RFC 8702
Use of the SHAKE One-Way Hash Functions in the Cryptographic Message Syntax (CMS)
RFC 8702: Use of the SHAKE One-Way Hash Functions in the Cryptographic Message Syntax (CMS) 🦋
Okay bestie, this is RFC 8702 from the Internet Engineering Task Force (IETF) 💅 It's Request for Comments 8702, written by P. Kampanakis (Cisco Systems) and Q. Dang (NIST). It's a Standards Track doc (ISSN: 2070-1721), dated January 2020, and it updates RFC 3370. The header doesn't list anything it obsoletes. 🎀
Abstract 🌸
So this doc updates "Cryptographic Message Syntax (CMS) Algorithms" (RFC 3370) and explains how to use the SHAKE family of hash functions in CMS as one-way hash functions with RSASSA-PSS and ECDSA. It also covers the conventions for the signer public keys that go with them in CMS. ✨
Status of This Memo 📜
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community, got public review, and was approved for publication by the Internet Engineering Steering Group (IESG). For more on Internet Standards, check Section 2 of RFC 7841.
For info about the current status of this doc, any errata, and how to send feedback, go to https://www.rfc-editor.org/info/rfc8702. 🔗
Copyright Notice 💜
Copyright (c) 2020 IETF Trust and the persons identified as the document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please read these carefully, because they describe your rights and restrictions for this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions, and they're provided without warranty as described in the Simplified BSD License. 🫶
Table of Contents 🧚
1. Introduction
1.1. Terminology
2. Identifiers
3. Use in CMS
3.1. Message Digests
3.2. Signatures
3.2.1. RSASSA-PSS Signatures
3.2.2. ECDSA Signatures
3.3. Public Keys
3.4. Message Authentication Codes
4. IANA Considerations
5. Security Considerations
6. References
6.1. Normative References
6.2. Informative References
Appendix A. ASN.1 Module
Acknowledgements
Authors' Addresses1. Introduction ✨
"Cryptographic Message Syntax (CMS)" [RFC5652] is the syntax used to digitally sign, digest, authenticate, or encrypt arbitrary message contents. "Cryptographic Message Syntax (CMS) Algorithms" [RFC3370] defines how common crypto algorithms get used with CMS. This spec updates RFC 3370 and describes using SHAKE128 and SHAKE256, which are specified in [SHA3], as new hash functions in CMS. It also describes using these functions with the RSA Probabilistic Signature Scheme (RSASSA-PSS) signature algorithm [RFC8017] and the Elliptic Curve Digital Signature Algorithm (ECDSA) [X9.62], with the CMS signed-data content type. 💖
The SHA-3 family has two extendable-output functions (SHAKEs), SHAKE128 and SHAKE256. Four other hash function instances (SHA3-224, SHA3-256, SHA3-384, and SHA3-512) are also defined, but they're out of scope for this doc. 🙈 A SHAKE is a variable-length hash function defined as SHAKE(M, d), where the output is a d-bit-long digest of message M. For SHAKE128, the corresponding collision and second-preimage-resistance strengths are min(d/2,128) and min(d,128) bits, respectively (see Appendix A.1 of [SHA3]). For SHAKE256, the corresponding collision and second-preimage-resistance strengths are min(d/2,256) and min(d,256) bits, respectively. In this specification, we use d=256 (for SHAKE128) and d=512 (for SHAKE256). 🔥
A SHAKE can be used in CMS as the message digest function (to hash the message to be signed) in RSASSA-PSS and ECDSA, as the message authentication code, and as the mask generation function (MGF) in RSASSA-PSS. This spec describes the identifiers for SHAKEs to be used in CMS and what they mean. 🎀
1.1. Terminology 🍓
Okay, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be read as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. Lowercase versions are just regular words, so no stress. 🌈
2. Identifiers 🔑
This section identifies eight new object identifiers (OIDs) for using SHAKE128 and SHAKE256 in CMS. 💅
Two OIDs for the SHAKE128 and SHAKE256 hash functions are defined in [shake-nist-oids], and we include them here for convenience.
