draft-ietf-smime-sha2-08.txt   draft-ietf-smime-sha2-09.txt 
S/MIME WG Sean Turner, IECA S/MIME WG Sean Turner, IECA
Intended Status: Standard Track Intended Status: Standard Track
Expires: March 24, 2009 Expires: April 6, 2009
Using SHA2 Algorithms with Cryptographic Message Syntax Using SHA2 Algorithms with Cryptographic Message Syntax
draft-ietf-smime-sha2-08.txt draft-ietf-smime-sha2-09.txt
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Abstract Abstract
This document describes the conventions for using the Secure Hash This document describes the conventions for using the Secure Hash
Algorithm (SHA) message digest algorithms (SHA-224, SHA-256, SHA-384, Algorithm (SHA) message digest algorithms (SHA-224, SHA-256, SHA-384,
SHA-512) with the Cryptographic Message Syntax (CMS). It also SHA-512) with the Cryptographic Message Syntax (CMS). It also
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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
2. Message Digest Algorithms......................................3 2. Message Digest Algorithms......................................3
2.1. SHA-224...................................................4 2.1. SHA-224...................................................3
2.2. SHA-256...................................................4 2.2. SHA-256...................................................4
2.3. SHA-384...................................................4 2.3. SHA-384...................................................4
2.4. SHA-512...................................................4 2.4. SHA-512...................................................4
3. Signature Algorithms...........................................5 3. Signature Algorithms...........................................4
3.1. DSA.......................................................5 3.1. DSA.......................................................5
3.2. RSA.......................................................6 3.2. RSA.......................................................5
3.3. ECDSA.....................................................6 3.3. ECDSA.....................................................6
4. Security Considerations........................................7 4. Security Considerations........................................7
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 [SHS] and [RFC3852]. The message digest algorithms are defined in [SHS] and
reference code is provided in [RFC4634]. reference code is provided in [RFC4634].
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 [DSS], RSA for use of SHA-224, SHA-256, SHA-384, and SHA-512 with DSA [DSS], RSA
[RFC2313], and ECDSA [X9.62]. [RFC2313], and ECDSA [DSS].
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], and [RFC3278]. Additionally, the [RFC3874], [RFC4055], and [ECCADD]. Additionally, the parameters
parameters follow the conventions specified therein. Therefore, follow the conventions specified therein. Therefore, there is no
there is no Abstract Syntax Notation One (ASN.1) module included in Abstract Syntax Notation One (ASN.1) module included in this
this document. document.
Note that [RFC4231] specifies the conventions for the message Note that [RFC4231] specifies the conventions for the message
authentication code (MAC) algorithms: HMAC with SHA-224, HMAC with authentication code (MAC) algorithms: HMAC with SHA-224, HMAC 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
Digest algorithm identifiers are located in the SignedData Digest algorithm identifiers are located in the SignedData
digestAlgorithms field, the SignerInfo digestAlgorithm field, the digestAlgorithms field, the SignerInfo digestAlgorithm field, the
DigestedData digestAlgorithm field, and the AuthenticatedData DigestedData digestAlgorithm field, and the AuthenticatedData
digestAlgorithm field. digestAlgorithm field. The object identifiers are taken from
[RFC4055].
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.
There are two possible encodings for the SHA AlgorithmIdentifier The AlgorithmIdentifier parameters field is OPTIONAL. Implementations
parameters field. The two alternatives arise from the fact that when MUST accept SHA2 AlgorithmIdentifiers with absent parameters.
the 1988 syntax for AlgorithmIdentifier was translated into the 1997
syntax, the OPTIONAL associated with the AlgorithmIdentifier
parameters got lost. Later the OPTIONAL was recovered via a defect
report, but by then many people thought that algorithm parameters
were mandatory. Because of this history some implementations encode
parameters as a NULL element and others omit them entirely. The
correct encoding is to omit the parameters field; however,
implementations MUST also handle a SHA AlgorithmIdentifier parameters
field which contains a NULL.
The AlgorithmIdentifier parameters field is OPTIONAL. If present,
the parameters field MUST contain a NULL. Implementations MUST
accept SHA2 AlgorithmIdentifiers with absent parameters.
Implementations MUST accept SHA2 AlgorithmIdentifiers with NULL Implementations MUST accept SHA2 AlgorithmIdentifiers with NULL
parameters. Implementations SHOULD generate SHA2 parameters. Implementations MUST generate SHA2 AlgorithmIdentifiers
AlgorithmIdentifiers with absent parameters. with absent parameters.
2.1. SHA-224 2.1. SHA-224
The SHA-224 message digest algorithm is defined in [SHS]. The The SHA-224 message digest algorithm is defined in [SHS]. The
algorithm identifier for SHA-224 is: algorithm identifier for SHA-224 is:
id-sha224 OBJECT IDENTIFIER ::= { id-sha224 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) 4 } csor(3) nistalgorithm(4) hashalgs(2) 4 }
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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.
3.1. DSA 3.1. DSA
[RFC3370] section 3.1 specifies the conventions for DSA with SHA-1 [RFC3370] section 3.1 specifies the conventions for DSA with SHA-1
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. The
object identifiers are taken from [ECCADD].
