draft-ietf-ace-cbor-web-token-15.txt		rfc8392.txt
	ACE Working Group M. Jones		Internet Engineering Task Force (IETF) M. Jones
	Internet-Draft Microsoft		Request for Comments: 8392 Microsoft
	Intended status: Standards Track E. Wahlstroem		Category: Standards Track E. Wahlstroem
	Expires: September 20, 2018		ISSN: 2070-1721
	S. Erdtman		S. Erdtman
	Spotify AB		Spotify AB
	H. Tschofenig		H. Tschofenig
	ARM Ltd.		ARM Ltd.
	March 19, 2018		May 2018
	CBOR Web Token (CWT)		CBOR Web Token (CWT)
	draft-ietf-ace-cbor-web-token-15
	Abstract		Abstract
	CBOR Web Token (CWT) is a compact means of representing claims to be		CBOR Web Token (CWT) is a compact means of representing claims to be
	transferred between two parties. The claims in a CWT are encoded in		transferred between two parties. The claims in a CWT are encoded in
	the Concise Binary Object Representation (CBOR) and CBOR Object		the Concise Binary Object Representation (CBOR), and CBOR Object
	Signing and Encryption (COSE) is used for added application layer		Signing and Encryption (COSE) is used for added application-layer
	security protection. A claim is a piece of information asserted		security protection. A claim is a piece of information asserted
	about a subject and is represented as a name/value pair consisting of		about a subject and is represented as a name/value pair consisting of
	a claim name and a claim value. CWT is derived from JSON Web Token		a claim name and a claim value. CWT is derived from JSON Web Token
	(JWT) but uses CBOR rather than JSON.		(JWT) but uses CBOR rather than JSON.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This is an Internet Standards Track document.
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			and how to provide feedback on it may be obtained at
			https://www.rfc-editor.org/info/rfc8392.
	Copyright Notice		Copyright Notice
	Copyright (c) 2018 IETF Trust and the persons identified as the		Copyright (c) 2018 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
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	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
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	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
	1.1. CBOR Related Terminology . . . . . . . . . . . . . . . . 3		1.1. CBOR-Related Terminology . . . . . . . . . . . . . . . . 4
	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3		2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
	3. Claims . . . . . . . . . . . . . . . . . . . . . . . . . . . 4		3. Claims . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
	3.1. Registered Claims . . . . . . . . . . . . . . . . . . . . 5		3.1. Registered Claims . . . . . . . . . . . . . . . . . . . . 5
	3.1.1. iss (Issuer) Claim . . . . . . . . . . . . . . . . . 5		3.1.1. iss (Issuer) Claim . . . . . . . . . . . . . . . . . 5
	3.1.2. sub (Subject) Claim . . . . . . . . . . . . . . . . . 5		3.1.2. sub (Subject) Claim . . . . . . . . . . . . . . . . . 6
	3.1.3. aud (Audience) Claim . . . . . . . . . . . . . . . . 5		3.1.3. aud (Audience) Claim . . . . . . . . . . . . . . . . 6
	3.1.4. exp (Expiration Time) Claim . . . . . . . . . . . . . 5		3.1.4. exp (Expiration Time) Claim . . . . . . . . . . . . . 6
	3.1.5. nbf (Not Before) Claim . . . . . . . . . . . . . . . 5		3.1.5. nbf (Not Before) Claim . . . . . . . . . . . . . . . 6
	3.1.6. iat (Issued At) Claim . . . . . . . . . . . . . . . . 6		3.1.6. iat (Issued At) Claim . . . . . . . . . . . . . . . . 6
	3.1.7. cti (CWT ID) Claim . . . . . . . . . . . . . . . . . 6		3.1.7. cti (CWT ID) Claim . . . . . . . . . . . . . . . . . 6
	4. Summary of the claim names, keys, and value types . . . . . . 6		4. Summary of the Claim Names, Keys, and Value Types . . . . . . 7
	5. CBOR Tags and Claim Values . . . . . . . . . . . . . . . . . 6		5. CBOR Tags and Claim Values . . . . . . . . . . . . . . . . . 7
