CBOR Object Signing and Encryption (COSE)

Created

2017-01-11

Last Updated

2026-08-25

Available Formats

COSE Header Parameters

Expert(s)

Francesca Palombini, Carsten Bormann

Reference

RFC 9052: CBOR Object Signing and Encryption (COSE): Structures and Process

Available Formats

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 Use	less than -65536				RFC 9052
delegated to the COSE Header Algorithm Parameters registry	-65536 to -1
Reserved	0				RFC 9052
alg	1	int / tstr	COSE Algorithms	Cryptographic algorithm to use	RFC 9052
crit	2	[+ label]	COSE Header Parameters	Critical headers to be understood	RFC 9052
content type	3	tstr / uint	COAP Content-Formats or Media Types	Content type of the payload	RFC 9052
kid	4	bstr		Key identifier	RFC 9052
IV	5	bstr		Full Initialization Vector	RFC 9052
Partial IV	6	bstr		Partial Initialization Vector	RFC 9052
counter signature	7	COSE_Signature / [+ COSE_Signature ]		CBOR-encoded signature structure (Deprecated by RFC 9338)	RFC 8152
Unassigned	8
CounterSignature0	9	bstr		Counter signature with implied signer and headers (Deprecated by RFC 9338)	RFC 8152
kid context	10	bstr		Identifies the context for the key identifier	RFC 8613, Section 5.1
Countersignature version 2	11	COSE_Countersignature / [+ COSE_Countersignature]		V2 countersignature attribute	RFC 9338
Countersignature0 version 2	12	COSE_Countersignature0		V2 Abbreviated Countersignature	RFC 9338
kcwt	13	COSE_Messages		A CBOR Web Token (CWT) containing a COSE_Key in a 'cnf' claim and possibly other claims. CWT is defined in RFC 8392. COSE_Messages is defined in RFC 9052.	RFC 9528
kccs	14	map		A CWT Claims Set (CCS) containing a COSE_Key in a 'cnf' claim and possibly other claims. CCS is defined in RFC 8392.	RFC 9528
CWT Claims	15	map	map keys in CWT Claims	Location for CWT Claims in COSE Header Parameters.	RFC 9597, Section 2
typ (type)	16	uint / tstr	COAP Content-Formats or Media Types	Content type of the complete COSE object	RFC 9596, Section 2
sd_claims (TEMPORARY - registered 2026-01-16, expires 2027-01-16)	17	[ +bstr ]		A list of selectively disclosed claims, which were originally redacted, then later disclosed at the discretion of the sender.	RFC-ietf-spice-sd-cwt-06, Section 4
Unassigned	18-21
c5t	22	COSE_CertHash		Hash of a C509Certificate	RFC-ietf-cose-cbor-encoded-cert-20
c5u	23	uri		URI pointing to a C509 certificate	RFC-ietf-cose-cbor-encoded-cert-20
c5b	24	COSE_C509		An unordered bag of C509 certificates	RFC-ietf-cose-cbor-encoded-cert-20
c5c	25	COSE_C509		An ordered chain of C509 certificates	RFC-ietf-cose-cbor-encoded-cert-20
Unassigned	26-31
x5bag	32	COSE_X509		An unordered bag of X.509 certificates	RFC 9360
x5chain	33	COSE_X509		An ordered chain of X.509 certificates	RFC 9360
x5t	34	COSE_CertHash		Hash of an X.509 certificate	RFC 9360
x5u	35	uri		URI pointing to an X.509 certificate	RFC 9360
Unassigned	36-169
sd_alg (TEMPORARY - registered 2026-01-16, expires 2027-01-16)	170	int	COSE Algorithms	The hash algorithm used for redacting disclosures.	RFC-ietf-spice-sd-cwt-06, Section 7
