SLH-DSA for JOSE and COSE

SLH-DSA for JOSE and COSE mesur.io

mprorock@mesur.io

Tradeverifyd

orie@or13.io

University of Applied Sciences Bonn-Rhein-Sieg

Germany hannes.tschofenig@gmx.net

Security CBOR Object Signing and Encryption JOSE COSE PQC SPHINCS+ SLH-DSA This document specifies JSON Object Signing and Encryption (JOSE) and CBOR Object Signing and Encryption (COSE) serializations for Stateless Hash-Based Digital Signature Standard (SLH-DSA), a Post-Quantum Cryptography (PQC) digital signature scheme defined in US NIST FIPS 205. About This Document The latest revision of this draft can be found at . Status information for this document may be found at . Discussion of this document takes place on the CBOR Object Signing and Encryption Working Group mailing list (), which is archived at . Subscribe at . Source for this draft and an issue tracker can be found at .

Introduction This document specifies JSON Object Signing and Encryption (JOSE) and CBOR Object Signing and Encryption (COSE) serializations for the Stateless Hash-Based Digital Signature Standard (SLH-DSA), which was derived from Version 3.1 of SPHINCS+, a Post-Quantum Cryptography (PQC) based digital signature scheme standardized in . This document builds on the Algorithm Key Pair (AKP) type, as defined in . The AKP type enables flexible representation of keys used across different post-quantum cryptographic algorithms, including SLH-DSA.

Terminology 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 interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.

The SLH-DSA Algorithm Family The SLH-DSA Signature Scheme is parameterized to support different security levels. This document introduces the registration of the following algorithms in : JOSE Algorithms for SLH-DSA

Name	alg	Description
SLH-DSA-SHA2-128s	SLH-DSA-SHA2-128s	JSON Web Signature Algorithm for SLH-DSA-SHA2-128s
SLH-DSA-SHAKE-128s	SLH-DSA-SHAKE-128s	JSON Web Signature Algorithm for SLH-DSA-SHAKE-128s
SLH-DSA-SHA2-128f	SLH-DSA-SHA2-128f	JSON Web Signature Algorithm for SLH-DSA-SHA2-128f

This document introduces the registration of the following algorithms in : COSE Algorithms for SLH-DSA

Name	alg	Description
SLH-DSA-SHA2-128s	TBD1 (-51)	CBOR Object Signing Algorithm for SLH-DSA-SHA2-128s
SLH-DSA-SHAKE-128s	TBD2 (-52)	CBOR Object Signing Algorithm for SLH-DSA-SHAKE-128s
SLH-DSA-SHA2-128f	TBD3 (-53)	CBOR Object Signing Algorithm for SLH-DSA-SHA2-128f

SLH-DSA Keys Private and public keys are produced to enable the sign and verify operations for each of the SLH-DSA algorithms. The SLH-DSA Algorithm Family uses the Algorithm Key Pair (AKP) key type, as defined in . This ensures compatibility across different cryptographic algorithms that use AKP for key representation. The specific algorithms for SLH-DSA, such as SLH-DSA-SHA2-128s, SLH-DSA-SHAKE-128s, and SLH-DSA-SHA2-128f, are defined in this document and are used in the alg value of an AKP key representation to specify the corresponding algorithm. Thumbprints for SLH-DSA keys are computed according to the process described in .

Security Considerations The security considerations of , and apply to this specification as well. A detailed security analysis of SLH-DSA is beyond the scope of this specification; see for additional details. The following considerations apply to all parameter sets described in this specification.

Validating Public Keys All algorithms that operate on public keys require validation before use. For sign, verify and proof schemes, the use of KeyValidate is REQUIRED.

Side-Channel Attacks Implementations of the signing algorithm SHOULD protect the secret key from side-channel attacks. Any implementation of SLH-DSA signing algorithms SHOULD employ at least the following best practices:

Constant-time operation
Consistent instruction sequence and memory access
Uniform sampling without information leakage

Randomness considerations All nonces MUST originate from a trusted and cryptographically secure source of randomness.

IANA Considerations

New COSE Algorithms IANA is requested to add the following entries to the COSE Algorithms Registry. The following registration templates are provided in accordance with the procedures described in and .

SLH-DSA-SHA2-128s

Name: SLH-DSA-SHA2-128s
Value: TBD1 (requested assignment -51)
Description: CBOR Object Signing Algorithm for SLH-DSA-SHA2-128s
Capabilities: [kty]
Change Controller: IETF
Reference: RFC XXXX
Recommended: Yes

SLH-DSA-SHAKE-128s

Name: SLH-DSA-SHAKE-128s
Value: TBD2 (requested assignment -52)
Description: CBOR Object Signing Algorithm for SLH-DSA-SHAKE-128s
Capabilities: [kty]
Change Controller: IETF
Reference: RFC XXXX
Recommended: Yes

SLH-DSA-SHA2-128f

Name: SLH-DSA-SHA2-128f
Value: TBD3 (requested assignment -53)
Description: CBOR Object Signing Algorithm for SLH-DSA-SHA2-128f
Capabilities: [kty]
Change Controller: IETF
Reference: RFC XXXX
Recommended: Yes

New JOSE Algorithms IANA is requested to add the following entries to the JSON Web Signature and Encryption Algorithms Registry. The following completed registration templates are provided as described in .