id-shake128 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2)
country(16) us(840) organization(1) gov(101) csor(3)
nistAlgorithm(4) 2 11 }
id-shake256 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2)
country(16) us(840) organization(1) gov(101) csor(3)
nistAlgorithm(4) 2 12 }When you use the id-shake128 or id-shake256 algorithm identifiers in this spec, the parameters MUST be absent. So the identifier SHALL be a SEQUENCE of one component, the OID. 👑
Heads up: "parameters MUST be absent" is a hard rule here, not a suggestion. Don't add parameters to these identifiers. 🙅♀️
[RFC8692] defines two identifiers for RSASSA-PSS signatures using SHAKEs, which we include here for convenience. 🧚
id-RSASSA-PSS-SHAKE128 OBJECT IDENTIFIER ::= { iso(1)
identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) algorithms(6) 30 }
id-RSASSA-PSS-SHAKE256 OBJECT IDENTIFIER ::= { iso(1)
identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) algorithms(6) 31 }The same RSASSA-PSS algorithm identifiers can be used for identifying public keys and signatures. 🦋
[RFC8692] also defines two algorithm identifiers for ECDSA signatures using SHAKEs, which we include here for convenience. ✨
id-ecdsa-with-shake128 OBJECT IDENTIFIER ::= { iso(1)
identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) algorithms(6) 32 }
id-ecdsa-with-shake256 OBJECT IDENTIFIER ::= { iso(1)
identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) algorithms(6) 33 }The parameters for the four RSASSA-PSS and ECDSA identifiers MUST be absent. So each identifier SHALL be a SEQUENCE of one component, the OID. It's the same no-parameters energy as before, bestie. 💀
In [shake-nist-oids], the National Institute of Standards and Technology (NIST) defines two OIDs for Keccak message authentication codes (KMACs) using SHAKE128 and SHAKE256, and we include them here for convenience. 🌸
id-KmacWithSHAKE128 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2)
country(16) us(840) organization(1) gov(101) csor(3)
nistAlgorithm(4) 2 19 }
id-KmacWithSHAKE256 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2)
country(16) us(840) organization(1) gov(101) csor(3)
nistAlgorithm(4) 2 20 }The parameters for id-KmacWithSHAKE128 and id-KmacWithSHAKE256 are OPTIONAL. You get to choose whether to include them. 🙌
Sections 3.1, 3.2.1, 3.2.2, and 3.4 specify the required output length for each use of SHAKE128 or SHAKE256 in message digests, RSASSA-PSS, ECDSA, and KMAC. So go check those sections for the lengths. 📏
3. Use in CMS 💌
3.1. Message Digests 🧁
The id-shake128 and id-shake256 OIDs (see Section 2) can be used as the digest algorithm identifiers in the SignedData, SignerInfo, DigestedData, and AuthenticatedData digestAlgorithm fields in CMS [RFC5652]. The OID encoding MUST omit the parameters field, and the output length of SHAKE128 or SHAKE256 as the message digest MUST be 32 or 64 bytes, respectively. Two rules, no drama. 💅
The digest values are located in the DigestedData field and in the Message Digest authenticated attribute included in the signedAttributes of the SignedData signerInfos. Digest values are also input to signature algorithms. The digest algorithm MUST be the same as the message hash algorithms used in signatures. 🔗
3.2. Signatures ✍️
In CMS, signature algorithm identifiers are located in the SignerInfo signatureAlgorithm field of the signed-data content type and the countersignature attribute. Signature values are located in the SignerInfo signature field of the signed-data content type and the countersignature attribute. 📦
Conforming implementations that process RSASSA-PSS and ECDSA with SHAKE signatures when processing CMS data MUST recognize the corresponding OIDs specified in Section 2. Non-negotiable, bestie. 🫶
When using RSASSA-PSS or ECDSA with SHAKEs, the RSA modulus or ECDSA curve order SHOULD be chosen in line with the SHAKE output length. For more details, look at Section 5. 🌟
3.2.1. RSASSA-PSS Signatures 🌊
