of an electronic signature consisting of
the following components: the following components:
* The general CMS syntax and content type as defined in RFC 2630
(see sections 4.1 and 4.2).
* CMS SignedData as defined in RFC 2630 with version set to 3 * The general CMS syntax and content type as defined in RFC 2630
and at least one SignerInfo must be present (see clauses 4.1 and 4.2).
(see sections 4.3, 4.4, 4.5, 4.6).
* The following CMS Attributes as defined in RFC 2630 : * CMS SignedData as defined in RFC 2630 with version set to 3 and
at least one SignerInfo must be present (see clauses 4.3, 4.4,
4.5, 4.6).
- ContentType; This must always be present * The following CMS Attributes as defined in RFC 2630:
(see section 3.7.1);
- MessageDigest; This must always be present - ContentType; This must always be present
(see section 3.7.2); (see clause 3.7.1);
- SigningTime; This must always be present - MessageDigest; This must always be present
(see section 3.7.3). (see clause 3.7.2);
Internet Draft Electronic Signature Formats - SigningTime; This must always be present
(see clause 3.7.3).
* The following ESS Attributes as defined in RFC 2634 : * The following ESS Attributes as defined in RFC 2634:
- SigningCertificate: This must be set as defined - SigningCertificate: This must be set as defined in clauses
in sections 3.8.1 and 3.8.2. 3.8.1 and 3.8.2.
* The following Attributes as defined in section 3.9: * The following Attributes as defined in clause 3.9:
- SignaturePolicyIdentifier; This must always be present.
* Public Key Certificates as defined in ITU-T Recommendation - SignaturePolicyIdentifier; This must always be present.
X.509 [1] and profiled in RFC 2459 [7] (see section 9.1).
6.2 Verifier using timestamping * Public Key Certificates as defined in ITU-T Recommendation
X.509 [1] and profiled in RFC 2459 [7] (see clause 9.1).
A system supporting verifiers according to this document with 6.2 Verifier using time-stamping
timestamping facilities must, at a minimum, support:
* Verification of the mandated components of an electronic A system supporting verifiers according to this document with time-
signature, as defined in section 5.1. stamping facilities must, at a minimum, support:
* Signature Timestamp attribute, as defined in section 4.1.1. * Verification of the mandated components of an electronic
signature, as defined in clause 5.1.
* Complete Certificate Refs attribute, as defined in * Signature Time-Stamp attribute, as defined in clause 4.1.1.
section 4.2.1.
* Complete Revocation Refs Attribute, as defined in * Complete Certificate Refs attribute, as defined in clause
section 4.2.2. 4.2.1.
* Public Key Certificates, as defined in ITU-T * Complete Revocation Refs Attribute, as defined in clause
Recommendation X.509 and profiled in RFC 2459. 4.2.2.
* Either of: * Public Key Certificates, as defined in ITU-T Recommendation
X.509 and profiled in RFC 2459.
- Certificate Revocation Lists. as defined in ITU-T * Either of:
Recommendation X.509 [1] and profiled in RFC 2459 [7];
or
- On-line Certificate Status Protocol responses, as - Certificate Revocation Lists, as defined in ITU-T
defined in RFC 2560. Recommendation X.509 [1] and profiled in RFC 2459 [7]; or
6.3 Verifier using secure records - On-line Certificate Status Protocol responses, as defined in
RFC 2560.
A system supporting verifiers according to the present document shall, 6.3 Verifier using secure records
at a minimum, support:
* Verification of the mandated components of an electronic A system supporting verifiers according to the present document
signature, as defined in subsection 5.1. shall, at a minimum, support:
* Complete Certificate Refs attribute, as defined in * Verification of the mandated components of an electronic
subsection 4.2.1. signature, as defined in subclause 5.1.
Internet Draft Electronic Signature Formats * Complete Certificate Refs attribute, as defined in subclause
4.2.1.
* Complete Revocation Refs Attribute, as defined in * Complete Revocation Refs Attribute, as defined in subclause
subsection 9.2.2. 9.2.2.
* A record shall be maintained, which cannot be undetectably * A record shall be maintained, which cannot be undetectably
modified, of the electronic signature and the time when the modified, of the electronic signature and the time when the
signature was first validated using the referenced signature was first validated using the referenced certificates
certificates and revocation information. and revocation information.
* Public Key Certificates, as defined in ITU-T Recommendation * Public Key Certificates, as defined in ITU-T Recommendation
X.509 [1] and profiled in RFC 2459 [7] (see subsection 10.1). X.509 [1] and profiled in RFC 2459 [7] (see subclause 10.1).
* Either of: * Either of:
- Certificate Revocation Lists. as defined in ITU-T
Recommendation X.509 [1] and profiled in RFC 2459 [7]
Or
- On-line Certificate Status Protocol, as defined - Certificate Revocation Lists, as defined in ITU-T
in RFC 2560 [8] (see subsection 10.3). Recommendation X.509 [1] and profiled in RFC 2459 [7] Or
7. References - On-line Certificate Status Protocol, as defined in RFC 2560
[8] (see subclause 10.3).
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 7. References
Requirement Levels", BCP 14, RFC 2119, March 1997.
[ESS] P. Hoffman, "Enhanced Security Services for S/MIME", [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
RFC 2634, June 1999 Requirement Levels", BCP 14, RFC 2119, March 1997.
[CMS] R. Housley, "Cryptographic Message Syntax", RFC 2630, [ESS] Hoffman, P., "Enhanced Security Services for S/MIME", RFC
June 1999. 2634, June 1999.
[OCSP] M. Myers, R. Ankney, A. Malpani, S. Galperin, C. Adams. [CMS] Housley, R., "Cryptographic Message Syntax", RFC 2630,
On-line Status Certificate Protocol, RFC 2560. June 1999.
[TSP] C. Adams, P. Cain, D. Pinkas, R. Zuccherato. Time Stamp Protocol [OCSP] Myers, M., Ankney, R., Malpani, A., Galperin, S. and C.
(TSP), (under progress). June 2000. Adams, "On-line Status Certificate Protocol", RFC 2560,
June 1999.
[PTS] Public Telegram Service. ITU-T Recommendation F1. XXXX [TSP] Adams, C., Cain, P., Pinkas, D. and R. Zuccherato,
"Internet X.509 Public Key Infrastructure Time-Stamp
Protocol (TSP)", RFC 3161, August 2001.
[RFC2459] R. Housley, W. Ford, W. Polk, D. Solo, "Internet X.509 Public [PTS] Public Telegram Service. ITU-T Recommendation F1.
Key Infrastructure, Certificate and CRL Profile," RFC 2459, January
1999.
[PKCS9] RSA Laboratories, "The Public-Key Cryptography Standards [RFC2459] Housley, R., Ford, W., Polk, W. and D. Solo, "Internet
(PKCS)", RSA Data Security Inc., Redwood City, California, November X.509 Public Key Infrastructure, Certificate and CRL
1993 Release. Profile", RFC 2459, January 1999.
[ISONR] ISO/IEC 10181-5: Security Frameworks in Open Systems. [PKCS9] RSA Laboratories, "The Public-Key Cryptography Standards
Non-Repudiation Framework. April 1997. (PKCS)", RSA Data Security Inc., Redwood City, California,
November 1993 Release.
[ES201733] ETSI Standard ES 201 733 V1.1.3 (2000-05) Electronic [ISONR] ISO/IEC 10181-5: Security Frameworks in Open Systems.
Signature Formats. Note: copies of ETSI ES 210 733 can be freely Non-Repudiation Framework. April 1997.
downloaded from the ETSI web site www.etsi.org.
Internet Draft Electronic Signature Formats [TS101733] ETSI Standard TS 101 733 V.1.2.2 (2000-12) Electronic
Signature Formats. Note: copies of ETSI TS 101 733 can be
freely downloaded from the ETSI web site www.etsi.org.
8. Authors' Addresses 8. Authors' Addresses
This Informational RFC has been produced in ETSI TC-SEC. This Informational RFC has been produced in ETSI TC-SEC.
ETSI
F-06921 Sophia Antipolis, Cedex - FRANCE
650 Route des Lucioles - Sophia Antipolis
Valbonne - France
Tel: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16
secretariat@etsi.fr
http://www.etsi.org
Contact Point
Harri Rasilainen ETSI
ETSI F-06921 Sophia Antipolis, Cedex - FRANCE
650 Route des Lucioles 650 Route des Lucioles - Sophia Antipolis
F-06921 Sophia Antipolis, Cedex Valbonne - France
FRANCE Tel: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16
harri.rasilainen@etsi.fr secretariat@etsi.fr
http://www.etsi.org
Denis Pinkas Contact Point
Bull S.A.
12, rue de Paris
B.P. 59
78231 Le Pecq
FRANCE
Denis.Pinkas @bull.net
John Ross Harri Rasilainen
Security & Standards ETSI
192 Moulsham Street 650 Route des Lucioles
Chelmsford, Essex F-06921 Sophia Antipolis, Cedex
CM2 0LG FRANCE
United Kingdom
ross@secstan.com
Nick Pope EMail: harri.rasilainen@etsi.fr
Security & Standards
192 Moulsham Street
Chelmsford, Essex
CM2 0LG
United Kingdom
pope@secstan.com
Internet Draft Electronic Signature Formats Denis Pinkas
Integris
68, Route de Versailles
78434 Louveciennes CEDEX
FRANCE
9. Full Copyright Statement EMail: Denis.Pinkas@bull.net
Copyright (C) The Internet Society (2000). All Rights Reserved. John Ross
This document and translations of it may be copied and furnished to Security & Standards
others, and derivative works that comment on or otherwise explain it 192 Moulsham Street
or assist in its implementation may be prepared, copied, published and Chelmsford, Essex
distributed, in whole or in part, without restriction of any kind, CM2 0LG
provided that the above copyright notice and this paragraph are United Kingdom
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of developing
Internet standards in which case the procedures for copyrights defined
in the Internet Standards process must be followed, or as required to
translate it into languages other than English.
The limited permissions granted above are perpetual and will not be EMail: ross@secstan.com
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an Nick Pope
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING Security & Standards
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT 192 Moulsham Street
NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN Chelmsford, Essex
WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF CM2 0LG
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. United Kingdom
Internet Draft Electronic Signature Formats EMail: pope@secstan.com
Annex A (normative): ASN.1 Definitions Annex A (normative): ASN.1 Definitions
This annex provides a summary of all the ASN.1 syntax definitions for This annex provides a summary of all the ASN.1 syntax definitions for
new syntax defined in this document. new syntax defined in this document.
A.1 Definitions Using X.208 (1988) ASN.1 Syntax A.1 Definitions Using X.208 (1988) ASN.1 Syntax
NOTE: The ASN.1 module defined in section A.1 has precedence over that NOTE: The ASN.1 module defined in clause A.1 has precedence over
defined in Annex A-2 in the case of any conflict. that defined in Annex A-2 in the case of any conflict.
