draft-ietf-smime-rfc2632bis-00.txt   draft-ietf-smime-rfc2632bis-01.txt 
Internet Draft Editor: Blake Ramsdell, Internet Draft Editor: Blake Ramsdell,
draft-ietf-smime-rfc2632bis-00.txt Brute Squad Labs draft-ietf-smime-rfc2632bis-01.txt Brute Squad Labs
February 8, 2002 June 30, 2002
Expires August 8, 2002 Expires December 30, 2002
S/MIME Version 3.1 Certificate Handling S/MIME Version 3.1 Certificate Handling
Status of this memo Status of this memo
This document is an Internet-Draft and is in full conformance with all This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of RFC2026. provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Task Internet-Drafts are working documents of the Internet Engineering Task
Force (IETF), its areas, and its working groups. Note that other Force (IETF), its areas, and its working groups. Note that other
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For the purposes of this draft, the following definitions apply. For the purposes of this draft, the following definitions apply.
ASN.1: Abstract Syntax Notation One, as defined in ITU-T X.680-689. ASN.1: Abstract Syntax Notation One, as defined in ITU-T X.680-689.
Attribute Certificate (AC): An X.509 AC is a separate structure from a Attribute Certificate (AC): An X.509 AC is a separate structure from a
subject's public key X.509 Certificate. A subject may have multiple subject's public key X.509 Certificate. A subject may have multiple
X.509 ACs associated with each of its public key X.509 Certificates. X.509 ACs associated with each of its public key X.509 Certificates.
Each X.509 AC binds one or more Attributes with one of the subject's Each X.509 AC binds one or more Attributes with one of the subject's
public key X.509 Certificates. The X.509 AC syntax is defined in public key X.509 Certificates. The X.509 AC syntax is defined in
[X.509] [KEYMAC].
BER: Basic Encoding Rules for ASN.1, as defined in ITU-T X.690. BER: Basic Encoding Rules for ASN.1, as defined in ITU-T X.690.
Certificate: A type that binds an entity's distinguished name to a Certificate: A type that binds an entity's distinguished name to a
public key with a digital signature. This type is defined in the public key with a digital signature. This type is defined in the
Internet X.509 Public Key Infrastructure (PKIX) Certificate and CRL Internet X.509 Public Key Infrastructure (PKIX) Certificate and CRL
Profile [KEYM]. This type also contains the distinguished name of the Profile [KEYM]. This type also contains the distinguished name of the
certificate issuer (the signer), an issuer-specific serial number, the certificate issuer (the signer), an issuer-specific serial number, the
issuer's signature algorithm identifier, a validity period, and issuer's signature algorithm identifier, a validity period, and
extensions also defined in that document. extensions also defined in that document.
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The CMS message format allows for a wide variety of options in content The CMS message format allows for a wide variety of options in content
and algorithm support. This section puts forth a number of support and algorithm support. This section puts forth a number of support
requirements and recommendations in order to achieve a base level of requirements and recommendations in order to achieve a base level of
interoperability among all S/MIME implementations. Most of the CMS interoperability among all S/MIME implementations. Most of the CMS
format for S/MIME messages is defined in [SMIME-MSG]. format for S/MIME messages is defined in [SMIME-MSG].
2.1 CertificateRevocationLists 2.1 CertificateRevocationLists
Receiving agents MUST support the Certificate Revocation List (CRL) Receiving agents MUST support the Certificate Revocation List (CRL)
format defined in [KEYM]. If sending agents include CRLs in outgoing format defined in [KEYM]. If sending agents include CRLs in outgoing
messages, the CRL format defined in [KEYM] MUST be used. messages, the CRL format defined in [KEYM] MUST be used. In all cases,
both v1 and v2 CRLs MUST be supported.
All agents MUST be capable of performing revocation checks using CRLs All agents MUST be capable of performing revocation checks using CRLs
as specified in [KEYM]. All agents MUST perform revocation status as specified in [KEYM]. All agents MUST perform revocation status
checking in accordance with [KEYM]. Receiving agents MUST recognize checking in accordance with [KEYM]. Receiving agents MUST recognize
CRLs in received S/MIME messages. CRLs in received S/MIME messages.