DSA has not been specified with SHA-384 and SHA-512. SHA-384 and 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 SHA-512 are not supported because the maximum bit length of p
(specified as L) is 3072 for DSA. For consistent cryptographic (specified as L) is 3072 for DSA. For consistent cryptographic
strength, SHA-384 would be used with DSA where L is 7680, and SHA-512 strength, SHA-384 would be used with DSA where L is 7680, and SHA-512
would be used with DSA where L is 15360. 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)
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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
[RFC3370] section 3.2 specifies the conventions for RSA with SHA-1 [RFC3370] section 3.2 specifies the conventions for RSA with SHA-1
(PKCS #1 v1.5) public key algorithm identifiers, parameters, public (PKCS #1 v1.5) public key algorithm identifiers, parameters, public
keys, and signature values. RSA with SHA2 algorithms uses the same keys, and signature values. RSA 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. RSA (PKCS #1 v1.5) MAY be used public keys, and signature values. RSA (PKCS #1 v1.5) MAY be used
with SHA-224, SHA-256, SHA-384, or SHA-512. with SHA-224, SHA-256, SHA-384, or SHA-512. The object identifiers
are taken from [RFC4055].
The object identifier for RSA with SHA-224 signature values is: The object identifier for RSA with SHA-224 signature values is:
sha224WithRSAEncryption OBJECT IDENTIFIER ::= { iso(1) sha224WithRSAEncryption OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-1(1) 14 } member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-1(1) 14 }
The object identifier for RSA with SHA-256 signature values is: The object identifier for RSA with SHA-256 signature values is:
sha256WithRSAEncryption OBJECT IDENTIFIER ::= { iso(1) sha256WithRSAEncryption OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-1(1) 11 } member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-1(1) 11 }
The object identifier for RSA with SHA-384 signature values is: The object identifier for RSA with SHA-384 signature values is:
sha384WithRSAEncryption OBJECT IDENTIFIER ::= { iso(1) sha384WithRSAEncryption OBJECT IDENTIFIER ::= { iso(1)
member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-1(1) 12 } member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-1(1) 12 }
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3.3. ECDSA 3.3. ECDSA
[RFC3278] section 2.1 specifies the conventions for ECDSA with SHA-1 [RFC3278] section 2.1 specifies the conventions for ECDSA with SHA-1
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 the 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 object identifiers are taken from
[ECCADD].
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)
us(840)ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 2 } us(840)ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 2 }
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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)
us(840)ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 2 } us(840)ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 2 }
The algorithm identifier for ECDSA with SHA-384 signature values is: The algorithm identifier for ECDSA with SHA-384 signature values is:
ecdsa-with-SHA384 OBJECT IDENTIFIER ::= { iso(1) member-body(2) ecdsa-with-SHA384 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 3 } us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 3 }
The algorithm identifier for ECDSA with SHA-512 signature values is: The algorithm identifier for ECDSA with SHA-512 signature values is:
ecdsa-with-SHA512 OBJECT IDENTIFIER ::= { iso(1) member-body(2) ecdsa-with-SHA512 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 4 } us(840) ansi-X9-62(10045) signatures(4) ecdsa-with-SHA2(3) 4 }
When any of these four object identifiers appears within an When any of these four object identifiers appears within an
AlgorithmIdentifier, the parameters MUST omit the parameters field. AlgorithmIdentifier, the parameters filed MUST be absent. That is,
That is, the AlgorithmIdentifier SHALL be a SEQUENCE of one the AlgorithmIdentifier SHALL be a SEQUENCE of one component: the OID
component: the OID ecdsa-with-SHA224, ecdsa-with-SHA256, ecdsa-with-SHA224, ecdsa-with-SHA256,
ecdsa-with-SHA384 or ecdsa-with-SHA512. ecdsa-with-SHA384 or ecdsa-with-SHA512.
4. Security Considerations 4. Security Considerations
The security considerations in [RFC3278], [RFC3370], [RFC3874], The security considerations in [RFC3370], [RFC3874], [RFC4055], and
[RFC4055], and [ECCADD] apply. No new security considerations are [ECCADD] apply. No new security considerations are introduced as a
introduced as a result of this specification. result of this specification.
5. IANA Considerations 5. IANA Considerations
None: All identifiers are already registered. Please remove this None: All identifiers are already registered. Please remove this
section prior to publication as an RFC. section prior to publication as an RFC.
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", draft-
progress. ietf-pkix-sha2-dsa-ecdsa-04.txt (work-in-progress).
[DSS] National Institute of Standards and Technology (NIST), [DSS] National Institute of Standards and Technology (NIST),
FIPS Publication 186-3: Digital Signature Standard, March FIPS Publication 186-3: Digital Signature Standard,
2006. (draft) March 2006.
[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
Elliptic Curve Cryptography (ECC) Algorithms in
Cryptographic Message Syntax (CMS)", RFC 3278, April
2002.
[RFC3370] Housley, R., "Cryptographic Message Syntax (CMS) [RFC3370] Housley, R., "Cryptographic Message Syntax (CMS)
Algorithms", RFC 3370, August 2002. Algorithms", RFC 3370, August 2002.
[RFC3852] Housley, R., "The Cryptographic Message Syntax (CMS)", [RFC3852] Housley, R., "The Cryptographic Message Syntax (CMS)",
RFC 3852. July 2004. RFC 3852. July 2004.
[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 2003. FIPS Publication 180-3: Secure Hash Standard, (draft)
June 2003.
[X9.62] X9.62-2005, "Public Key Cryptography for the Financial
Services Industry: The Elliptic Curve Digital Signature
Standard (ECDSA)", November, 2005.
6.2. Informative References 6.2. Informative References
[RFC3278] Blake-Wilson, S., Brown, D., and P. Lambert, "Use of
Elliptic Curve Cryptography (ECC) Algorithms in
Cryptographic Message Syntax (CMS)", RFC 3278, April
2002.
[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.
[RFC4634] Eastlake, D., and T. Hansen, "US Secure Hash Algorithms [RFC4634] Eastlake, D., and T. Hansen, "US Secure Hash Algorithms
(SHA and HMAC-SHA)", RFC 4634, July 2006. (SHA and HMAC-SHA)", RFC 4634, July 2006.
Author's Addresses Author's Addresses
Sean Turner Sean Turner
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