ETS-ElectronicSignatureFormats-88syntax { iso(1) member-body(2) ETS-ElectronicSignatureFormats-88syntax { iso(1) member-body(2)
us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-mod(0) 5} us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-mod(0) 5}
DEFINITIONS EXPLICIT TAGS ::= DEFINITIONS EXPLICIT TAGS ::=
BEGIN BEGIN
-- EXPORTS All - -- EXPORTS All -
IMPORTS IMPORTS
-- Crypographic Message Syntax (CMS): RFC 2630 -- Crypographic Message Syntax (CMS): RFC 2630
skipping to change at page 47, line 5 skipping to change at page 50, line 7
pkcs(1) pkcs-9(9) smime(16) modules(0) ess(2) } pkcs(1) pkcs-9(9) smime(16) modules(0) ess(2) }
-- Internet X.509 Public Key Infrastructure -- Internet X.509 Public Key Infrastructure
-- Certificate and CRL Profile: RFC 2459 -- Certificate and CRL Profile: RFC 2459
Certificate, AlgorithmIdentifier, CertificateList, Name, Certificate, AlgorithmIdentifier, CertificateList, Name,
GeneralNames, GeneralName, DirectoryString,Attribute, GeneralNames, GeneralName, DirectoryString,Attribute,
AttributeTypeAndValue, AttributeType, AttributeValue, AttributeTypeAndValue, AttributeType, AttributeValue,
PolicyInformation, BMPString, UTF8String PolicyInformation, BMPString, UTF8String
Internet Draft Electronic Signature Formats
FROM PKIX1Explicit88 FROM PKIX1Explicit88
{iso(1) identified-organization(3) dod(6) internet(1) {iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0) id-pkix1-explicit- security(5) mechanisms(5) pkix(7) id-mod(0) id-pkix1-explicit-
88(1)} 88(1)}
-- X.509 '97 Authentication Framework -- X.509 '97 Authentication Framework
AttributeCertificate AttributeCertificate
FROM AuthenticationFramework FROM AuthenticationFramework
skipping to change at page 47, line 29 skipping to change at page 50, line 29
-- The imported AttributeCertificate is defined using the X.680 1997 -- The imported AttributeCertificate is defined using the X.680 1997
-- ASN.1 Syntax, -- ASN.1 Syntax,
-- an equivalent using the 88 ASN.1 syntax may be used. -- an equivalent using the 88 ASN.1 syntax may be used.
-- OCSP 2560 -- OCSP 2560
BasicOCSPResponse, ResponderID BasicOCSPResponse, ResponderID
FROM OCSP {-- OID not assigned -- } FROM OCSP {-- OID not assigned -- }
-- Time Stamp Protocol Work in Progress
TimeStampToken TimeStampToken
FROM PKIXTSP FROM PKIXTSP
{iso(1) identified-organization(3) dod(6) internet(1) {iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-tsp(13)} security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-tsp(13)}
-- S/MIME Object Identifier arcs used in this document -- S/MIME Object Identifier arcs used in this document
-- =================================================== -- ===================================================
skipping to change at page 48, line 5 skipping to change at page 51, line 9
-- modules -- modules
-- id-ct OBJECT IDENTIFIER ::= { id-smime 1 } -- id-ct OBJECT IDENTIFIER ::= { id-smime 1 }
-- content types -- content types
-- id-aa OBJECT IDENTIFIER ::= { id-smime 2 } -- id-aa OBJECT IDENTIFIER ::= { id-smime 2 }
-- attributes -- attributes
-- id-spq OBJECT IDENTIFIER ::= { id-smime 5 } -- id-spq OBJECT IDENTIFIER ::= { id-smime 5 }
-- signature policy qualifier -- signature policy qualifier
-- id-cti OBJECT IDENTIFIER ::= { id-smime 6 } -- id-cti OBJECT IDENTIFIER ::= { id-smime 6 }
-- commitment type identifier -- commitment type identifier
Internet Draft Electronic Signature Formats
-- Definitions of Object Identifier arcs used in this document -- Definitions of Object Identifier arcs used in this document
-- =========================================================== -- ===========================================================
-- The allocation of OIDs to specific objects are given below with the -- The allocation of OIDs to specific objects are given below with the
-- associated ASN.1 syntax definition -- associated ASN.1 syntax definition
-- OID used referencing electronic signature mechanisms based on this -- OID used referencing electronic signature mechanisms based on this
-- standard for use with the IDUP API (see annex D) -- standard for use with the IDUP API (see annex D)
id-etsi-es-IDUP-Mechanism-v1 OBJECT IDENTIFIER ::= id-etsi-es-IDUP-Mechanism-v1 OBJECT IDENTIFIER ::=
skipping to change at page 48, line 49 skipping to change at page 52, line 4
otherCertHash OtherHash, otherCertHash OtherHash,
issuerSerial IssuerSerial OPTIONAL issuerSerial IssuerSerial OPTIONAL
} }
OtherHash ::= CHOICE { OtherHash ::= CHOICE {
sha1Hash OtherHashValue, -- This contains a SHA-1 hash sha1Hash OtherHashValue, -- This contains a SHA-1 hash
otherHash OtherHashAlgAndValue otherHash OtherHashAlgAndValue
} }
OtherHashValue ::= OCTET STRING OtherHashValue ::= OCTET STRING
OtherHashAlgAndValue ::= SEQUENCE { OtherHashAlgAndValue ::= SEQUENCE {
hashAlgorithm AlgorithmIdentifier, hashAlgorithm AlgorithmIdentifier,
hashValue OtherHashValue hashValue OtherHashValue
} }
Internet Draft Electronic Signature Formats
-- Signature Policy Identifier -- Signature Policy Identifier
id-aa-ets-sigPolicyId OBJECT IDENTIFIER ::= { iso(1) id-aa-ets-sigPolicyId OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
smime(16) id-aa(2) 15 } smime(16) id-aa(2) 15 }
"SignaturePolicy CHOICE { "SignaturePolicy CHOICE {
SignaturePolicyId SignaturePolicyId, SignaturePolicyId SignaturePolicyId,
SignaturePolicyImplied SignaturePolicyImplied SignaturePolicyImplied SignaturePolicyImplied
} }
skipping to change at page 49, line 29 skipping to change at page 52, line 31
sigPolicyIdentifier SigPolicyId, sigPolicyIdentifier SigPolicyId,
sigPolicyHash SigPolicyHash, sigPolicyHash SigPolicyHash,
sigPolicyQualifiers SEQUENCE SIZE (1..MAX) OF sigPolicyQualifiers SEQUENCE SIZE (1..MAX) OF
SigPolicyQualifierInfo OPTIONAL SigPolicyQualifierInfo OPTIONAL
} }
SignaturePolicyImplied ::= NULL SignaturePolicyImplied ::= NULL
SigPolicyId ::= OBJECT IDENTIFIER SigPolicyId ::= OBJECT IDENTIFIER
SigPolicyHash ::= ETSIHashAlgAndValue SigPolicyHash ::= OtherHashAlgAndValue
SigPolicyQualifierInfo ::= SEQUENCE { SigPolicyQualifierInfo ::= SEQUENCE {
sigPolicyQualifierId SigPolicyQualifierId, sigPolicyQualifierId SigPolicyQualifierId,
sigQualifier ANY DEFINED BY sigPolicyQualifierId sigQualifier ANY DEFINED BY sigPolicyQualifierId
} }
SigPolicyQualifierId ::= SigPolicyQualifierId ::=
OBJECT IDENTIFIER OBJECT IDENTIFIER
id-spq-ets-uri OBJECT IDENTIFIER ::= { iso(1) id-spq-ets-uri OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
smime(16) id-spq(5) 1 } smime(16) id-spq(5) 1 }
SPuri ::= IA5String SPuri ::= IA5String
id-spq-ets-unotice OBJECT IDENTIFIER ::= { iso(1) id-spq-ets-unotice OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
smime(16) id-spq(5) 2 } smime(16) id-spq(5) 2 }
Internet Draft Electronic Signature Formats
SPUserNotice ::= SEQUENCE { SPUserNotice ::= SEQUENCE {
noticeRef NoticeReference OPTIONAL, noticeRef NoticeReference OPTIONAL,
explicitText DisplayText OPTIONAL explicitText DisplayText OPTIONAL
} }
NoticeReference ::= SEQUENCE { NoticeReference ::= SEQUENCE {
organization DisplayText, organization DisplayText,
noticeNumbers SEQUENCE OF INTEGER noticeNumbers SEQUENCE OF INTEGER
} }
skipping to change at page 51, line 5 skipping to change at page 53, line 51
cti(6) 1} cti(6) 1}
id-cti-ets-proofOfReceipt OBJECT IDENTIFIER ::= { iso(1) member- id-cti-ets-proofOfReceipt OBJECT IDENTIFIER ::= { iso(1) member-
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
cti(6) 2} cti(6) 2}
id-cti-ets-proofOfDelivery OBJECT IDENTIFIER ::= { iso(1) member- id-cti-ets-proofOfDelivery OBJECT IDENTIFIER ::= { iso(1) member-
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
cti(6) 3} cti(6) 3}
Internet Draft Electronic Signature Formats
id-cti-ets-proofOfSender OBJECT IDENTIFIER ::= { iso(1) member- id-cti-ets-proofOfSender OBJECT IDENTIFIER ::= { iso(1) member-
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
cti(6) 4} cti(6) 4}
id-cti-ets-proofOfApproval OBJECT IDENTIFIER ::= { iso(1) member- id-cti-ets-proofOfApproval OBJECT IDENTIFIER ::= { iso(1) member-
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
cti(6) 5} cti(6) 5}
id-cti-ets-proofOfCreation OBJECT IDENTIFIER ::= { iso(1) member- id-cti-ets-proofOfCreation OBJECT IDENTIFIER ::= { iso(1) member-
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
skipping to change at page 52, line 5 skipping to change at page 54, line 47
SignerAttribute ::= SEQUENCE OF CHOICE { SignerAttribute ::= SEQUENCE OF CHOICE {
claimedAttributes [0] ClaimedAttributes, claimedAttributes [0] ClaimedAttributes,
certifiedAttributes [1] CertifiedAttributes certifiedAttributes [1] CertifiedAttributes
} }
ClaimedAttributes ::= SEQUENCE OF Attribute ClaimedAttributes ::= SEQUENCE OF Attribute
CertifiedAttributes ::= AttributeCertificate -- as defined in X.509 : CertifiedAttributes ::= AttributeCertificate -- as defined in X.509 :
see section 10.3 see section 10.3
Internet Draft Electronic Signature Formats -- Content Time-Stamp
id-aa-ets-contentTimestamp OBJECT IDENTIFIER ::= { iso(1) member- id-aa-ets-contentTimestamp OBJECT IDENTIFIER ::= { iso(1) member-
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
id-aa(2) 20} id-aa(2) 20}
ContentTimestamp::= TimeStampToken ContentTimestamp::= TimeStampToken
-- Validation Data -- Validation Data
-- Signature Time-Stamp
id-aa-signatureTimeStampToken OBJECT IDENTIFIER ::= { iso(1) id-aa-signatureTimeStampToken OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
id-aa(2) 14} id-aa(2) 14}
SignatureTimeStampToken ::= TimeStampToken SignatureTimeStampToken ::= TimeStampToken
-- Complete Certificate Refs. -- Complete Certificate Refs.