	6. CWT CBOR Tag . . . . . . . . . . . . . . . . . . . . . . . . 6		6. CWT CBOR Tag . . . . . . . . . . . . . . . . . . . . . . . . 7
	7. Creating and Validating CWTs . . . . . . . . . . . . . . . . 7		7. Creating and Validating CWTs . . . . . . . . . . . . . . . . 8
	7.1. Creating a CWT . . . . . . . . . . . . . . . . . . . . . 7		7.1. Creating a CWT . . . . . . . . . . . . . . . . . . . . . 8
	7.2. Validating a CWT . . . . . . . . . . . . . . . . . . . . 8		7.2. Validating a CWT . . . . . . . . . . . . . . . . . . . . 9
	8. Security Considerations . . . . . . . . . . . . . . . . . . . 9		8. Security Considerations . . . . . . . . . . . . . . . . . . . 10
	9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10		9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
	9.1. CBOR Web Token (CWT) Claims Registry . . . . . . . . . . 10		9.1. CBOR Web Token (CWT) Claims Registry . . . . . . . . . . 11
	9.1.1. Registration Template . . . . . . . . . . . . . . . . 11		9.1.1. Registration Template . . . . . . . . . . . . . . . . 12
	9.1.2. Initial Registry Contents . . . . . . . . . . . . . . 11		9.1.2. Initial Registry Contents . . . . . . . . . . . . . . 12
	9.2. Media Type Registration . . . . . . . . . . . . . . . . . 13		9.2. Media Type Registration . . . . . . . . . . . . . . . . . 14
	9.2.1. Registry Contents . . . . . . . . . . . . . . . . . . 13		9.2.1. Registry Contents . . . . . . . . . . . . . . . . . . 14
	9.3. CoAP Content-Formats Registration . . . . . . . . . . . . 14		9.3. CoAP Content-Formats Registration . . . . . . . . . . . . 14
	9.3.1. Registry Contents . . . . . . . . . . . . . . . . . . 14		9.3.1. Registry Contents . . . . . . . . . . . . . . . . . . 15
	9.4. CBOR Tag registration . . . . . . . . . . . . . . . . . . 14		9.4. CBOR Tag registration . . . . . . . . . . . . . . . . . . 15
	9.4.1. Registry Contents . . . . . . . . . . . . . . . . . . 14		9.4.1. Registry Contents . . . . . . . . . . . . . . . . . . 15
	10. References . . . . . . . . . . . . . . . . . . . . . . . . . 14		10. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
	10.1. Normative References . . . . . . . . . . . . . . . . . . 14		10.1. Normative References . . . . . . . . . . . . . . . . . . 15
	10.2. Informative References . . . . . . . . . . . . . . . . . 15		10.2. Informative References . . . . . . . . . . . . . . . . . 16
	Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 16		Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 17
	A.1. Example CWT Claims Set . . . . . . . . . . . . . . . . . 16		A.1. Example CWT Claims Set . . . . . . . . . . . . . . . . . 17
	A.2. Example keys . . . . . . . . . . . . . . . . . . . . . . 16		A.2. Example Keys . . . . . . . . . . . . . . . . . . . . . . 17
	A.2.1. 128-bit Symmetric Key . . . . . . . . . . . . . . . . 17		A.2.1. 128-Bit Symmetric Key . . . . . . . . . . . . . . . . 18
	A.2.2. 256-bit Symmetric Key . . . . . . . . . . . . . . . . 17		A.2.2. 256-Bit Symmetric Key . . . . . . . . . . . . . . . . 18
	A.2.3. ECDSA P-256 256-bit COSE Key . . . . . . . . . . . . 17		A.2.3. Elliptic Curve Digital Signature Algorithm (ECDSA)
	A.3. Example Signed CWT . . . . . . . . . . . . . . . . . . . 18		P-256 256-Bit COSE Key . . . . . . . . . . . . . . . 19
	A.4. Example MACed CWT . . . . . . . . . . . . . . . . . . . . 19		A.3. Example Signed CWT . . . . . . . . . . . . . . . . . . . 19
	A.5. Example Encrypted CWT . . . . . . . . . . . . . . . . . . 20		A.4. Example MACed CWT . . . . . . . . . . . . . . . . . . . . 20
	A.6. Example Nested CWT . . . . . . . . . . . . . . . . . . . 21		A.5. Example Encrypted CWT . . . . . . . . . . . . . . . . . . 21
	A.7. Example MACed CWT with a floating-point value . . . . . . 22		A.6. Example Nested CWT . . . . . . . . . . . . . . . . . . . 22
	Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 23		A.7. Example MACed CWT with a Floating-Point Value . . . . . . 23
	Appendix C. Document History . . . . . . . . . . . . . . . . . . 23		Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 24
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25
	1. Introduction		1. Introduction
	The JSON Web Token (JWT) [RFC7519] is a standardized security token		The JSON Web Token (JWT) [RFC7519] is a standardized security token
	format that has found use in OAuth 2.0 and OpenID Connect		format that has found use in OAuth 2.0 and OpenID Connect
	deployments, among other applications. JWT uses JSON Web Signature		deployments, among other applications. JWT uses JSON Web Signature
	(JWS) [RFC7515] and JSON Web Encryption (JWE) [RFC7516] to secure the		(JWS) [RFC7515] and JSON Web Encryption (JWE) [RFC7516] to secure the
	contents of the JWT, which is a set of claims represented in JSON.		contents of the JWT, which is a set of claims represented in JSON.
	The use of JSON for encoding information is popular for Web and		The use of JSON for encoding information is popular for Web and
	native applications, but it is considered inefficient for some		native applications, but it is considered inefficient for some
	Internet of Things (IoT) systems that use low power radio		Internet of Things (IoT) systems that use low-power radio
	technologies.		technologies.
	An alternative encoding of claims is defined in this document.		An alternative encoding of claims is defined in this document.
	Instead of using JSON, as provided by JWTs, this specification uses		Instead of using JSON, as provided by JWTs, this specification uses
	CBOR [RFC7049] and calls this new structure "CBOR Web Token (CWT)",		CBOR [RFC7049] and calls this new structure "CBOR Web Token (CWT)",
	which is a compact means of representing secured claims to be		which is a compact means of representing secured claims to be
	transferred between two parties. CWT is closely related to JWT. It		transferred between two parties. CWT is closely related to JWT. It
	references the JWT claims and both its name and pronunciation are		references the JWT claims and both its name and pronunciation are
	derived from JWT. To protect the claims contained in CWTs, the CBOR		derived from JWT (the suggested pronunciation of CWT is the same as
	Object Signing and Encryption (COSE) [RFC8152] specification is used.		the English word "cot"). To protect the claims contained in CWTs,
			the CBOR Object Signing and Encryption (COSE) [RFC8152] specification
	The suggested pronunciation of CWT is the same as the English word		is used.
	"cot".
	1.1. CBOR Related Terminology		1.1. CBOR-Related Terminology
	In JSON, maps are called objects and only have one kind of map key: a		In JSON, maps are called objects and only have one kind of map key: a
	string. CBOR uses strings, negative integers, and unsigned integers		string. CBOR uses strings, negative integers, and unsigned integers
	as map keys. The integers are used for compactness of encoding and		as map keys. The integers are used for compactness of encoding and
	easy comparison. The inclusion of strings allows for an additional		easy comparison. The inclusion of strings allows for an additional
	range of short encoded values to be used.		range of short encoded values to be used.
	2. Terminology		2. Terminology
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and		"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
	"OPTIONAL" in this document are to be interpreted as described in BCP		"OPTIONAL" in this document are to be interpreted as described in
	14 [RFC2119] [RFC8174] when, and only when, they appear in all		BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
	capitals, as shown here.		capitals, as shown here.
