draft-ietf-cose-webauthn-algorithms-00.txt		draft-ietf-cose-webauthn-algorithms-01.txt
	COSE Working Group M. Jones		COSE Working Group M. Jones
	Internet-Draft Microsoft		Internet-Draft Microsoft
	Intended status: Standards Track March 26, 2019		Intended status: Standards Track July 8, 2019
	Expires: September 27, 2019		Expires: January 9, 2020
	COSE and JOSE Registrations for WebAuthn Algorithms		COSE and JOSE Registrations for WebAuthn Algorithms
	draft-ietf-cose-webauthn-algorithms-00		draft-ietf-cose-webauthn-algorithms-01
	Abstract		Abstract
	The W3C Web Authentication (WebAuthn) specification and the FIDO2		The W3C Web Authentication (WebAuthn) specification and the FIDO2
	Client to Authenticator Protocol (CTAP) specification use COSE		Client to Authenticator Protocol (CTAP) specification use COSE
	algorithm identifiers. This specification registers algorithms in		algorithm identifiers. This specification registers algorithms in
	the IANA "COSE Algorithms" registry that are used by WebAuthn and		the IANA "COSE Algorithms" registry that are used by WebAuthn and
	CTAP implementations that are not already registered. Also, they are		CTAP implementations that are not already registered. Also, they are
	registered in the IANA "JSON Web Signature and Encryption Algorithms"		registered in the IANA "JSON Web Signature and Encryption Algorithms"
	registry, when not already registered there.		registry, when not already registered there.
	skipping to change at page 1, line 36 ¶		skipping to change at page 1, line 36 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at https://datatracker.ietf.org/drafts/current/.		Drafts is at https://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on September 27, 2019.		This Internet-Draft will expire on January 9, 2020.
	Copyright Notice		Copyright Notice
	Copyright (c) 2019 IETF Trust and the persons identified as the		Copyright (c) 2019 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 2, line 15 ¶		skipping to change at page 2, line 15 ¶
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	1.1. Requirements Notation and Conventions . . . . . . . . . . 2		1.1. Requirements Notation and Conventions . . . . . . . . . . 2
	2. RSASSA-PKCS1-v1_5 Signature Algorithm . . . . . . . . . . . . 3		2. RSASSA-PKCS1-v1_5 Signature Algorithm . . . . . . . . . . . . 3
	3. Using secp256k1 with JOSE and COSE . . . . . . . . . . . . . 3		3. Using secp256k1 with JOSE and COSE . . . . . . . . . . . . . 3
	3.1. JOSE and COSE secp256k1 Curve Key Representations . . . . 3		3.1. JOSE and COSE secp256k1 Curve Key Representations . . . . 3
	3.2. ECDSA Signature with secp256k1 Curve . . . . . . . . . . 4		3.2. ECDSA Signature with secp256k1 Curve . . . . . . . . . . 4
	4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4		4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
	4.1. COSE Algorithms Registrations . . . . . . . . . . . . . . 4		4.1. COSE Algorithms Registrations . . . . . . . . . . . . . . 5
	4.2. COSE Elliptic Curves Registrations . . . . . . . . . . . 5		4.2. COSE Elliptic Curves Registrations . . . . . . . . . . . 6
	4.3. JOSE Algorithms Registrations . . . . . . . . . . . . . . 5		4.3. JOSE Algorithms Registrations . . . . . . . . . . . . . . 6
	4.4. JSON Web Key Elliptic Curves Registrations . . . . . . . 5		4.4. JSON Web Key Elliptic Curves Registrations . . . . . . . 6
	5. Security Considerations . . . . . . . . . . . . . . . . . . . 6		5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
	5.1. RSA Key Size Security Considerations . . . . . . . . . . 6		5.1. RSA Key Size Security Considerations . . . . . . . . . . 6
	5.2. RSASSA-PKCS1-v1_5 with SHA-2 Security Considerations . . 6		5.2. RSASSA-PKCS1-v1_5 with SHA-2 Security Considerations . . 7
	5.3. RSASSA-PKCS1-v1_5 with SHA-1 Security Considerations . . 6		5.3. RSASSA-PKCS1-v1_5 with SHA-1 Security Considerations . . 7
	5.4. secp256k1 Security Considerations . . . . . . . . . . . . 6		5.4. secp256k1 Security Considerations . . . . . . . . . . . . 7
	6. References . . . . . . . . . . . . . . . . . . . . . . . . . 6		6. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