Agents SHOULD store CRLs received in messages for use in processing Agents SHOULD store CRLs received in messages for use in processing
later messages. later messages.
Agents MUST handle multiple valid Certificate Authority (CA)
certificates containing the same subject name and the same public keys
but with overlapping validity intervals.
2.2 CertificateChoices 2.2 CertificateChoices
Receiving agents MUST support PKIX v1 and PKIX v3 certificates. See Receiving agents MUST support PKIX v1 and PKIX v3 certificates. See
[KEYM] for details about the profile for certificate formats. End [KEYM] for details about the profile for certificate formats. End
entity certificates MAY include an Internet mail address, as described entity certificates MAY include an Internet mail address, as described
in section 3.1. in section 3.
Receiving agents SHOULD support X.509 attribute certificates. Receiving agents SHOULD support X.509 version 2 attribute
certificates. See [KEYMAC] for details about the profile for attribute
certificates.
2.2.1 Historical Note About CMS Certificates 2.2.1 Historical Note About CMS Certificates
The CMS message format supports a choice of certificate formats for The CMS message format supports a choice of certificate formats for
public key content types: PKIX, PKCS #6 Extended Certificates and public key content types: PKIX, PKCS #6 Extended Certificates and
X.509 Attribute Certificates. The PKCS #6 format is not in widespread X.509 Attribute Certificates.
use. In addition, PKIX certificate extensions address much of the same
functionality and flexibility as was intended in the PKCS #6. Thus, The PKCS #6 format is not in widespread use. In addition, PKIX
sending and receiving agents MUST NOT use PKCS #6 extended certificate extensions address much of the same functionality and
flexibility as was intended in the PKCS #6. Thus, sending and
receiving agents MUST NOT use PKCS #6 extended certificates.
X.509 version 1 attribute certificates are also not widely
implemented, and have been superceded with version 2 attribute
certificates. Sending agents MUST NOT send version 1 attribute
certificates. certificates.
2.3 CertificateSet 2.3 CertificateSet
Receiving agents MUST be able to handle an arbitrary number of Receiving agents MUST be able to handle an arbitrary number of
certificates of arbitrary relationship to the message sender and to certificates of arbitrary relationship to the message sender and to
each other in arbitrary order. In many cases, the certificates each other in arbitrary order. In many cases, the certificates
included in a signed message may represent a chain of certification included in a signed message may represent a chain of certification
from the sender to a particular root. There may be, however, from the sender to a particular root. There may be, however,
situations where the certificates in a signed message may be unrelated situations where the certificates in a signed message may be unrelated
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A sending agent SHOULD include at least one chain of certificates up A sending agent SHOULD include at least one chain of certificates up
to, but not including, a Certificate Authority (CA) that it believes to, but not including, a Certificate Authority (CA) that it believes
that the recipient may trust as authoritative. A receiving agent that the recipient may trust as authoritative. A receiving agent
SHOULD be able to handle an arbitrarily large number of certificates SHOULD be able to handle an arbitrarily large number of certificates
and chains. and chains.
Agents MAY send CA certificates, that is, certificates that are self- Agents MAY send CA certificates, that is, certificates that are self-
signed and can be considered the "root" of other chains. Note that signed and can be considered the "root" of other chains. Note that
receiving agents SHOULD NOT simply trust any self-signed certificates receiving agents SHOULD NOT simply trust any self-signed certificates
as valid CAs, but SHOULD use some other mechanism to determine if this as valid CAs, but SHOULD use some other mechanism to determine if this
is a CA that should be trusted. Also note that in the case of DSA is a CA that should be trusted. Also note that when certificates
certificates the parameters may be located in the root certificate. contain DSA public keys the parameters may be located in the root
This would require that the recipient possess the root certificate in certificate. This would require that the recipient possess both the
order to perform a signature verification, and is a valid example of a end-entity certificate as well as the root certificate to perform a
case where transmitting the root certificate may be required. signature verification, and is a valid example of a case where
transmitting the root certificate may be required.
Receiving agents MUST support chaining based on the distinguished name Receiving agents MUST support chaining based on the distinguished name
fields. Other methods of building certificate chains may be supported fields. Other methods of building certificate chains may be supported.
but are not currently recommended.