sd_aead_encrypted_claims (TEMPORARY - registered 2026-01-16, expires 2027-01-16)	171	[ +[bstr,bstr,bstr] ]		A list of AEAD encrypted selectively disclosed claims, which were originally redacted, then later disclosed at the discretion of the sender.	RFC-ietf-spice-sd-cwt-06, Section 12.1
sd_aead (TEMPORARY - registered 2026-01-16, expires 2027-01-16)	172	uint .size 2	AEAD Algorithms	The AEAD algorithm used for encrypting disclosures.	RFC-ietf-spice-sd-cwt-06, Section 12.1
Unassigned	173-255
CUPHNonce	256	bstr		Challenge Nonce	FIDO Device Onboard Specification
CUPHOwnerPubKey	257	array		Public Key	FIDO Device Onboard Specification
payload-hash-alg	258	int	COSE Algorithms	The hash algorithm used to produce the payload of a COSE_Sign1	RFC 9995, Section 3
preimage-content-type	259	uint / tstr	CoAP Content-Formats	The content-format number or content-type (media-type name) of data that has been hashed to produce the payload of the COSE_Sign1	RFC 9995, Section 3
payload-location	260	tstr		The string or URI hint for the location of the data hashed to produce the payload of a COSE_Sign1	RFC 9995, Section 3
x5ts	261	array of COSE_CertHash		CBOR array of instances of COSE_CertHash	TS 119 152-1 V0.0.9, Clause 5.2.2
srCms	262	array of SrCm		set of commitments and optional commitments qualifiers	TS 119 152-1 V0.0.9, Clause 5.2.3
sigPl	263	map		CBOR map for indicating the location where the signature was generated. It may contain an indication of the country, the locality, the region, a box number in a post office, the postal code, and the street address	TS 119 152-1 V0.0.9, Clause 5.2.4
srAts	264	map		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 attribute certificates or 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	TS 119 152-1 V0.0.9, Clause 5.2.5
adoTst	265	map		CBOR map that encapsulates one or more electronic time-stamps, generated before the signature production, and whose message imprint computation input is the COSE Payload of the CB-AdES signature	TS 119 152-1 V0.0.9, Clause 5.2.6
sigPId	266	map		CBOR map that identifies a certain signature policy and may contain the digest of the document defining this signature policy.	TS 119 152-1 V0.0.9, Clause 5.2.7
sigD	267	map		CBOR map that references data objects that are detached from the CB-AdES signature and that are collectively signed.	TS 119 152-1 V0.0.9, Clause 5.2.8
uHeaders	268	[+bstr]		CBOR array that contains a number of CBOR elements that are placed within the array in the order they are incorporated into the CB-AdES signature	TS 119 152-1 V0.0.9, Clause 5.3.1
3161-ttc	269	bstr		Timestamp Token per RFC 3161: Timestamp, Then COSE	RFC 9921, Section 3.2
3161-ctt	270	bstr		Timestamp Token per RFC 3161: COSE, Then Timestamp	RFC 9921, Section 3.1
Unassigned	271-393
receipts	394	array		Priority ordered sequence of CBOR encoded Receipts	RFC 9942, Section 2
vds	395	int	COSE Verifiable Data Structure Algorithms	Algorithm identifier for verifiable data structures, used to produce verifiable data structure proofs	RFC 9942, Section 2
vdp	396	map	map key in COSE Verifiable Data Structure Proofs	Location for verifiable data structure proofs in COSE Header Parameters	RFC 9942, Section 2