	6.1. Normative References . . . . . . . . . . . . . . . . . . 7		6.1. Normative References . . . . . . . . . . . . . . . . . . 7
	6.2. Informative References . . . . . . . . . . . . . . . . . 8		6.2. Informative References . . . . . . . . . . . . . . . . . 8
	Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 9		Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 9
	Document History . . . . . . . . . . . . . . . . . . . . . . . . 9		Document History . . . . . . . . . . . . . . . . . . . . . . . . 9
	Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 9		Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 10
	1. Introduction		1. Introduction
	This specification defines how to use several algorithms with COSE		This specification defines how to use several algorithms with COSE
	[RFC8152] that are used by implementations of the W3C Web		[RFC8152] that are used by implementations of the W3C Web
	Authentication (WebAuthn) [WebAuthn] and FIDO2 Client to		Authentication (WebAuthn) [WebAuthn] and FIDO2 Client to
	Authenticator Protocol (CTAP) [CTAP] specifications. These		Authenticator Protocol (CTAP) [CTAP] specifications. These
	algorithms are registered in the IANA "COSE Algorithms" registry		algorithms are registered in the IANA "COSE Algorithms" registry
	[IANA.COSE.Algorithms] and also in the IANA "JSON Web Signature and		[IANA.COSE.Algorithms] and also in the IANA "JSON Web Signature and
	Encryption Algorithms" registry [IANA.JOSE.Algorithms], when not		Encryption Algorithms" registry [IANA.JOSE.Algorithms], when not
	skipping to change at page 3, line 22 ¶		skipping to change at page 3, line 22 ¶
	Implementations need to check that the key type is 'RSA' when		Implementations need to check that the key type is 'RSA' when
	creating or verifying a signature.		creating or verifying a signature.
	The RSASSA-PKCS1-v1_5 algorithms specified in this document are in		The RSASSA-PKCS1-v1_5 algorithms specified in this document are in
	the following table.		the following table.
	+-------+-----------------------------+---------+-------------------+		+-------+-----------------------------+---------+-------------------+
	| Name | Value | Hash | Description |		| Name | Value | Hash | Description |
	+-------+-----------------------------+---------+-------------------+		+-------+-----------------------------+---------+-------------------+
	| RS256 | TBD (temporary assignment | SHA-256 | RSASSA-PKCS1-v1_5 |		| RS256 | TBD (temporary assignment | SHA-256 | RSASSA-PKCS1-v1_5 |
	| | -257 already in place) | | w/ SHA-256 |		| | -257 already in place) | | using SHA-256 |
	| RS384 | TBD (temporary assignment | SHA-384 | RSASSA-PKCS1-v1_5 |		| RS384 | TBD (temporary assignment | SHA-384 | RSASSA-PKCS1-v1_5 |
	| | -258 already in place) | | w/ SHA-384 |		| | -258 already in place) | | using SHA-384 |
	| RS512 | TBD (temporary assignment | SHA-512 | RSASSA-PKCS1-v1_5 |		| RS512 | TBD (temporary assignment | SHA-512 | RSASSA-PKCS1-v1_5 |
	| | -259 already in place) | | w/ SHA-512 |		| | -259 already in place) | | using SHA-512 |
	| RS1 | TBD (temporary assignment | SHA-1 | RSASSA-PKCS1-v1_5 |		| RS1 | TBD (temporary assignment | SHA-1 | RSASSA-PKCS1-v1_5 |
	| | -65535 already in place) | | w/ SHA-1 |		| | -65535 already in place) | | using SHA-1 |
	+-------+-----------------------------+---------+-------------------+		+-------+-----------------------------+---------+-------------------+
	Table 1: RSASSA-PKCS1-v1_5 Algorithm Values		Table 1: RSASSA-PKCS1-v1_5 Algorithm Values
	3. Using secp256k1 with JOSE and COSE		3. Using secp256k1 with JOSE and COSE
	This section defines algorithm encodings and representations enabling		This section defines algorithm encodings and representations enabling
	the Standards for Efficient Cryptography Group (SECG) elliptic curve		the Standards for Efficient Cryptography Group (SECG) elliptic curve
	"secp256k1" [SEC2] to be used for JSON Object Signing and Encryption		secp256k1 [SEC2] to be used for JSON Object Signing and Encryption
	(JOSE) [RFC7515] and CBOR Object Signing and Encryption (COSE)		(JOSE) [RFC7515] and CBOR Object Signing and Encryption (COSE)
	[RFC8152] messages.		[RFC8152] messages.
