draft-ietf-smime-sha2-03.txt   draft-ietf-smime-sha2-04.txt 
S/MIME WG Sean Turner, IECA S/MIME WG Sean Turner, IECA
Intended Status: Standard Track Intended Status: Standard Track
Expires: July 30, 2008 Expires: September 11, 2008
Using SHA2 Algorithms with Cryptographic Message Syntax Using SHA2 Algorithms with Cryptographic Message Syntax
draft-ietf-smime-sha2-03.txt draft-ietf-smime-sha2-04.txt
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Abstract Abstract
This document describes the conventions for using the message digest This document describes the conventions for using the Secure Hash
algorithms SHA-224, SHA-256, SHA-384, SHA-512, as defined in FIPS Algorithm (SHA) message digest algorithms (SHA-224, SHA-256, SHA-384,
180-3, with the Cryptographic Message Syntax (CMS). It also describes SHA-512) with the Cryptographic Message Syntax (CMS). It also
the conventions for using these algorithms with CMS and the DSA, RSA, describes the conventions for using these algorithms with CMS and the
and ECDSA signature algorithms. Digital Signature Algorithm (DSA), Rivest Shamir Adleman (RSA), and
Elliptic Curve DSA (ECDSA) signature algorithms.
Conventions used in this document Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
Table of Contents Table of Contents
1. Introduction...................................................2 1. Introduction...................................................2
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5. IANA Considerations............................................7 5. IANA Considerations............................................7
6. References.....................................................7 6. References.....................................................7
6.1. Normative References......................................7 6.1. Normative References......................................7
6.2. Informative References....................................8 6.2. Informative References....................................8
1. Introduction 1. Introduction
This document specifies the algorithm identifiers and specifies This document specifies the algorithm identifiers and specifies
parameters for the message digest algorithms SHA-224, SHA-256, SHA- parameters for the message digest algorithms SHA-224, SHA-256, SHA-
384, and SHA-512 for use with the Cryptographic Message Syntax (CMS) 384, and SHA-512 for use with the Cryptographic Message Syntax (CMS)
[RFC3852]. The message digest algorithms are defined in and [SHS]. [RFC3852]. The message digest algorithms are defined in [SHS].
If an implementation chooses to support one of the algorithms
discussed in this document, then the implementation MUST do so as
described in this document.
This document also specifies the algorithm identifiers and parameters This document also specifies the algorithm identifiers and parameters
for use of SHA-224, SHA-256, SHA-384, and SHA-512 with DSA, RSA, and for use of SHA-224, SHA-256, SHA-384, and SHA-512 with DSA [DSS], RSA
ECDSA. If an implementation chooses to support one of the algorithms [RFC2313], and ECDSA [X9.62].
discussed in this document, then the implementation MUST do so as
described in this document.
This document does not define new identifiers; they are taken from This document does not define new identifiers; they are taken from
[RFC3874], [RFC4055], [ECCADD], [RFC3278], and [RFC3370]. [RFC3874], [RFC4055], [ECCADD], and [RFC3278]. Additionally, the
Additionally, the parameters follow the conventions specified parameters follow the conventions specified therein. Therefore,
therein. Therefore, there is no ASN.1 module included in this there is no Abstract Syntax Notation One (ASN.1) module included in
document. this document.
Note that [RFC4231] specifies the conventions for use of for the Note that [RFC4231] specifies the conventions for the message
message authentication code (MAC) algorithms: HMAC with SHA-224, HMAC authentication code (MAC) algorithms: HMAC with SHA-224, HMAC with
with SHA-256, HMAC with SHA-384, and HMAC with SHA-512. SHA-256, HMAC with SHA-384, and HMAC with SHA-512.
