< draft-ietf-ace-cwt-proof-of-possession-09.txt		draft-ietf-ace-cwt-proof-of-possession-10.txt >
	ACE M. Jones		ACE M. Jones
	Internet-Draft Microsoft		Internet-Draft Microsoft
	Intended status: Standards Track L. Seitz		Intended status: Standards Track L. Seitz
	Expires: April 20, 2020 RISE SICS		Expires: May 2, 2020 RISE SICS
	G. Selander		G. Selander
	Ericsson AB		Ericsson AB
	S. Erdtman		S. Erdtman
	Spotify		Spotify
	H. Tschofenig		H. Tschofenig
	Arm Ltd.		Arm Ltd.
	October 18, 2019		October 30, 2019
	Proof-of-Possession Key Semantics for CBOR Web Tokens (CWTs)		Proof-of-Possession Key Semantics for CBOR Web Tokens (CWTs)
	draft-ietf-ace-cwt-proof-of-possession-09		draft-ietf-ace-cwt-proof-of-possession-10
	Abstract		Abstract
	This specification describes how to declare in a CBOR Web Token (CWT)		This specification describes how to declare in a CBOR Web Token (CWT)
	(which is defined by RFC 8392) that the presenter of the CWT		(which is defined by RFC 8392) that the presenter of the CWT
	possesses a particular proof-of-possession key. Being able to prove		possesses a particular proof-of-possession key. Being able to prove
	possession of a key is also sometimes described as being the holder-		possession of a key is also sometimes described as being the holder-
	of-key. This specification provides equivalent functionality to		of-key. This specification provides equivalent functionality to
	"Proof-of-Possession Key Semantics for JSON Web Tokens (JWTs)" (RFC		"Proof-of-Possession Key Semantics for JSON Web Tokens (JWTs)" (RFC
	7800) but using Concise Binary Object Representation (CBOR) and CWTs		7800) but using Concise Binary Object Representation (CBOR) and CWTs
	skipping to change at page 1, line 45 ¶		skipping to change at page 1, line 45 ¶
	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 April 20, 2020.		This Internet-Draft will expire on May 2, 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 4, line 10 ¶		skipping to change at page 4, line 10 ¶
	By including a "cnf" (confirmation) claim in a CWT, the issuer of the		By including a "cnf" (confirmation) claim in a CWT, the issuer of the
	CWT declares that the presenter possesses a particular key and that		CWT declares that the presenter possesses a particular key and that
	the recipient can cryptographically confirm that the presenter has		the recipient can cryptographically confirm that the presenter has
	possession of that key. The value of the "cnf" claim is a CBOR map		possession of that key. The value of the "cnf" claim is a CBOR map
	(which is defined in Section 2.1 of [RFC7049]) and the members of		(which is defined in Section 2.1 of [RFC7049]) and the members of
	that map identify the proof-of-possession key.		that map identify the proof-of-possession key.
	The presenter can be identified in one of several ways by the CWT,		The presenter can be identified in one of several ways by the CWT,
	depending upon the application requirements. For instance, some		depending upon the application requirements. For instance, some
	applications may use the CWT "sub" (subject) claim [RFC8392], to		applications may use the CWT "sub" (subject) claim [RFC8392], to
	identify the presenter. Other applications may use the "iss" claim		identify the presenter. Other applications may use the "iss"
	to identify the presenter. In some applications, the subject		(issuer) claim [RFC8392] to identify the presenter. In some
	identifier might be relative to the issuer identified by the "iss"		applications, the subject identifier might be relative to the issuer
	(issuer) claim [RFC8392]. The actual mechanism used is dependent		identified by the "iss" claim. The actual mechanism used is
	upon the application. The case in which the presenter is the subject		dependent upon the application. The case in which the presenter is
	of the CWT is analogous to Security Assertion Markup Language (SAML)		the subject of the CWT is analogous to Security Assertion Markup
	2.0 [OASIS.saml-core-2.0-os] SubjectConfirmation usage.		Language (SAML) 2.0 [OASIS.saml-core-2.0-os] SubjectConfirmation
			usage.
	3.1. Confirmation Claim		3.1. Confirmation Claim
	The "cnf" claim in the CWT is used to carry confirmation methods.		The "cnf" claim in the CWT is used to carry confirmation methods.