COSE Header Algorithm Parameters

Registration Procedure(s)

Expert Review

Expert(s)

Göran Selander, Derek Atkins, Sean Turner

Reference

RFC 9053: CBOR Object Signing and Encryption (COSE): Initial Algorithms

Available Formats

CSV

Name	Algorithm	Label	Type	Description	Reference
Unassigned		-65536 to -33
c5u-sender	ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW	-32	uri	URI pointing to a C509 certificate	RFC-ietf-cose-cbor-encoded-cert-20
c5t-sender	ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW	-31	COSE_CertHash	Hash of a C509Certificate	RFC-ietf-cose-cbor-encoded-cert-20
c5c-sender	ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW	-30	COSE_C509	An ordered chain of C509 certificates	RFC-ietf-cose-cbor-encoded-cert-20
x5chain-sender	ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW	-29	COSE_X509	static key X.509 certificate chain	RFC 9360
x5u-sender	ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW	-28	uri	URI for the sender's X.509 certificate	RFC 9360
x5t-sender	ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW	-27	COSE_CertHash	Thumbprint for the sender's X.509 certificate	RFC 9360
PartyV other	direct+HKDF-SHA-256, direct+HKDF-SHA-512, direct+HKDF-AES-128, direct+HKDF-AES-256, ECDH-ES+HKDF-256, ECDH-ES+HKDF-512, ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-ES+A128KW, ECDH-ES+A192KW, ECDH-ES+A256KW, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW	-26	bstr	Party V other provided information	RFC 9053
PartyV nonce	direct+HKDF-SHA-256, direct+HKDF-SHA-512, direct+HKDF-AES-128, direct+HKDF-AES-256, ECDH-ES+HKDF-256, ECDH-ES+HKDF-512, ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-ES+A128KW, ECDH-ES+A192KW, ECDH-ES+A256KW, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW	-25	bstr / int	Party V provided nonce	RFC 9053
PartyV identity	direct+HKDF-SHA-256, direct+HKDF-SHA-512, direct+HKDF-AES-128, direct+HKDF-AES-256, ECDH-ES+HKDF-256, ECDH-ES+HKDF-512, ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-ES+A128KW, ECDH-ES+A192KW, ECDH-ES+A256KW, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW	-24	bstr	Party V identity information	RFC 9053
PartyU other	direct+HKDF-SHA-256, direct+HKDF-SHA-512, direct+HKDF-AES-128, direct+HKDF-AES-256, ECDH-ES+HKDF-256, ECDH-ES+HKDF-512, ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-ES+A128KW, ECDH-ES+A192KW, ECDH-ES+A256KW, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW	-23	bstr	Party U other provided information	RFC 9053
PartyU nonce	direct+HKDF-SHA-256, direct+HKDF-SHA-512, direct+HKDF-AES-128, direct+HKDF-AES-256, ECDH-ES+HKDF-256, ECDH-ES+HKDF-512, ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-ES+A128KW, ECDH-ES+A192KW, ECDH-ES+A256KW, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW	-22	bstr / int	Party U provided nonce	RFC 9053
PartyU identity	direct+HKDF-SHA-256, direct+HKDF-SHA-512, direct+HKDF-AES-128, direct+HKDF-AES-256, ECDH-ES+HKDF-256, ECDH-ES+HKDF-512, ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-ES+A128KW, ECDH-ES+A192KW, ECDH-ES+A256KW, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW	-21	bstr	Party U identity information	RFC 9053
salt	direct+HKDF-SHA-256, direct+HKDF-SHA-512, direct+HKDF-AES-128, direct+HKDF-AES-256, ECDH-ES+HKDF-256, ECDH-ES+HKDF-512, ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-ES+A128KW, ECDH-ES+A192KW, ECDH-ES+A256KW, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW	-20	bstr	Random salt	RFC 9053
Unassigned		-19 to -4
static key id	ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW	-3	bstr	Static public key identifier for the sender	RFC 9053
static key	ECDH-SS+HKDF-256, ECDH-SS+HKDF-512, ECDH-SS+A128KW, ECDH-SS+A192KW, ECDH-SS+A256KW	-2	COSE_Key	Static public key for the sender	RFC 9053
ephemeral key	ECDH-ES+HKDF-256, ECDH-ES+HKDF-512, ECDH-ES+A128KW, ECDH-ES+A192KW, ECDH-ES+A256KW	-1	COSE_Key	Ephemeral public key for the sender	RFC 9053

COSE Algorithms

Expert(s)