id-aa-ets-certificateRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2) id-aa-ets-certificateRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2)
skipping to change at page 52, line 50 skipping to change at page 55, line 42
CrlOcspRef ::= SEQUENCE { CrlOcspRef ::= SEQUENCE {
crlids [0] CRLListID OPTIONAL, crlids [0] CRLListID OPTIONAL,
ocspids [1] OcspListID OPTIONAL, ocspids [1] OcspListID OPTIONAL,
otherRev [2] OtherRevRefs OPTIONAL otherRev [2] OtherRevRefs OPTIONAL
} }
CRLListID ::= SEQUENCE { CRLListID ::= SEQUENCE {
crls SEQUENCE OF CrlValidatedID} crls SEQUENCE OF CrlValidatedID}
CrlValidatedID ::= SEQUENCE { CrlValidatedID ::= SEQUENCE {
crlHash ETSIHash, crlHash OtherHash,
crlIdentifier CrlIdentifier OPTIONAL crlIdentifier CrlIdentifier OPTIONAL
} }
Internet Draft Electronic Signature Formats
CrlIdentifier ::= SEQUENCE { CrlIdentifier ::= SEQUENCE {
crlissuer Name, crlissuer Name,
crlIssuedTime UTCTime, crlIssuedTime UTCTime,
crlNumber INTEGER OPTIONAL crlNumber INTEGER OPTIONAL
} }
OcspListID ::= SEQUENCE { OcspListID ::= SEQUENCE {
ocspResponses SEQUENCE OF OcspResponsesID} ocspResponses SEQUENCE OF OcspResponsesID}
OcspResponsesID ::= SEQUENCE { OcspResponsesID ::= SEQUENCE {
ocspIdentifier OcspIdentifier, ocspIdentifier OcspIdentifier,
ocspRepHash ETSIHash OPTIONAL ocspRepHash OtherHash OPTIONAL
} }
OcspIdentifier ::= SEQUENCE { OcspIdentifier ::= SEQUENCE {
ocspResponderID ResponderID, ocspResponderID ResponderID,
-- as in OCSP response data -- as in OCSP response data
producedAt GeneralizedTime producedAt GeneralizedTime
-- as in OCSP response data -- as in OCSP response data
} }
OtherRevRefs ::= SEQUENCE { OtherRevRefs ::= SEQUENCE {
skipping to change at page 54, line 5 skipping to change at page 56, line 44
id-aa-ets-revocationValues OBJECT IDENTIFIER ::= { iso(1) member- id-aa-ets-revocationValues OBJECT IDENTIFIER ::= { iso(1) member-
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
id-aa(2) 24} id-aa(2) 24}
RevocationValues ::= SEQUENCE { RevocationValues ::= SEQUENCE {
crlVals [0] SEQUENCE OF CertificateList OPTIONAL, crlVals [0] SEQUENCE OF CertificateList OPTIONAL,
ocspVals [1] SEQUENCE OF BasicOCSPResponse OPTIONAL, ocspVals [1] SEQUENCE OF BasicOCSPResponse OPTIONAL,
otherRevVals [2] OtherRevVals otherRevVals [2] OtherRevVals
} }
Internet Draft Electronic Signature Formats
OtherRevVals ::= SEQUENCE { OtherRevVals ::= SEQUENCE {
otherRevValType OtherRevValType, otherRevValType OtherRevValType,
otherRevVals ANY DEFINED BY otherRevValType otherRevVals ANY DEFINED BY otherRevValType
} }
OtherRevValType ::= OBJECT IDENTIFIER OtherRevValType ::= OBJECT IDENTIFIER
-- ES-C Time-Stamp
id-aa-ets-escTimeStamp OBJECT IDENTIFIER ::= { iso(1) member-body(2) id-aa-ets-escTimeStamp OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 25} us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 25}
ESCTimeStampToken ::= TimeStampToken ESCTimeStampToken ::= TimeStampToken
-- Time-Stamped Certificates and CRLs -- Time-Stamped Certificates and CRLs
id-aa-ets-certCRLTimestamp OBJECT IDENTIFIER ::= { iso(1) member- id-aa-ets-certCRLTimestamp OBJECT IDENTIFIER ::= { iso(1) member-
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
id-aa(2) 26} id-aa(2) 26}
TimestampedCertsCRLs ::= TimeStampToken TimestampedCertsCRLs ::= TimeStampToken
-- Archive Time-Stamp
id-aa-ets-archiveTimestamp OBJECT IDENTIFIER ::= { iso(1) member- id-aa-ets-archiveTimestamp OBJECT IDENTIFIER ::= { iso(1) member-
body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
id-aa(2) 27} id-aa(2) 27}
ArchiveTimeStampToken ::= TimeStampToken ArchiveTimeStampToken ::= TimeStampToken
END -- ETS-ElectronicSignatureFormats-88syntax -- END -- ETS-ElectronicSignatureFormats-88syntax --
Internet Draft Electronic Signature Formats
A.2 Definitions Using X.680 1997 ASN.1 Syntax A.2 Definitions Using X.680 1997 ASN.1 Syntax
NOTE: The ASN.1 module defined in section A.1 has precedence over that NOTE: The ASN.1 module defined in clause A.1 has precedence over that
defined in section A.2 in the case of any conflict. defined in clause A.2 in the case of any conflict.
ETS-ElectronicSignatureFormats-97Syntax { iso(1) member-body(2) ETS-ElectronicSignatureFormats-97Syntax { iso(1) member-body(2)
us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-mod(0) 6} us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-mod(0) 6}
DEFINITIONS EXPLICIT TAGS ::= DEFINITIONS EXPLICIT TAGS ::=
BEGIN BEGIN
-- EXPORTS All - -- EXPORTS All -
IMPORTS IMPORTS
-- Cryptographic Message Syntax (CMS): RFC 2630 -- Cryptographic Message Syntax (CMS): RFC 2630
skipping to change at page 56, line 5 skipping to change at page 58, line 30
Certificate, AlgorithmIdentifier, CertificateList, Name, Certificate, AlgorithmIdentifier, CertificateList, Name,
GeneralNames, GeneralName, DirectoryString, Attribute, GeneralNames, GeneralName, DirectoryString, Attribute,
AttributeTypeAndValue, AttributeType, AttributeValue, AttributeTypeAndValue, AttributeType, AttributeValue,
PolicyInformation. PolicyInformation.
FROM PKIX1Explicit93 FROM PKIX1Explicit93
{iso(1) identified-organization(3) dod(6) internet(1) {iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0) security(5) mechanisms(5) pkix(7) id-mod(0)
id-pkix1-explicit-88(1)} id-pkix1-explicit-88(1)}
Internet Draft Electronic Signature Formats
-- X.509 '97 Authentication Framework -- X.509 '97 Authentication Framework
AttributeCertificate AttributeCertificate
FROM AuthenticationFramework FROM AuthenticationFramework
{joint-iso-ccitt ds(5) module(1) authenticationFramework(7) 3} {joint-iso-ccitt ds(5) module(1) authenticationFramework(7) 3}
-- OCSP 2560 -- OCSP 2560
BasicOCSPResponse, ResponderID BasicOCSPResponse, ResponderID
FROM OCSP FROM OCSP
-- { OID not assigned } -- { OID not assigned }
-- Time Stamp Protocol Work in Progress TimeStampToken
FROM PKIXTSP FROM PKIXTSP
{iso(1) identified-organization(3) dod(6) internet(1) {iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-tsp(13)} security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-tsp(13)}
-- S/MIME Object Identifier arcs used in this document -- S/MIME Object Identifier arcs used in this document
-- =================================================== -- ===================================================
-- S/MIME OID arc used in this document -- S/MIME OID arc used in this document
-- id-smime OBJECT IDENTIFIER ::= { iso(1) member-body(2) -- id-smime OBJECT IDENTIFIER ::= { iso(1) member-body(2)
skipping to change at page 57, line 5 skipping to change at page 59, line 33
-- Definitions of Object Identifier arcs used in this document -- Definitions of Object Identifier arcs used in this document
-- =========================================================== -- ===========================================================
-- The allocation of OIDs to specific objects are given below with the -- The allocation of OIDs to specific objects are given below with the
-- associated ASN.1 syntax definition -- associated ASN.1 syntax definition
-- OID used referencing electronic signature mechanisms based on this -- OID used referencing electronic signature mechanisms based on this
-- standard for use with the IDUP API (see annex D) -- standard for use with the IDUP API (see annex D)
Internet Draft Electronic Signature Formats
id-etsi-es-IDUP-Mechanism-v1 OBJECT IDENTIFIER ::= id-etsi-es-IDUP-Mechanism-v1 OBJECT IDENTIFIER ::=
{ itu-t(0) identified-organization(4) etsi(0) { itu-t(0) identified-organization(4) etsi(0)
electronic-signature-standard (1733) part1 (1) electronic-signature-standard (1733) part1 (1)
idupMechanism (4)etsiESv1(1) } idupMechanism (4)etsiESv1(1) }
-- CMS Attributes Defined in this document -- CMS Attributes Defined in this document
-- ======================================= -- =======================================
-- Mandatory Electronic Signature Attributes -- Mandatory Electronic Signature Attributes
-- OtherSigningCertificate -- OtherSigningCertificate
skipping to change at page 58, line 5 skipping to change at page 60, line 32
id-aa-ets-sigPolicyId OBJECT IDENTIFIER ::= { iso(1) id-aa-ets-sigPolicyId OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
smime(16) id-aa(2) 15 } smime(16) id-aa(2) 15 }
"SignaturePolicy CHOICE { "SignaturePolicy CHOICE {
SignaturePolicyId SignaturePolicyId, SignaturePolicyId SignaturePolicyId,
SignaturePolicyImplied SignaturePolicyImplied SignaturePolicyImplied SignaturePolicyImplied
} }
Internet Draft Electronic Signature Formats
SignaturePolicyId ::= SEQUENCE { SignaturePolicyId ::= SEQUENCE {
sigPolicyIdentifier SigPolicyId, sigPolicyIdentifier SigPolicyId,
sigPolicyHash SigPolicyHash, sigPolicyHash SigPolicyHash,
sigPolicyQualifiers SEQUENCE SIZE (1..MAX) OF sigPolicyQualifiers SEQUENCE SIZE (1..MAX) OF
SigPolicyQualifierInfo OPTIONAL SigPolicyQualifierInfo OPTIONAL
} }
SignaturePolicyImplied ::= NULL SignaturePolicyImplied ::= NULL
SigPolicyId ::= OBJECT IDENTIFIER SigPolicyId ::= OBJECT IDENTIFIER
SigPolicyHash ::= ETSIHashAlgAndValue SigPolicyHash ::= OtherHashAlgAndValue
SigPolicyQualifierInfo ::= SEQUENCE { SigPolicyQualifierInfo ::= SEQUENCE {
sigPolicyQualifierId SIG-POLICY-QUALIFIER.&id sigPolicyQualifierId SIG-POLICY-QUALIFIER.&id
({SupportedSigPolicyQualifiers}), ({SupportedSigPolicyQualifiers}),
qualifier SIG-POLICY-QUALIFIER.&Qualifier qualifier SIG-POLICY-QUALIFIER.&Qualifier
({SupportedSigPolicyQualifiers} ({SupportedSigPolicyQualifiers}
{@sigPolicyQualifierId})OPTIONAL } {@sigPolicyQualifierId})OPTIONAL }
SupportedSigPolicyQualifiers SIG-POLICY-QUALIFIER ::= SupportedSigPolicyQualifiers SIG-POLICY-QUALIFIER ::=
{ noticeToUser | pointerToSigPolSpec } { noticeToUser | pointerToSigPolSpec }
skipping to change at page 59, line 5 skipping to change at page 61, line 30
pointerToSigPolSpec SIG-POLICY-QUALIFIER ::= { pointerToSigPolSpec SIG-POLICY-QUALIFIER ::= {
SIG-POLICY-QUALIFIER-ID id-sqt-uri SIG-QUALIFIER-TYPE SPuri } SIG-POLICY-QUALIFIER-ID id-sqt-uri SIG-QUALIFIER-TYPE SPuri }
id-spq-ets-uri OBJECT IDENTIFIER ::= { iso(1) id-spq-ets-uri OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
smime(16) id-spq(5) 1 } smime(16) id-spq(5) 1 }
SPuri ::= IA5String SPuri ::= IA5String
Internet Draft Electronic Signature Formats
id-spq-ets-unotice OBJECT IDENTIFIER ::= { iso(1) id-spq-ets-unotice OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
smime(16) id-spq(5) 2 } smime(16) id-spq(5) 2 }
SPUserNotice ::= SEQUENCE { SPUserNotice ::= SEQUENCE {
noticeRef NoticeReference OPTIONAL, noticeRef NoticeReference OPTIONAL,
explicitText DisplayText OPTIONAL explicitText DisplayText OPTIONAL
} }
NoticeReference ::= SEQUENCE { NoticeReference ::= SEQUENCE {
skipping to change at page 60, line 5 skipping to change at page 62, line 31
&id OBJECT IDENTIFIER UNIQUE, &id OBJECT IDENTIFIER UNIQUE,
&Qualifier OPTIONAL } &Qualifier OPTIONAL }
WITH SYNTAX { WITH SYNTAX {
COMMITMENT-QUALIFIER-ID &id COMMITMENT-QUALIFIER-ID &id
[COMMITMENT-TYPE &Qualifier] } [COMMITMENT-TYPE &Qualifier] }
id-cti-ets-proofOfOrigin OBJECT IDENTIFIER ::= { iso(1) id-cti-ets-proofOfOrigin OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) cti(6) 1} smime(16) cti(6) 1}
Internet Draft Electronic Signature Formats
id-cti-ets-proofOfReceipt OBJECT IDENTIFIER ::= { iso(1) id-cti-ets-proofOfReceipt OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) cti(6) 2} smime(16) cti(6) 2}
id-cti-ets-proofOfDelivery OBJECT IDENTIFIER ::= { iso(1) id-cti-ets-proofOfDelivery OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) cti(6) 3} smime(16) cti(6) 3}
id-cti-ets-proofOfSender OBJECT IDENTIFIER ::= { iso(1) id-cti-ets-proofOfSender OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
skipping to change at page 61, line 5 skipping to change at page 63, line 31
SignerAttribute ::= SEQUENCE OF CHOICE { SignerAttribute ::= SEQUENCE OF CHOICE {
claimedAttributes [0] ClaimedAttributes, claimedAttributes [0] ClaimedAttributes,
certifiedAttributes [1] CertifiedAttributes } certifiedAttributes [1] CertifiedAttributes }
ClaimedAttributes ::= SEQUENCE OF Attribute ClaimedAttributes ::= SEQUENCE OF Attribute
CertifiedAttributes ::= AttributeCertificate CertifiedAttributes ::= AttributeCertificate
-- As defined in X.509 : see section 10.3 -- As defined in X.509 : see section 10.3
Internet Draft Electronic Signature Formats -- Content Time-Stamp
id-aa-ets-contentTimestamp OBJECT IDENTIFIER ::= { iso(1) id-aa-ets-contentTimestamp OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) id-aa(2) 20} smime(16) id-aa(2) 20}
ContentTimestamp::= TimeStampToken ContentTimestamp::= TimeStampToken
-- Validation Data -- Validation Data
-- Signature Time-Stamp
id-aa-signatureTimeStampToken OBJECT IDENTIFIER ::= { iso(1) id-aa-signatureTimeStampToken OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) id-aa(2) 14} smime(16) id-aa(2) 14}
SignatureTimeStampToken ::= TimeStampToken SignatureTimeStampToken ::= TimeStampToken
-- Complete Certificate Refs. -- Complete Certificate Refs.