In CMS, the various algorithm identifiers use the AlgorithmIdentifier In CMS, the various algorithm identifiers use the AlgorithmIdentifier
syntax, which is included here for convenience: syntax, which is included here for convenience:
AlgorithmIdentifier ::= SEQUENCE { AlgorithmIdentifier ::= SEQUENCE {
algorithm OBJECT IDENTIFIER, algorithm OBJECT IDENTIFIER,
parameters ANY DEFINED BY algorithm OPTIONAL } parameters ANY DEFINED BY algorithm OPTIONAL }
2. Message Digest Algorithms 2. Message Digest Algorithms
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Digest values are located in the DigestedData digest field and the Digest values are located in the DigestedData digest field and the
Message Digest authenticated attribute. In addition, digest values Message Digest authenticated attribute. In addition, digest values
are input to signature algorithms. are input to signature algorithms.
The digest algorithm identifiers use the AlgorithmIdentifier syntax The digest algorithm identifiers use the AlgorithmIdentifier syntax
elaborated upon in Section 1. elaborated upon in Section 1.
The algorithm field is discussed in Sections 2.1-2.4 for each message The algorithm field is discussed in Sections 2.1-2.4 for each message
digest algorithm. digest algorithm.
The following addresses the parameters field:
There are two possible encodings for the SHA AlgorithmIdentifier There are two possible encodings for the SHA AlgorithmIdentifier
parameters field. The two alternatives arise from the fact that when parameters field. The two alternatives arise from the fact that when
the 1988 syntax for AlgorithmIdentifier was translated into the 1997 the 1988 syntax for AlgorithmIdentifier was translated into the 1997
syntax, the OPTIONAL associated with the AlgorithmIdentifier syntax, the OPTIONAL associated with the AlgorithmIdentifier
parameters got lost. Later the OPTIONAL was recovered via a defect parameters got lost. Later the OPTIONAL was recovered via a defect
report, but by then many people thought that algorithm parameters report, but by then many people thought that algorithm parameters
were mandatory. Because of this history some implementations encode were mandatory. Because of this history some implementations encode
parameters as a NULL element and others omit them entirely. The parameters as a NULL element and others omit them entirely. The
correct encoding is to omit the parameters field; however, correct encoding is to omit the parameters field; however,
implementations MUST also handle a SHA AlgorithmIdentifier parameters implementations MUST also handle a SHA AlgorithmIdentifier parameters
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algorithm identifier for SHA-384 is: algorithm identifier for SHA-384 is:
id-sha384 OBJECT IDENTIFIER ::= { id-sha384 OBJECT IDENTIFIER ::= {
joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
csor(3) nistalgorithm(4) hashalgs(2) 2 } csor(3) nistalgorithm(4) hashalgs(2) 2 }
The parameters are as specified in Section 2. The parameters are as specified in Section 2.
2.4. SHA-512 2.4. SHA-512
The SHA-256 message digest algorithm is defined in [SHS]. The The SHA-512 message digest algorithm is defined in [SHS]. The
algorithm identifier for SHA-512 is: algorithm identifier for SHA-512 is:
id-sha512 OBJECT IDENTIFIER ::= { id-sha512 OBJECT IDENTIFIER ::= {
joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101)
csor(3) nistalgorithm(4) hashalgs(2) 3 } csor(3) nistalgorithm(4) hashalgs(2) 3 }
The parameters are as specified in Section 2. The parameters are as specified in Section 2.
3. Signature Algorithms 3. Signature Algorithms
This section specifies the conventions employed by CMS This section specifies the conventions employed by CMS
implementations that support DSA [DSS], ECDSA [X9.62], and RSA implementations that support DSA, RSA, and ECDSA with SHA2
[RFC2313] with SHA2 algorithms. algorithms.
Signature algorithm identifiers are located in the SignerInfo Signature algorithm identifiers are located in the SignerInfo
signatureAlgorithm field of SignedData. Also, signature algorithm signatureAlgorithm field of SignedData. Also, signature algorithm
identifiers are located in the SignerInfo signatureAlgorithm field of identifiers are located in the SignerInfo signatureAlgorithm field of
countersignature attributes. countersignature attributes.