	This document reuses terminology from JWT [RFC7519] and COSE		This document reuses terminology from JWT [RFC7519] and COSE
	[RFC8152].		[RFC8152].
	StringOrURI		StringOrURI
	The "StringOrURI" term in this specification has the same meaning		The "StringOrURI" term in this specification has the same meaning
	and processing rules as the JWT "StringOrURI" term defined in		and processing rules as the JWT "StringOrURI" term defined in
	Section 2 of [RFC7519], except that it is represented as a CBOR		Section 2 of [RFC7519], except that it is represented as a CBOR
	text string instead of a JSON text string.		text string instead of a JSON text string.
	skipping to change at page 5, line 8 ¶		skipping to change at page 5, line 41 ¶
	the absence of such requirements, all claims that are not understood		the absence of such requirements, all claims that are not understood
	by implementations MUST be ignored.		by implementations MUST be ignored.
	To keep CWTs as small as possible, the Claim Keys are represented		To keep CWTs as small as possible, the Claim Keys are represented
	using integers or text strings. Section 4 summarizes all keys used		using integers or text strings. Section 4 summarizes all keys used
	to identify the claims defined in this document.		to identify the claims defined in this document.
	3.1. Registered Claims		3.1. Registered Claims
	None of the claims defined below are intended to be mandatory to use		None of the claims defined below are intended to be mandatory to use
	or implement. They rather provide a starting point for a set of		or implement. Rather, they provide a starting point for a set of
	useful, interoperable claims. Applications using CWTs should define		useful, interoperable claims. Applications using CWTs should define
	which specific claims they use and when they are required or		which specific claims they use and when they are required or
	optional.		optional.
	3.1.1. iss (Issuer) Claim		3.1.1. iss (Issuer) Claim
	The "iss" (issuer) claim has the same meaning and processing rules as		The "iss" (issuer) claim has the same meaning and processing rules as
	the "iss" claim defined in Section 4.1.1 of [RFC7519], except that		the "iss" claim defined in Section 4.1.1 of [RFC7519], except that
	the value is a StringOrURI, as defined in Section 2 of this		the value is a StringOrURI, as defined in Section 2 of this
	specification. The Claim Key 1 is used to identify this claim.		specification. The Claim Key 1 is used to identify this claim.
	skipping to change at page 6, line 19 ¶		skipping to change at page 7, line 5 ¶
	the value is a NumericDate, as defined in Section 2 of this		the value is a NumericDate, as defined in Section 2 of this
	specification. The Claim Key 6 is used to identify this claim.		specification. The Claim Key 6 is used to identify this claim.
	3.1.7. cti (CWT ID) Claim		3.1.7. cti (CWT ID) Claim
	The "cti" (CWT ID) claim has the same meaning and processing rules as		The "cti" (CWT ID) claim has the same meaning and processing rules as
	the "jti" claim defined in Section 4.1.7 of [RFC7519], except that		the "jti" claim defined in Section 4.1.7 of [RFC7519], except that
	the value is a byte string. The Claim Key 7 is used to identify this		the value is a byte string. The Claim Key 7 is used to identify this
	claim.		claim.