	3.1. JOSE and COSE secp256k1 Curve Key Representations		3.1. JOSE and COSE secp256k1 Curve Key Representations
	The Standards for Efficient Cryptography Group (SECG) elliptic curve		The Standards for Efficient Cryptography Group (SECG) elliptic curve
	"secp256k1" [SEC2] is represented in a JSON Web Key (JWK) [RFC7517]		secp256k1 [SEC2] is represented in a JSON Web Key (JWK) [RFC7517]
	using these values:		using these values:
	o "kty": "EC"		o "kty": "EC"
	o "crv": "P-256K"		o "crv": "secp256k1"
	plus "x" and "y" values to represent the curve point for the key.		plus "x" and "y" values to represent the curve point for the key.
	Other optional values such as "alg" MAY also be present.		Other optional values such as "alg" MAY also be present.
	It is represented in a COSE_Key [RFC8152] using these values:		It is represented in a COSE_Key [RFC8152] using these values:
	o "kty" (1): "EC2" (2)		o "kty" (1): "EC2" (2)
	o "crv" (-1): "P-256K" (TBD - requested assignment 8)		o "crv" (-1): "secp256k1" (TBD - requested assignment 8)
	plus "x" (-2) and "y" (-3) values to represent the curve point for		plus "x" (-2) and "y" (-3) values to represent the curve point for
	the key. Other optional values such as "alg" (3) MAY also be		the key. Other optional values such as "alg" (3) MAY also be
	present.		present.
	3.2. ECDSA Signature with secp256k1 Curve		3.2. ECDSA Signature with secp256k1 Curve
	The ECDSA signature algorithm is defined in [DSS]. Implementations		The ECDSA signature algorithm is defined in [DSS]. This
	need to check that the key type is "EC" for JOSE or "EC2" (2) for		specification defines the use of ECDSA with the secp256k1 curve and
	COSE when creating or verifying a signature.		the SHA-256 [DSS] cryptographic hash function. Implementations need
			to check that the key type is "EC" for JOSE or "EC2" (2) for COSE
			when creating or verifying a signature.
	The ECDSA algorithm specified in this document is:		The ECDSA secp256k1 SHA-256 digital signature is generated as
			follows:
	+--------------+---------------------------+------------------------+		1. Generate a digital signature of the JWS Signing Input or the COSE
	| JOSE Alg | COSE Alg Value | Description |		payload using ECDSA secp256k1 SHA-256 with the desired private
	| Name | | |		key. The output will be the pair (R, S), where R and S are
	+--------------+---------------------------+------------------------+		256-bit unsigned integers.
	| ES256K | TBD (requested assignment | ECDSA w/ secp256k1 |
	| | -43) | Curve |		2. Turn R and S into octet sequences in big-endian order, with each
	+--------------+---------------------------+------------------------+		array being be 32 octets long. The octet sequence
			representations MUST NOT be shortened to omit any leading zero
			octets contained in the values.
			3. Concatenate the two octet sequences in the order R and then S.
			(Note that many ECDSA implementations will directly produce this
			concatenation as their output.)
			4. The resulting 64-octet sequence is the JWS Signature or COSE
			signature value.
