draft-ietf-smime-x400wrap-00.txt   draft-ietf-smime-x400wrap-01.txt 
Internet Draft Paul Hoffman, IMC Internet Draft Paul Hoffman, IMC
draft-ietf-smime-x400wrap-00.txt Chris Bonatti, IECA draft-ietf-smime-x400wrap-01.txt Chris Bonatti, IECA
November 2, 2000 Anders Eggen, FFI November 22, 2000 Anders Eggen, FFI
Expires in six months Expires May 22, 2001
Securing X.400 Content with S/MIME Securing X.400 Content with S/MIME
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 groups Force (IETF), its areas, and its working groups. Note that other groups
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The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
Abstract Abstract
This document describes a protocol for adding cryptographic signature This document describes a protocol for adding cryptographic signature
and encryption services to X.400 content. and encryption services to X.400 content.
1. Introduction 1. Introduction
The techniques described in Cryptographic Message Syntax [CMS] The techniques described in the Cryptographic Message Syntax [CMS]
specification are general enough to support many different content specification are general enough to support many different content
types. The [CMS] specification thus provides many options for providing types. The [CMS] specification thus provides many options for providing
different security mechanisms. In order to ensure interoperability of different security mechanisms. In order to ensure interoperability of
systems within the X.400 community, it is necessary to specify the use systems within the X.400 community, it is necessary to specify the use
of CMS features to protect X.400 content (called "CMS-X.400" in this of CMS features to protect X.400 content (called "CMS-X.400" in this
document). document).
1.1 Specification Overview 1.1 Specification Overview
This document is intended to be similar to the S/MIME Version 3 Message This document is intended to be similar to the S/MIME Version 3 Message
Specification [MSG] except that it is tailored to the requirements of Specification [MSG] except that it is tailored to the requirements of
X.400 content rather than Multipurpose Internet Mail Extensions (MIME). X.400 content rather than Multipurpose Internet Mail Extensions (MIME).
This document defines how to create an X.400 content type that has been This document defines how to create an X.400 content type that has been
cryptographically enhanced according to [CMS]. In order to create S/MIME cryptographically enhanced according to [CMS]. In order to create S/MIME
messages, an S/MIME agent has to follow specifications in this document, messages carrying X.400 content, an S/MIME agent has to follow
as well as the specifications listed in [CMS]. This memo also defines specifications in this document, as well as the specifications listed in
new parameter values for the application/pkcs7-mime MIME type that can [CMS]. This memo also defines new parameter values for the
be used to transport those body parts. application/pkcs7-mime MIME type that can be used to transport those
body parts.
Throughout this document, there are requirements and recommendations Throughout this document, there are requirements and recommendations
made for how receiving agents handle incoming messages. There are made for how receiving agents handle incoming messages. There are
separate requirements and recommendations for how sending agents create separate requirements and recommendations for how sending agents create
outgoing messages. In general, the best strategy is to "be liberal in outgoing messages. In general, the best strategy is to "be liberal in
what you receive and conservative in what you send". Most of the what you receive and conservative in what you send". Most of the
requirements are placed on the handling of incoming messages while the requirements are placed on the handling of incoming messages while the
recommendations are mostly on the creation of outgoing messages. recommendations are mostly on the creation of outgoing messages.
This document does not address transport of CMS-X.400 content. It is This document does not address transport of CMS-X.400 content. It is
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For the purposes of this document, the following definitions apply. For the purposes of this document, the following definitions apply.
ASN.1: Abstract Syntax Notation One, as defined in ISO/IEC 8824. ASN.1: Abstract Syntax Notation One, as defined in ISO/IEC 8824.
BER: Basic Encoding Rules for ASN.1, as defined in ISO/IEC 8825-1. BER: Basic Encoding Rules for ASN.1, as defined in ISO/IEC 8825-1.
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. public key with a digital signature.
DER: Distinguished Encoding Rules for ASN.1, as defined in ISO/IEC DER: Distinguished Encoding Rules for ASN.1, as defined in ISO/IEC
8825-x. 8825-1.
7-bit data: Text data with lines less than 998 characters long, where 7-bit data: Text data with lines less than 998 characters long, where
none of the characters have the 8th bit set, and there are no NULL none of the characters have the 8th bit set, and there are no NULL
characters. <CR> and <LF> occur only as part of a <CR><LF> end of line characters. <CR> and <LF> occur only as part of a <CR><LF> end of line
delimiter. delimiter.