	4. Summary of the claim names, keys, and value types		4. Summary of the Claim Names, Keys, and Value Types
	+------+-----+----------------------------------+		+------+-----+----------------------------------+
	| Name | Key | Value type |		| Name | Key | Value Type |
	+------+-----+----------------------------------+		+------+-----+----------------------------------+
	| iss | 1 | text string |		| iss | 1 | text string |
	| sub | 2 | text string |		| sub | 2 | text string |
	| aud | 3 | text string |		| aud | 3 | text string |
	| exp | 4 | integer or floating-point number |		| exp | 4 | integer or floating-point number |
	| nbf | 5 | integer or floating-point number |		| nbf | 5 | integer or floating-point number |
	| iat | 6 | integer or floating-point number |		| iat | 6 | integer or floating-point number |
	| cti | 7 | byte string |		| cti | 7 | byte string |
	+------+-----+----------------------------------+		+------+-----+----------------------------------+
	Table 1: Summary of the claim names, keys, and value types		Table 1: Summary of the Claim Names, Keys, and Value Types
	5. CBOR Tags and Claim Values		5. CBOR Tags and Claim Values
	The claim values defined in this specification MUST NOT be prefixed		The claim values defined in this specification MUST NOT be prefixed
	with any CBOR tag. For instance, while CBOR tag 1 (epoch-based date/		with any CBOR tag. For instance, while CBOR tag 1 (epoch-based date/
	time) could logically be prefixed to values of the "exp", "nbf", and		time) could logically be prefixed to values of the "exp", "nbf", and
	"iat" claims, this is unnecessary, since the representation of the		"iat" claims, this is unnecessary since the representation of the
	claim values is already specified by the claim definitions. Tagging		claim values is already specified by the claim definitions. Tagging
	claim values would only take up extra space without adding		claim values would only take up extra space without adding
	information. However, this does not prohibit future claim		information. However, this does not prohibit future claim
	definitions from requiring the use of CBOR tags for those specific		definitions from requiring the use of CBOR tags for those specific
	claims.		claims.
	6. CWT CBOR Tag		6. CWT CBOR Tag
	How to determine that a CBOR data structure is a CWT is application-		How to determine that a CBOR data structure is a CWT is application
	dependent. In some cases, this information is known from the		dependent. In some cases, this information is known from the
	application context, such as from the position of the CWT in a data		application context, such as from the position of the CWT in a data
	structure at which the value must be a CWT. One method of indicating		structure at which the value must be a CWT. One method of indicating
	that a CBOR object is a CWT is the use of the "application/cwt"		that a CBOR object is a CWT is the use of the "application/cwt"
	content type by a transport protocol.		content type by a transport protocol.
	This section defines the CWT CBOR tag as another means for		This section defines the CWT CBOR tag as another means for
	applications to declare that a CBOR data structure is a CWT. Its use		applications to declare that a CBOR data structure is a CWT. Its use
	is optional and is intended for use in cases in which this		is optional and is intended for use in cases in which this
	information would not otherwise be known.		information would not otherwise be known.
	skipping to change at page 7, line 22 ¶		skipping to change at page 8, line 15 ¶
	If present, the CWT tag MUST prefix a tagged object using one of the		If present, the CWT tag MUST prefix a tagged object using one of the
	COSE CBOR tags. In this example, the COSE_Mac0 tag is used. The		COSE CBOR tags. In this example, the COSE_Mac0 tag is used. The
	actual COSE_Mac0 object has been excluded from this example.		actual COSE_Mac0 object has been excluded from this example.
	/ CWT CBOR tag / 61(		/ CWT CBOR tag / 61(
	/ COSE_Mac0 CBOR tag / 17(		/ COSE_Mac0 CBOR tag / 17(
	/ COSE_Mac0 object /		/ COSE_Mac0 object /
	)		)
	)		)
	Figure 1: Example of a CWT tag usage		Figure 1: Example of CWT Tag Usage
	7. Creating and Validating CWTs		7. Creating and Validating CWTs
	7.1. Creating a CWT		7.1. Creating a CWT
	To create a CWT, the following steps are performed. The order of the		To create a CWT, the following steps are performed. The order of the
	steps is not significant in cases where there are no dependencies		steps is not significant in cases where there are no dependencies
	between the inputs and outputs of the steps.		between the inputs and outputs of the steps.
	1. Create a CWT Claims Set containing the desired claims.		1. Create a CWT Claims Set containing the desired claims.
	skipping to change at page 8, line 51 ¶		skipping to change at page 9, line 43 ¶
	4. Verify that the resulting COSE Header includes only parameters		4. Verify that the resulting COSE Header includes only parameters
	and values whose syntax and semantics are both understood and		and values whose syntax and semantics are both understood and
	supported or that are specified as being ignored when not		supported or that are specified as being ignored when not
	understood.		understood.