id-aa-ets-certificateRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2) id-aa-ets-certificateRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2)
skipping to change at page 61, line 49 skipping to change at page 64, line 25
CrlOcspRef ::= SEQUENCE { CrlOcspRef ::= SEQUENCE {
crlids [0] CRLListID OPTIONAL, crlids [0] CRLListID OPTIONAL,
ocspids [1] OcspListID OPTIONAL, ocspids [1] OcspListID OPTIONAL,
otherRev [2] OtherRevRefs OPTIONAL otherRev [2] OtherRevRefs OPTIONAL
} }
CRLListID ::= SEQUENCE { CRLListID ::= SEQUENCE {
crls SEQUENCE OF CrlValidatedID} crls SEQUENCE OF CrlValidatedID}
CrlValidatedID ::= SEQUENCE { CrlValidatedID ::= SEQUENCE {
crlHash ETSIHash, crlHash OtherHash,
crlIdentifier CrlIdentifier OPTIONAL} crlIdentifier CrlIdentifier OPTIONAL}
CrlIdentifier ::= SEQUENCE { CrlIdentifier ::= SEQUENCE {
crlissuer Name, crlissuer Name,
crlIssuedTime UTCTime, crlIssuedTime UTCTime,
crlNumber INTEGER OPTIONAL crlNumber INTEGER OPTIONAL
} }
Internet Draft Electronic Signature Formats
OcspListID ::= SEQUENCE { OcspListID ::= SEQUENCE {
ocspResponses SEQUENCE OF OcspResponsesID} ocspResponses SEQUENCE OF OcspResponsesID}
OcspResponsesID ::= SEQUENCE { OcspResponsesID ::= SEQUENCE {
ocspIdentifier OcspIdentifier, ocspIdentifier OcspIdentifier,
ocspRepHash ETSIHash OPTIONAL ocspRepHash OtherHash OPTIONAL
} }
OcspIdentifier ::= SEQUENCE { OcspIdentifier ::= SEQUENCE {
ocspResponderID ResponderID, ocspResponderID ResponderID,
-- As in OCSP response data -- As in OCSP response data
producedAt GeneralizedTime producedAt GeneralizedTime
-- As in OCSP response data -- As in OCSP response data
} }
OtherRevRefs ::= SEQUENCE { OtherRevRefs ::= SEQUENCE {
skipping to change at page 63, line 5 skipping to change at page 65, line 35
RevocationValues ::= SEQUENCE { RevocationValues ::= SEQUENCE {
crlVals [0] SEQUENCE OF CertificateList OPTIONAL, crlVals [0] SEQUENCE OF CertificateList OPTIONAL,
ocspVals [1] SEQUENCE OF BasicOCSPResponse OPTIONAL, ocspVals [1] SEQUENCE OF BasicOCSPResponse OPTIONAL,
otherRevVals [2] OtherRevVals } otherRevVals [2] OtherRevVals }
OtherRevVals ::= SEQUENCE { OtherRevVals ::= SEQUENCE {
otherRevValType OTHER-REVOCATION-VAL.&id, otherRevValType OTHER-REVOCATION-VAL.&id,
otherRevVals OTHER-REVOCATION-VAL.&Type otherRevVals OTHER-REVOCATION-VAL.&Type
} }
Internet Draft Electronic Signature Formats
OTHER-REVOCATION-VAL ::= CLASS { OTHER-REVOCATION-VAL ::= CLASS {
&Type, &Type,
&id OBJECT IDENTIFIER UNIQUE } &id OBJECT IDENTIFIER UNIQUE }
WITH SYNTAX { WITH SYNTAX {
&Type ID &id } &Type ID &id }
-- ES-C Time-Stamp
id-aa-ets-escTimeStamp OBJECT IDENTIFIER ::= { iso(1) id-aa-ets-escTimeStamp OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) id-aa(2) 25} smime(16) id-aa(2) 25}
ESCTimeStampToken ::= TimeStampToken ESCTimeStampToken ::= TimeStampToken
-- Time-Stamped Certificates and CRLs -- Time-Stamped Certificates and CRLs
id-aa-ets-certCRLTimestamp OBJECT IDENTIFIER ::= { iso(1) id-aa-ets-certCRLTimestamp OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) id-aa(2) 26} smime(16) id-aa(2) 26}
TimestampedCertsCRLs ::= TimeStampToken TimestampedCertsCRLs ::= TimeStampToken
-- Archive Time-Stamp
id-aa-ets-archiveTimestamp OBJECT IDENTIFIER ::= { iso(1) id-aa-ets-archiveTimestamp OBJECT IDENTIFIER ::= { iso(1)
member-body(2)us(840) rsadsi(113549) pkcs(1) pkcs-9(9) member-body(2)us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) id-aa(2) 27} smime(16) id-aa(2) 27}
ArchiveTimeStampToken ::= TimeStampToken ArchiveTimeStampToken ::= TimeStampToken
END -- ETS-ElectronicSignatureFormats-97Syntax END -- ETS-ElectronicSignatureFormats-97Syntax
Internet Draft Electronic Signature Formats
Annex B (informative): General Description Annex B (informative): General Description
This annex captures the concepts that apply to this document and the This annex captures the concepts that apply to this document and the
rational for the elements of the specification defined using ASN.1 in rational for the elements of the specification defined using ASN.1 in
the main text of this document. the main text of this document.
The specification below includes a description why the component is The specification below includes a description why the component is
needed, with a brief description of the vulnerabilities and threats needed, with a brief description of the vulnerabilities and threats
and the manner by which they are countered. and the manner by which they are countered.
B.1 The Signature Policy B.1 The Signature Policy
The signature policy is a set of rules for the creation and validation The signature policy is a set of rules for the creation and
of an electronic signature, under which the signature can be validation of an electronic signature, under which the signature can
determined to be valid. A given legal/contractual context may be determined to be valid. A given legal/contractual context may
recognize a particular signature policy as meeting its requirements. recognize a particular signature policy as meeting its requirements.
A signature policy may be issued, for example, by a party relying on A signature policy may be issued, for example, by a party relying on
the electronic signatures and selected by the signer for use with that the electronic signatures and selected by the signer for use with
relying party. Alternatively, a signature policy may be established that relying party. Alternatively, a signature policy may be
through an electronic trading association for use amongst its members. established through an electronic trading association for use amongst
Both the signer and verifier use the same signature policy. its members. Both the signer and verifier use the same signature
policy.
The signature policy may be explicitly identified or may be implied by
the semantics of the data being signed and other external data like a
contract being referenced which itself refers to a signature policy.
An explicit signature policy has a globally unique reference, which is The signature policy may be explicitly identified or may be implied
bound to an electronic signature by the signer as part of the signature by the semantics of the data being signed and other external data
calculation. like a contract being referenced which itself refers to a signature
policy.
The signature policy needs to be available in human readable form so An explicit signature policy has a globally unique reference, which
that it can be assessed to meet the requirements of the legal and is bound to an electronic signature by the signer as part of the
contractual context in which it is being applied. To facilitate the signature calculation.
automatic processing of an electronic signature the parts of the
signature policy which specify the electronic rules for the creation
and validation of the electronic signature also needs to be in a
computer processable form.
The signature policy thus includes the following: The signature policy needs to be available in human readable form so
that it can be assessed to meet the requirements of the legal and
contractual context in which it is being applied. To facilitate the
automatic processing of an electronic signature the parts of the
signature policy which specify the electronic rules for the creation
and validation of the electronic signature also needs to be in a
computer processable form.
* Information about the signature policy that can be displayed The signature policy thus includes the following:
to the signer or the verifiers.
* Rules, which apply to functionality, covered by this document
(referred to as the Signature Validation Policy).
* Rules which may be implied through adoption of Certificate
Policies that apply to the electronic signature (e.g. rules for
ensuring the secrecy of the private signing key).
* Rules, which relate to the environment used by the signer,
e.g. the use of an agreed CAD (Card Accepting Device) used
in conjunction with a smart card.
Internet Draft Electronic Signature Formats * Information about the signature policy that can be displayed to
the signer or the verifiers.
* Rules, which apply to functionality, covered by this document
(referred to as the Signature Validation Policy).
* Rules which may be implied through adoption of Certificate
Policies that apply to the electronic signature (e.g., rules
for ensuring the secrecy of the private signing key).
* Rules, which relate to the environment used by the signer,
e.g., the use of an agreed CAD (Card Accepting Device) used in
conjunction with a smart card.
An explicit Signature Validation Policy may be structured so that it An explicit Signature Validation Policy may be structured so that it
can be computer processable. Any format of the signature validation can be computer processable. Any format of the signature validation
policy is allowed by this document. However, for a given explicit policy is allowed by this document. However, for a given explicit
signature policy there must be one definitive form that has a unique signature policy there must be one definitive form that has a unique
binary encoded value. binary encoded value.