Göran Selander, Derek Atkins, Sean Turner

Reference

RFC 9053: CBOR Object Signing and Encryption (COSE): Initial Algorithms
RFC 9054: CBOR Object Signing and Encryption (COSE): Hash Algorithms
RFC 9864, Section 4.2: Fully-Specified Algorithms for JSON Object Signing and Encryption (JOSE) and CBOR Object Signing and Encryption (COSE)

Available Formats

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 Controller	Reference	Recommended
Reserved for Private Use	less than -65536				RFC 9053	No
Unassigned	-65536
RS1	-65535	RSASSA-PKCS1-v1_5 using SHA-1	[kty]	IESG	RFC 8812; RFC 9053	Deprecated
A128CTR	-65534	AES-CTR w/ 128-bit key	[kty]	IETF	RFC 9459	Deprecated
A192CTR	-65533	AES-CTR w/ 192-bit key	[kty]	IETF	RFC 9459	Deprecated
A256CTR	-65532	AES-CTR w/ 256-bit key	[kty]	IETF	RFC 9459	Deprecated
A128CBC	-65531	AES-CBC w/ 128-bit key	[kty]	IETF	RFC 9459	Deprecated
A192CBC	-65530	AES-CBC w/ 192-bit key	[kty]	IETF	RFC 9459	Deprecated
A256CBC	-65529	AES-CBC w/ 256-bit key	[kty]	IETF	RFC 9459	Deprecated
Unassigned	-65528 to -269
ESB512	-268	ECDSA using BrainpoolP512r1 curve and SHA-512	[kty]	IETF	RFC 9864, Section 2.1	No
ESB384	-267	ECDSA using BrainpoolP384r1 curve and SHA-384	[kty]	IETF	RFC 9864, Section 2.1	No
ESB320	-266	ECDSA using BrainpoolP320r1 curve and SHA-384	[kty]	IETF	RFC 9864, Section 2.1	No
ESB256	-265	ECDSA using BrainpoolP256r1 curve and SHA-256	[kty]	IETF	RFC 9864, Section 2.1	No
KT256	-264	KT256 XOF	[kty]	IETF	RFC 9861	No
KT128	-263	KT128 XOF	[kty]	IETF	RFC 9861	No
TurboSHAKE256	-262	TurboSHAKE256 XOF	[kty]	IETF	RFC 9861	No
TurboSHAKE128	-261	TurboSHAKE128 XOF	[kty]	IETF	RFC 9861	No
WalnutDSA	-260	WalnutDSA signature	[kty]		RFC 9021; RFC 9053	No
RS512	-259	RSASSA-PKCS1-v1_5 using SHA-512	[kty]	IESG	RFC 8812; RFC 9053	No
RS384	-258	RSASSA-PKCS1-v1_5 using SHA-384	[kty]	IESG	RFC 8812; RFC 9053	No
RS256	-257	RSASSA-PKCS1-v1_5 using SHA-256	[kty]	IESG	RFC 8812; RFC 9053	No
Unassigned	-256 to -54
Ed448	-53	EdDSA using the Ed448 parameter set in Section 5.2 of RFC 8032	[kty]	IETF	RFC 9864, Section 2.2	Yes
ESP512	-52	ECDSA using P-521 curve and SHA-512	[kty]	IETF	RFC 9864, Section 2.1	Yes
ESP384	-51	ECDSA using P-384 curve and SHA-384	[kty]	IETF	RFC 9864, Section 2.1	Yes
ML-DSA-87	-50	CBOR Object Signing Algorithm for ML-DSA-87	[kty]	IETF	RFC 9964	Yes
ML-DSA-65	-49	CBOR Object Signing Algorithm for ML-DSA-65	[kty]	IETF	RFC 9964	Yes
ML-DSA-44	-48	CBOR Object Signing Algorithm for ML-DSA-44	[kty]	IETF	RFC 9964	Yes