8-bit data: Text data with lines less than 998 characters, and where 8-bit data: Text data with lines less than 998 characters, and where
none of the characters are NULL characters. <CR> and <LF> occur only as none of the characters are NULL characters. <CR> and <LF> occur only as
part of a <CR><LF> end of line delimiter. part of a <CR><LF> end of line delimiter.
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[DH]. [DH].
Receiving agents MAY support rsaEncryption. Incoming encrypted messages Receiving agents MAY support rsaEncryption. Incoming encrypted messages
contain symmetric keys which are to be decrypted with a user's private contain symmetric keys which are to be decrypted with a user's private
key. The size of the private key is determined during key generation. key. The size of the private key is determined during key generation.
Sending agents MAY support rsaEncryption. Sending agents MAY support rsaEncryption.
2.4 General Syntax 2.4 General Syntax
The general syntax of CMS objects consist of an instance of ContentInfo The general syntax of CMS objects consist of an instance of the
structure containing one of several defined CMS content types. CMS ContentInfo structure containing one of several defined CMS content
defines multiple content types. Of these, only the SignedData and types. CMS defines multiple content types. Of these, only the SignedData
EnvelopedData content types are used for CMS-X.400. and EnvelopedData content types are used for CMS-X.400.
2.4.1 SignedData Content Type 2.4.1 SignedData Content Type
Sending agents MUST use the signedData content type to apply a digital Sending agents MUST use the signedData content type to apply a digital
signature to a message or, in a degenerate case where there is no signature to a message or, in a degenerate case where there is no
signature information, to convey certificates. signature information, to convey certificates.
2.4.2 EnvelopedData Content Type 2.4.2 EnvelopedData Content Type
This content type is used to apply privacy protection to a message. A This content type is used to apply privacy protection to a message. A
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recipient to use this service. This content type does not provide recipient to use this service. This content type does not provide
authentication. authentication.
2.5 Attribute SignerInfo Type 2.5 Attribute SignerInfo Type
The SignerInfo type allows the inclusion of unsigned and signed The SignerInfo type allows the inclusion of unsigned and signed
attributes to be included along with a signature. attributes to be included along with a signature.
Receiving agents MUST be able to handle zero or one instance of each of Receiving agents MUST be able to handle zero or one instance of each of
the signed attributes listed here. Sending agents SHOULD generate one the signed attributes listed here. Sending agents SHOULD generate one
instance of each of the following signed attributes in each CMS/X400 instance of each of the following signed attributes in each CMS-X400
message: message:
- signingTime - signingTime
- sMIMECapabilities - sMIMECapabilities
- sMIMEEncryptionKeyPreference - sMIMEEncryptionKeyPreference
Requirements for processing of these attributes MUST be in accordance Requirements for processing of these attributes MUST be in accordance
with the S/MIME Message Specification [MSG]. Handling of the signingTime with the S/MIME Message Specification [MSG]. Handling of the signingTime
attribute MUST comply with clause 2.5.1 of [MSG]. Handling of the attribute MUST comply with clause 2.5.1 of [MSG]. Handling of the
sMIMECapabilities attribute MUST comply with clause 2.5.2 of [MSG]. sMIMECapabilities attribute MUST comply with clause 2.5.2 of [MSG].
Handling of the sMIMEEncryptionKeyPreference attribute MUST comply with Handling of the sMIMEEncryptionKeyPreference attribute MUST comply with
clause 2.5.3 of [MSG]. clause 2.5.3 of [MSG].
Further, receiving agents SHOULD be able to handle zero or one instance Further, receiving agents SHOULD be able to handle zero or one instance
in the signed attributes of the signingCertificate attribute. in the signed attributes of the signingCertificate attribute.
Sending agents SHOULD generate one instance of the signingCertificate Sending agents SHOULD generate one instance of the signingCertificate
signed attribute in each CMS/X400 message. signed attribute in each CMS-X400 message.
Additional attributes and values for these attributes may be defined in Additional attributes and values for these attributes may be defined in
the future. Receiving agents SHOULD handle attributes or values that it the future. Receiving agents SHOULD handle attributes or values that it
does not recognize in a graceful manner. does not recognize in a graceful manner.
Sending agents that include signed attributes that are not listed here Sending agents that include signed attributes that are not listed here
SHOULD display those attributes to the user, so that the user is aware SHOULD display those attributes to the user, so that the user is aware
of all of the data being signed. of all of the data being signed.