Receiving agents SHOULD support the decoding of X.509 attribute Receiving agents SHOULD support the decoding of X.509 attribute
certificates included in CMS objects. All other issues regarding the certificates included in CMS objects. All other issues regarding the
generation and use of X.509 attribute certificates are outside of the generation and use of X.509 attribute certificates are outside of the
scope of this specification. scope of this specification. One specification that addresses
attribute certificate use is defined in [SECLABEL].
3. Using Distinguished Names for Internet Mail 3. Using Distinguished Names for Internet Mail
End-entity certificates MAY contain an Internet mail address as End-entity certificates MAY contain an Internet mail address as
described in [RFC-2822]. The address must be an "addr-spec" as defined described in [RFC-2822]. The address must be an "addr-spec" as defined
in Section 3.4.1 of that specification. The email address SHOULD be in in Section 3.4.1 of that specification. The email address SHOULD be in
the subjectAltName extension, and SHOULD NOT be in the subject the subjectAltName extension, and SHOULD NOT be in the subject
distinguished name. distinguished name.
Receiving agents MUST recognize email addresses in the subjectAltName Receiving agents MUST recognize email addresses in the subjectAltName
field. Receiving agents MUST recognize email addresses in the field. Receiving agents MUST recognize email addresses in the
Distinguished Name field in the PKCS #9 emailAddress attribute. Distinguished Name field in the PKCS #9 [PKCS9] emailAddress
attribute:
pkcs-9-at-emailAddress OBJECT IDENTIFIER ::=
{iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) 1 }
Sending agents SHOULD make the address in the From or Sender header in Sending agents SHOULD make the address in the From or Sender header in
a mail message match an Internet mail address in the signer's a mail message match an Internet mail address in the signer's
certificate. Receiving agents MUST check that the address in the From certificate. Receiving agents MUST check that the address in the From
or Sender header of a mail message matches an Internet mail address in or Sender header of a mail message matches an Internet mail address in
the signer's certificate, if mail addresses are present in the the signer's certificate, if mail addresses are present in the
certificate. A receiving agent SHOULD provide some explicit alternate certificate. A receiving agent SHOULD provide some explicit alternate
processing of the message if this comparison fails, which may be to processing of the message if this comparison fails, which may be to
display a message that shows the recipient the addresses in the display a message that shows the recipient the addresses in the
certificate or other certificate details. certificate or other certificate details.
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For instance, a secure Internet mail agent may resort to checking a For instance, a secure Internet mail agent may resort to checking a
centralized certificate retrieval mechanism for a certificate if it centralized certificate retrieval mechanism for a certificate if it
can not be found in a user's local certificate storage/retrieval can not be found in a user's local certificate storage/retrieval
database. database.
Receiving and sending agents SHOULD provide a mechanism for the import Receiving and sending agents SHOULD provide a mechanism for the import
and export of certificates, using a CMS certs-only message. This and export of certificates, using a CMS certs-only message. This
allows for import and export of full certificate chains as opposed to allows for import and export of full certificate chains as opposed to
just a single certificate. This is described in [SMIME-MSG]. just a single certificate. This is described in [SMIME-MSG].
Agents MUST handle multiple valid Certificate Authority (CA)
certificates containing the same subject name and the same public keys
but with overlapping validity intervals.
4.1 Certificate Revocation Lists 4.1 Certificate Revocation Lists
In general, it is always better to get the latest CRL information from In general, it is always better to get the latest CRL information from
a CA than to get information stored away from incoming messages. A a CA than to get information stored away from incoming messages. A
receiving agent SHOULD have access to some certificate-revocation list receiving agent SHOULD have access to some certificate revocation list
(CRL) retrieval mechanism in order to gain access to certificate- (CRL) retrieval mechanism in order to gain access to certificate
revocation information when validating certificate chains. A receiving revocation information when validating certification paths. A
or sending agent SHOULD also provide a mechanism to allow a user to receiving or sending agent SHOULD also provide a mechanism to allow a
store incoming certificate-revocation information for correspondents user to store incoming certificate revocation information for
in such a way so as to guarantee its later retrieval. correspondents in such a way so as to guarantee its later retrieval.