The Signature Validation Policy includes rules regarding use of TSPs The Signature Validation Policy includes rules regarding use of TSPs
(CA, Attribute Authorities, Time Stamping Authorities) as well as (CA, Attribute Authorities, Time Stamping Authorities) as well as
rules defining the components of the electronic signature that must be rules defining the components of the electronic signature that must
provided by the signer with data required by the verifier to provide be provided by the signer with data required by the verifier to
long term proof. provide long term proof.
B.2 Signed Information B.2 Signed Information
The information being signed may be defined as a MIME-encapsulated The information being signed may be defined as a MIME-encapsulated
message which can be used to signal the format of the content in order message which can be used to signal the format of the content in
to select the right display or application. It can be composed of order to select the right display or application. It can be composed
formatted text (e.g. EDIFACT), free text or of fields from an of formatted text (e.g., EDIFACT), free text or of fields from an
electronic form (e-form). For example, the Adobe(tm) format "pdf" may electronic form (e-form). For example, the Adobe(tm) format "pdf"
be used or the eXtensible Mark up Language (XML). may be used or the eXtensible Mark up Language (XML).
B.3 Components of an Electronic Signature B.3 Components of an Electronic Signature
B.3.1 Reference to the Signature Policy B.3.1 Reference to the Signature Policy
The definition of electronic signature includes: "a commitment has The definition of electronic signature includes: "a commitment has
been explicitly endorsed under a "Signature policy", at a given time, been explicitly endorsed under a "Signature policy", at a given time,
by a signer under an identifier, e.g. a name or a pseudonym, and by a signer under an identifier, e.g., a name or a pseudonym, and
optionally a role". optionally a role".
When two independent parties want to evaluate an electronic signature,
it is fundamental that they get the same result. To meet this
requirement same signature policy must be used by the signer and
verifier.
The signature policy may be explicitly identified or may be implied by When two independent parties want to evaluate an electronic
the semantics of the data being signed and other external data which signature, it is fundamental that they get the same result. To meet
designate the signature policy to be used. this requirement same signature policy must be used by the signer and
verifier.
By signing over the signature policy identifier the signer explicitly The signature policy may be explicitly identified or may be implied
indicates that he or she has applied the signature policy in creating by the semantics of the data being signed and other external data
the signature. Thus, undertakes any explicit or implied commitments. which designate the signature policy to be used.
In order to unambiguously identify an explicit signature policy that is By signing over the signature policy identifier the signer explicitly
to be used to verify the signature an identifier and hash of the indicates that he or she has applied the signature policy in creating
"Signature policy" shall be part of the signed data. Additional the signature. Thus, undertakes any explicit or implied commitments.
information about the explicit policy (e.g. web reference to the
document) may be carried as "qualifiers" to the signature policy
identifier.
Internet Draft Electronic Signature Formats In order to unambiguously identify an explicit signature policy that
is to be used to verify the signature an identifier and hash of the
"Signature policy" shall be part of the signed data. Additional
information about the explicit policy (e.g., web reference to the
document) may be carried as "qualifiers" to the signature policy
identifier.
When the signature policy not explicitly identified, but is implied by When the signature policy not explicitly identified, but is implied
the semantics of the data being signed, then the signature will include by the semantics of the data being signed, then the signature will
a signature policy identifier that indicates that the signature policy include a signature policy identifier that indicates that the
is implied. In this case the verification rules must be determined by signature policy is implied. In this case the verification rules
using other external data which will designate the signature policy to must be determined by using other external data which will designate
be used. If it may be determined from the context that all the the signature policy to be used. If it may be determined from the
documents to be verified refer to the same signature policy, then that context that all the documents to be verified refer to the same
policy may be predetermined or fixed within the application. signature policy, then that policy may be predetermined or fixed
within the application.
In order to identify unambiguously the "Signature Validation Policy" In order to identify unambiguously the "Signature Validation Policy"
to be used to verify the signature an identifier and hash of the to be used to verify the signature an identifier and hash of the
"Signature policy" must be part of the signed data. Additional "Signature policy" must be part of the signed data. Additional
information about the policy (e.g. web reference to the document) may information about the policy (e.g., web reference to the document)
be carried as "qualifiers" to the signature policy identifier. may be carried as "qualifiers" to the signature policy identifier.
B.3.2 Commitment Type Indication B.3.2 Commitment Type Indication
The definition of electronic signature includes: "a commitment has The definition of electronic signature includes: "a commitment has
been explicitly endorsed under a signature policy, at a given time, been explicitly endorsed under a signature policy, at a given time,
by a signer under an identifier, e.g. a name or a pseudonym, and by a signer under an identifier, e.g., a name or a pseudonym, and
optionally a role". optionally a role".
The commitment type can be indicated in the electronic signature
either:
* explicitly using a "commitment type indication" in the The commitment type can be indicated in the electronic signature
electronic signature; either:
* implicitly or explicitly from the semantics of the signed data. * explicitly using a "commitment type indication" in the
electronic signature;
If the indicated commitment type is explicit using a "commitment type * implicitly or explicitly from the semantics of the signed data.
indication" in the electronic signature, acceptance of a verified
signature implies acceptance of the semantics of that commitment type.
The semantics of explicit commitment types indications must be
specified either as part of the signature policy or may be registered
for generic use across multiple policies.
If a signature includes a commitment type indication other than one of If the indicated commitment type is explicit using a "commitment type
those recognized under the signature policy the signature must be indication" in the electronic signature, acceptance of a verified
treated as invalid. signature implies acceptance of the semantics of that commitment
type. The semantics of explicit commitment types indications must be
specified either as part of the signature policy or may be registered
for generic use across multiple policies.
How commitment is indicated using the semantics of the data being If a signature includes a commitment type indication other than one
signed is outside the scope of this document. of those recognized under the signature policy the signature must be
treated as invalid.
NOTE: Examples of commitment indicated through the semantics of the How commitment is indicated using the semantics of the data being
data being signed, are: signed is outside the scope of this document.
* An explicit commitment made by the signer indicated by the type NOTE: Examples of commitment indicated through the semantics of the
of data being signed over. Thus, the data structure being data being signed, are:
signed can have an explicit commitment within the context of
the application (e.g. EDIFACT purchase order).
Internet Draft Electronic Signature Formats * An explicit commitment made by the signer indicated by the type
of data being signed over. Thus, the data structure being
signed can have an explicit commitment within the context of
the application (e.g., EDIFACT purchase order).
* An implicit commitment which is a commitment made by the signer * An implicit commitment which is a commitment made by the signer
because the data being signed over has specific semantics because the data being signed over has specific semantics
(meaning) which is only interpretable by humans, (i.e. free (meaning) which is only interpretable by humans, (i.e., free
text). text).
B.3.3 Certificate Identifier from the Signer B.3.3 Certificate Identifier from the Signer
The definition of the ETSI electronic signature includes: "a The definition of the ETSI electronic signature includes: "a
commitment has been explicitly endorsed under a signature policy, commitment has been explicitly endorsed under a signature policy, at
at a given time, by a signer under an identifier, e.g. a name or a a given time, by a signer under an identifier, e.g., a name or a
pseudonym, and optionally a role." pseudonym, and optionally a role."
In many real life environments users will be able to get from
In many real life environments users will be able to get from different CAs or even from the same CA, different certificates
different CAs or even from the same CA, different certificates containing the same public key for different names. The prime
containing the same public key for different names. The prime advantage is that a user can use the same private key for different
advantage is that a user can use the same private key for different purposes. Multiple use of the private key is an advantage when a
purposes. Multiple use of the private key is an advantage when a smart smart card is used to protect the private key, since the storage of a
card is used to protect the private key, since the storage of a smart smart card is always limited. When several CAs are involved, each
card is always limited. When several CAs are involved, each different different certificate may contain a different identity, e.g., as a
certificate may contain a different identity, e.g. as a national or as national or as an employee from a company. Thus when a private key
an employee from a company. Thus when a private key is used for is used for various purposes, the certificate is needed to clarify
various purposes, the certificate is needed to clarify the context in the context in which the private key was used when generating the
which the private key was used when generating the signature. Where signature. Where there is the possibility of multiple use of private
there is the possibility of multiple use of private keys it is keys it is necessary for the signer to indicate to the verifier the
necessary for the signer to indicate to the verifier the precise precise certificate to be used.
certificate to be used.
Many current schemes simply add the certificate after the signed data
and thus are subject to various substitution attacks. An example of a
substitution attack is a "bad" CA that would issue a certificate to
someone with the public key of someone else. If the certificate from
the signer was simply appended to the signature and thus not protected
by the signature, any one could substitute one certificate by another
and the message would appear to be signed by some one else.
In order to counter this kind of attack, the identifier of the signer Many current schemes simply add the certificate after the signed data
has to be protected by the digital signature from the signer. and thus are subject to various substitution attacks. An example of
a substitution attack is a "bad" CA that would issue a certificate to
someone with the public key of someone else. If the certificate from
the signer was simply appended to the signature and thus not
protected by the signature, any one could substitute one certificate
by another and the message would appear to be signed by some one
else.
Although it does not provide the same advantages as the previous In order to counter this kind of attack, the identifier of the signer
technique, another technique to counter that threat has been has to be protected by the digital signature from the signer.
identified. It requires all CAs to perform a Proof Of Possession of
the private key at the time of registration. The problem with that
technique is that it does not provide any guarantee at the time of
verification and only some proof "after the event" may be obtained, if
and only if the CA keeps the Proof Of Possession in audit trail.
In order to identify unambiguously the certificate to be used for the Although it does not provide the same advantages as the previous
verification of the signature an identifier of the certificate from technique, another technique to counter that threat has been
the signer must be part of the signed data. identified. It requires all CAs to perform a Proof Of Possession of
the private key at the time of registration. The problem with that
technique is that it does not provide any guarantee at the time of
verification and only some proof "after the event" may be obtained,
if and only if the CA keeps the Proof Of Possession in audit trail.
Internet Draft Electronic Signature Formats In order to identify unambiguously the certificate to be used for the
verification of the signature an identifier of the certificate from
the signer must be part of the signed data.
B.3.4 Role Attributes B.3.4 Role Attributes
The definition of electronic signature includes: "a commitment has The definition of electronic signature includes: "a commitment has
been explicitly endorsed under a non repudiation security policy, been explicitly endorsed under a non repudiation security policy, at
at a given time, by a signer under an identifier, e.g. a name or a a given time, by a signer under an identifier, e.g., a name or a
pseudonym, and optionally a role. " pseudonym, and optionally a role."
While the name of the signer is important, the position of the signer
While the name of the signer is important, the position of the signer within a company or an organization can be even more important. Some
within a company or an organization can be even more important. Some contracts may only be valid if signed by a user in a particular role,
contracts may only be valid if signed by a user in a particular role, e.g., a Sales Director. In many cases whom the sales Director really
e.g. a Sales Director. In many cases whom the sales Director really is, is not that important but being sure that the signer is empowered
is, is not that important but being sure that the signer is empowered by his company to be the Sales Director is fundamental.
by his company to be the Sales Director is fundamental.
This document defines two different ways for providing this feature:
* by placing a claimed role name in the CMS signed This document defines two different ways for providing this feature:
attributes field;
* by placing a attribute certificate containing a certified * by placing a claimed role name in the CMS signed attributes
role name in the CMS signed attributes field. field;
NOTE: Another possible approach would have been to use additional * by placing a attribute certificate containing a certified role
attributes containing the roles name(s) in the signer's certificate. name in the CMS signed attributes field.
