Internet Assigned Numbers Authority • Domains • Protocols • Numbers • About CBOR Object Signing and Encryption (COSE) Created 2017-01-11 Last Updated 2025-11-04 Available Formats [IMG] XML [IMG] HTML [IMG] Plain text Registries Included Below • COSE Header Parameters • COSE Header Algorithm Parameters • COSE Algorithms • COSE Key Common Parameters • COSE Key Type Parameters • COSE Key Types • COSE Elliptic Curves • COSE Verifiable Data Structure Algorithms • COSE Verifiable Data Structure Proofs COSE Header Parameters Expert(s) Francesca Palombini, Carsten Bormann Reference [RFC9052] Available Formats [IMG] CSV Range Registration Procedures Integers less than -65536 Private Use Integer values in the range -1 to -65536 delegated to the COSE Header Algorithm Parameters registry Integer values between 1 and 255 Standards Action With Expert Review Integer values from 256 to 65535 Specification Required Integer values greater than 65535 Expert Review Strings of length 1 Standards Action With Expert Review Strings of length 2 Specification Required Strings of length greater than 2 Expert Review Name Label Value Type Value Registry Description Reference Reserved for Private less than [RFC9052] Use -65536 delegated to the COSE -65536 to Header Algorithm -1 Parameters registry Reserved 0 [RFC9052] alg 1 int / tstr COSE Algorithms Cryptographic algorithm to [RFC9052] registry use COSE Header Critical headers to be crit 2 [+ label] Parameters understood [RFC9052] registry [COAP content type 3 tstr / uint Content-Formats] Content type of the [RFC9052] or [Media Types] payload registry kid 4 bstr Key identifier [RFC9052] IV 5 bstr Full Initialization Vector [RFC9052] Partial IV 6 bstr Partial Initialization [RFC9052] Vector COSE_Signature / [+ CBOR-encoded signature counter signature 7 COSE_Signature ] structure (Deprecated by [RFC8152] [RFC9338]) Unassigned 8 Counter signature with CounterSignature0 9 bstr implied signer and headers [RFC8152] (Deprecated by [RFC9338]) kid context 10 bstr Identifies the context for [RFC8613, Section 5.1] the key identifier Countersignature COSE_Countersignature / V2 countersignature version 2 11 [+ attribute [RFC9338] COSE_Countersignature] Countersignature0 12 COSE_Countersignature0 V2 Abbreviated [RFC9338] version 2 Countersignature A CBOR Web Token (CWT) containing a COSE_Key in a 'cnf' claim and possibly kcwt 13 COSE_Messages other claims. CWT is [RFC9528] defined in [RFC8392]. COSE_Messages is defined in [RFC9052]. A CWT Claims Set (CCS) containing a COSE_Key in a kccs 14 map 'cnf' claim and possibly [RFC9528] other claims. CCS is defined in [RFC8392]. CWT Claims 15 map map keys in [CWT Location for CWT Claims in [RFC9597, Section 2] Claims] COSE Header Parameters. [COAP typ (type) 16 uint / tstr Content-Formats] Content type of the [RFC9596, Section 2] or [Media Types] complete COSE object registry Unassigned 17-21 Hash of a C509Certificate (TEMPORARY - registered c5t 22 COSE_CertHash 2024-03-11, extension [draft-ietf-cose-cbor-encoded-cert-12] registered 2025-02-28, expires 2025-03-11) URI