Receiving and sending agents SHOULD retrieve and utilize CRL Receiving and sending agents SHOULD retrieve and utilize CRL
information every time a certificate is verified as part of a information every time a certificate is verified as part of a
certificate chain validation even if the certificate was already certification path validation even if the certificate was already
verified in the past. However, in many instances (such as off-line verified in the past. However, in many instances (such as off-line
verification) access to the latest CRL information may be difficult or verification) access to the latest CRL information may be difficult or
impossible. The use of CRL information, therefore, may be dictated by impossible. The use of CRL information, therefore, may be dictated by
the value of the information that is protected. The value of the CRL the value of the information that is protected. The value of the CRL
information in a particular context is beyond the scope of this draft information in a particular context is beyond the scope of this
but may be governed by the policies associated with particular specification but may be governed by the policies associated with
certificate hierarchies. particular certification paths.
All agents MUST be capable of performing revocation checks using CRLs All agents MUST be capable of performing revocation checks using CRLs
as specified in [KEYM]. All agents MUST perform revocation status as specified in [KEYM]. All agents MUST perform revocation status
checking in accordance with [KEYM]. Receiving agents MUST recognize checking in accordance with [KEYM]. Receiving agents MUST recognize
CRLs in received S/MIME messages. CRLs in received S/MIME messages.
4.2 Certificate Chain Validation 4.2 Certification Path Validation
In creating a user agent for secure messaging, certificate, CRL, and In creating a user agent for secure messaging, certificate, CRL, and
certificate chain validation SHOULD be highly automated while still certification path validation SHOULD be highly automated while still
acting in the best interests of the user. Certificate, CRL, and chain acting in the best interests of the user. Certificate, CRL, and path
validation MUST be performed as per [KEYM] when validating a validation MUST be performed as per [KEYM] when validating a
correspondent's public key. This is necessary before using a public correspondent's public key. This is necessary before using a public
key to provide security services such as: verifying a signature; key to provide security services such as: verifying a signature;
encrypting a content-encryption key (ex: RSA); or forming a pairwise encrypting a content-encryption key (ex: RSA); or forming a pairwise
symmetric key (ex: Diffie-Hellman) to be used to encrypt or decrypt a symmetric key (ex: Diffie-Hellman) to be used to encrypt or decrypt a
content-encryption key. content-encryption key.
Certificates and CRLs are made available to the chain validation Certificates and CRLs are made available to the path validation
procedure in two ways: a) incoming messages, and b) certificate and procedure in two ways: a) incoming messages, and b) certificate and
CRL retrieval mechanisms. Certificates and CRLs in incoming messages CRL retrieval mechanisms. Certificates and CRLs in incoming messages
are not required to be in any particular order nor are they required are not required to be in any particular order nor are they required
to be in any way related to the sender or recipient of the message to be in any way related to the sender or recipient of the message
(although in most cases they will be related to the sender). Incoming (although in most cases they will be related to the sender). Incoming
certificates and CRLs SHOULD be cached for use in chain validation and certificates and CRLs SHOULD be cached for use in path validation and
optionally stored for later use. This temporary certificate and CRL optionally stored for later use. This temporary certificate and CRL
cache SHOULD be used to augment any other certificate and CRL cache SHOULD be used to augment any other certificate and CRL
retrieval mechanisms for chain validation on incoming signed messages. retrieval mechanisms for path validation on incoming signed messages.
4.3 Certificate and CRL Signing Algorithms 4.3 Certificate and CRL Signing Algorithms
Certificates and Certificate-Revocation Lists (CRLs) are signed by the Certificates and Certificate Revocation Lists (CRLs) are signed by the
certificate issuer. A receiving agent MUST be capable of verifying the certificate issuer. A receiving agent MUST be capable of verifying the
signatures on certificates and CRLs made with id-dsa-with-sha1 signatures on certificates and CRLs made with id-dsa-with-sha1
[CMSALG]. [CMSALG].