However, it was decided not to follow this approach as it breaks the
basic philosophy of the certificate being issued for one primary
purpose. Also, by using separate certificates for management of the
signer's identity certificate and management of additional roles can
simplify the management, as new identity keys need not be issued if a
use of role is to be changed.
B.3.5.1 Claimed Role NOTE: Another possible approach would have been to use additional
attributes containing the roles name(s) in the signer's certificate.
However, it was decided not to follow this approach as it breaks the
basic philosophy of the certificate being issued for one primary
purpose. Also, by using separate certificates for management of the
signer's identity certificate and management of additional roles can
simplify the management, as new identity keys need not be issued if a
use of role is to be changed.
The signer may be trusted to state his own role without any B.3.4.1 Claimed Role
certificate to corroborate this claim. In which case the claimed role
can be added to the signature as a signed attribute.
B.3.5.2 Certified Role The signer may be trusted to state his own role without any
certificate to corroborate this claim. In which case the claimed
role can be added to the signature as a signed attribute.
Unlike public key certificates that bind an identifier to a public B.3.4.2 Certified Role
key, Attribute Certificates bind the identifier of a certificate to
some attributes, like a role. An Attribute Certificate is NOT issued
by a CA but by an Attribute Authority (AA). The Attribute Authority
will be most of the time under the control of an organization or a
company that is best placed to know which attributes are relevant for
which individual.
Internet Draft Electronic Signature Formats Unlike public key certificates that bind an identifier to a public
key, Attribute Certificates bind the identifier of a certificate to
some attributes, like a role. An Attribute Certificate is NOT issued
by a CA but by an Attribute Authority (AA). The Attribute Authority
will be most of the time under the control of an organization or a
company that is best placed to know which attributes are relevant for
which individual.
The Attribute Authority may use or point to public key certificates The Attribute Authority may use or point to public key certificates
issued by any CA, provided that the appropriate trust may be placed issued by any CA, provided that the appropriate trust may be placed
in that CA. Attribute Certificates may have various periods of in that CA. Attribute Certificates may have various periods of
validity. That period may be quite short, e.g. one day. While this validity. That period may be quite short, e.g., one day. While this
requires that a new Attribute Certificate is obtained every day, valid requires that a new Attribute Certificate is obtained every day,
for that day, this can be advantageous since revocation of such valid for that day, this can be advantageous since revocation of such
certificates may not be needed. When signing, the signer will have to certificates may not be needed. When signing, the signer will have
specify which Attribute Certificate it selects. In order to do to specify which Attribute Certificate it selects. In order to do
so, a reference to the Attribute Certificate will have to be included so, a reference to the Attribute Certificate will have to be included
in the signed data in order to be protected by the digital signature in the signed data in order to be protected by the digital signature
from the signer. from the signer.
In order to identify unambiguously the attribute certificate(s) to be In order to identify unambiguously the attribute certificate(s) to be
used for the verification of the signature an identifier of the used for the verification of the signature an identifier of the
attribute certificate(s) from the signer must be part of the signed attribute certificate(s) from the signer must be part of the signed
data. data.
B.3.5 Signer Location B.3.5 Signer Location
In some transactions the purported location of the signer at the time In some transactions the purported location of the signer at the time
he or she applies his signature may need to be indicated. For this he or she applies his signature may need to be indicated. For this
reason an optional location indicator must be able to be included. reason an optional location indicator must be able to be included.
In order to provide indication of the location of the signer at the In order to provide indication of the location of the signer at the
time he or she applied his signature a location attribute may be time he or she applied his signature a location attribute may be
included in the signature. included in the signature.
B.3.6 Signing Time B.3.6 Signing Time
The definition of electronic signature includes: "a commitment has The definition of electronic signature includes: "a commitment has
been explicitly endorsed under a signature policy, at a given time, been explicitly endorsed under a signature policy, at a given time,
by a signer under an identifier, e.g. a name or a pseudonym, and by a signer under an identifier, e.g., a name or a pseudonym, and
optionally a optionally a role."
role. "
There are several ways to address this problem. The solution adopted
in this document is to sign over a time which the signer claims is the
signing time (i.e. claimed signing time) and to require a trusted
time stamp to be obtained when building a ES with Timestamp. When a
verifier accepts a signature, the two times must be within acceptable
limits.
The solution that is adopted in this document offers the major There are several ways to address this problem. The solution adopted
advantage that electronic signatures can be generated without any on- in this document is to sign over a time which the signer claims is
line connection to a trusted time source (i.e. they may be generated the signing time (i.e., claimed signing time) and to require a
off-line). trusted time stamp to be obtained when building a ES with Time-Stamp.
When a verifier accepts a signature, the two times must be within
acceptable limits.
Thus two dates and two signatures are required: The solution that is adopted in this document offers the major
advantage that electronic signatures can be generated without any
on-line connection to a trusted time source (i.e., they may be
generated off-line).
* a signing time indicated by the signer and which is part of Thus two dates and two signatures are required:
the data signed by the signer (i.e. part of the basic
electronic signature);
Internet Draft Electronic Signature Formats * a signing time indicated by the signer and which is part of the
data signed by the signer (i.e., part of the basic electronic
signature);
* a time indicated by a TimeStamping Authority (TSA) which is * a time indicated by a Time-Stamping Authority (TSA) which is
signed over the digital signature value of the basic electronic signed over the digital signature value of the basic electronic
signature. The signer, verifier or both may obtain the TSA signature. The signer, verifier or both may obtain the TSA
timestamp. time-stamp.
In order for an electronic signature to be valid under a signature In order for an electronic signature to be valid under a signature
policy, it must be timestamped by a TSA where the signing time as policy, it must be time-stamped by a TSA where the signing time as
indicated by the signer and the time of time stamping as indicated by indicated by the signer and the time of time stamping as indicated by
a TSA must be "close enough" to meet the requirements of the signature a TSA must be "close enough" to meet the requirements of the
validation policy. signature validation policy.
"Close enough" means a few minutes, hours or even days according to "Close enough" means a few minutes, hours or even days according to
the "Signature Validation Policy". the "Signature Validation Policy".
NOTE: The need for Timestamping is further explained in section B.4.5. NOTE: The need for Time-Stamping is further explained in clause
A further optional attribute is defined in this document to timestamp B.4.5. A further optional attribute is defined in this document to
the content, to provide proof of the existence of the content, at the time-stamp the content, to provide proof of the existence of the
time indicated by the timestamp. content, at the time indicated by the time-stamp.
Using this optional attribute a trusted secure time may be obtained Using this optional attribute a trusted secure time may be obtained
before the document is signed and included under the digital signature. before the document is signed and included under the digital
This solution requires an on-line connection to a trusted timestamping signature. This solution requires an on-line connection to a trusted
service before generating the signature and may not represent the time-stamping service before generating the signature and may not
precise signing time, since it can be obtained in advance. However, represent the precise signing time, since it can be obtained in
this optional attribute may be used by the signer to prove that the advance. However, this optional attribute may be used by the signer
signed object existed before the date included in the timestamp (see to prove that the signed object existed before the date included in
3.12.3, Content Timestamp). the time-stamp (see 3.12.3, Content Time-Stamp).
Also, the signing time should be between the time indicated by this Also, the signing time should be between the time indicated by this
timestamp and time indicated by the ES-T timestamp. time-stamp and time indicated by the ES-T time-stamp.
B.3.7 Content Format B.3.7 Content Format
When presenting signed data to a human user it may be important that When presenting signed data to a human user it may be important that
there is no ambiguity as to the presentation of the signed information there is no ambiguity as to the presentation of the signed
to the relying party. In order for the appropriate representation information to the relying party. In order for the appropriate
(text, sound or video) to be selected by the relying party a content representation (text, sound or video) to be selected by the relying
hint may be indicated by the signer. If a relying party system does not party a content hint may be indicated by the signer. If a relying
use the format specified in the content hints to present the data to party system does not use the format specified in the content hints
the relying party, the electronic signature may not be valid. to present the data to the relying party, the electronic signature
may not be valid.
B.4 Components of Validation Data B.4 Components of Validation Data
B.4.1 Revocation Status Information B.4.1 Revocation Status Information
A verifier will have to prove that the certificate of the signer was A verifier will have to prove that the certificate of the signer was
valid at the time of the signature. This can be done by either: valid at the time of the signature. This can be done by either:
* using Certificate Revocation Lists (CRLs);
* using responses from an on-line certificate status server * using Certificate Revocation Lists (CRLs);
(for example; obtained through the OCSP protocol).
Internet Draft Electronic Signature Formats * using responses from an on-line certificate status server (for
example; obtained through the OCSP protocol).
B.4.2 CRL Information B.4.2 CRL Information
When using CRLs to get revocation information, a verifier will have to When using CRLs to get revocation information, a verifier will have
make sure that he or she gets at the time of the first verification the to make sure that he or she gets at the time of the first
appropriate certificate revocation information from the signer's CA. verification the appropriate certificate revocation information from
This should be done as soon as possible to minimize the time delay the signer's CA. This should be done as soon as possible to minimize
between the generation and verification of the signature. This involves the time delay between the generation and verification of the
checking that the signer certificate serial number is not included in signature. This involves checking that the signer certificate serial
the CRL. The signer, the verifier or any other third party may obtain number is not included in the CRL. The signer, the verifier or any
either this CRL. If obtained by the signer, then it must be conveyed other third party may obtain either this CRL. If obtained by the
to the verifier. It may be convenient to archive the CRL for ease of signer, then it must be conveyed to the verifier. It may be
subsequent verification or arbitration. convenient to archive the CRL for ease of subsequent verification or
arbitration.
Alternatively, provided the CRL is archived elsewhere which is
accessible for the purpose of arbitration, then the serial number of
the CRL used may be archived together with the verified electronic
signature.
It may happen that the certificate serial number appears in the CRL Alternatively, provided the CRL is archived elsewhere which is
but with the status "suspended" (i.e. on hold). In such a case, the accessible for the purpose of arbitration, then the serial number of
electronic signature is not yet valid, since it is not possible to the CRL used may be archived together with the verified electronic
know whether the certificate will or will not be revoked at the end signature.
of the suspension period. If a decision has to be taken immediately
then the signature has to be considered as invalid. If a decision can
wait until the end of the suspension period, then two cases are
possible:
* the certificate serial number has disappeared from the list It may happen that the certificate serial number appears in the CRL
and thus the certificate can be considered as valid and that but with the status "suspended" (i.e., on hold). In such a case, the
CRL must be captured and archived either by the verifier or electronic signature is not yet valid, since it is not possible to
elsewhere and be kept accessible for the purpose of arbitration. know whether the certificate will or will not be revoked at the end
of the suspension period. If a decision has to be taken immediately
then the signature has to be considered as invalid. If a decision
can wait until the end of the suspension period, then two cases are
possible:
* the certificate serial number has been maintained on the list * the certificate serial number has disappeared from the list and
with the status definitively revoked and thus the electronic thus the certificate can be considered as valid and that CRL
signature must be considered as invalid and discarded. must be captured and archived either by the verifier or
elsewhere and be kept accessible for the purpose of
arbitration.
At this point the verifier may be convinced that he or she got a valid * the certificate serial number has been maintained on the list
signature, but is not yet in a position to prove at a later time that with the status definitively revoked and thus the electronic
the signature was verified as valid. Before addressing this point, an signature must be considered as invalid and discarded.
alternative to CRL is to use OCSP responses.
Internet Draft Electronic Signature Formats At this point the verifier may be convinced that he or she got a
valid signature, but is not yet in a position to prove at a later
time that the signature was verified as valid. Before addressing
this point, an alternative to CRL is to use OCSP responses.
