CBOR Object Signing and Encryption (cose) Internet Drafts

      
 CBOR Encoded X.509 Certificates (C509 Certificates)
 
 draft-ietf-cose-cbor-encoded-cert-15.txt
 Date: 18/08/2025
 Authors: John Mattsson, Goeran Selander, Shahid Raza, Joel Hoglund, Martin Furuhed
 Working Group: CBOR Object Signing and Encryption (cose)
 This document specifies a CBOR encoding of X.509 certificates. The resulting certificates are called C509 Certificates. The CBOR encoding supports a large subset of RFC 5280 and all certificates compatible with the RFC 7925, IEEE 802.1AR (DevID), CNSA 1.0, RPKI, GSMA eUICC, and CA/Browser Forum Baseline Requirements profiles. C509 is deployed in different settings including, in-vehicle and vehicle-to-cloud communication, Unmanned Aircraft Systems (UAS), and Global Navigation Satellite System (GNSS). When used to re-encode DER encoded X.509 certificates, the CBOR encoding can in many cases reduce the size of RFC 7925 profiled certificates by over 50% while also significantly reducing memory and code size compared to ASN.1. The CBOR encoded structure can alternatively be signed directly ("natively signed"), which does not require re-encoding for the signature to be verified. The TLSA selectors registry defined in RFC 6698 is extended to include C509 certificates. The document also specifies C509 Certificate Requests, C509 COSE headers, a C509 TLS certificate type, and a C509 file format.
 Use of Hybrid Public-Key Encryption (HPKE) with CBOR Object Signing and Encryption (COSE)
 
 draft-ietf-cose-hpke-18.txt
 Date: 19/10/2025
 Authors: Hannes Tschofenig, Orie Steele, Ajitomi, Daisuke, Laurence Lundblade
 Working Group: CBOR Object Signing and Encryption (cose)
 This specification defines hybrid public-key encryption (HPKE) for use with CBOR Object Signing and Encryption (COSE). HPKE offers a variant of public-key encryption of arbitrary-sized plaintexts for a recipient public key. HPKE is a general encryption framework utilizing an asymmetric key encapsulation mechanism (KEM), a key derivation function (KDF), and an Authenticated Encryption with Associated Data (AEAD) algorithm. This document defines the use of HPKE with COSE. Authentication for HPKE in COSE is provided by COSE-native security mechanisms or by the pre-shared key authenticated variant of HPKE.
 Barreto-Lynn-Scott Elliptic Curve Key Representations for JOSE and COSE
 
 draft-ietf-cose-bls-key-representations-07.txt
 Date: 20/07/2025
 Authors: Tobias Looker, Michael Jones
 Working Group: CBOR Object Signing and Encryption (cose)
 This specification defines how to represent cryptographic keys for the pairing-friendly elliptic curves known as Barreto-Lynn-Scott (BLS), for use with the key representation formats of JSON Web Key (JWK) and COSE (COSE_Key). Discussion Venues This note is to be removed before publishing as an RFC. Source for this draft and an issue tracker can be found at https://github.com/tplooker/draft-ietf-cose-bls-key-representations.
 ML-DSA for JOSE and COSE
 
 draft-ietf-cose-dilithium-10.txt
 Date: 14/10/2025
 Authors: Michael Prorock, Orie Steele
 Working Group: CBOR Object Signing and Encryption (cose)
 This document specifies 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 US NIST FIPS 204.
 FN-DSA for JOSE and COSE
 
 draft-ietf-cose-falcon-03.txt
 Date: 12/10/2025
 Authors: Michael Prorock, Orie Steele, Hannes Tschofenig
 Working Group: CBOR Object Signing and Encryption (cose)
 This document specifies JSON Object Signing and Encryption (JOSE) and CBOR Object Signing and Encryption (COSE) serializations for FFT (fast-Fourier transform) over NTRU-Lattice-Based Digital Signature Algorithm (FN-DSA), a Post-Quantum Cryptography (PQC) digital signature scheme defined in US NIST FIPS 206 (expected to be published in late 2026 early 2027). It does not define new cryptographic primitives; rather, it specifies how existing FN-DSA mechanisms are serialized for use in JOSE and COSE. This document registers signature algorithms for JOSE and COSE, specifically FN-DSA-512 and FN-DSA-1024.
 SLH-DSA for JOSE and COSE
 
 draft-ietf-cose-sphincs-plus-06.txt
 Date: 12/10/2025
 Authors: Michael Prorock, Orie Steele, Hannes Tschofenig
 Working Group: CBOR Object Signing and Encryption (cose)
 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.
 COSE (CBOR Object Signing and Encryption) Receipts
 