ES256K	-47	ECDSA using secp256k1 curve and SHA-256	[kty]	IESG	RFC 8812; RFC 9053	No
HSS-LMS	-46	HSS/LMS hash-based digital signature	[kty]		RFC 8778; RFC 9053	Yes
SHAKE256	-45	SHAKE-256 512-bit Hash Value	[kty]		RFC 9054; RFC 9053	Yes
SHA-512	-44	SHA-2 512-bit Hash	[kty]		RFC 9054; RFC 9053	Yes
SHA-384	-43	SHA-2 384-bit Hash	[kty]		RFC 9054; RFC 9053	Yes
RSAES-OAEP w/ SHA-512	-42	RSAES-OAEP w/ SHA-512	[kty]		RFC 8230; RFC 9053	Yes
RSAES-OAEP w/ SHA-256	-41	RSAES-OAEP w/ SHA-256	[kty]		RFC 8230; RFC 9053	Yes
RSAES-OAEP w/ RFC 8017 default parameters	-40	RSAES-OAEP w/ SHA-1	[kty]		RFC 8230; RFC 9053	Yes
PS512	-39	RSASSA-PSS w/ SHA-512	[kty]		RFC 8230; RFC 9053	Yes
PS384	-38	RSASSA-PSS w/ SHA-384	[kty]		RFC 8230; RFC 9053	Yes
PS256	-37	RSASSA-PSS w/ SHA-256	[kty]		RFC 8230; RFC 9053	Yes
ES512	-36	ECDSA w/ SHA-512	[kty]	IETF	RFC 9053; RFC 9864	Deprecated
ES384	-35	ECDSA w/ SHA-384	[kty]	IETF	RFC 9053; RFC 9864	Deprecated
ECDH-SS + A256KW	-34	ECDH SS w/ Concat KDF and AES Key Wrap w/ 256-bit key	[kty]		RFC 9053	Yes
ECDH-SS + A192KW	-33	ECDH SS w/ Concat KDF and AES Key Wrap w/ 192-bit key	[kty]		RFC 9053	Yes
ECDH-SS + A128KW	-32	ECDH SS w/ Concat KDF and AES Key Wrap w/ 128-bit key	[kty]		RFC 9053	Yes
ECDH-ES + A256KW	-31	ECDH ES w/ Concat KDF and AES Key Wrap w/ 256-bit key	[kty]		RFC 9053	Yes
ECDH-ES + A192KW	-30	ECDH ES w/ Concat KDF and AES Key Wrap w/ 192-bit key	[kty]		RFC 9053	Yes
ECDH-ES + A128KW	-29	ECDH ES w/ Concat KDF and AES Key Wrap w/ 128-bit key	[kty]		RFC 9053	Yes
ECDH-SS + HKDF-512	-28	ECDH SS w/ HKDF - generate key directly	[kty]		RFC 9053	Yes
ECDH-SS + HKDF-256	-27	ECDH SS w/ HKDF - generate key directly	[kty]		RFC 9053	Yes
ECDH-ES + HKDF-512	-26	ECDH ES w/ HKDF - generate key directly	[kty]		RFC 9053	Yes
ECDH-ES + HKDF-256	-25	ECDH ES w/ HKDF - generate key directly	[kty]		RFC 9053	Yes
Unassigned	-24 to -20
Ed25519	-19	EdDSA using the Ed25519 parameter set in Section 5.1 of RFC 8032	[kty]	IETF	RFC 9864, Section 2.2	Yes
SHAKE128	-18	SHAKE-128 256-bit Hash Value	[kty]		RFC 9054; RFC 9053	Yes
SHA-512/256	-17	SHA-2 512-bit Hash truncated to 256-bits	[kty]		RFC 9054; RFC 9053	Yes
SHA-256	-16	SHA-2 256-bit Hash	[kty]		RFC 9054; RFC 9053	Yes
SHA-256/64	-15	SHA-2 256-bit Hash truncated to 64-bits	[kty]		RFC 9054; RFC 9053	Filter Only
SHA-1	-14	SHA-1 Hash	[kty]		RFC 9054; RFC 9053	Filter Only
direct+HKDF-AES-256	-13	Shared secret w/ AES-MAC 256-bit key	[kty]		RFC 9053	Yes