The RSASSA-PSS algorithm is defined in [RFC8017]. When id-RSASSA-PSS-SHAKE128 or id-RSASSA-PSS-SHAKE256 (specified in Section 2) is used, the encoding MUST omit the parameters field. So the AlgorithmIdentifier SHALL be a SEQUENCE of one component: id-RSASSA-PSS-SHAKE128 or id-RSASSA-PSS-SHAKE256. [RFC4055] defines RSASSA-PSS-params, which are used to define the algorithms and inputs to the algorithm. This specification doesn't use parameters, because the hash, mask generation algorithm, trailer, and salt are already embedded in the OID definition. It's all baked in, iykyk. 🧠
The hash algorithm used to hash a message being signed and the hash algorithm used as the mask generation function in RSASSA-PSS MUST be the same: both SHAKE128 or both SHAKE256. The output length of the hash algorithm that hashes the message SHALL be 32 bytes (for SHAKE128) or 64 bytes (for SHAKE256). ✨
The mask generation function takes an octet string of variable length and a desired output length as input, and outputs an octet string of the desired length. In RSASSA-PSS with SHAKEs, the SHAKEs MUST be used natively as the MGF, instead of the MGF1 algorithm that uses the hash function in multiple iterations, as specified in Appendix B.2.1 of [RFC8017]. In other words, the MGF is defined as SHAKE128 or SHAKE256, with input being the mgfSeed for id-RSASSA-PSS-SHAKE128 and id-RSASSA-PSS-SHAKE256, respectively. The mgfSeed is an octet string used as the seed to generate the mask [RFC8017]. As explained in Step 9 of Section 9.1.1 of [RFC8017], the output length of the MGF is emLen - hLen - 1 bytes. emLen is the maximum message length ceil((n-1)/8), where n is the RSA modulus in bits. hLen is 32 and 64 bytes for id-RSASSA-PSS-SHAKE128 and id-RSASSA-PSS-SHAKE256, respectively. So, when SHAKE is used as the MGF, the SHAKE output length maskLen is (8*emLen - 264) or (8*emLen - 520) bits, respectively. 🧮
For example, when the RSA modulus n is 2048, the output length of SHAKE128 or SHAKE256 as the MGF will be 1784 or 1528 bits when id-RSASSA-PSS-SHAKE128 or id-RSASSA-PSS-SHAKE256 is used, respectively. Math checks out, periodt. 💜
The RSASSA-PSS saltLength MUST be 32 bytes for id-RSASSA-PSS-SHAKE128 or 64 bytes for id-RSASSA-PSS-SHAKE256. Finally, the trailerField MUST be 1, which represents the trailer field with hexadecimal value 0xBC [RFC8017]. And that's the vibe for the RSASSA-PSS part, bestie. 🎀
3.2.2. ECDSA Signatures ✨
Okay so ECDSA (the Elliptic Curve Digital Signature Algorithm) is defined in [X9.62] 💅. When the id-ecdsa-with-shake128 or id-ecdsa-with-shake256 algorithm identifier shows up (it's specified in Section 2), the matching SHAKE function gets used as the hash. The encoding MUST omit the parameters field. So the AlgorithmIdentifier SHALL be a SEQUENCE of one component, which is the OID id-ecdsa-with-shake128 or id-ecdsa-with-shake256. Just that one thing, no extras 🫶
For simplicity and compliance with the ECDSA standard specification [X9.62], the output length of the hash function must be explicitly determined. The output length for SHAKE128 or SHAKE256 used in ECDSA MUST be 32 or 64 bytes, respectively. Non-negotiable, bestie 💀
Conforming Certification Authority (CA) implementations that generate ECDSA with SHAKE signatures in certificates or Certificate Revocation Lists (CRLs) SHOULD generate those signatures with a deterministically generated, nonrandom k, following all the requirements in [RFC6979] 🌸 They MAY also generate signatures following all the other recommendations in [X9.62] or [SEC1] if they have a stated policy that requires conformance to those standards. Those standards never specified SHAKE128 and SHAKE256 as hash algorithm options, though. Still, SHAKE128 and SHAKE256 with output lengths of 32 and 64 octets can be used instead of 256 and 512-bit output hash algorithms, like SHA256 and SHA512. It's giving substitute energy 🦋
3.3. Public Keys 🔑
In CMS, the signer's public key algorithm identifiers live in the OriginatorPublicKey's algorithm attribute. The conventions and encoding for RSASSA-PSS and ECDSA public key algorithm identifiers are as specified in Section 2.3 of [RFC3279], Section 3.1 of [RFC4055], and Section 2.1 of [RFC5480] 📖