Signature values are located in the SignerInfo signature field of Signature values are located in the SignerInfo signature field of
SignedData. Also, signature values are located in the SignerInfo SignedData. Also, signature values are located in the SignerInfo
signature field of countersignature attributes. signature field of countersignature attributes.
NOTE [to be removed upon publication as an RFC]: NIST has not yet
finalized FIPS 186-3 and there is a chance that the draft may be
changed. This may result in differences between what is documented
in the current version of this document and what is in the FIPS. It
is intended to synchronize the final version of this draft with the
FIPS before publication as an RFC.
3.1. DSA 3.1. DSA
[RFC3370] section 3.1 specifies the conventions for DSA with SHA1 [RFC3370] section 3.1 specifies the conventions for DSA with SHA1
public key algorithm identifiers, parameters, public keys, and public key algorithm identifiers, parameters, public keys, and
signature values. DSA with SHA2 algorithms uses the same conventions signature values. DSA with SHA2 algorithms uses the same conventions
for these public key algorithm identifiers, parameters, public keys, for these public key algorithm identifiers, parameters, public keys,
and signature values. DSA MAY be used with SHA-224 and SHA-256. and signature values. DSA MAY be used with SHA-224 and SHA-256.
DSA has not been specified with SHA-384 and SHA-512. SHA-384 and
SHA-512 are not supported because the maximum bit length of p
(specified as L) is 3072 for DSA. For consistent cryptographic
strength, SHA-384 would be used with DSA where L is 7068, and SHA-512
would be used with DSA where L is 15360.
The algorithm identifier for DSA with SHA-224 signature values is: The algorithm identifier for DSA with SHA-224 signature values is:
id-dsa-with-sha224 OBJECT IDENTIFIER ::= { joint-iso-ccitt(2) id-dsa-with-sha224 OBJECT IDENTIFIER ::= { joint-iso-ccitt(2)
country(16) us(840) organization(1) gov(101) csor(3) country(16) us(840) organization(1) gov(101) csor(3)
algorithms(4) id-dsa-with-sha2(3) 1 } algorithms(4) id-dsa-with-sha2(3) 1 }
The algorithm identifier for DSA with SHA-224 signature values is: The algorithm identifier for DSA with SHA-256 signature values is:
id-dsa-with-sha256 OBJECT IDENTIFIER ::= { joint-iso-ccitt(2) id-dsa-with-sha256 OBJECT IDENTIFIER ::= { joint-iso-ccitt(2)
country(16) us(840) organization(1) gov(101) csor(3) country(16) us(840) organization(1) gov(101) csor(3)
algorithms(4) id-dsa-with-sha2(3) 2 } algorithms(4) id-dsa-with-sha2(3) 2 }
When either of these algorithm identifiers is used, the When either of these algorithm identifiers is used, the
AlgorithmIdentifier parameters field MUST be absent. AlgorithmIdentifier parameters field MUST be absent.
3.2. RSA 3.2. RSA
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MUST accept the parameters being absent as well as present. MUST accept the parameters being absent as well as present.
3.3. ECDSA 3.3. ECDSA
[RFC3278] section 2.1 specifies the conventions for ECDSA with SHA1 [RFC3278] section 2.1 specifies the conventions for ECDSA with SHA1
public key algorithm identifiers, parameters, public keys, and public key algorithm identifiers, parameters, public keys, and
signature values. ECDSA with SHA2 algorithms uses the same signature values. ECDSA with SHA2 algorithms uses the same
conventions for these public key algorithm identifiers, parameters, conventions for these public key algorithm identifiers, parameters,
public keys, and signature values, except that the digestAlgorithm public keys, and signature values, except that the digestAlgorithm
MUST include the corresponding message digest algorithm identifier, MUST include the corresponding message digest algorithm identifier,
and not sha-1 object identifier. ECDSA MAY be used with SHA-224, and not the sha-1 object identifier. ECDSA MAY be used with SHA-224,
SHA-256, SHA-384, or SHA-512. SHA-256, SHA-384, or SHA-512.