	Some of them use proof-of-possession keys while others do not. This		Some of them use proof-of-possession keys while others do not. This
	design is analogous to the SAML 2.0 [OASIS.saml-core-2.0-os]		design is analogous to the SAML 2.0 [OASIS.saml-core-2.0-os]
	SubjectConfirmation element in which a number of different subject		SubjectConfirmation element in which a number of different subject
	confirmation methods can be included (including proof-of-possession		confirmation methods can be included (including proof-of-possession
	key information).		key information).
	skipping to change at page 6, line 17 ¶		skipping to change at page 6, line 17 ¶
	When the key held by the presenter is a symmetric key, the		When the key held by the presenter is a symmetric key, the
	"Encrypted_COSE_Key" member is an encrypted COSE_Key [RFC8152]		"Encrypted_COSE_Key" member is an encrypted COSE_Key [RFC8152]
	representing the symmetric key encrypted to a key known to the		representing the symmetric key encrypted to a key known to the
	recipient using COSE_Encrypt or COSE_Encrypt0.		recipient using COSE_Encrypt or COSE_Encrypt0.
	The following example illustrates a symmetric key that could		The following example illustrates a symmetric key that could
	subsequently be encrypted for use in the "Encrypted_COSE_Key" member:		subsequently be encrypted for use in the "Encrypted_COSE_Key" member:
	{		{
	/kty/ 1 : /Symmetric/ 4,		/kty/ 1 : /Symmetric/ 4,
	/alg/ 3 : /HMAC256//256/ 5,		/alg/ 3 : /HMAC 256-256/ 5,
	/k/ -1 : h'6684523ab17337f173500e5728c628547cb37df		/k/ -1 : h'6684523ab17337f173500e5728c628547cb37df
	e68449c65f885d1b73b49eae1'		e68449c65f885d1b73b49eae1'
	}		}
	The COSE_Key representation is used as the plaintext when encrypting		The COSE_Key representation is used as the plaintext when encrypting
	the key.		the key.
	The following example CWT Claims Set of a CWT illustrates the use of		The following example CWT Claims Set of a CWT illustrates the use of
	an encrypted symmetric key as the "Encrypted_COSE_Key" member value:		an encrypted symmetric key as the "Encrypted_COSE_Key" member value:
	skipping to change at page 14, line 24 ¶		skipping to change at page 14, line 24 ¶
	[RFC8610] Birkholz, H., Vigano, C., and C. Bormann, "Concise Data		[RFC8610] Birkholz, H., Vigano, C., and C. Bormann, "Concise Data
	Definition Language (CDDL): A Notational Convention to		Definition Language (CDDL): A Notational Convention to
	Express Concise Binary Object Representation (CBOR) and		Express Concise Binary Object Representation (CBOR) and
	JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610,		JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610,
	June 2019, <https://www.rfc-editor.org/info/rfc8610>.		June 2019, <https://www.rfc-editor.org/info/rfc8610>.
	Acknowledgements		Acknowledgements
	Thanks to the following people for their reviews of the		Thanks to the following people for their reviews of the
	specification: Roman Danyliw, Christer Holmberg, Benjamin Kaduk, Yoav		specification: Roman Danyliw, Christer Holmberg, Benjamin Kaduk,
	Nir, Michael Richardson, and Jim Schaad.		Mirja Kuehlewind, Yoav Nir, Michael Richardson, Adam Roach, Eric
			Vyncke, and Jim Schaad.
	Ludwig Seitz and Goeran Selander worked on this document as part of		Ludwig Seitz and Goeran Selander worked on this document as part of
	the CelticPlus projects CyberWI and CRITISEC, with funding from		the CelticPlus projects CyberWI and CRITISEC, with funding from
	Vinnova.		Vinnova.
	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 ]]
			-10
			o Addressed IESG review comments by Adam Roach and Eric Vyncke.
	-09		-09
	o Addressed Gen-ART review comments by Christer Holmberg and SecDir		o Addressed Gen-ART review comments by Christer Holmberg and SecDir
	review comments by Yoav Nir.		review comments by Yoav Nir.
	-08		-08
	o Addressed remaining Area Director review comments by Benjamin		o Addressed remaining Area Director review comments by Benjamin
	Kaduk.		Kaduk.
End of changes. 8 change blocks.
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