			The ECDSA secp256k1 SHA-256 algorithm specified in this document uses
			these identifiers:
			+------------+------------------------+-----------------------------+
			| JOSE Alg | COSE Alg Value | Description |
			| Name | | |
			+------------+------------------------+-----------------------------+
			| ES256K | TBD (requested | ECDSA using secp256k1 curve |
			| | assignment -43) | and SHA-256 |
			+------------+------------------------+-----------------------------+
	Table 2: ECDSA Algorithm Values		Table 2: ECDSA Algorithm Values
	4. IANA Considerations		4. IANA Considerations
	4.1. COSE Algorithms Registrations		4.1. COSE Algorithms Registrations
	This section registers the following values in the IANA "COSE		This section registers the following values in the IANA "COSE
	Algorithms" registry [IANA.COSE.Algorithms].		Algorithms" registry [IANA.COSE.Algorithms].
	o Name: RS256		o Name: RS256
	o Value: TBD (temporary assignment -257 already in place)		o Value: TBD (temporary assignment -257 already in place)
	o Description: RSASSA-PKCS1-v1_5 w/ SHA-256		o Description: RSASSA-PKCS1-v1_5 using SHA-256
	o Reference: Section 2 of this document		o Reference: Section 2 of this document
	o Recommended: No		o Recommended: No
	o Name: RS384		o Name: RS384
	o Value: TBD (temporary assignment -258 already in place)		o Value: TBD (temporary assignment -258 already in place)
	o Description: RSASSA-PKCS1-v1_5 w/ SHA-384		o Description: RSASSA-PKCS1-v1_5 using SHA-384
	o Reference: Section 2 of this document		o Reference: Section 2 of this document
	o Recommended: No		o Recommended: No
	o Name: RS512		o Name: RS512
	o Value: TBD (temporary assignment -259 already in place)		o Value: TBD (temporary assignment -259 already in place)
	o Description: RSASSA-PKCS1-v1_5 w/ SHA-512		o Description: RSASSA-PKCS1-v1_5 using SHA-512
	o Reference: Section 2 of this document		o Reference: Section 2 of this document
	o Recommended: No		o Recommended: No
	o Name: RS1		o Name: RS1
	o Value: TBD (temporary assignment -65535 already in place)		o Value: TBD (temporary assignment -65535 already in place)
	o Description: RSASSA-PKCS1-v1_5 w/ SHA-1		o Description: RSASSA-PKCS1-v1_5 using SHA-1
	o Reference: Section 2 of this document		o Reference: Section 2 of this document
	o Recommended: Deprecated		o Recommended: Deprecated
	o Name: ES256K		o Name: ES256K
	o Value: TBD (requested assignment -43)		o Value: TBD (requested assignment -43)
	o Description: ECDSA w/ secp256k1 Curve		o Description: ECDSA using secp256k1 curve and SHA-256
	o Reference: Section 3.2 of this document		o Reference: Section 3.2 of this document
	o Recommended: Yes		o Recommended: Yes
	4.2. COSE Elliptic Curves Registrations		4.2. COSE Elliptic Curves Registrations
	This section registers the following value in the IANA "COSE Elliptic		This section registers the following value in the IANA "COSE Elliptic
	Curves" registry [IANA.COSE.Curves].		Curves" registry [IANA.COSE.Curves].
	o Name: P-256K		o Name: secp256k1
	o Value: TBD (requested assignment 8)		o Value: TBD (requested assignment 8)
	o Key Type: EC2		o Key Type: EC2
	o Description: SECG secp256k1 Curve		o Description: SECG secp256k1 curve
	o Change Controller: IESG		o Change Controller: IESG
	o Reference: Section 3.1 of [[ this specification ]]		o Reference: Section 3.1 of [[ this specification ]]
	o Recommended: Yes		o Recommended: Yes
	4.3. JOSE Algorithms Registrations		4.3. JOSE Algorithms Registrations
	This section registers the following value in the IANA "JSON Web		This section registers the following value in the IANA "JSON Web
	Signature and Encryption Algorithms" registry [IANA.JOSE.Algorithms].		Signature and Encryption Algorithms" registry [IANA.JOSE.Algorithms].