B.4.3 OCSP Information B.4.3 OCSP Information
When using OCSP to get revocation information , a verifier will have When using OCSP to get revocation information , a verifier will have
to make sure that he or she gets at the time of the first verification to make sure that he or she gets at the time of the first
an OCSP response that contains the status "valid". This should be done verification an OCSP response that contains the status "valid". This
as soon as possible after the generation of the signature. The signer, should be done as soon as possible after the generation of the
the verifier or any other third party may fetch this OCSP response. signature. The signer, the verifier or any other third party may
Since OSCP responses are transient and thus are not archived by any fetch this OCSP response. Since OSCP responses are transient and thus
TSP including CA, it is the responsibility of every verifier to make are not archived by any TSP including CA, it is the responsibility of
sure that it is stored in a safe place. The simplest way is to store every verifier to make sure that it is stored in a safe place. The
them associated with the electronic signature. An alternative would be simplest way is to store them associated with the electronic
to store them in some storage so that they can then be easily signature. An alternative would be to store them in some storage so
retrieved. that they can then be easily retrieved.
In the same way as for the case of the CRL, it may happen that the In the same way as for the case of the CRL, it may happen that the
certificate is declared as invalid but with the secondary status certificate is declared as invalid but with the secondary status
"suspended". "suspended".
In such a case, the electronic signature is not yet valid, since it is In such a case, the electronic signature is not yet valid, since it
not possible to know whether the certificate will or will not be is not possible to know whether the certificate will or will not be
revoked at the end of the suspension period. If a decision has to be revoked at the end of the suspension period. If a decision has to be
taken immediately then the electronic signature has to be considered taken immediately then the electronic signature has to be considered
as invalid. If a decision can wait until the end of the suspension as invalid. If a decision can wait until the end of the suspension
period, then two cases are possible: period, then two cases are possible:
* An OCSP response with a valid status is obtained at a later * An OCSP response with a valid status is obtained at a later
date and thus the certificate can be considered as valid and date and thus the certificate can be considered as valid and
that OCSP response must be captured. that OCSP response must be captured.
* An OCSP response with an invalid status is obtained with a * An OCSP response with an invalid status is obtained with a
secondary status indicating that the certificate is secondary status indicating that the certificate is
definitively revoked and thus the electronic signature must be definitively revoked and thus the electronic signature must be
considered as invalid and discarded. considered as invalid and discarded.
As in the CRL case, at this point, the verifier may be convinced that As in the CRL case, at this point, the verifier may be convinced that
he or she got a valid signature, but is not yet in a position to prove he or she got a valid signature, but is not yet in a position to
at a later time that the signature was verified as valid. prove at a later time that the signature was verified as valid.
B.4.4 Certification Path B.4.4 Certification Path
A verifier will have to prove that the certification path was valid, A verifier will have to prove that the certification path was valid,
at the time of the signature, up to a trust point according to the at the time of the signature, up to a trust point according to the
naming constraints and the certificate policy constraints from the naming constraints and the certificate policy constraints from the
"Signature Validation Policy". It will be necessary to capture all the "Signature Validation Policy". It will be necessary to capture all
certificates from the certification path, starting with those from the the certificates from the certification path, starting with those
signer and ending up with those of the self-signed certificate from from the signer and ending up with those of the self-signed
one trusted root of the "Signature Validation Policy". In addition, it certificate from one trusted root of the "Signature Validation
will be necessary to capture the Authority Revocation Lists (ARLs) to Policy". In addition, it will be necessary to capture the Authority
prove than none of the CAs from the chain was revoked at the time of Revocation Lists (ARLs) to prove than none of the CAs from the chain
the signature. was revoked at the time of the signature.
Internet Draft Electronic Signature Formats
As in the OCSP case, at this point, the verifier may be convinced that
he or she got a valid signature, but is not yet in a position to prove
at a later time that the signature was verified as valid.
B.4.5 Timestamping for Long Life of Signature
An important property for long standing signatures is that a
signature, having been found once to be valid, must continue to be so
months or years later.
A signer, verifier or both may be required to provide on request,
proof that a digital signature was created or verified during the
validity period of the all the certificates that make up the
certificate path. In this case, the signer, verifier or both will
also be required to provide proof that all the user and CA
certificates used were not revoked when the signature was created
or verified.
It would be quite unacceptable, to consider a signature as invalid As in the OCSP case, at this point, the verifier may be convinced
even if the keys or certificates were later compromised. Thus there that he or she got a valid signature, but is not yet in a position to
is a need to be able to demonstrate that the signature keys was valid prove at a later time that the signature was verified as valid.
around the time that the signature was created to provide long term
evidence of the validity of a signature.
It could be the case that a certificate was valid at the time of the B.4.5 Time-Stamping for Long Life of Signature
signature but revoked some time later. In this event, evidence must be
provided that the document was signed before the signing key was
revoked.
Timestamping by a Time Stamping Authority (TSA) can provide such An important property for long standing signatures is that a
evidence. A time stamp is obtained by sending the hash value of the signature, having been found once to be valid, must continue to be so
given data to the TSA. The returned "timestamp" is a signed document months or years later.
that contains the hash value, the identity of the TSA, and the time of
stamping. This proves that the given data existed before the time of
stamping. Timestamping a digital signature (by sending a hash of the
signature to the TSA) before the revocation of the signer's private
key, provides evidence that the signature has been created before the
key was revoked.
If a recipient wants to hold a valid electronic signature he will have A signer, verifier or both may be required to provide on request,
to ensure that he has obtained a valid time stamp for it, before that proof that a digital signature was created or verified during the
key (and any key involved in the validation) is revoked. The sooner validity period of the all the certificates that make up the
the timestamp is obtained after the signing time, the better. certificate path. In this case, the signer, verifier or both will
also be required to provide proof that all the user and CA
certificates used were not revoked when the signature was created or
verified.
It is important to note that signatures may be generated "off-line" It would be quite unacceptable, to consider a signature as invalid
and time-stamped at a later time by anyone, for example by the signer even if the keys or certificates were later compromised. Thus there
or any recipient interested in the value of the signature. The time is a need to be able to demonstrate that the signature keys was valid
stamp can thus be provided by the signer together with the signed around the time that the signature was created to provide long term
document, or obtained by the recipient following receipt of the signed evidence of the validity of a signature.
document.
Internet Draft Electronic Signature Formats It could be the case that a certificate was valid at the time of the
signature but revoked some time later. In this event, evidence must
be provided that the document was signed before the signing key was
revoked.
The time stamp is NOT a component of the Electronic Signature, but the Time-Stamping by a Time Stamping Authority (TSA) can provide such
essential component of the ES with Timestamp. evidence. A time stamp is obtained by sending the hash value of the
given data to the TSA. The returned "time-stamp" is a signed
document that contains the hash value, the identity of the TSA, and
the time of stamping. This proves that the given data existed before
the time of stamping. Time-Stamping a digital signature (by sending
a hash of the signature to the TSA) before the revocation of the
signer's private key, provides evidence that the signature has been
created before the key was revoked.
It is required in this document that signer's digital signature value If a recipient wants to hold a valid electronic signature he will
is timestamped by a trusted source, known as a TimeStamping Authority. have to ensure that he has obtained a valid time stamp for it, before
that key (and any key involved in the validation) is revoked. The
sooner the time-stamp is obtained after the signing time, the better.
This document requires that the signer's digital signature value is It is important to note that signatures may be generated "off-line"
timestamped by a trusted source before the electronic signature can and time-stamped at a later time by anyone, for example by the signer
become a ES with Complete validation data (ES-C). The acceptable TSAs or any recipient interested in the value of the signature. The time
are specified in the Signature Validation Policy. stamp can thus be provided by the signer together with the signed
document, or obtained by the recipient following receipt of the
signed document.
Should both the signer and verifier be required to timestamp the The time stamp is NOT a component of the Electronic Signature, but
signature value to meet the requirements of the signature policy, the the essential component of the ES with Time-Stamp.
signature policy MAY specify a permitted time delay between the two
time stamps.
B.4.6 Timestamping before CA Key Compromises It is required in this document that signer's digital signature value
is time-stamped by a trusted source, known as a Time-Stamping
Authority.
Timestamped extended electronic signatures are needed when there is a This document requires that the signer's digital signature value is
requirement to safeguard against the possibility of a CA key in the time-stamped by a trusted source before the electronic signature can
certificate chain ever being compromised. A verifier may be required become a ES with Complete validation data (ES-C). The acceptable
to provide on request, proof that the certification path and the TSAs are specified in the Signature Validation Policy.
revocation information used a the time of the signature were valid,
even in the case where one of the issuing keys or OCSP responder keys
is later compromised.
The current document defines two ways of using timestamps to protect Should both the signer and verifier be required to time-stamp the
against this compromise: signature value to meet the requirements of the signature policy, the
signature policy MAY specify a permitted time delay between the two
time stamps.
* Timestamp the ES with Complete validation data, when an OCSP B.4.6 Time-Stamping before CA Key Compromises
response is used to get the status of the certificate from the
signer.
* Timestamp only the certification path and revocation information Time-Stamped extended electronic signatures are needed when there is
references when a CRL is used to get the status of the a requirement to safeguard against the possibility of a CA key in the
certificate from the signer. certificate chain ever being compromised. A verifier may be required
to provide on request, proof that the certification path and the
revocation information used a the time of the signature were valid,
even in the case where one of the issuing keys or OCSP responder keys
is later compromised.
NOTE: the signer, verifier or both may obtain the timestamp. The current document defines two ways of using time-stamps to protect
against this compromise:
Internet Draft Electronic Signature Formats * Time-Stamp the ES with Complete validation data, when an OCSP
response is used to get the status of the certificate from the
signer.
B.4.6.1 Timestamping the ES with Complete validation data * Time-Stamp only the certification path and revocation
information references when a CRL is used to get the status of
the certificate from the signer.
When an OCSP response is used, it is necessary to time stamp in NOTE: the signer, verifier or both may obtain the time-stamp.
particular that response in the case the key from the responder would
be compromised. Since the information contained in the OCSP response
is user specific and time specific, an individual time stamp is needed
for every signature received. Instead of placing the time stamp only
over the certification path references and the revocation information
references, which include the OCSP response, the time stamp is placed
on the ES-C. Since the certification path and revocation information
references are included in the ES with Complete validation data they
are also protected. For the same cryptographic price, this provides an
integrity mechanism over the ES with Complete validation data. Any
modification can be immediately detected. It should be noticed that
other means of protecting/detecting the integrity of the ES with
Complete Validation Data exist and could be used.
Although the technique requires a time stamp for every signature, it B.4.6.1 Time-Stamping the ES with Complete validation data
is well suited for individual users wishing to have an integrity
protected copy of all the validated signatures they have received.
By timestamping the complete electronic signature, including the When an OCSP response is used, it is necessary to time stamp in
digital signature as well as the references to the certificates and particular that response in the case the key from the responder would
revocation status information used to support validation of that be compromised. Since the information contained in the OCSP response
signature, the timestamp ensures that there is no ambiguity in the is user specific and time specific, an individual time stamp is
means of validating that signature. needed for every signature received. Instead of placing the time
stamp only over the certification path references and the revocation
information references, which include the OCSP response, the time
stamp is placed on the ES-C. Since the certification path and
revocation information references are included in the ES with
Complete validation data they are also protected. For the same
cryptographic price, this provides an integrity mechanism over the ES
with Complete validation data. Any modification can be immediately
detected. It should be noticed that other means of
protecting/detecting the integrity of the ES with Complete Validation
Data exist and could be used.
This technique is referred to as ES with eXtended validation data Although the technique requires a time stamp for every signature, it
(ES-X), type 1 Timestamped in this document. is well suited for individual users wishing to have an integrity
protected copy of all the validated signatures they have received.