	5. Depending upon whether the CWT is a signed, MACed, or encrypted,		5. Depending upon whether the CWT is a signed, MACed, or encrypted,
	there are three cases:		there are three cases:
	* If the CWT is a COSE_Sign/COSE_Sign1, follow the steps		* If the CWT is a COSE_Sign/COSE_Sign1, follow the steps
	specified in [RFC8152] Section 4 (Signing Objects) for		specified in Section 4 of [RFC8152] ("Signing Objects") for
	validating a COSE_Sign/COSE_Sign1 object. Let the Message be		validating a COSE_Sign/COSE_Sign1 object. Let the Message be
	the COSE_Sign/COSE_Sign1 payload.		the COSE_Sign/COSE_Sign1 payload.
	* Else, if the CWT is a COSE_Mac/COSE_Mac0, follow the steps		* Else, if the CWT is a COSE_Mac/COSE_Mac0, follow the steps
	specified in [RFC8152] Section 6 (MAC Objects) for validating		specified in Section 6 of [RFC8152] ("MAC Objects") for
	a COSE_Mac/COSE_Mac0 object. Let the Message be the COSE_Mac/		validating a COSE_Mac/COSE_Mac0 object. Let the Message be
	COSE_Mac0 payload.		the COSE_Mac/COSE_Mac0 payload.
	* Else, if the CWT is a COSE_Encrypt/COSE_Encrypt0 object,		* Else, if the CWT is a COSE_Encrypt/COSE_Encrypt0 object,
	follow the steps specified in [RFC8152] Section 5 (Encryption		follow the steps specified in Section 5 of [RFC8152]
	Objects) for validating a COSE_Encrypt/COSE_Encrypt0 object.		("Encryption Objects") for validating a COSE_Encrypt/
	Let the Message be the resulting plaintext.		COSE_Encrypt0 object. Let the Message be the resulting
			plaintext.
	6. If the Message begins with a COSE CBOR tag, then the Message is a		6. If the Message begins with a COSE CBOR tag, then the Message is a
	CWT that was the subject of nested signing, MACing, or encryption		CWT that was the subject of nested signing, MACing, or encryption
	operations. In this case, return to Step 1, using the Message as		operations. In this case, return to Step 1, using the Message as
	the CWT.		the CWT.
	7. Verify that the Message is a valid CBOR map; let the CWT Claims		7. Verify that the Message is a valid CBOR map; let the CWT Claims
	Set be this CBOR map.		Set be this CBOR map.
	8. Security Considerations		8. Security Considerations
	skipping to change at page 9, line 41 ¶		skipping to change at page 10, line 35 ¶
	Since the claims conveyed in a CWT may be used to make authorization		Since the claims conveyed in a CWT may be used to make authorization
	decisions, it is not only important to protect the CWT in transit but		decisions, it is not only important to protect the CWT in transit but
	also to ensure that the recipient can authenticate the party that		also to ensure that the recipient can authenticate the party that
	assembled the claims and created the CWT. Without trust of the		assembled the claims and created the CWT. Without trust of the
	recipient in the party that created the CWT, no sensible		recipient in the party that created the CWT, no sensible
	authorization decision can be made. Furthermore, the creator of the		authorization decision can be made. Furthermore, the creator of the
	CWT needs to carefully evaluate each claim value prior to including		CWT needs to carefully evaluate each claim value prior to including
	it in the CWT so that the recipient can be assured of the validity of		it in the CWT so that the recipient can be assured of the validity of
	the information provided.		the information provided.
	While syntactically the signing and encryption operations for Nested		Syntactically, the signing and encryption operations for Nested CWTs
	CWTs may be applied in any order, if both signing and encryption are		may be applied in any order; however, if both signing and encryption
	necessary, normally producers should sign the message and then		are necessary, producers normally should sign the message and then
	encrypt the result (thus encrypting the signature). This prevents		encrypt the result (thus encrypting the signature). This prevents
	attacks in which the signature is stripped, leaving just an encrypted		attacks in which the signature is stripped, leaving just an encrypted
	message, as well as providing privacy for the signer. Furthermore,		message, as well as providing privacy for the signer. Furthermore,
	signatures over encrypted text are not considered valid in many		signatures over encrypted text are not considered valid in many
	jurisdictions.		jurisdictions.