3. Creating S/MIME Messages 3. Creating S/MIME Messages
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This section reviews the X.400 message format. An X.400 message has two This section reviews the X.400 message format. An X.400 message has two
parts, the envelope and the content, as described in X.402 [X.400]: parts, the envelope and the content, as described in X.402 [X.400]:
Envelope -- An information object whose composition varies from one Envelope -- An information object whose composition varies from one
transmittal step to another and that variously identifies the message's transmittal step to another and that variously identifies the message's
originator and potential recipients, documents its previous conveyance originator and potential recipients, documents its previous conveyance
and directs its subsequent conveyance by the Message Transfer System and directs its subsequent conveyance by the Message Transfer System
(MTS), and characterizes its content. (MTS), and characterizes its content.
Content -- The content is the piece of information that the originating Content -- The content is the piece of information that the originating
User Agent which is delivered to one or more recipients. The MTS neither User Agent wants to be delivered to one or more recipients. The MTS
examines nor modifies the content, except for conversion, during its neither examines nor modifies the content, except for conversion, during
conveyance of the message. its conveyance of the message.
One piece of information borne by the envelope identifies the type of One piece of information borne by the envelope identifies the type of
the content. The content type is an identifier (an ASN.1 OID or Integer) the content. The content type is an identifier (an ASN.1 OID or Integer)
that denotes the syntax and semantics of the content overall. This that denotes the syntax and semantics of the content overall. This
identifier enables the MTS to determine the message's deliverability to identifier enables the MTS to determine the message's deliverability to
particular users, and enables User Agents and Message Stores to particular users, and enables User Agents and Message Stores to
interpret and process the content. interpret and process the content.
Another piece of information borne by the envelope identifies the types Another piece of information borne by the envelope identifies the types
of encoded information represented in the content. An encoded of encoded information represented in the content. An encoded
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facsimile) of individual portions of the content. It further enables the facsimile) of individual portions of the content. It further enables the
MTS to determine the message's deliverability to particular users, and MTS to determine the message's deliverability to particular users, and
to identify opportunities for it to make the message deliverable by to identify opportunities for it to make the message deliverable by
converting a portion of the content from one EIT to another. converting a portion of the content from one EIT to another.
This document describes how S/MIME CMS is used to secure the content This document describes how S/MIME CMS is used to secure the content
part of X.400 messages. part of X.400 messages.
3.2 Creating a Signed-only Message with X.400 Content 3.2 Creating a Signed-only Message with X.400 Content
The signedData format as described in the Cryptographic Message Syntax The SignedData format as described in the Cryptographic Message Syntax
[CMS] MUST be used for signing of X.400 contents. [CMS] MUST be used for signing of X.400 contents.
The protected X.400 content MUST then be placed in the eContent field of The protected X.400 content MUST then be placed in the SignedData
the signedData element. Note that this X.400 content SHOULD be ASN.1 encapContentInfo eContent field. Note that this X.400 content SHOULD
encoded, but SHOULD NOT be MIME wrapped. The object identifier for maintain the encoding defined by the content type, but SHOULD NOT be
content type of the protected X.400 content MUST be placed in the MIME wrapped. The object identifier for content type of the protected
eContentType field of the signedData element. The resulting signedData X.400 content MUST be placed in the SignedData encapContentInfo
object MAY optionally be wrapped in a MIME encoding. eContentType field. The resulting signedData object MAY optionally be
wrapped in a MIME encoding.
The signedData structure is encapsulated by a ContentInfo SEQUENCE with The signedData object is encapsulated by a ContentInfo SEQUENCE with
a contentType of id-signedData. a contentType of id-signedData.
Note that if SMTP is used to transport the resulting signed-only message Note that if SMTP is used to transport the resulting signed-only message
then the optional MIME encoding SHOULD be used. If other 8-bit transport then the optional MIME encoding SHOULD be used. If other 8-bit
(e.g., X.400) is used then the optional MIME encoding SHOULD NOT be transports (e.g., X.400) are used then the optional MIME encoding SHOULD
used. NOT be used.