A receiving agent MUST be capable of verifying the signatures on A receiving agent MUST be capable of verifying the signatures on
certificates and CRLs made with md2WithRSAEncryption, certificates and CRLs made with md5WithRSAEncryption and
md5WithRSAEncryption and sha-1WithRSAEncryption signature algorithms sha1WithRSAEncryption signature algorithms with key sizes from 512
with key sizes from 512 bits to 2048 bits described in [CMSALG]. bits to 2048 bits described in [CMSALG].
Because of the security issues surrounding MD2 [RC95], and in light of
current use, md2WithRSAEncryption MAY be supported.
4.4 PKIX Certificate Extensions 4.4 PKIX Certificate Extensions
PKIX describes an extensible framework in which the basic certificate PKIX describes an extensible framework in which the basic certificate
information can be extended and how such extensions can be used to information can be extended and how such extensions can be used to
control the process of issuing and validating certificates. The PKIX control the process of issuing and validating certificates. The PKIX
Working Group has ongoing efforts to identify and create extensions Working Group has ongoing efforts to identify and create extensions
which have value in particular certification environments. Further, which have value in particular certification environments. Further,
there are active efforts underway to issue PKIX certificates for there are active efforts underway to issue PKIX certificates for
business purposes. This document identifies the minimum required set business purposes. This document identifies the minimum required set
of certificate extensions which have the greatest value in the S/MIME of certificate extensions which have the greatest value in the S/MIME
environment. The syntax and semantics of all the identified extensions environment. The syntax and semantics of all the identified extensions
are defined in [KEYM]. are defined in [KEYM].
Sending and receiving agents MUST correctly handle the Basic Sending and receiving agents MUST correctly handle the basic
Constraints Certificate Extension, the Key Usage Certificate constraints, key usage, authority key identifier, subject key
Extension, authorityKeyID, subjectKeyID, and the subjectAltNames when identifier, and subject alternative names certificate extensions when
they appear in end-user certificates. Some mechanism SHOULD exist to they appear in end-entity certificates. Some mechanism SHOULD exist to
handle the defined certificate extensions when they appear in gracefully handle other certificate extensions when they appear in
intermediate or CA certificates. end-entity or CA certificates.
Certificates issued for the S/MIME environment SHOULD NOT contain any Certificates issued for the S/MIME environment SHOULD NOT contain any
critical extensions (extensions that have the critical field set to critical extensions (extensions that have the critical field set to
TRUE) other than those listed here. These extensions SHOULD be marked TRUE) other than those listed here. These extensions SHOULD be marked
as non-critical unless the proper handling of the extension is deemed as non-critical unless the proper handling of the extension is deemed
critical to the correct interpretation of the associated certificate. critical to the correct interpretation of the associated certificate.
Other extensions may be included, but those extensions SHOULD NOT be Other extensions may be included, but those extensions SHOULD NOT be
marked as critical. marked as critical.
Interpretation and syntax for all extensions MUST follow [KEYM], Interpretation and syntax for all extensions MUST follow [KEYM],
unless otherwise specified here. unless otherwise specified here.
4.4.1 Basic Constraints Certificate Extension 4.4.1 Basic Constraints Certificate Extension
The basic constraints extension serves to delimit the role and The basic constraints extension serves to delimit the role and
position of an issuing authority or end-entity certificate plays in a position of an issuing authority or end-entity certificate plays in a
chain of certificates. certification path.
For example, certificates issued to CAs and subordinate CAs contain a For example, certificates issued to CAs and subordinate CAs contain a
basic constraint extension that identifies them as issuing authority basic constraint extension that identifies them as issuing authority
certificates. End-entity certificates contain an extension that certificates. End-entity certificates contain an extension that
constrains the certificate from being an issuing authority constrains the certificate from being an issuing authority
certificate. certificate.
Certificates SHOULD contain a basicConstraints extension in CA Certificates SHOULD contain a basicConstraints extension in CA
certificates, and SHOULD NOT contain that extension in end entity certificates, and SHOULD NOT contain that extension in end entity
certificates. certificates.
4.4.2 Key Usage Certificate Extension 4.4.2 Key Usage Certificate Extension
The key usage extension serves to limit the technical purposes for The key usage extension serves to limit the technical purposes for
which a public key listed in a valid certificate may be used. Issuing which a public key listed in a valid certificate may be used. Issuing
authority certificates may contain a key usage extension that authority certificates may contain a key usage extension that
restricts the key to signing certificates, certificate revocation restricts the key to signing certificates, certificate revocation
lists and other data. lists and other data.