Traditionally, the rsaEncryption object identifier is used to identify RSA public keys. rsaEncryption keeps identifying the public key when the RSA private key owner doesn't want to limit the key to RSASSA-PSS with SHAKEs. The plot twist: when the RSA private key owner does want to limit the public key exclusively to RSASSA-PSS, the AlgorithmIdentifier for RSASSA-PSS defined in Section 2 SHOULD be used as the algorithm attribute in the OriginatorPublicKey sequence. Conforming client implementations that process RSASSA-PSS with SHAKE public keys in CMS message MUST recognize the corresponding OIDs in Section 2. Main character energy 👑
Conforming implementations MUST specify and process the algorithms explicitly, using the OIDs from Section 2, when encoding ECDSA with SHAKE public keys in CMS messages. No guessing allowed 🙈
The identifier parameters, as explained in Section 2, MUST be absent. Literally no parameters, periodt ✨
3.4. Message Authentication Codes 🔐
Keccak message authentication code (KMAC) is specified in [SP800-185]. In CMS, KMAC algorithm identifiers are located in the AuthenticatedData macAlgorithm field. The KMAC values are located in the AuthenticatedData mac field 🧚
When the id-KmacWithSHAKE128 or id-KmacWithSHAKE256 OID is used as the MAC algorithm identifier, the parameters field is optional (absent or present). If it's absent, the SHAKE256 output length used in KMAC is 32 or 64 bytes, respectively, and the customization string is an empty string by default. Two options, both valid, iconic 🌈
Conforming implementations that process KMACs with the SHAKEs when processing CMS data MUST recognize these identifiers. No skipping them 💜
When calculating the KMAC output, the variable N is 0xD2B282C2, S is an empty string, and L (the integer representing the requested output length in bits) is 256 or 512 for KmacWithSHAKE128 or KmacWithSHAKE256, respectively, in this specification. Bookmark that one 🍓
4. IANA Considerations 🦋
One object identifier for the ASN.1 module in Appendix A was updated in the "Structure of Management Information (SMI) Security for S/MIME Module Identifier (1.2.840.113549.1.9.16.0)" registry:
+---------+----------------------+------------+
| Decimal | Description | References |
+=========+======================+============+
| 70 | CMSAlgsForSHAKE-2019 | RFC 8702 |
+---------+----------------------+------------+
Table 15. Security Considerations 🚨
This document updates [RFC3370]. The security considerations section of that document applies to this specification as well. Read it, no skipping 😭
NIST has defined appropriate use of the hash functions in terms of the algorithm strengths and expected time frames for secure use in Special Publications (SPs) [SP800-78-4] and [SP800-107]. These documents can be used as guides to choose appropriate key sizes for various security scenarios 📚
SHAKE128 with an output length of 32 bytes offers 128 bits of collision and preimage resistance. Thus, SHAKE128 OIDs in this specification are RECOMMENDED with a 2048- (112-bit security) or 3072-bit (128-bit security) RSA modulus, or curves with a group order of 256 bits (128-bit security). SHAKE256 with a 64-byte output length offers 256 bits of collision and preimage resistance. Thus, the SHAKE256 OIDs in this specification are RECOMMENDED with a 4096-bit RSA modulus or higher, or curves with a group order of at least 512 bits, such as NIST curve P-521 (256-bit security). Note that we recommended a 4096-bit RSA because we would need a 15360-bit modulus for 256 bits of security, which is impractical for today's technology 🥹
When more than two parties share the same message-authentication key, data origin authentication is not provided. Any party that knows the message-authentication key can compute a valid MAC, so the content could originate from any one of the parties. Trust no one, not even your group chat 🙈💀
6. References 📚
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3370] Housley, R., "Cryptographic Message Syntax (CMS)
Algorithms", RFC 3370, DOI 10.17487/RFC3370, August 2002,
<https://www.rfc-editor.org/info/rfc3370>.