SLH-DSA-SHA2-128s

Algorithm Name: SLH-DSA-SHA2-128s
Algorithm Description: SLH-DSA-SHA2-128s as described in FIPS 205.
Algorithm Usage Location(s): alg
JOSE Implementation Requirements: Optional
Change Controller: IETF
Specification Document(s): RFC XXXX
Algorithm Analysis Documents(s):

SLH-DSA-SHAKE-128s

Algorithm Name: SLH-DSA-SHAKE-128s
Algorithm Description: SLH-DSA-SHAKE-128s as described in FIPS 205.
Algorithm Usage Location(s): alg
JOSE Implementation Requirements: Optional
Change Controller: IETF
Specification Document(s): RFC XXXX
Algorithm Analysis Documents(s):

SLH-DSA-SHA2-128f

Algorithm Name: SLH-DSA-SHA2-128f
Algorithm Description: SLH-DSA-SHA2-128f as described in FIPS 205.
Algorithm Usage Location(s): alg
JOSE Implementation Requirements: Optional
Change Controller: IETF
Specification Document(s): RFC XXXX
Algorithm Analysis Documents(s):

References Normative References JSON Web Signature (JWS) JSON Web Signature (JWS) represents content secured with digital signatures or Message Authentication Codes (MACs) using JSON-based data structures. Cryptographic algorithms and identifiers for use with this specification are described in the separate JSON Web Algorithms (JWA) specification and an IANA registry defined by that specification. Related encryption capabilities are described in the separate JSON Web Encryption (JWE) specification. JSON Web Key (JWK) A JSON Web Key (JWK) is a JavaScript Object Notation (JSON) data structure that represents a cryptographic key. This specification also defines a JWK Set JSON data structure that represents a set of JWKs. Cryptographic algorithms and identifiers for use with this specification are described in the separate JSON Web Algorithms (JWA) specification and IANA registries established by that specification. JSON Web Algorithms (JWA) This specification registers cryptographic algorithms and identifiers to be used with the JSON Web Signature (JWS), JSON Web Encryption (JWE), and JSON Web Key (JWK) specifications. It defines several IANA registries for these identifiers. CBOR Object Signing and Encryption (COSE): Structures and Process Concise Binary Object Representation (CBOR) is a data format designed for small code size and small message size. There is a need to be able to define basic security services for this data format. This document defines the CBOR Object Signing and Encryption (COSE) protocol. This specification describes how to create and process signatures, message authentication codes, and encryption using CBOR for serialization. This specification additionally describes how to represent cryptographic keys using CBOR. This document, along with RFC 9053, obsoletes RFC 8152. CBOR Object Signing and Encryption (COSE): Initial Algorithms Concise Binary Object Representation (CBOR) is a data format designed for small code size and small message size. There is a need to be able to define basic security services for this data format. This document defines a set of algorithms that can be used with the CBOR Object Signing and Encryption (COSE) protocol (RFC 9052). This document, along with RFC 9052, obsoletes RFC 8152. CBOR Object Signing and Encryption (COSE): Hash Algorithms The CBOR Object Signing and Encryption (COSE) syntax (see RFC 9052) does not define any direct methods for using hash algorithms. There are, however, circumstances where hash algorithms are used, such as indirect signatures, where the hash of one or more contents are signed, and identification of an X.509 certificate or other object by the use of a fingerprint. This document defines hash algorithms that are identified by COSE algorithm identifiers. ML-DSA for JOSE and COSE Tradeverifyd Tradeverifyd This document describes JSON Object Signing and Encryption (JOSE) and CBOR Object Signing and Encryption (COSE) serializations for Module- Lattice-Based Digital Signature Standard (ML-DSA), a Post-Quantum Cryptography (PQC) digital signature scheme defined in FIPS 204. Stateless Hash-Based Digital Signature Standard n.d. Key words for use in RFCs to Indicate Requirement Levels In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. Informative References JSON Object Signing and Encryption (JOSE) IANA CBOR Object Signing and Encryption (COSE) IANA

Examples

JOSE

Key Pair

Example SLH-DSA-SHA2-128s Private JSON Web Key

Example SLH-DSA-SHA2-128s Public JSON Web Key

JSON Web Signature

Example SLH-DSA-SHA2-128s Compact JSON Web Signature

COSE

Key Pair

Example SLH-DSA-SHA2-128s Private COSE Key

Example SLH-DSA-SHA2-128s Public COSE Key

COSE_Sign1 Example

Example SLH-DSA-SHA2-128s COSE Sign1 >, {}, h'66616b65', h'53e855e8...0f263549' ]) ]]>

Acknowledgments We would like to thank Roy Williams, Cedric Fournet, Simo Sorce, Ilari Liusvaara, Neil Madden, Anders Rundgren, David Waite, and Russ Housley for their review feedback.

Contributors Google

rafaelmisoczki@google.com

IBM

osb@zurich.ibm.com

NXP

christine.cloostermans@nxp.com