pointing to a COSE_C509 containing an ordered chain of c5u 23 uri certificates (TEMPORARY - [draft-ietf-cose-cbor-encoded-cert-12] registered 2024-03-11, extension registered 2025-02-28, expires 2025-03-11) An unordered bag of C509 certificates (TEMPORARY - c5b 24 COSE_C509 registered 2024-03-11, [draft-ietf-cose-cbor-encoded-cert-12] extension registered 2025-02-28, expires 2025-03-11) An ordered chain of C509 certificates (TEMPORARY - c5c 25 COSE_C509 registered 2024-03-11, [draft-ietf-cose-cbor-encoded-cert-12] extension registered 2025-02-28, expires 2025-03-11) Unassigned 26-31 x5bag 32 COSE_X509 An unordered bag of X.509 [RFC9360] certificates x5chain 33 COSE_X509 An ordered chain of X.509 [RFC9360] certificates x5t 34 COSE_CertHash Hash of an X.509 [RFC9360] certificate x5u 35 uri URI pointing to an X.509 [RFC9360] certificate Unassigned 36-255 CUPHNonce 256 bstr Challenge Nonce [FIDO Device Onboard Specification] CUPHOwnerPubKey 257 array Public Key [FIDO Device Onboard Specification] [COSE Algorithms] The hash algorithm used to payload-hash-alg 258 int registry produce the payload of a [RFC-ietf-cose-hash-envelope-09, Section 3] COSE_Sign1 The content-format number [CoAP or content-type preimage-content-type 259 uint / tstr Content-Formats] (media-type name) of data [RFC-ietf-cose-hash-envelope-09, Section 3] registry that has been hashed to produce the payload of the COSE_Sign1 The string or URI hint for payload-location 260 tstr the location of the data [RFC-ietf-cose-hash-envelope-09, Section 3] hashed to produce the payload of a COSE_Sign1 x5ts 261 array of COSE_CertHash CBOR array of instances of [Clause 5.2.2 of ETSI TS 119152-1 V0.0.9] COSE_CertHash set of commitments and srCms 262 array of SrCm optional commitments [Clause 5.2.3 of ETSI TS 119152-1 V0.0.9] qualifiers CBOR map for indicating the location where the signature was generated. It may contain an sigPl 263 map indication of the country, [Clause 5.2.4 of ETSI TS 119152-1 V0.0.9] the locality, the region, a box number in a post office, the postal code, and the street address CBOR map that may contain: an array of attributes that the signer claims to be in possession of, an array of attribute certificates (X.509 srAts 264 map attribute certificates or [Clause 5.2.5 of ETSI TS 119152-1 V0.0.9] other) issued to the signer, an array of signed assertions issued by a third party to the signer, or any combination of the three aforementioned CBOR arrays CBOR map that encapsulates one or more electronic time-stamps, generated before the signature adoTst 265 map production, and whose [Clause 5.2.6 of ETSI TS 119152-1 V0.0.9] message imprint computation input is the COSE Payload of the CB-AdES signature CBOR map that identifies a certain signature policy sigPId 266 map and may contain the digest [Clause 5.2.7 of ETSI TS 119152-1 V0.0.9] of the document defining this signature policy. CBOR map that references data objects that are sigD 267 map detached from the CB-AdES [Clause 5.2.8 of ETSI TS 119152-1 V0.0.9] signature and that are collectively