direct+HKDF-AES-128	-12	Shared secret w/ AES-MAC 128-bit key	[kty]		RFC 9053	Yes
direct+HKDF-SHA-512	-11	Shared secret w/ HKDF and SHA-512	[kty]		RFC 9053	Yes
direct+HKDF-SHA-256	-10	Shared secret w/ HKDF and SHA-256	[kty]		RFC 9053	Yes
ESP256	-9	ECDSA using P-256 curve and SHA-256	[kty]	IETF	RFC 9864, Section 2.1	Yes
EdDSA	-8	EdDSA	[kty]	IETF	RFC 9053; RFC 9864	Deprecated
ES256	-7	ECDSA w/ SHA-256	[kty]	IETF	RFC 9053; RFC 9864	Deprecated
direct	-6	Direct use of CEK	[kty]		RFC 9053	Yes
A256KW	-5	AES Key Wrap w/ 256-bit key	[kty]		RFC 9053	Yes
A192KW	-4	AES Key Wrap w/ 192-bit key	[kty]		RFC 9053	Yes
A128KW	-3	AES Key Wrap w/ 128-bit key	[kty]		RFC 9053	Yes
Unassigned	-2 to -1
Reserved	0				RFC 9053	No
A128GCM	1	AES-GCM mode w/ 128-bit key, 128-bit tag	[kty]		RFC 9053	Yes
A192GCM	2	AES-GCM mode w/ 192-bit key, 128-bit tag	[kty]		RFC 9053	Yes
A256GCM	3	AES-GCM mode w/ 256-bit key, 128-bit tag	[kty]		RFC 9053	Yes
HMAC 256/64	4	HMAC w/ SHA-256 truncated to 64 bits	[kty]		RFC 9053	Yes
HMAC 256/256	5	HMAC w/ SHA-256	[kty]		RFC 9053	Yes
HMAC 384/384	6	HMAC w/ SHA-384	[kty]		RFC 9053	Yes
HMAC 512/512	7	HMAC w/ SHA-512	[kty]		RFC 9053	Yes
Unassigned	8-9
AES-CCM-16-64-128	10	AES-CCM mode 128-bit key, 64-bit tag, 13-byte nonce	[kty]		RFC 9053	Yes
AES-CCM-16-64-256	11	AES-CCM mode 256-bit key, 64-bit tag, 13-byte nonce	[kty]		RFC 9053	Yes
AES-CCM-64-64-128	12	AES-CCM mode 128-bit key, 64-bit tag, 7-byte nonce	[kty]		RFC 9053	Yes
AES-CCM-64-64-256	13	AES-CCM mode 256-bit key, 64-bit tag, 7-byte nonce	[kty]		RFC 9053	Yes
AES-MAC 128/64	14	AES-MAC 128-bit key, 64-bit tag	[kty]		RFC 9053	Yes
AES-MAC 256/64	15	AES-MAC 256-bit key, 64-bit tag	[kty]		RFC 9053	Yes
Unassigned	16-23
ChaCha20/Poly1305	24	ChaCha20/Poly1305 w/ 256-bit key, 128-bit tag	[kty]		RFC 9053	Yes
AES-MAC 128/128	25	AES-MAC 128-bit key, 128-bit tag	[kty]		RFC 9053	Yes
AES-MAC 256/128	26	AES-MAC 256-bit key, 128-bit tag	[kty]		RFC 9053	Yes
Unassigned	27-29
AES-CCM-16-128-128	30	AES-CCM mode 128-bit key, 128-bit tag, 13-byte nonce	[kty]		RFC 9053	Yes
AES-CCM-16-128-256	31	AES-CCM mode 256-bit key, 128-bit tag, 13-byte nonce	[kty]		RFC 9053	Yes
AES-CCM-64-128-128	32	AES-CCM mode 128-bit key, 128-bit tag, 7-byte nonce	[kty]		RFC 9053	Yes
AES-CCM-64-128-256	33	AES-CCM mode 256-bit key, 128-bit tag, 7-byte nonce	[kty]		RFC 9053	Yes
IV-GENERATION	34	For doing IV generation for symmetric algorithms.			RFC 9053	No