[RFC4055] Schaad, J., Kaliski, B., and R. Housley, "Additional
Algorithms and Identifiers for RSA Cryptography for use in
the Internet X.509 Public Key Infrastructure Certificate and
Certificate Revocation List (CRL) Profile", RFC 4055,
DOI 10.17487/RFC4055, June 2005,
<https://www.rfc-editor.org/info/rfc4055>.
[RFC5480] Turner, S., Brown, D., Yiu, K., Housley, R., and T. Polk,
"Elliptic Curve Cryptography Subject Public Key
Information", RFC 5480, DOI 10.17487/RFC5480, March 2009,
<https://www.rfc-editor.org/info/rfc5480>.
[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
RFC 5652, DOI 10.17487/RFC5652, September 2009,
<https://www.rfc-editor.org/info/rfc5652>.
[RFC8017] Moriarty, K., Ed., Kaliski, B., Jonsson, J., and A. Rusch,
"PKCS #1: RSA Cryptography Specifications Version 2.2",
RFC 8017, DOI 10.17487/RFC8017, November 2016,
<https://www.rfc-editor.org/info/rfc8017>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[SHA3] National Institute of Standards and Technology (NIST),
"SHA-3 Standard: Permutation-Based Hash and Extendable-
Output Functions", FIPS PUB 202,
DOI 10.6028/NIST.FIPS.202, August 2015,
<https://nvlpubs.nist.gov/nistpubs/FIPS/
NIST.FIPS.202.pdf>.
[SP800-185]
National Institute of Standards and Technology (NIST),
"SHA-3 Derived Functions: cSHAKE, KMAC, TupleHash and
ParallelHash", NIST Special Publication 800-185,
DOI 10.6028/NIST.SP.800-185, December 2016,
<http://nvlpubs.nist.gov/nistpubs/SpecialPublications/
NIST.SP.800-185.pdf>.6.2. Informative References
[CMS-SHA3] Housley, R., "Use of the SHA3 One-way Hash Functions in
the Cryptographic Message Syntax (CMS)", Work in Progress,
Internet-Draft, draft-housley-lamps-cms-sha3-hash-00, 27
March 2017, <https://tools.ietf.org/html/draft-housley-
lamps-cms-sha3-hash-00>.
[RFC3279] Bassham, L., Polk, W., and R. Housley, "Algorithms and
Identifiers for the Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 3279, DOI 10.17487/RFC3279, April
2002, <https://www.rfc-editor.org/info/rfc3279>.
[RFC5753] Turner, S. and D. Brown, "Use of Elliptic Curve
Cryptography (ECC) Algorithms in Cryptographic Message
Syntax (CMS)", RFC 5753, DOI 10.17487/RFC5753, January
2010, <https://www.rfc-editor.org/info/rfc5753>.
[RFC5911] Hoffman, P. and J. Schaad, "New ASN.1 Modules for
Cryptographic Message Syntax (CMS) and S/MIME", RFC 5911,
DOI 10.17487/RFC5911, June 2010,
<https://www.rfc-editor.org/info/rfc5911>.
[RFC6268] Schaad, J. and S. Turner, "Additional New ASN.1 Modules
for the Cryptographic Message Syntax (CMS) and the Public
Key Infrastructure Using X.509 (PKIX)", RFC 6268,
DOI 10.17487/RFC6268, July 2011,
<https://www.rfc-editor.org/info/rfc6268>.