 draft-ietf-cose-merkle-tree-proofs-17.txt
 Date: 10/09/2025
 Authors: Orie Steele, Henk Birkholz, Antoine Delignat-Lavaud, Cedric Fournet
 Working Group: CBOR Object Signing and Encryption (cose)
 COSE (CBOR Object Signing and Encryption) Receipts prove properties of a verifiable data structure to a verifier. Verifiable data structures and associated proof types enable security properties, such as minimal disclosure, transparency and non-equivocation. Transparency helps maintain trust over time, and has been applied to certificates, end to end encrypted messaging systems, and supply chain security. This specification enables concise transparency oriented systems, by building on CBOR (Concise Binary Object Representation) and COSE. The extensibility of the approach is demonstrated by providing CBOR encodings for Merkle inclusion and consistency proofs.
 COSE Header parameter for RFC 3161 Time-Stamp Tokens
 
 draft-ietf-cose-tsa-tst-header-parameter-08.txt
 Date: 29/08/2025
 Authors: Henk Birkholz, Thomas Fossati, Maik Riechert
 Working Group: CBOR Object Signing and Encryption (cose)
 This document defines two CBOR Signing And Encrypted (COSE) header parameters for incorporating RFC 3161-based timestamping into COSE message structures (COSE_Sign and COSE_Sign1). This enables the use of established RFC 3161 timestamping infrastructure in COSE-based protocols.
 COSE Hash Envelope
 
 draft-ietf-cose-hash-envelope-09.txt
 Date: 22/10/2025
 Authors: Orie Steele, Steve Lasker, Henk Birkholz
 Working Group: CBOR Object Signing and Encryption (cose)
 This document defines new COSE header parameters for signaling a payload as an output of a hash function. This mechanism enables faster validation, as access to the original payload is not required for signature validation. Additionally, hints of the detached payload's content format and availability are defined, providing references to optional discovery mechanisms that can help to find original payload content.

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CBOR Object Signing and Encryption (cose)

WG Name CBOR Object Signing and Encryption
Acronym cose
Area Security Area (sec)
State Active
Charter charter-ietf-cose-05 Approved
Document dependencies
Additional resources Issue tracker, Wiki, Zulip Stream
Personnel Chairs Ivaylo Petrov, Michael B. Jones
Area Director Paul Wouters
Mailing list Address cose@ietf.org
To subscribe https://www.ietf.org/mailman/listinfo/cose
Archive https://mailarchive.ietf.org/arch/browse/cose/
Chat Room address https://zulip.ietf.org/#narrow/stream/cose

Charter for Working Group

CBOR Object Signing and Encryption (COSE, RFC 9052) describes how to
create and process signatures, message authentication codes, and
encryption using Concise Binary Object Representation (CBOR, RFC 8949)
for serialization. COSE additionally describes a representation for
cryptographic keys.

The COSE working group handles four types of (intended status Standard Track) documents:

  1. Documents that describe the use of cryptographic algorithms in COSE.
  2. Documents that describe additional attributes for COSE.
  3. Documents that define header parameters to be used in COSE objects.
  4. Documents that define COSE key representations.

The WG will evaluate, and potentially adopt, documents dealing with algorithms
that would fit the criteria of being IETF consensus algorithms.

Key management and binding of keys to identities are out of scope for
the working group. The COSE WG will not innovate in terms of
cryptography. The specification of algorithms in COSE is limited to
those in RFCs, active IRTF CFRG or IETF WG documents, or algorithms which
have been positively reviewed by the IRTF CFRG.

The COSE WG will also work on a CBOR encoding of the certificate profile
defined in RFC 5280. It is expected that the encoding works with RFC 7925.
The main objective is to define a method of encoding current X.509
certificates that meet a specific profile into a smaller format. This
encoding shall be invertible, so they can be expanded and normal X.509 certificate
processing can be used. This work is currently happening in draft-ietf-cose-cbor-encoded-cert.

Milestones

Date Milestone Associated documents
Jan 2026 One or more documents describing the proper use of algorithms. draft-ietf-cose-sphincs-plus
draft-ietf-cose-hpke
draft-ietf-cose-dilithium
draft-ietf-cose-falcon
Nov 2025 A CBOR encoding of the certificate profile to the IESG draft-ietf-cose-cbor-encoded-cert
Jul 2025 COSE header parameters for COSE objects that carry a payload that is an output of a hash function on an original payload to IESG draft-ietf-cose-hash-envelope
Jun 2025 COSE header parameters for incorporating “COSE Receipts” into COSE objects to IESG draft-ietf-cose-merkle-tree-proofs
Jun 2025 COSE header parameters for RFC 3161-based timestamping into COSE objects to IESG draft-ietf-cose-tsa-tst-header-parameter