COSE Key Common Parameters

Expert(s)

Francesca Palombini, Carsten Bormann

Reference

RFC 9052: CBOR Object Signing and Encryption (COSE): Structures and Process

Available Formats

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				RFC 9052
used for key parameters specific to a single algorithm delegated to the COSE Key Type Parameters registry	-65536 to -1				RFC 9052
Reserved	0				RFC 9052
kty	1	tstr / int	COSE Key Types	Identification of the key type	RFC 9052
kid	2	bstr		Key identification value - match to kid in message	RFC 9052
alg	3	tstr / int	COSE Algorithms	Key usage restriction to this algorithm	RFC 9052
key_ops	4	[+ (tstr/int)]		Restrict set of permissible operations	RFC 9052
Base IV	5	bstr		Base IV to be XORed with Partial IVs	RFC 9052

COSE Key Type Parameters

Registration Procedure(s)

Expert Review

Expert(s)

Göran Selander, Derek Atkins, Sean Turner

Reference

RFC 9053: CBOR Object Signing and Encryption (COSE): Initial Algorithms

Available Formats

CSV

Key Type	Name	Label	CBOR Type	Description	Reference
1	crv	-1	int / tstr	EC identifier -- Taken from the "COSE Elliptic Curves" registry	RFC 9053
1	x	-2	bstr	Public Key	RFC 9053
1	d	-4	bstr	Private key	RFC 9053
2	crv	-1	int / tstr	EC identifier -- Taken from the "COSE Elliptic Curves" registry	RFC 9053
2	x	-2	bstr	x-coordinate	RFC 9053
2	y	-3	bstr / bool	y-coordinate	RFC 9053
2	d	-4	bstr	Private key	RFC 9053
3	n	-1	bstr	the RSA modulus n	RFC 8230
3	e	-2	bstr	the RSA public exponent e	RFC 8230
3	d	-3	bstr	the RSA private exponent d	RFC 8230
3	p	-4	bstr	the prime factor p of n	RFC 8230
3	q	-5	bstr	the prime factor q of n	RFC 8230
3	dP	-6	bstr	dP is d mod (p - 1)	RFC 8230
3	dQ	-7	bstr	dQ is d mod (q - 1)	RFC 8230
3	qInv	-8	bstr	qInv is the CRT coefficient q^(-1) mod p	RFC 8230
3	other	-9	array	other prime infos, an array	RFC 8230
3	r_i	-10	bstr	a prime factor r_i of n, where i >= 3	RFC 8230
3	d_i	-11	bstr	d_i = d mod (r_i - 1)	RFC 8230
3	t_i	-12	bstr	the CRT coefficient t_i = (r_1 * r_2 * ... * r_(i-1))^(-1) mod r_i	RFC 8230
4	k	-1	bstr	Key Value	RFC 9053
5	pub	-1	bstr	Public key for HSS/LMS hash-based digital signature	RFC 8778
6	N	-1	uint	Group and Matrix (NxN) size	RFC 9021
6	q	-2	uint	Finite field F_q	RFC 9021
6	t-values	-3	array (of uint)	List of T-values, entries in F_q	RFC 9021
6	matrix 1	-4	array (of array of uint)	NxN Matrix of entries in F_q in column-major form	RFC 9021
6	permutation 1	-5	array (of uint)	Permutation associated with matrix 1	RFC 9021
6	matrix 2	-6	array (of array of uint)	NxN Matrix of entries in F_q in column-major form	RFC 9021
7	pub	-1	bstr	Public key	RFC 9964
7	priv	-2	bstr	Private key	RFC 9964

COSE Key Types

Registration Procedure(s)

Expert Review

Expert(s)