signed. CBOR array that contains a number of CBOR elements uHeaders 268 [+bstr] that are placed within the [Clause 5.3.1 of ETSI TS 119152-1 V0.0.9] array in the order they are incorporated into the CB-AdES signature 3161-ttc 269 bstr [RFC3161] timestamp token: [RFC-ietf-cose-tsa-tst-header-parameter-07, Timestamp then COSE Section 3.2] 3161-ctt 270 bstr [RFC3161] timestamp token: [RFC-ietf-cose-tsa-tst-header-parameter-07, COSE then Timestamp Section 3.1] Unassigned 271-393 receipts 394 array Priority ordered sequence [RFC-ietf-cose-merkle-tree-proofs-17, of CBOR encoded Receipts Section 2] [COSE Verifiable Algorithm identifier for Data Structure verifiable data [RFC-ietf-cose-merkle-tree-proofs-17, vds 395 int Algorithms] structures, used to Section 2] registry produce verifiable data structure proofs map key in [COSE Location for verifiable vdp 396 map Verifiable Data data structure proofs in [RFC-ietf-cose-merkle-tree-proofs-17, Structure Proofs] COSE Header Parameters Section 2] registry COSE Header Algorithm Parameters Registration Procedure(s) Expert Review Expert(s) Göran Selander, Derek Atkins, Sean Turner Reference [RFC9053] Available Formats [IMG] CSV Name Algorithm Label Type Description Reference Unassigned -65536 to -30 x5chain-sender ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-SS+A128KW, -29 COSE_X509 static key X.509 [RFC9360] ECDH-SS+A192KW, ECDH-SS+A256KW certificate chain x5u-sender ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-SS+A128KW, -28 uri URI for the sender's X.509 [RFC9360] ECDH-SS+A192KW, ECDH-SS+A256KW certificate x5t-sender ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-SS+A128KW, -27 COSE_CertHash Thumbprint for the sender's [RFC9360] ECDH-SS+A192KW, ECDH-SS+A256KW X.509 certificate direct+HKDF-SHA-256, direct+HKDF-SHA-512, direct+HKDF-AES-128, direct+HKDF-AES-256, ECDH-ES+HKDF-256, ECDH-ES+HKDF-512, Party V other provided PartyV other ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-ES+A128KW, -26 bstr information [RFC9053] ECDH-ES+A192KW, ECDH-ES+A256KW, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW direct+HKDF-SHA-256, direct+HKDF-SHA-512, direct+HKDF-AES-128, direct+HKDF-AES-256, ECDH-ES+HKDF-256, ECDH-ES+HKDF-512, PartyV nonce ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-ES+A128KW, -25 bstr / int Party V provided nonce [RFC9053] ECDH-ES+A192KW, ECDH-ES+A256KW, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW direct+HKDF-SHA-256, direct+HKDF-SHA-512, direct+HKDF-AES-128, direct+HKDF-AES-256, ECDH-ES+HKDF-256, ECDH-ES+HKDF-512, Party V identity PartyV identity ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-ES+A128KW, -24 bstr information [RFC9053] ECDH-ES+A192KW, ECDH-ES+A256KW, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW direct+HKDF-SHA-256, direct+HKDF-SHA-512, direct+HKDF-AES-128, direct+HKDF-AES-256, ECDH-ES+HKDF-256, ECDH-ES+HKDF-512, Party U other provided PartyU other ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-ES+A128KW, -23 bstr information [RFC9053] ECDH-ES+A192KW, ECDH-ES+A256KW, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW direct+HKDF-SHA-256, direct+HKDF-SHA-512, direct+HKDF-AES-128, direct+HKDF-AES-256, ECDH-ES+HKDF-256, ECDH-ES+HKDF-512, PartyU nonce ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-ES+A128KW, -22 bstr / int Party U provided nonce [RFC9053] ECDH-ES+A192KW, ECDH-ES+A256KW, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW direct+HKDF-SHA-256, direct+HKDF-SHA-512, direct+HKDF-AES-128, direct+HKDF-AES-256, ECDH-ES+HKDF-256, ECDH-ES+HKDF-512, Party U identity PartyU identity ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-ES+A128KW, -21 bstr information [RFC9053] ECDH-ES+A192KW, ECDH-ES+A256KW, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW direct+HKDF-SHA-256, direct+HKDF-SHA-512, direct+HKDF-AES-128, direct+HKDF-AES-256, ECDH-ES+HKDF-256, ECDH-ES+HKDF-512, salt ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-ES+A128KW, -20 bstr Random salt [RFC9053] ECDH-ES+A192KW, ECDH-ES+A256KW, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW Unassigned -19 to -4 static key id ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-SS+A128KW, -3 bstr Static public key [RFC9053] ECDH-SS+A192KW, ECDH-SS+A256KW identifier for the sender static key ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-SS+A128KW, -2 COSE_Key Static public key for the [RFC9053] ECDH-SS+A192KW, ECDH-SS+A256KW sender ephemeral key ECDH-ES+HKDF-256, ECDH-ES+HKDF-512, ECDH-ES+A128KW, -1 COSE_Key Ephemeral public key for [RFC9053] ECDH-ES+A192KW, ECDH-ES+A256KW the sender COSE Algorithms Expert(s) Göran Selander, Derek Atkins, Sean Turner Reference [RFC9053][RFC9054][RFC9864, Section 4.2] Available Formats [IMG] CSV Range Registration Procedures Integers less than -65536 Private Use Integer values from -65536 to -257 Specification Required Integer values between -256 and 255 Standards Action With Expert Review Integer values from 256 to 65535 Specification Required Integer values greater than 65535 Expert Review Strings of length 1 Standards Action With Expert Review Strings of length 2 Specification Required Strings of length greater than 2 Expert Review Name Value Description Capabilities Change Reference Recommended Controller Reserved for Private Use less than [RFC9053] No -65536 Unassigned -65536 RS1 -65535 RSASSA-PKCS1-v1_5 using SHA-1 [kty] IESG [RFC8812][RFC9053] Deprecated A128CTR -65534 AES-CTR w/ 128-bit key [kty] IETF [RFC9459] Deprecated A192CTR -65533 AES-CTR w/ 192-bit key [kty] IETF [RFC9459] Deprecated A256CTR -65532 AES-CTR w/ 256-bit key [kty] IETF [RFC9459] Deprecated A128CBC -65531 AES-CBC w/ 128-bit key [kty] IETF [RFC9459] Deprecated A192CBC -65530 AES-CBC w/ 192-bit key [kty] IETF [RFC9459] Deprecated A256CBC -65529 AES-CBC w/ 256-bit key [kty] IETF [RFC9459] Deprecated Unassigned -65528 to -269 ESB512 -268 ECDSA using BrainpoolP512r1 curve and [kty] IETF [RFC9864, Section 2.1] No SHA-512 ESB384 -267 ECDSA using BrainpoolP384r1 curve and [kty] IETF [RFC9864, Section 2.1] No SHA-384 ESB320 -266 ECDSA using BrainpoolP320r1 curve and [kty] IETF [RFC9864, Section 2.1] No