NOTE: Trust is achieved in the references by including a hash of the By time-stamping the complete electronic signature, including the
data being referenced. digital signature as well as the references to the certificates and
revocation status information used to support validation of that
signature, the time-stamp ensures that there is no ambiguity in the
means of validating that signature.
If it is desired for any reason to keep a copy of the additional data This technique is referred to as ES with eXtended validation data
being referenced, the additional data may be attached to the (ES-X), type 1 Time-Stamped in this document.
electronic signature, in which case the electronic signature becomes
a ES-X Long as defined by this document.
A ES-X Long Timestamped is simply the concatenation of a ES-X NOTE: Trust is achieved in the references by including a hash of the
Timestamped with a copy of the additional data being referenced. data being referenced.
B.4.6.2 Timestamping Certificates and Revocation Information If it is desired for any reason to keep a copy of the additional data
being referenced, the additional data may be attached to the
electronic signature, in which case the electronic signature becomes
a ES-X Long as defined by this document.
References Timestamping each ES with Complete validation data as A ES-X Long Time-Stamped is simply the concatenation of a ES-X Time-
defined above may not be efficient, particularly when the same set of Stamped with a copy of the additional data being referenced.
CA certificates and CRL information is used to validate many
signatures.
Internet Draft Electronic Signature Formats B.4.6.2 Time-Stamping Certificates and Revocation Information
Timestamping CA certificates will stop any attacker from issuing bogus References Time-Stamping each ES with Complete validation data as
CA certificates that could be claimed to existing before the CA key defined above may not be efficient, particularly when the same set of
was compromised. Any bogus timestamped CA certificates will show that CA certificates and CRL information is used to validate many
the certificate was created after the legitimate CA key was signatures.
compromised. In the same way, timestamping CA CRLs, will stop any
attacker from issuing bogus CA CRLs which could be claimed to existing
before the CA key was compromised.
Timestamping of commonly used certificates and CRLs can be done Time-Stamping CA certificates will stop any attacker from issuing
centrally, e.g. inside a company or by a service provider. This method bogus CA certificates that could be claimed to existing before the CA
reduces the amount of data the verifier has to timestamp, for example key was compromised. Any bogus time-stamped CA certificates will
it could reduce to just one time stamp per day (i.e. in the case were show that the certificate was created after the legitimate CA key was
all the signers use the same CA and the CRL applies for the whole day). compromised. In the same way, time-stamping CA CRLs, will stop any
The information that needs to be time stamped is not the actual attacker from issuing bogus CA CRLs which could be claimed to
certificates and CRLs but the unambiguous references to those existing before the CA key was compromised.
certificates and CRLs.
To comply with extended validation data, type 2 Timestamped, this Time-Stamping of commonly used certificates and CRLs can be done
document requires the following: centrally, e.g., inside a company or by a service provider. This
method reduces the amount of data the verifier has to time-stamp, for
example it could reduce to just one time stamp per day (i.e., in the
case were all the signers use the same CA and the CRL applies for the
whole day). The information that needs to be time stamped is not the
actual certificates and CRLs but the unambiguous references to those
certificates and CRLs.
* All the CA certificates references and revocation information To comply with extended validation data, type 2 Time-stamped, this
references (i.e. CRLs) used in validating the ES-C are covered document requires the following:
by one or more timestamp.
Thus a ES-C with a timestamp signature value at time T1, can be proved * All the CA certificates references and revocation information
valid if all the CA and CRL references are timestamped at time T1+. references (i.e., CRLs) used in validating the ES-C are covered
by one or more time-stamp.
B.4.7 Timestamping for Long Life of Signature Thus a ES-C with a time-stamp signature value at time T1, can be
proved valid if all the CA and CRL references are time-stamped at
time T1+.
Advances in computing increase the probability of being able to break B.4.7 Time-Stamping for Long Life of Signature
algorithms and compromise keys. There is therefore a requirement to be
able to protect electronic signatures against this probability.
Over a period of time weaknesses may occur in the cryptographic Advances in computing increase the probability of being able to break
algorithms used to create an electronic signature (e.g. due to the algorithms and compromise keys. There is therefore a requirement to
time available for cryptoanalysis, or improvements in cryptoanalytical be able to protect electronic signatures against this probability.
techniques). Before this such weaknesses become likely, a verifier
should take extra measures to maintain the validity of the electronic
signature. Several techniques could be used to achieve this goal
depending on the nature of the weakened cryptography. In order to
simplify, a single technique, called Archive validation data, covering
all the cases is being used in this document.
Archive validation data consists of the Complete validation data and Over a period of time weaknesses may occur in the cryptographic
the complete certificate and revocation data, time stamped together algorithms used to create an electronic signature (e.g., due to the
with the electronic signature. The Archive validation data is time available for cryptoanalysis, or improvements in
necessary if the hash function and the crypto algorithms that were cryptoanalytical techniques). Before this such weaknesses become
used to create the signature are no longer secure. Also, if it cannot likely, a verifier should take extra measures to maintain the
be assumed that the hash function used by the Time Stamping Authority validity of the electronic signature. Several techniques could be
is secure, then nested timestamps of Archived Electronic Signature are used to achieve this goal depending on the nature of the weakened
required. cryptography. In order to simplify, a single technique, called
Archive validation data, covering all the cases is being used in this
document.
Internet Draft Electronic Signature Formats Archive validation data consists of the Complete validation data and
the complete certificate and revocation data, time stamped together
with the electronic signature. The Archive validation data is
necessary if the hash function and the crypto algorithms that were
used to create the signature are no longer secure. Also, if it
cannot be assumed that the hash function used by the Time Stamping
Authority is secure, then nested time-stamps of Archived Electronic
Signature are required.
The potential for Trusted Service Provider (TSP) key compromise should The potential for Trusted Service Provider (TSP) key compromise
be significantly lower than user keys, because TSP(s) are expected to should be significantly lower than user keys, because TSP(s) are
use stronger cryptography and better key protection. It can be expected expected to use stronger cryptography and better key protection. It
that new algorithms (or old ones with greater key lengths) will be can be expected that new algorithms (or old ones with greater key
used. In such a case, a sequence of timestamps will protect against lengths) will be used. In such a case, a sequence of time-stamps
forgery. Each timestamp needs to be affixed before either the will protect against forgery. Each time-stamp needs to be affixed
compromise of the signing key or of the cracking of the algorithms used before either the compromise of the signing key or of the cracking of
by the TSA. TSAs (TimeStamping Authorities) should have long keys (e.g. the algorithms used by the TSA. TSAs (Time-Stamping Authorities)
which at the time of drafting this document was 2048 bits for the should have long keys (e.g., which at the time of drafting this
signing RSA algorithm) and/or a "good" or different algorithm. document was 2048 bits for the signing RSA algorithm) and/or a "good"
or different algorithm.
Nested timestamps will also protect the verifier against key compromise Nested time-stamps will also protect the verifier against key
or cracking the algorithm on the old electronic signatures. compromise or cracking the algorithm on the old electronic
signatures.
The process will need to be performed and iterated before the The process will need to be performed and iterated before the
cryptographic algorithms used for generating the previous time stamp cryptographic algorithms used for generating the previous time stamp
are no longer secure. Archive validation data may thus bear multiple are no longer secure. Archive validation data may thus bear multiple
embedded time stamps. embedded time stamps.
B.4.8 Reference to Additional Data B.4.8 Reference to Additional Data
Using type 1 or 2 of Timestamped extended validation data verifiers Using type 1 or 2 of Time-Stamped extended validation data verifiers
still needs to keep track of all the components that were used to still needs to keep track of all the components that were used to
validate the signature, in order to be able to retrieve them again validate the signature, in order to be able to retrieve them again
later on. These components may be archived by an external source like later on. These components may be archived by an external source
a trusted service provider, in which case referenced information that like a trusted service provider, in which case referenced information
is provided as part of the ES with Complete validation data (ES-C) is that is provided as part of the ES with Complete validation data
adequate. The actual certificates and CRL information reference in the (ES-C) is adequate. The actual certificates and CRL information
ES-C can be gathered when needed for arbitration. reference in the ES-C can be gathered when needed for arbitration.
B.4.9 Timestamping for Mutual Recognition
In some business scenarios both the signer and the verifier need to B.4.9 Time-Stamping for Mutual Recognition
timestamp their own copy of the signature value. Ideally the two
timestamps should be as close as possible to each other.
Example: A contract is signed by two parties A and B representing In some business scenarios both the signer and the verifier need to
their respective organizations, to timestamp the signer and verifier time-stamp their own copy of the signature value. Ideally the two
data two approaches are possible: time-stamps should be as close as possible to each other.
* under the terms of the contract pre-defined common "trusted" Example: A contract is signed by two parties A and B representing
TSA may be used; their respective organizations, to time-stamp the signer and verifier
data two approaches are possible:
Internet Draft Electronic Signature Formats * under the terms of the contract pre-defined common "trusted"
TSA may be used;
* if both organizations run their own timestamping services, A * if both organizations run their own time-stamping services, A
and B can have the transaction timestamped by these two and B can have the transaction time-stamped by these two time-
timestamping services. In the latter case, the electronic stamping services. In the latter case, the electronic
signature will only be considered as valid, if both timestamps signature will only be considered as valid, if both time-stamps
were obtained in due time (i.e. there should not be a long were obtained in due time (i.e., there should not be a long
delay between obtaining the two timestamps). Thus, neither A delay between obtaining the two time-stamps). Thus, neither A
nor B can repudiate the signing time indicated by their own nor B can repudiate the signing time indicated by their own
timestamping service. time-stamping service.
Therefore, A and B do not need to agree on a common "trusted" TSA to Therefore, A and B do not need to agree on a common "trusted" TSA to
get a valid transaction. get a valid transaction.
It is important to note that signatures may be generated "off-line" It is important to note that signatures may be generated "off-line"
and timestamped at a later time by anyone, e.g. by the signer or any and time-stamped at a later time by anyone, e.g., by the signer or
recipient interested in validating the signature. The timestamp over any recipient interested in validating the signature. The time-stamp
the signature from the signer can thus be provided by the signer over the signature from the signer can thus be provided by the signer
together with the signed document, and /or obtained by the verifier together with the signed document, and /or obtained by the verifier
following receipt of the signed document. following receipt of the signed document.
The business scenarios may thus dictate that one or more of the long- The business scenarios may thus dictate that one or more of the
term signature timestamping methods describe above be used. This will long-term signature time-stamping methods describe above be used.
need to be part of a mutually agreed the Signature Validation Policy This will need to be part of a mutually agreed the Signature
with is part of the overall signature policy under which digital Validation Policy with is part of the overall signature policy under
signature may be used to support the business relationship between the which digital signature may be used to support the business
two parties. relationship between the two parties.
B.4.10 TSA Key Compromise B.4.10 TSA Key Compromise
TSA servers should be built in such a way that once the private TSA servers should be built in such a way that once the private
signature key is installed, that there is minimal likelihood of signature key is installed, that there is minimal likelihood of
compromise over as long as possible period. Thus the validity period compromise over as long as possible period. Thus the validity period
for the TSA's keys should be as long as possible. for the TSA's keys should be as long as possible.
Both the ES-T and the ES-C contain at least one time stamp over the
signer's signature. In order to protect against the compromise of the
private signature key used to produce that timestamp, the Archive
validation data can be used when a different TimeStamping Authority key
is involved to produce the additional timestamp. If it is believed that
the TSA key used in providing an earlier timestamp may ever be
compromised (e.g. outside its validity period), then the ES-A should be
used. For extremely long periods this may be applied repeatedly using
new TSA