[RFC6979] Pornin, T., "Deterministic Usage of the Digital Signature
Algorithm (DSA) and Elliptic Curve Digital Signature
Algorithm (ECDSA)", RFC 6979, DOI 10.17487/RFC6979, August
2013, <https://www.rfc-editor.org/info/rfc6979>.
[RFC8692] Kampanakis, P. and Q. Dang, "Internet X.509 Public Key
Infrastructure: Additional Algorithm Identifiers for
RSASSA-PSS and ECDSA Using SHAKEs", RFC 8692,
DOI 10.17487/RFC8692, December 2019,
<https://www.rfc-editor.org/info/rfc8692>.
[SEC1] Standards for Efficient Cryptography Group, "SEC 1:
Elliptic Curve Cryptography", May 2009,
<http://www.secg.org/sec1-v2.pdf>.
[shake-nist-oids]
National Institute of Standards and Technology (NIST),
"Computer Security Objects Register", October 2019,
<https://csrc.nist.gov/Projects/Computer-Security-Objects-
Register/Algorithm-Registration>.
[SP800-107]
National Institute of Standards and Technology (NIST),
"Recommendation for Applications Using Approved Hash
Algorithms", Draft NIST Special Publication 800-107
Revised, August 2012,
<https://nvlpubs.nist.gov/nistpubs/Legacy/SP/
nistspecialpublication800-107r1.pdf>.
[SP800-78-4]
National Institute of Standards and Technology (NIST),
"Cryptographic Algorithms and Key Sizes for Personal
Identity Verification", NIST Special Publication 800-78-4,
DOI 10.6028/NIST.SP.800-78-4, May 2015,
<https://nvlpubs.nist.gov/nistpubs/SpecialPublications/
NIST.SP.800-78-4.pdf>.
[X9.62] American National Standard for Financial Services (ANSI),
"Public Key Cryptography for the Financial Services
Industry: the Elliptic Curve Digital Signature Algorithm
(ECDSA)", ANSI X9.62, November 2005.Appendix A. ASN.1 Module ✨
okay bestie, this is the appendix where the whole thing gets written out as actual ASN.1 modules 🧚 it's giving formal, but we're keeping every single character exact, no cap 💅
This appendix includes the ASN.1 modules for SHAKEs in CMS. This module includes some ASN.1 from other standards for reference. 🎀
CMSAlgsForSHAKE-2019 { iso(1) member-body(2) us(840)
rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) modules(0)
id-mod-cms-shakes-2019(70) }
DEFINITIONS EXPLICIT TAGS ::=
BEGIN
-- EXPORTS ALL;
IMPORTS
DIGEST-ALGORITHM, MAC-ALGORITHM, SMIME-CAPS
FROM AlgorithmInformation-2009
{ iso(1) identified-organization(3) dod(6) internet(1) security(5)
mechanisms(5) pkix(7) id-mod(0)
id-mod-algorithmInformation-02(58) }
RSAPublicKey, rsaEncryption, id-ecPublicKey
FROM PKIXAlgs-2009 { iso(1) identified-organization(3) dod(6)
internet(1) security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-pkix1-algorithms2008-02(56) }
sa-rsassapssWithSHAKE128, sa-rsassapssWithSHAKE256,
sa-ecdsaWithSHAKE128, sa-ecdsaWithSHAKE256
FROM PKIXAlgsForSHAKE-2019 {
iso(1) identified-organization(3) dod(6)
internet(1) security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-pkix1-shakes-2019(94) } ;
-- Message digest Algorithms (mda-)
-- used in SignedData, SignerInfo, DigestedData,
-- and the AuthenticatedData digestAlgorithm
-- fields in CMS
--
-- This expands MessageAuthAlgs from [RFC5652] and
-- MessageDigestAlgs in [RFC5753]
--
-- MessageDigestAlgs DIGEST-ALGORITHM ::= {
-- mda-shake128 |
-- mda-shake256,
-- ...