SHA-384 ESB256 -265 ECDSA using BrainpoolP256r1 curve and [kty] IETF [RFC9864, Section 2.1] No SHA-256 KT256 -264 KT256 XOF [kty] IETF [RFC9861] No KT128 -263 KT128 XOF [kty] IETF [RFC9861] No TurboSHAKE256 -262 TurboSHAKE256 XOF [kty] IETF [RFC9861] No TurboSHAKE128 -261 TurboSHAKE128 XOF [kty] IETF [RFC9861] No WalnutDSA -260 WalnutDSA signature [kty] [RFC9021][RFC9053] No RS512 -259 RSASSA-PKCS1-v1_5 using SHA-512 [kty] IESG [RFC8812][RFC9053] No RS384 -258 RSASSA-PKCS1-v1_5 using SHA-384 [kty] IESG [RFC8812][RFC9053] No RS256 -257 RSASSA-PKCS1-v1_5 using SHA-256 [kty] IESG [RFC8812][RFC9053] No Unassigned -256 to -54 Ed448 -53 EdDSA using the Ed448 parameter set in [kty] IETF [RFC9864, Section 2.2] Yes Section 5.2 of [RFC8032] ESP512 -52 ECDSA using P-521 curve and SHA-512 [kty] IETF [RFC9864, Section 2.1] Yes ESP384 -51 ECDSA using P-384 curve and SHA-384 [kty] IETF [RFC9864, Section 2.1] Yes ML-DSA-87 -50 CBOR Object Signing Algorithm for [kty] IETF [RFC-ietf-cose-dilithium-10] Yes ML-DSA-87 ML-DSA-65 -49 CBOR Object Signing Algorithm for [kty] IETF [RFC-ietf-cose-dilithium-10] Yes ML-DSA-65 ML-DSA-44 -48 CBOR Object Signing Algorithm for [kty] IETF [RFC-ietf-cose-dilithium-10] Yes ML-DSA-44 ES256K -47 ECDSA using secp256k1 curve and SHA-256 [kty] IESG [RFC8812][RFC9053] No HSS-LMS -46 HSS/LMS hash-based digital signature [kty] [RFC8778][RFC9053] Yes SHAKE256 -45 SHAKE-256 512-bit Hash Value [kty] [RFC9054][RFC9053] Yes SHA-512 -44 SHA-2 512-bit Hash [kty] [RFC9054][RFC9053] Yes SHA-384 -43 SHA-2 384-bit Hash [kty] [RFC9054][RFC9053] Yes RSAES-OAEP w/ SHA-512 -42 RSAES-OAEP w/ SHA-512 [kty] [RFC8230][RFC9053] Yes RSAES-OAEP w/ SHA-256 -41 RSAES-OAEP w/ SHA-256 [kty] [RFC8230][RFC9053] Yes RSAES-OAEP w/ RFC 8017 -40 RSAES-OAEP w/ SHA-1 [kty] [RFC8230][RFC9053] Yes default parameters PS512 -39 RSASSA-PSS w/ SHA-512 [kty] [RFC8230][RFC9053] Yes PS384 -38 RSASSA-PSS w/ SHA-384 [kty] [RFC8230][RFC9053] Yes PS256 -37 RSASSA-PSS w/ SHA-256 [kty] [RFC8230][RFC9053] Yes ES512 -36 ECDSA w/ SHA-512 [kty] IETF [RFC9053][RFC9864] Deprecated ES384 -35 ECDSA w/ SHA-384 [kty] IETF [RFC9053][RFC9864] Deprecated ECDH-SS + A256KW -34 ECDH SS w/ Concat KDF and AES Key Wrap w/ [kty] [RFC9053] Yes 256-bit key ECDH-SS + A192KW -33 ECDH SS w/ Concat KDF and AES Key Wrap w/ [kty] [RFC9053] Yes 192-bit key ECDH-SS + A128KW -32 ECDH SS w/ Concat KDF and AES Key Wrap w/ [kty] [RFC9053] Yes 128-bit key ECDH-ES + A256KW -31 ECDH ES w/ Concat KDF and AES Key Wrap w/ [kty] [RFC9053] Yes 256-bit key ECDH-ES + A192KW -30 ECDH ES w/ Concat KDF and AES Key Wrap w/ [kty] [RFC9053] Yes 192-bit key ECDH-ES + A128KW -29 ECDH ES w/ Concat KDF and AES Key Wrap w/ [kty] [RFC9053] Yes 128-bit key ECDH-SS + HKDF-512 -28 ECDH SS w/ HKDF - generate key directly [kty] [RFC9053] Yes ECDH-SS + HKDF-256 -27 ECDH SS w/ HKDF - generate key directly [kty] [RFC9053] Yes ECDH-ES + HKDF-512 -26 ECDH ES w/ HKDF - generate key directly [kty] [RFC9053] Yes ECDH-ES + HKDF-256 -25 ECDH ES w/ HKDF - generate key directly [kty] [RFC9053] Yes Unassigned -24 to -20 Ed25519 -19 