3.2.1 MIME Wrapping to Dynamically Support 7-bit Transport 3.2.1 MIME Wrapping to Dynamically Support 7-bit Transport
The signedData object MAY optionally be wrapped in MIME to dynamically The signedData object MAY optionally be wrapped in MIME to dynamically
support 7-bit transport. In this case the application/pkcs7-mime type as support 7-bit transport. In this case the application/pkcs7-mime type as
defined in S/MIME Version 3 Message Specification [MSG] SHOULD be used defined in S/MIME Version 3 Message Specification [MSG] SHOULD be used
with the following parameters: with the following parameters:
Content-Type: application/pkcs7-mime; smime-type=signed-data Content-Type: application/pkcs7-mime; smime-type=signed-data
Content-Transfer-Encoding: base64 Content-Transfer-Encoding: base64
If the application/pkcs7-mime MIME type is used to support 7 bit If the application/pkcs7-mime MIME type is used to support 7 bit
transport, the steps to create this format are: transport, the steps to create this format are:
Step 1. The X.400 content to be signed is ASN.1 encoded. Step 1. The X.400 content to be signed is ASN.1 encoded.
Step 2. The ASN.1 encoded X.400 content and other required data is Step 2. The ASN.1 encoded X.400 content and other required data is
processed into a CMS object of type signedData. processed into a CMS object of type SignedData.
Step 3. The CMS object is inserted into an application/pkcs7-mime MIME Step 3. The CMS object is inserted into an application/pkcs7-mime MIME
entity. entity.
The smime-type parameter for messages using application/pkcs7-mime with The smime-type parameter for messages using application/pkcs7-mime with
SignedData is "signed-x400". SignedData is "signed-x400".
3.3 Creating an Enveloped-only Message with X.400 Content 3.3 Creating an Enveloped-only Message with X.400 Content
This section describes the format for enveloping an X.400 content This section describes the format for enveloping an X.400 content
without signing it. It is important to note that sending enveloped but without signing it. It is important to note that sending enveloped but
not signed messages does not provide for data integrity. It is possible not signed messages does not provide for data integrity. It is possible
to replace ciphertext in such a way that the processed message will to replace ciphertext in such a way that the processed message will
still be valid, but the meaning may be altered. still be valid, but the meaning may be altered.
The envelopedData format as described in [CMS] may be used for privacy of The EnvelopedData format as described in [CMS] may be used for privacy of
the X.400 contents. the X.400 contents.
The protected X.400 content MUST be placed in the eContent field of the The protected X.400 content MUST be placed in the EnvelopedData
envelopedData element. Note that this X.400 content should be ASN.1 encryptedContentInfo encryptedContent field. Note that this X.400
encoded, but should not be MIME wrapped. The object identifier for content SHOULD maintain the encoding defined by the content type, but
content type of the protected X.400 content MUST be placed in the SHOULD NOT be MIME wrapped. The object identifier for content type of
eContentType field of the envelopedData element. The resulting the protected X.400 content MUST be placed in the EnvelopedData
envelopedData object MAY optionally be wrapped in a MIME encoding. encryptedContentInfo contentType field. The resulting envelopedData
object MAY optionally be wrapped in a MIME encoding.
The envelopedData structure is encapsulated by a ContentInfo SEQUENCE The envelopedData object is encapsulated by a ContentInfo SEQUENCE
with a contentType of id-envelopedData. with a contentType of id-envelopedData.
Note that if SMTP is used to transport the resulting enveloped-only Note that if SMTP is used to transport the resulting enveloped-only
message then the optional MIME encoding SHOULD be used. If other 8-bit message then the optional MIME encoding SHOULD be used. If other 8-bit
transport (e.g., X.400) is used then the optional MIME encoding SHOULD transport (e.g., X.400) is used then the optional MIME encoding SHOULD
NOT be used. NOT be used.
3.3.1 MIME Wrapping to Dynamically Support 7-bits Transport 3.3.1 MIME Wrapping to Dynamically Support 7-bits Transport
The envelopedData object MAY optionally be wrapped in MIME to The envelopedData object MAY optionally be wrapped in MIME to
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Content-Type: application/pkcs7-mime; smime-type=enveloped-data Content-Type: application/pkcs7-mime; smime-type=enveloped-data
Content-Transfer-Encoding: base64 Content-Transfer-Encoding: base64
If the application/pkcs7-mime MIME type is used to support 7 bit If the application/pkcs7-mime MIME type is used to support 7 bit
transport, the steps to create this format are: transport, the steps to create this format are:
Step 1. The X.400 content to be enveloped is ASN.1 encoded. Step 1. The X.400 content to be enveloped is ASN.1 encoded.