	o Algorithm Name: ES256K		o Algorithm Name: ES256K
	o Algorithm Description: ECDSA w/ secp256k1 Curve		o Algorithm Description: ECDSA using secp256k1 curve and SHA-256
	o Algorithm Usage Locations: alg		o Algorithm Usage Locations: alg
	o JOSE Implementation Requirements: Optional		o JOSE Implementation Requirements: Optional
	o Change Controller: IESG		o Change Controller: IESG
	o Reference: Section 3.2 of [[ this specification ]]		o Reference: Section 3.2 of [[ this specification ]]
	o Algorithm Analysis Document(s): [SEC2]		o Algorithm Analysis Document(s): [SEC2]
	4.4. JSON Web Key Elliptic Curves Registrations		4.4. JSON Web Key Elliptic Curves Registrations
	This section registers the following value in the IANA "JSON Web Key		This section registers the following value in the IANA "JSON Web Key
	Elliptic Curve" registry [IANA.JOSE.Curves].		Elliptic Curve" registry [IANA.JOSE.Curves].
	o Curve Name: P-256K		o Curve Name: secp256k1
	o Curve Description: SECG secp256k1 Curve		o Curve Description: SECG secp256k1 curve
	o JOSE Implementation Requirements: Optional		o JOSE Implementation Requirements: Optional
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): Section 3.1 of [[ this specification ]]		o Specification Document(s): Section 3.1 of [[ this specification ]]
	5. Security Considerations		5. Security Considerations
	5.1. RSA Key Size Security Considerations		5.1. RSA Key Size Security Considerations
	The security considerations on key sizes for RSA algorithms from		The security considerations on key sizes for RSA algorithms from
	Section 6.1 of [RFC8230] also apply to the RSA algorithms in this		Section 6.1 of [RFC8230] also apply to the RSA algorithms in this
	skipping to change at page 9, line 15 ¶		skipping to change at page 9, line 42 ¶
	[WebAuthn]		[WebAuthn]
	Balfanz, D., Czeskis, A., Hodges, J., Jones, J., Jones,		Balfanz, D., Czeskis, A., Hodges, J., Jones, J., Jones,
	M., Kumar, A., Liao, A., Lindemann, R., and E. Lundberg,		M., Kumar, A., Liao, A., Lindemann, R., and E. Lundberg,
	"Web Authentication: An API for accessing Public Key		"Web Authentication: An API for accessing Public Key
	Credentials - Level 1", World Wide Web Consortium		Credentials - Level 1", World Wide Web Consortium
	(W3C) Recommendation, March 2019,		(W3C) Recommendation, March 2019,
	<https://www.w3.org/TR/2019/REC-webauthn-1-20190304/>.		<https://www.w3.org/TR/2019/REC-webauthn-1-20190304/>.
	Acknowledgements		Acknowledgements
	Thanks to John Fontana, Jeff Hodges, Tony Nadalin, Jim Schaad, Goeran		Thanks to Stephen Farrell, John Fontana, Jeff Hodges, John Mattsson,
	Selander, Wendy Seltzer, Sean Turner, and Samuel Weiler for their		Tony Nadalin, Matt Palmer, Jim Schaad, Goeran Selander, Wendy
	roles in registering these algorithm identifiers.		Seltzer, Sean Turner, and Samuel Weiler for their roles in
			registering these algorithm identifiers.
	Document History		Document History
	[[ to be removed by the RFC Editor before publication as an RFC ]]		[[ to be removed by the RFC Editor before publication as an RFC ]]
			-01
			o Changed the JOSE curve identifier from "P-256K" to "secp256k1".
			o Specified that secp256k1 signing is done using the SHA-256 hash
			function.
	-00		-00
	o Created the initial working group draft from draft-jones-cose-		o Created the initial working group draft from draft-jones-cose-
	additional-algorithms-00, changing only the title, date, and		additional-algorithms-00, changing only the title, date, and
	history entry.		history entry.
	Author's Address		Author's Address
	Michael B. Jones		Michael B. Jones
	Microsoft		Microsoft
End of changes. 28 change blocks.
	46 lines changed or deleted		76 lines changed or added
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