Göran Selander, Derek Atkins, Sean Turner

Reference

RFC 9053: CBOR Object Signing and Encryption (COSE): Initial Algorithms

Available Formats

CSV

Name	Value	Description	Capabilities	Reference
Reserved	0	This value is reserved		RFC 9053
OKP	1	Octet Key Pair	[kty(1), crv]	RFC 9053
EC2	2	Elliptic Curve Keys w/ x- and y-coordinate pair	[kty(2), crv]	RFC 9053
RSA	3	RSA Key	[kty(3)]	RFC 8230; RFC 9053
Symmetric	4	Symmetric Keys	[kty(4)]	RFC 9053
HSS-LMS	5	Public key for HSS/LMS hash-based digital signature	[kty(5), hash algorithm]	RFC 8778; RFC 9053
WalnutDSA	6	WalnutDSA public key	[kty(6)]	RFC 9021; RFC 9053
AKP	7	COSE Key Type for Algorithm Key Pairs	[kty(7)]	RFC 9964

COSE Elliptic Curves

Expert(s)

Göran Selander, Derek Atkins, Sean Turner

Reference

RFC 9053: CBOR Object Signing and Encryption (COSE): Initial Algorithms

Available Formats

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 than -65536				RFC 9053	No
Unassigned	-65536 to -1
Reserved	0				RFC 9053	No
P-256	1	EC2	NIST P-256 also known as secp256r1		RFC 9053	Yes
P-384	2	EC2	NIST P-384 also known as secp384r1		RFC 9053	Yes
P-521	3	EC2	NIST P-521 also known as secp521r1		RFC 9053	Yes
X25519	4	OKP	X25519 for use w/ ECDH only		RFC 9053	Yes
X448	5	OKP	X448 for use w/ ECDH only		RFC 9053	Yes
Ed25519	6	OKP	Ed25519 for use w/ EdDSA only		RFC 9053	Yes
Ed448	7	OKP	Ed448 for use w/ EdDSA only		RFC 9053	Yes
secp256k1	8	EC2	SECG secp256k1 curve	IESG	RFC 8812	No
Unassigned	9-255
brainpoolP256r1	256	EC2	BrainpoolP256r1	ISO/IEC JTC 1/SC 17/WG 10	ISO/IEC 18013-5:2021, 9.1.5.2	No
brainpoolP320r1	257	EC2	BrainpoolP320r1	ISO/IEC JTC 1/SC 17/WG 10	ISO/IEC 18013-5:2021, 9.1.5.2	No
brainpoolP384r1	258	EC2	BrainpoolP384r1	ISO/IEC JTC 1/SC 17/WG 10	ISO/IEC 18013-5:2021, 9.1.5.2	No
brainpoolP512r1	259	EC2	BrainpoolP512r1	ISO/IEC JTC 1/SC 17/WG 10	ISO/IEC 18013-5:2021, 9.1.5.2	No

COSE Verifiable Data Structure Algorithms

Registration Procedure(s)

Specification Required

Expert(s)

Mike Jones, Orie Steele

Reference

RFC 9942: CBOR Object Signing and Encryption (COSE) Receipts

Available Formats

CSV

Name	Value	Description	Change Controller	Reference
Reserved	0	Reserved		RFC 9942
RFC9162_SHA256	1	SHA256 Binary Merkle Tree	IETF	RFC 9162, Section 2.1

COSE Verifiable Data Structure Proofs

Registration Procedure(s)

Specification Required

Expert(s)

Mike Jones, Orie Steele

Reference

RFC 9942: CBOR Object Signing and Encryption (COSE) Receipts

Available Formats

CSV

Verifiable Data Structure	Name	Label	CBOR Type	Description	Change Controller	Reference
1	inclusion proofs	-1	array (of bstr)	Proof of inclusion	IETF	RFC 9942, Section 5.2
1	consistency proofs	-2	array (of bstr)	Proof of append only property	IETF	RFC 9942, Section 5.3