Step 2. The ASN.1 encoded X.400 content and other required data is Step 2. The ASN.1 encoded X.400 content and other required data is
processed into a CMS object of type envelopedData. In addition to processed into a CMS object of type EnvelopedData. In addition to
encrypting a copy of the content-encryption key for each recipient, a encrypting a copy of the content-encryption key for each recipient, a
copy of the content encryption key SHOULD be encrypted for the copy of the content encryption key SHOULD be encrypted for the
originator and included in the envelopedData (see CMS Section 6). originator and included in the envelopedData (see CMS Section 6).
Step 3. Optionally the CMS object may be inserted into an Step 3. Optionally the CMS object may be inserted into an
application/pkcs7-mime MIME entity to allow for 7-bit transport. application/pkcs7-mime MIME entity to allow for 7-bit transport.
If the application/pkcs7-mime MIME entity is used, the smime-type If the application/pkcs7-mime MIME entity is used, the smime-type
parameter for enveloped-only messages is "enveloped-x400". parameter for enveloped-only messages is "enveloped-x400".
3.4 Nested CMS Structures 3.4 Nested CMS Structures
To achieve signing and enveloping, any of the signed-only and To achieve signing and enveloping, any of the signed-only and
encrypted-only CMS objects may be nested. encrypted-only CMS objects may be nested.
When nesting is used, backwards compatibility with S/MIME version 2 When nesting is used, backwards compatibility with S/MIME version 2
requires that each layer of the nested message are identified with the requires that each layer of the nested message are identified with the
OID id-data, and when is-data is used a MIME wrapper is required. This OID id-data, and when id-data is used a MIME wrapper is required. This
can potentially lead to an enormous amount of overhead and should be can potentially lead to an enormous amount of overhead and should be
avoided. If S/MIME version 2 compatibility is of no concern, avoided. If S/MIME version 2 compatibility is of no concern,
implementations should use id-ct-contentInfo to circumvent the MIME implementations should use id-ct-contentInfo to circumvent the MIME
wrappers. wrappers.
MIME wrapping to support 7-bit transport, is optional and need only be MIME wrapping to support 7-bit transport, is optional and need only be
used around the outermost CMS structure. In this case, the used around the outermost CMS structure. In this case, the
application/pkcs7 content type MUST be used. application/pkcs7 content type MUST be used.
An S/MIME implementation MUST be able to receive and process arbitrarily An S/MIME implementation MUST be able to receive and process arbitrarily
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The Enhanced Security Services for S/MIME [ESS] document provides The Enhanced Security Services for S/MIME [ESS] document provides
examples of how nested, secured S/MIME messages are formatted. ESS examples of how nested, secured S/MIME messages are formatted. ESS
provides an example of how a triple-wrapped S/MIME message is formatted provides an example of how a triple-wrapped S/MIME message is formatted
using application/pkcs7-mime for the signatures. using application/pkcs7-mime for the signatures.
This section explains how an X.400 content may be conveyed within a This section explains how an X.400 content may be conveyed within a
Triple Wrapped Message if S/MIME version 2 compatibility is of no Triple Wrapped Message if S/MIME version 2 compatibility is of no
concern: concern:
1. Start with the X.400 content (called the "original content"). The Step 1. Start with the X.400 content (called the "original content").
X.400 content MUST be ASN.1 encoded, but SHOULD NOT be MIME wrapped. The X.400 content MUST be ASN.1 encoded, but SHOULD NOT be MIME wrapped.
2. Place the protected ASN.1 encoded X.400 content in the eContent field Step 2. Place the protected ASN.1 encoded X.400 content in the
of the signedData element. Add any attributes to be signed. SignedData encapContentInfo eContent field. Add any attributes to be
signed.
3. Sign the result of step 2 (the original content). The SignedData Step 3. Sign the result of step 2 (the original content). The SignedData
encapContentInfo eContentType MUST contain the object identifier of the encapContentInfo eContentType MUST contain the object identifier of the
X.400 content. The SignedData structure is encapsulated by a ContentInfo X.400 content. The SignedData structure is encapsulated by a ContentInfo
SEQUENCE with a contentType of id-signedData. SEQUENCE with a contentType of id-signedData.