	9. IANA Considerations		9. IANA Considerations
	9.1. CBOR Web Token (CWT) Claims Registry		9.1. CBOR Web Token (CWT) Claims Registry
	This section establishes the IANA "CBOR Web Token (CWT) Claims"		IANA has created the "CBOR Web Token (CWT) Claims" registry
	registry.		[IANA.CWT.Claims].
	Registration requests are evaluated using the criteria described in		Registration requests are evaluated using the criteria described in
	the Claim Key instructions in the registration template below after a		the Claim Key instructions in the registration template below after a
	three-week review period on the cwt-reg-review@ietf.org mailing list,		three-week review period on the cwt-reg-review@ietf.org mailing list,
	on the advice of one or more Designated Experts. However, to allow		on the advice of one or more Designated Experts [RFC8126]. However,
	for the allocation of values prior to publication, the Designated		to allow for the allocation of values prior to publication, the
	Experts may approve registration once they are satisfied that such a		Designated Experts may approve registration once they are satisfied
	specification will be published. [[ Note to the RFC Editor: The name		that such a specification will be published.
	of the mailing list should be determined in consultation with the
	IESG and IANA. Suggested name: cwt-reg-review@ietf.org. ]]
	Registration requests sent to the mailing list for review should use		Registration requests sent to the mailing list for review should use
	an appropriate subject (e.g., "Request to register claim: example").		an appropriate subject (e.g., "Request to register claim: example").
	Registration requests that are undetermined for a period longer than		Registration requests that are undetermined for a period longer than
	21 days can be brought to the IESG's attention (using the		21 days can be brought to the IESG's attention (using the
	iesg@ietf.org mailing list) for resolution.		iesg@ietf.org mailing list) for resolution.
	Criteria that should be applied by the Designated Experts includes		Criteria that should be applied by the Designated Experts includes
	determining whether the proposed registration duplicates existing		determining whether the proposed registration duplicates existing
	functionality, whether it is likely to be of general applicability or		functionality, whether it is likely to be of general applicability or
	skipping to change at page 11, line 25 ¶		skipping to change at page 12, line 25 ¶
	[IANA.JWT.Claims]. CWT claims should normally have a		[IANA.JWT.Claims]. CWT claims should normally have a
	corresponding JWT claim. If a corresponding JWT claim would not		corresponding JWT claim. If a corresponding JWT claim would not
	make sense, the Designated Experts can choose to accept		make sense, the Designated Experts can choose to accept
	registrations for which the JWT Claim Name is listed as "N/A".		registrations for which the JWT Claim Name is listed as "N/A".
	Claim Key:		Claim Key:
	CBOR map key for the claim. Different ranges of values use		CBOR map key for the claim. Different ranges of values use
	different registration policies [RFC8126]. Integer values from		different registration policies [RFC8126]. Integer values from
	-256 to 255 and strings of length 1 are designated as Standards		-256 to 255 and strings of length 1 are designated as Standards
	Action. Integer values from -65536 to -257 and from 256 to 65535		Action. Integer values from -65536 to -257 and from 256 to 65535
	and strings of length 2 are designated as Specification Required.		along with strings of length 2 are designated as Specification
	Integer values greater than 65535 and strings of length greater		Required. Integer values greater than 65535 and strings of length
	than 2 are designated as Expert Review. Integer values less than		greater than 2 are designated as Expert Review. Integer values
	-65536 are marked as Private Use.		less than -65536 are marked as Private Use.
	Claim Value Type(s):		Claim Value Type(s):
	CBOR types that can be used for the claim value.		CBOR types that can be used for the claim value.