The algorithm identifier for ECDSA with SHA-224 signature values is: The algorithm identifier for ECDSA with SHA-224 signature values is:
ecdsa-with-SHA224 OBJECT IDENTIFIER ::= { iso(1) member-body(2) ecdsa-with-SHA224 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 1 } us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 1 }
The algorithm identifier for ECDSA with SHA-256 signature values is: The algorithm identifier for ECDSA with SHA-256 signature values is:
ecdsa-with-SHA256 OBJECT IDENTIFIER ::= { iso(1) member-body(2) ecdsa-with-SHA256 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
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6. References 6. References
6.1. Normative References 6.1. Normative References
[ECCADD] Dang, S., Santesson, S., Moriarty, K., and Brown, [ECCADD] Dang, S., Santesson, S., Moriarty, K., and Brown,
"Internet X.509 Public Key Infrastructure: Additional "Internet X.509 Public Key Infrastructure: Additional
Algorithms and Identifiers for DSA and ECDSA", work-in- Algorithms and Identifiers for DSA and ECDSA", work-in-
progress. progress.
[DSS] Federal Information Processing Standards Publication [DSS] Federal Information Processing Standards Publication
(FIPS PUB) 186-3, Secure Hash Standard (SHS), July 2007. (FIPS PUB) 186-2, Secure Hash Standard (SHS), 2000.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119. March 1997. Requirement Levels", BCP 14, RFC 2119. March 1997.
[RFC2313] Kaliski, B., "PKCS #1: RSA Encryption Version 1.5", RFC [RFC2313] Kaliski, B., "PKCS #1: RSA Encryption Version 1.5", RFC
2313, March 1998. 2313, March 1998.
[RFC3278] Blake-Wilson, S., Brown, D., and P. Lambert, "Use of [RFC3278] Blake-Wilson, S., Brown, D., and P. Lambert, "Use of
Elliptic Curve Cryptography (ECC) Algorithms in Elliptic Curve Cryptography (ECC) Algorithms in
Cryptographic Message Syntax (CMS)", RFC 3278, April Cryptographic Message Syntax (CMS)", RFC 3278, April
skipping to change at page 8, line 35 skipping to change at page 8, line 35
[RFC3874] Housley, R., "A 224-bit One Way Hash Function: SHA-224", [RFC3874] Housley, R., "A 224-bit One Way Hash Function: SHA-224",
RFC 3874. September 2004. RFC 3874. September 2004.
[RFC4055] Schaad, J., Kaliski, B., and R. Housley, "Additional [RFC4055] Schaad, J., Kaliski, B., and R. Housley, "Additional
Algorithms and Identifiers for RSA Cryptography for use Algorithms and Identifiers for RSA Cryptography for use
in the Internet Public Key Infrastructure Certificate and in the Internet Public Key Infrastructure Certificate and
Certificate Revocation List (CRL) Profile", RFC 4055. Certificate Revocation List (CRL) Profile", RFC 4055.
June 2005. June 2005.
[SHS] National Institute of Standards and Technology (NIST), [SHS] National Institute of Standards and Technology (NIST),
FIPS Publication 180-3: Secure Hash Standard, June 2007. FIPS Publication 180-2: Secure Hash Standard, 2002.
[X9.62] X9.62-2005, "Public Key Cryptography for the Financial [X9.62] X9.62-2005, "Public Key Cryptography for the Financial
Services Industry: The Elliptic Curve Digital Signature Services Industry: The Elliptic Curve Digital Signature
Standard (ECDSA)", November, 2005. Standard (ECDSA)", November, 2005.
6.2. Informative References 6.2. Informative References
[RFC4231] Nystrom, A. "Identifiers and Test Vectors for HMAC-SHA- [RFC4231] Nystrom, A. "Identifiers and Test Vectors for HMAC-SHA-
224, HMAC-SHA-256, HMAC-SHA-384, and HMAC-SHA-512", 224, HMAC-SHA-256, HMAC-SHA-384, and HMAC-SHA-512",
RFC4231. December 2005. RFC4231. December 2005.
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