4. Encrypt the result of step 3 as a single block. The EnvelopedData Step 4. Encrypt the result of step 3 as a single block. The
encryptedContentInfo contentType MUST be set to id-ct-contentInfo. This EnvelopedData encryptedContentInfo contentType MUST be set to
is called the "encrypted body". The EnvelopedData structure is id-ct-contentInfo. This is called the "encrypted body". The
encapsulated by a ContentInfo SEQUENCE with a contentType of EnvelopedData structure is encapsulated by a ContentInfo SEQUENCE with a
id-envelopedData. contentType of id-envelopedData.
5. Using the same logic as in step 2 and 3 above, sign the result of Step 5. Using the same logic as in step 2 and 3 above, sign the result
step 5 (the encrypted body) as a single block. The SignedData structure of step 5 (the encrypted body) as a single block. The SignedData
is encapsulated by a ContentInfo SEQUENCE with a contentType of structure is encapsulated by a ContentInfo SEQUENCE with a contentType
id-signedData. of id-signedData.
6. The resulting message is called the "outer signature", and is also Step 6. The resulting message is called the "outer signature", and is
the triple wrapped message. also the triple wrapped message.
MIME wrapping to support 7 bit transport, is optional and MUST only be MIME wrapping to support 7 bit transport, is optional and MUST only be
used around the outermost CMS structure. In this case, the used around the outermost CMS structure. In this case, the
application/pkcs7-mime content type MUST be used. application/pkcs7-mime content type MUST be used.
3.6 Certificate Enrollment 3.6 Certificate Enrollment
S/MIME v3 does not specify how to get a certificate from a certificate S/MIME v3 does not specify how to get a certificate from a certificate
authority, but instead mandates that every sending agent already has a authority, but instead mandates that every sending agent already has a
certificate. The PKIX Working Group of the IETF has, at the time of this certificate. The PKIX Working Group of the IETF has, at the time of this
writing, produced two separate standards for certificate enrollment. writing, produced two separate standards for certificate enrollment:
CMP (RFC 2510) and CMC(RFC 2792).
4. Certificate Processing 4. Certificate Processing
A receiving agent MUST provide some certificate retrieval mechanism in A receiving agent MUST provide some certificate retrieval mechanism in
order to gain access to certificates for recipients of digital order to gain access to certificates for recipients of digital
envelopes. This document does not cover how S/MIME agents handle envelopes. This document does not cover how S/MIME agents handle
certificates, only what they do after a certificate has been validated certificates, only what they do after a certificate has been validated
or rejected. S/MIME certification issues are covered in [CERT3]. or rejected. S/MIME certification issues are covered in [CERT3].
At a minimum, for initial S/MIME deployment, a user agent could At a minimum, for initial S/MIME deployment, a user agent could
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[SHA1] NIST FIPS PUB 180-1, "Secure Hash Standard," National [SHA1] NIST FIPS PUB 180-1, "Secure Hash Standard," National
Institute of Standards and Technology, U.S. Department of Commerce, 31 Institute of Standards and Technology, U.S. Department of Commerce, 31
May 1994. May 1994.
[X.400] ITU-T X.400 Series of Recommendations, Information technology [X.400] ITU-T X.400 Series of Recommendations, Information technology
- Message Handling Systems (MHS). X.400: System and Service Overview; - Message Handling Systems (MHS). X.400: System and Service Overview;
X.402: Overall Architecture; X.411: Message Transfer System: Abstract X.402: Overall Architecture; X.411: Message Transfer System: Abstract
Service Definition and Procedures; X.420: Interpersonal Messaging Service Definition and Procedures; X.420: Interpersonal Messaging
System; 1996. System; 1996.
B. Editor's Address B. Differences between version -00 and -01
Many small corrections from Bill Ottaway.
3.2 and 3.3: Clarified, based on the mailing list discussion with Graeme
Lunt. The new sentence reads: "Note that this X.400 content SHOULD
maintain the encoding defined by the content type, but SHOULD NOT be
MIME wrapped." Also made many small corrections to these sections to
make the ASN.1 objects and fields clearer.
C. Editor's Address
Paul Hoffman Paul Hoffman
Internet Mail Consortium Internet Mail Consortium
127 Segre Place 127 Segre Place
Santa Cruz, CA 95060 USA Santa Cruz, CA 95060 USA
phoffman@imc.org phoffman@imc.org
Chris Bonatti Chris Bonatti
IECA, Inc. IECA, Inc.
bonattic@ieca.com bonattic@ieca.com
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