EdDSA using the Ed25519 parameter set in [kty] IETF [RFC9864, Section 2.2] Yes Section 5.1 of [RFC8032] SHAKE128 -18 SHAKE-128 256-bit Hash Value [kty] [RFC9054][RFC9053] Yes SHA-512/256 -17 SHA-2 512-bit Hash truncated to 256-bits [kty] [RFC9054][RFC9053] Yes SHA-256 -16 SHA-2 256-bit Hash [kty] [RFC9054][RFC9053] Yes SHA-256/64 -15 SHA-2 256-bit Hash truncated to 64-bits [kty] [RFC9054][RFC9053] Filter Only SHA-1 -14 SHA-1 Hash [kty] [RFC9054][RFC9053] Filter Only direct+HKDF-AES-256 -13 Shared secret w/ AES-MAC 256-bit key [kty] [RFC9053] Yes direct+HKDF-AES-128 -12 Shared secret w/ AES-MAC 128-bit key [kty] [RFC9053] Yes direct+HKDF-SHA-512 -11 Shared secret w/ HKDF and SHA-512 [kty] [RFC9053] Yes direct+HKDF-SHA-256 -10 Shared secret w/ HKDF and SHA-256 [kty] [RFC9053] Yes ESP256 -9 ECDSA using P-256 curve and SHA-256 [kty] IETF [RFC9864, Section 2.1] Yes EdDSA -8 EdDSA [kty] IETF [RFC9053][RFC9864] Deprecated ES256 -7 ECDSA w/ SHA-256 [kty] IETF [RFC9053][RFC9864] Deprecated direct -6 Direct use of CEK [kty] [RFC9053] Yes A256KW -5 AES Key Wrap w/ 256-bit key [kty] [RFC9053] Yes A192KW -4 AES Key Wrap w/ 192-bit key [kty] [RFC9053] Yes A128KW -3 AES Key Wrap w/ 128-bit key [kty] [RFC9053] Yes Unassigned -2 to -1 Reserved 0 [RFC9053] No A128GCM 1 AES-GCM mode w/ 128-bit key, 128-bit tag [kty] [RFC9053] Yes A192GCM 2 AES-GCM mode w/ 192-bit key, 128-bit tag [kty] [RFC9053] Yes A256GCM 3 AES-GCM mode w/ 256-bit key, 128-bit tag [kty] [RFC9053] Yes HMAC 256/64 4 HMAC w/ SHA-256 truncated to 64 bits [kty] [RFC9053] Yes HMAC 256/256 5 HMAC w/ SHA-256 [kty] [RFC9053] Yes HMAC 384/384 6 HMAC w/ SHA-384 [kty] [RFC9053] Yes HMAC 512/512 7 HMAC w/ SHA-512 [kty] [RFC9053] Yes Unassigned 8-9 AES-CCM-16-64-128 10 AES-CCM mode 128-bit key, 64-bit tag, [kty] [RFC9053] Yes 13-byte nonce AES-CCM-16-64-256 11 AES-CCM mode 256-bit key, 64-bit tag, [kty] [RFC9053] Yes 13-byte nonce AES-CCM-64-64-128 12 AES-CCM mode 128-bit key, 64-bit tag, [kty] [RFC9053] Yes 7-byte nonce AES-CCM-64-64-256 13 AES-CCM mode 256-bit key, 64-bit tag, [kty] [RFC9053] Yes 7-byte nonce AES-MAC 128/64 14 AES-MAC 128-bit key, 64-bit tag [kty] [RFC9053] Yes AES-MAC 256/64 15 AES-MAC 256-bit key, 64-bit tag [kty] [RFC9053] Yes Unassigned 16-23 ChaCha20/Poly1305 24 ChaCha20/Poly1305 w/ 256-bit key, 128-bit [kty] [RFC9053] Yes tag AES-MAC 128/128 25 AES-MAC 128-bit key, 128-bit tag [kty] [RFC9053] Yes AES-MAC 256/128 26 AES-MAC 256-bit key, 128-bit tag [kty] [RFC9053] Yes Unassigned 27-29 AES-CCM-16-128-128 30 AES-CCM mode 128-bit key, 128-bit tag, [kty] [RFC9053] Yes 13-byte nonce AES-CCM-16-128-256 31 AES-CCM mode 256-bit key, 128-bit tag, [kty] [RFC9053] Yes 13-byte nonce AES-CCM-64-128-128 32 AES-CCM mode 128-bit key, 128-bit tag, [kty] [RFC9053] Yes 7-byte nonce AES-CCM-64-128-256 33 AES-CCM mode 256-bit key, 128-bit tag, [kty] [RFC9053] Yes 7-byte nonce IV-GENERATION 34 For doing IV generation for symmetric [RFC9053] No algorithms. COSE Key Common Parameters Expert(s) Francesca Palombini, Carsten Bormann Reference [RFC9052] Available Formats [IMG] CSV