For example, a certification authority may create subordinate issuer For example, a certification authority may create subordinate issuer
certificates which contain a keyUsage extension which specifies that certificates which contain a key usage extension which specifies that
the corresponding public key can be used to sign end user certs and the corresponding public key can be used to sign end user certificates
sign CRLs. and sign CRLs.
If a key usage extension is included in a PKIX certificate, then it If a key usage extension is included in a PKIX certificate, then it
MUST be marked as critical. MUST be marked as critical.
4.4.2.1 Key Usage in Diffie-Hellman Key Exchange Certificates 4.4.2.1 Key Usage in Diffie-Hellman Key Exchange Certificates
For Diffie-Hellman key exchange certificates (certificates in which For Diffie-Hellman key exchange certificates (certificates in which
the subject public key algorithm is dhpublicnumber), if the keyUsage the subject public key algorithm is dhpublicnumber), if the keyUsage
keyAgreement bit is set to 1 AND if the public key is to be used to keyAgreement bit is set to 1 AND if the public key is to be used to
form a pairwise key to decrypt data, then the S/MIME agent MUST only form a pairwise key to decrypt data, then the S/MIME agent MUST only
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handle such failures. Just because the methods to handle the failures handle such failures. Just because the methods to handle the failures
has not been listed, however, the reader should not assume that they has not been listed, however, the reader should not assume that they
are not important. The opposite is true: if a certificate is not are not important. The opposite is true: if a certificate is not
provably valid and associated with the message, the processing provably valid and associated with the message, the processing
software should take immediate and noticable steps to inform the end software should take immediate and noticable steps to inform the end
user about it. user about it.
Some of the many places where signature and certificate checking might Some of the many places where signature and certificate checking might
fail include: fail include:
- no Internet mail addresses in a certificate match the sender of a - no Internet mail addresses in a certificate matches the sender of a
message message
- no certificate chain leads to a trusted CA - no certificate chain leads to a trusted CA
- no ability to check the CRL for a certificate - no ability to check the CRL for a certificate
- an invalid CRL was received - an invalid CRL was received
- the CRL being checked is expired - the CRL being checked is expired
- the certificate is expired - the certificate is expired
- the certificate has been revoked - the certificate has been revoked
There are certainly other instances where a certificate may be There are certainly other instances where a certificate may be
invalid, and it is the responsibility of the processing software to invalid, and it is the responsibility of the processing software to
check them all thoroughly, and to decide what to do if the check check them all thoroughly, and to decide what to do if the check
fails. fails.
[TBD] -- PKCS #1 v1.5 warnings? At the Selected Areas in Cryptography '95 conference in May 1995,
Rogier and Chauvaud presented an attack on MD2 that can nearly find
collisions [RC95]. Collisions occur when one can find two different
messages that generate the same message digest. A checksum operation
in MD2 is the only remaining obstacle to the success of the attack.
For this reason, the use of MD2 for new applications is discouraged.
It is still reasonable to use MD2 to verify existing signatures, as
the ability to find collisions in MD2 does not enable an attacker to
find new messages having a previously computed hash value.