-- }
--
-- One-Way Hash Functions
-- SHAKE128
mda-shake128 DIGEST-ALGORITHM ::= {
IDENTIFIER id-shake128 -- with output length 32 bytes.
}
id-shake128 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16)
us(840) organization(1) gov(101)
csor(3) nistAlgorithm(4)
hashAlgs(2) 11 }
-- SHAKE256
mda-shake256 DIGEST-ALGORITHM ::= {
IDENTIFIER id-shake256 -- with output length 64 bytes.
}
id-shake256 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16)
us(840) organization(1) gov(101)
csor(3) nistAlgorithm(4)
hashAlgs(2) 12 }
--
-- Public key algorithm identifiers located in the
-- OriginatorPublicKey's algorithm attribute in CMS.
-- And Signature identifiers used in SignerInfo
-- signatureAlgorithm field of signed-data content
-- type and countersignature attribute in CMS.
--
-- From RFC 5280, for reference:
-- rsaEncryption OBJECT IDENTIFIER ::= { pkcs-1 1 }
-- When the rsaEncryption algorithm identifier is used
-- for a public key, the AlgorithmIdentifier parameters
-- field MUST contain NULL.
--
id-RSASSA-PSS-SHAKE128 OBJECT IDENTIFIER ::= { iso(1)
identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) algorithms(6) 30 }
id-RSASSA-PSS-SHAKE256 OBJECT IDENTIFIER ::= { iso(1)
identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) algorithms(6) 31 }
-- When the id-RSASSA-PSS-* algorithm identifiers are used
-- for a public key or signature in CMS, the AlgorithmIdentifier
-- parameters field MUST be absent. The message digest algorithm
-- used in RSASSA-PSS MUST be SHAKE128 or SHAKE256 with a 32- or
-- 64-byte output length, respectively. The mask generation
-- function MUST be SHAKE128 or SHAKE256 with an output length
-- of (8*ceil((n-1)/8) - 264) or (8*ceil((n-1)/8) - 520) bits,
-- respectively, where n is the RSA modulus in bits.
-- The RSASSA-PSS saltLength MUST be 32 or 64 bytes, respectively.
-- The trailerField MUST be 1, which represents the trailer
-- field with hexadecimal value 0xBC. Regardless of
-- id-RSASSA-PSS-* or rsaEncryption being used as the
-- AlgorithmIdentifier of the OriginatorPublicKey, the RSA
-- public key MUST be encoded using the RSAPublicKey type.
-- From RFC 4055, for reference:
-- RSAPublicKey ::= SEQUENCE {
-- modulus INTEGER, -- -- n
-- publicExponent INTEGER } -- -- e
id-ecdsa-with-shake128 OBJECT IDENTIFIER ::= { iso(1)
identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) algorithms(6) 32 }
id-ecdsa-with-shake256 OBJECT IDENTIFIER ::= { iso(1)
identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) algorithms(6) 33 }
-- When the id-ecdsa-with-shake* algorithm identifiers are
-- used in CMS, the AlgorithmIdentifier parameters field
-- MUST be absent and the signature algorithm should be
-- deterministic ECDSA [RFC6979]. The message digest MUST
-- be SHAKE128 or SHAKE256 with a 32- or 64-byte output
-- length, respectively. In both cases, the ECDSA public key,
-- MUST be encoded using the id-ecPublicKey type.
-- From RFC 5480, for reference:
-- id-ecPublicKey OBJECT IDENTIFIER ::= {
-- iso(1) member-body(2) us(840) ansi-X9-62(10045) keyType(2) 1 }
-- The id-ecPublicKey parameters must be absent or present
-- and are defined as:
-- ECParameters ::= CHOICE {
-- namedCurve OBJECT IDENTIFIER
-- -- -- implicitCurve NULL
-- -- -- specifiedCurve SpecifiedECDomain
-- }
-- This expands SignatureAlgs from [RFC5912]
--
-- SignatureAlgs SIGNATURE-ALGORITHM ::= {
-- sa-rsassapssWithSHAKE128 |
-- sa-rsassapssWithSHAKE256 |
-- sa-ecdsaWithSHAKE128 |
-- sa-ecdsaWithSHAKE256,
-- ...