Range Registration Procedures Integers less than -65536 Private Use Integer values in the range -65536 to -1 used for key parameters specific to a single algorithm delegated to the COSE Key Type Parameters registry Integer values between 0 and 255 Standards Action With Expert Review Integer values from 256 to 65535 Specification Required Integer values greater than 65535 Expert Review Strings of length 1 Standards Action With Expert Review Strings of length 2 Specification Required Strings of length greater than 2 Expert Review Name Label CBOR Type Value Registry Description Reference Reserved for Private Use less than -65536 [RFC9052] used for key parameters specific to a single algorithm delegated to the COSE Key Type -65536 to -1 [RFC9052] Parameters registry Reserved 0 [RFC9052] kty 1 tstr / int COSE Key Types Identification of the key type [RFC9052] kid 2 bstr Key identification value - match to [RFC9052] kid in message alg 3 tstr / int COSE Algorithms Key usage restriction to this [RFC9052] algorithm key_ops 4 [+ (tstr/int)] Restrict set of permissible [RFC9052] operations Base IV 5 bstr Base IV to be XORed with Partial IVs [RFC9052] COSE Key Type Parameters Registration Procedure(s) Expert Review Expert(s) Göran Selander, Derek Atkins, Sean Turner Reference [RFC9053] Available Formats [IMG] CSV Key Type Name Label CBOR Type Description Reference 1 crv -1 int / tstr EC identifier -- Taken from the "COSE Elliptic Curves" [RFC9053] registry 1 x -2 bstr Public Key [RFC9053] 1 d -4 bstr Private key [RFC9053] 2 crv -1 int / tstr EC identifier -- Taken from the "COSE Elliptic Curves" [RFC9053] registry 2 x -2 bstr x-coordinate [RFC9053] 2 y -3 bstr / bool y-coordinate [RFC9053] 2 d -4 bstr Private key [RFC9053] 3 n -1 bstr the RSA modulus n [RFC8230] 3 e -2 bstr the RSA public exponent e [RFC8230] 3 d -3 bstr the RSA private exponent d [RFC8230] 3 p -4 bstr the prime factor p of n [RFC8230] 3 q -5 bstr the prime factor q of n [RFC8230] 3 dP -6 bstr dP is d mod (p - 1) [RFC8230] 3 dQ -7 bstr dQ is d mod (q - 1) [RFC8230] 3 qInv -8 bstr qInv is the CRT coefficient q^(-1) mod p [RFC8230] 3 other -9 array other prime infos, an array [RFC8230] 3 r_i -10 bstr a prime factor r_i of n, where i >= 3 [RFC8230] 3 d_i -11 bstr d_i = d mod (r_i - 1) [RFC8230] 3 t_i -12 bstr the CRT coefficient t_i = (r_1 * r_2 * ... * r_(i-1))^(-1) [RFC8230] mod r_i 4 k -1 bstr Key Value [RFC9053] 5 pub -1 bstr Public key for HSS/LMS hash-based digital signature [RFC8778] 6 N -1 uint Group and Matrix (NxN) size [RFC9021] 6 q -2 uint Finite field F_q [RFC9021] 6 t-values -3 array (of uint) List of T-values, entries in F_q [RFC9021] 6 matrix 1 -4 array (of array of uint) NxN Matrix of entries in F_q in column-major form [RFC9021] 6 permutation 1 -5 array (of uint) Permutation associated with matrix 1 [RFC9021] 6 matrix 2 -6 array (of array of uint) NxN Matrix of entries in F_q in column-major form [RFC9021] 7 pub -1 bstr Public key [RFC-ietf-cose-dilithium-10] 7 priv -2 bstr Private key [RFC-ietf-cose-dilithium-10] COSE Key Types Registration