A. References A. References
[CERTV2] "S/MIME Version 2 Certificate Handling", RFC 2312 [CERTV2] "S/MIME Version 2 Certificate Handling", RFC 2312
[CMS] "Cryptographic Message Syntax", Internet Draft draft-housley- [CMS] "Cryptographic Message Syntax", Internet Draft
smime-cms draft-ietf-smime-rfc2630bis
[CMSALG] "Cryptographic Message Syntax (CMS) Algorithms", Internet- [CMSALG] "Cryptographic Message Syntax (CMS) Algorithms", Internet-
Draft draft-ietf-smime-cmsalg Draft draft-ietf-smime-cmsalg
[KEYM] "Internet X.509 Public Key Infrastructure Certificate and CRL [KEYM] "Internet X.509 Public Key Infrastructure Certificate and CRL
Profile", RFC 2459 Profile", RFC 3280
[KEYMAC] "An Internet Attribute Certificate Profile for
Authorization", RFC 3281
[KEYMALG] "Algorithms and Identifiers for the Internet X.509 Public
Key Infrastructure Certificate and CRL Profile ", RFC 3279
[MUSTSHOULD] "Key words for use in RFCs to Indicate Requirement [MUSTSHOULD] "Key words for use in RFCs to Indicate Requirement
Levels", RFC 2119 Levels", RFC 2119
[PKCS9] "PKCS #9: Selected Object Classes and Attribute Types Version
2.0", RFC 2985
[RC95] Rogier, N. and Chauvaud, P., "The compression function of MD2
is not collision free," Presented at Selected Areas in Cryptography
'95, May 1995
[RFC-2822], "Internet Message Format", RFC 2822 [RFC-2822], "Internet Message Format", RFC 2822
[SECLABEL] "Implementing Company Classification Policy with the S/MIME
Security Label", RFC 3114
[SMIME-MSG] "S/MIME Version 3 Message Specification ", Internet Draft [SMIME-MSG] "S/MIME Version 3 Message Specification ", Internet Draft
draft-ietf-smime-msg draft-ietf-smime-msg
[X.500] ITU-T Recommendation X.500 (1997) | ISO/IEC 9594-1:1997, [X.500] ITU-T Recommendation X.500 (1997) | ISO/IEC 9594-1:1997,
Information technology - Open Systems Interconnection - The Directory: Information technology - Open Systems Interconnection - The Directory:
Overview of concepts, models and services Overview of concepts, models and services
[X.501] ITU-T Recommendation X.501 (1997) | ISO/IEC 9594-2:1997, [X.501] ITU-T Recommendation X.501 (1997) | ISO/IEC 9594-2:1997,
Information technology - Open Systems Interconnection - The Directory: Information technology - Open Systems Interconnection - The Directory:
Models Models
skipping to change at line 501 skipping to change at line 542
Authentication framework Authentication framework
[X.520] ITU-T Recommendation X.520 (1997) | ISO/IEC 9594-6:1997, [X.520] ITU-T Recommendation X.520 (1997) | ISO/IEC 9594-6:1997,
Information technology - Open Systems Interconnection - The Directory: Information technology - Open Systems Interconnection - The Directory:
Selected attribute types. Selected attribute types.
B. Acknowledgements B. Acknowledgements
[tbd] [tbd]
C. Changes from last draft C. Editor's address
Edited as plain text due to unfortunate loss of original Word
document, so wrapping may change randomly, but strange 8bit characters
should no longer appear mysteriously (Blake Ramsdell)
D. Editor's address
Blake Ramsdell Blake Ramsdell
Brute Squad Labs Brute Squad Labs
Suite 217-C Suite 217-C
16451 Redmond Way 16451 Redmond Way
Redmond, WA 98052-4482 Redmond, WA 98052-4482
blake@brutesquadlabs.com blake@brutesquadlabs.com
D. Changes from last draft
Updated [KEYM] reference, added [KEYMALG] reference (Russ Housley)
Added [KEYMAC] reference and referred to it from section 2.2 (Russ
Housley)
Added clarification text to section 2.1 regarding all versions of CRLs
to be supported (Russ Housley)
Moved text regarding CA certificates and overlapping validity periods
from section 2.1 to section 4 (Russ Housley)
Changed reference to non-section section 3.1 to section 3 (Russ
Housley).
Clarification of v2 vs. v1 attribute certificates (Russ Housley)
MUST NOT use v1 attribute certificates (Russ Housley)
Clarification of DSA certificate language (Russ Housley)
Removed non-recommendation of non-DN chain building (Russ Housley)
Added [SECLABEL] and reference from section 2.3 (Russ Housley)
Added [PKCS9] and reference from section 3 (Russ Housley)
Changed references to "certificate-revocation" to "certificate
revocation (Russ Housley)
Changed references to "certificate chain" to "certification path"
(Russ Housley)
Clarification of extension handling (Russ Housley)
Removed PKCS#1 v1.5 warning (Russ Housley)
Added MD2 warnings, [RC95] reference and MAY language (Jim Schaad,
Blake Ramsdell, Russ Housley)
 End of changes. 

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