-- }
-- This expands MessageAuthAlgs from [RFC5652] and [RFC6268]
--
-- Message Authentication (maca-) Algorithms
-- used in AuthenticatedData macAlgorithm in CMS
--
MessageAuthAlgs MAC-ALGORITHM ::= {
maca-KMACwithSHAKE128 |
maca-KMACwithSHAKE256,
...
}
-- This expands SMimeCaps from [RFC5911]
--
SMimeCaps SMIME-CAPS ::= {
-- sa-rsassapssWithSHAKE128.&smimeCaps |
-- sa-rsassapssWithSHAKE256.&smimeCaps |
-- sa-ecdsaWithSHAKE128.&smimeCaps |
-- sa-ecdsaWithSHAKE256.&smimeCaps,
maca-KMACwithSHAKE128.&smimeCaps |
maca-KMACwithSHAKE256.&smimeCaps,
...
}
--
-- KMAC with SHAKE128
maca-KMACwithSHAKE128 MAC-ALGORITHM ::= {
IDENTIFIER id-KMACWithSHAKE128
PARAMS TYPE KMACwithSHAKE128-params ARE optional
-- If KMACwithSHAKE128-params parameters are absent,
-- the SHAKE128 output length used in KMAC is 256 bits
-- and the customization string is an empty string.
IS-KEYED-MAC TRUE
SMIME-CAPS {IDENTIFIED BY id-KMACWithSHAKE128}
}
id-KMACWithSHAKE128 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2)
country(16) us(840) organization(1)
gov(101) csor(3) nistAlgorithm(4)
hashAlgs(2) 19 }
KMACwithSHAKE128-params ::= SEQUENCE {
kMACOutputLength INTEGER DEFAULT 256, -- Output length in bits
customizationString OCTET STRING DEFAULT ''H
}
-- KMAC with SHAKE256
maca-KMACwithSHAKE256 MAC-ALGORITHM ::= {
IDENTIFIER id-KMACWithSHAKE256
PARAMS TYPE KMACwithSHAKE256-params ARE optional
-- If KMACwithSHAKE256-params parameters are absent,
-- the SHAKE256 output length used in KMAC is 512 bits
-- and the customization string is an empty string.
IS-KEYED-MAC TRUE
SMIME-CAPS {IDENTIFIED BY id-KMACWithSHAKE256}
}
id-KMACWithSHAKE256 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2)
country(16) us(840) organization(1)
gov(101) csor(3) nistAlgorithm(4)
hashAlgs(2) 20 }
KMACwithSHAKE256-params ::= SEQUENCE {
kMACOutputLength INTEGER DEFAULT 512, -- Output length in bits
customizationString OCTET STRING DEFAULT ''H
}
ENDAcknowledgements 🌸
okay so this bit is the shoutout section 🫶 this doc is based on Russ Housley's document [CMS-SHA3] 🔥. it swaps out the SHA3 hash functions for SHAKE128 and SHAKE256, which the LAMPS WG agreed on, so that's the whole glow-up ✨
the authors wanna thank Russ Housley for his guidance and super valuable contributions to the ASN.1 module 💜 and Eric Rescorla also gave valuable feedback 🎀 bestie squad goals, periodt 💅
Authors' Addresses 💌
Panos Kampanakis Cisco Systems
Email: pkampana@cisco.com
Quynh Dang NIST 100 Bureau Drive Gaithersburg, MD 20899 United States of America
Email: quynh.Dang@nist.gov
📦 where this page comes from
- ietf: rfc8702 2020-01
- 💖 girlified by claude-haiku-5-5 on : a language model's rewrite of the original, under its terms