Procedure(s) Expert Review Expert(s) Göran Selander, Derek Atkins, Sean Turner Reference [RFC9053] Available Formats [IMG] CSV Name Value Description Capabilities Reference Reserved 0 This value is reserved [RFC9053] OKP 1 Octet Key Pair [kty(1), crv] [RFC9053] EC2 2 Elliptic Curve Keys w/ x- and y-coordinate pair [kty(2), crv] [RFC9053] RSA 3 RSA Key [kty(3)] [RFC8230][RFC9053] Symmetric 4 Symmetric Keys [kty(4)] [RFC9053] HSS-LMS 5 Public key for HSS/LMS hash-based digital signature [kty(5), hash algorithm] [RFC8778][RFC9053] WalnutDSA 6 WalnutDSA public key [kty(6)] [RFC9021][RFC9053] AKP 7 COSE Key Type for Algorithm Key Pairs [kty(7)] [RFC-ietf-cose-dilithium-10] COSE Elliptic Curves Expert(s) Göran Selander, Derek Atkins, Sean Turner Reference [RFC9053] Available Formats [IMG] CSV Range Registration Procedures Integers less than -65536 Private Use Integer values -65536 to -257 Specification Required Integer values -256 to 255 Standards Action With Expert Review Integer values 256 to 65535 Specification Required Integer values greater than 65535 Expert Review Name Value Key Type Description Change Controller Reference Recommended Reserved for Private Use Integer values less [RFC9053] No than -65536 Unassigned -65536 to -1 Reserved 0 [RFC9053] No P-256 1 EC2 NIST P-256 also known as [RFC9053] Yes secp256r1 P-384 2 EC2 NIST P-384 also known as [RFC9053] Yes secp384r1 P-521 3 EC2 NIST P-521 also known as [RFC9053] Yes secp521r1 X25519 4 OKP X25519 for use w/ ECDH only [RFC9053] Yes X448 5 OKP X448 for use w/ ECDH only [RFC9053] Yes Ed25519 6 OKP Ed25519 for use w/ EdDSA only [RFC9053] Yes Ed448 7 OKP Ed448 for use w/ EdDSA only [RFC9053] Yes secp256k1 8 EC2 SECG secp256k1 curve IESG [RFC8812] No Unassigned 9-255 brainpoolP256r1 256 EC2 BrainpoolP256r1 [ISO/IEC JTC 1/SC [ISO/IEC 18013-5:2021, No 17/WG 10] 9.1.5.2] brainpoolP320r1 257 EC2 BrainpoolP320r1 [ISO/IEC JTC 1/SC [ISO/IEC 18013-5:2021, No 17/WG 10] 9.1.5.2] brainpoolP384r1 258 EC2 BrainpoolP384r1 [ISO/IEC JTC 1/SC [ISO/IEC 18013-5:2021, No 17/WG 10] 9.1.5.2] brainpoolP512r1 259 EC2 BrainpoolP512r1 [ISO/IEC JTC 1/SC [ISO/IEC 18013-5:2021, No 17/WG 10] 9.1.5.2] COSE Verifiable Data Structure Algorithms Registration Procedure(s) Specification Required Expert(s) Mike Jones, Orie Steele Reference [RFC-ietf-cose-merkle-tree-proofs-17] Available Formats [IMG] CSV Name Value Description Change Controller Reference Reserved 0 Reserved [RFC-ietf-cose-merkle-tree-proofs-17] RFC9162_SHA256 1 SHA256 Binary Merkle Tree IETF [RFC9162, Section 2.1] COSE Verifiable Data Structure Proofs Registration Procedure(s) Specification Required Expert(s) Mike Jones, Orie Steele Reference [RFC-ietf-cose-merkle-tree-proofs-17] Available Formats [IMG] CSV Verifiable Data Name Label CBOR Type Description Change Reference Structure Controller 1 inclusion proofs -1 array (of Proof of inclusion IETF [RFC-ietf-cose-merkle-tree-proofs-17, Section bstr) 5.2] 1 consistency proofs -2 array (of Proof of append IETF [RFC-ietf-cose-merkle-tree-proofs-17, Section bstr) only property 5.3] Licensing Terms