	Change Controller:		Change Controller:
	For Standards Track RFCs, list the "IESG". For others, give the		For Standards Track RFCs, list the "IESG". For others, give the
	name of the responsible party. Other details (e.g., postal		name of the responsible party. Other details (e.g., postal
	address, email address, home page URI) may also be included.		address, email address, home page URI) may also be included.
	Specification Document(s):		Specification Document(s):
	skipping to change at page 11, line 52 ¶		skipping to change at page 12, line 52 ¶
	included but is not required.		included but is not required.
	9.1.2. Initial Registry Contents		9.1.2. Initial Registry Contents
	o Claim Name: (RESERVED)		o Claim Name: (RESERVED)
	o Claim Description: This registration reserves the key value 0.		o Claim Description: This registration reserves the key value 0.
	o JWT Claim Name: N/A		o JWT Claim Name: N/A
	o Claim Key: 0		o Claim Key: 0
	o Claim Value Type(s): N/A		o Claim Value Type(s): N/A
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): [[ this specification ]]		o Specification Document(s): [RFC8392]
	o Claim Name: "iss"		o Claim Name: iss
	o Claim Description: Issuer		o Claim Description: Issuer
	o JWT Claim Name: "iss"		o JWT Claim Name: iss
	o Claim Key: 1		o Claim Key: 1
	o Claim Value Type(s): text string		o Claim Value Type(s): text string
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): Section 3.1.1 of [[ this specification		o Specification Document(s): Section 3.1.1 of [RFC8392]
	]]
	o Claim Name: "sub"		o Claim Name: sub
	o Claim Description: Subject		o Claim Description: Subject
	o JWT Claim Name: "sub"		o JWT Claim Name: sub
	o Claim Key: 2		o Claim Key: 2
	o Claim Value Type(s): text string		o Claim Value Type(s): text string
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): Section 3.1.2 of [[ this specification		o Specification Document(s): Section 3.1.2 of [RFC8392]
	]]
	o Claim Name: "aud"		o Claim Name: aud
	o Claim Description: Audience		o Claim Description: Audience
	o JWT Claim Name: "aud"		o JWT Claim Name: aud
	o Claim Key: 3		o Claim Key: 3
	o Claim Value Type(s): text string		o Claim Value Type(s): text string
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): Section 3.1.3 of [[ this specification		o Specification Document(s): Section 3.1.3 of [RFC8392]
	]]
	o Claim Name: "exp"		o Claim Name: exp
	o Claim Description: Expiration Time		o Claim Description: Expiration Time
	o JWT Claim Name: "exp"		o JWT Claim Name: exp
	o Claim Key: 4		o Claim Key: 4
	o Claim Value Type(s): integer or floating-point number		o Claim Value Type(s): integer or floating-point number
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): Section 3.1.4 of [[ this specification		o Specification Document(s): Section 3.1.4 of [RFC8392]
	]]
	o Claim Name: "nbf"		o Claim Name: nbf
	o Claim Description: Not Before		o Claim Description: Not Before
	o JWT Claim Name: "nbf"		o JWT Claim Name: nbf
	o Claim Key: 5		o Claim Key: 5
	o Claim Value Type(s): integer or floating-point number		o Claim Value Type(s): integer or floating-point number
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): Section 3.1.5 of [[ this specification		o Specification Document(s): Section 3.1.5 of [RFC8392]
	]]
	o Claim Name: "iat"		o Claim Name: iat
	o Claim Description: Issued At		o Claim Description: Issued At
	o JWT Claim Name: "iat"		o JWT Claim Name: iat
	o Claim Key: 6		o Claim Key: 6
	o Claim Value Type(s): integer or floating-point number		o Claim Value Type(s): integer or floating-point number
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): Section 3.1.6 of [[ this specification		o Specification Document(s): Section 3.1.6 of [RFC8392]
	]]		o Claim Name: cti
	o Claim Name: "cti"
	o Claim Description: CWT ID		o Claim Description: CWT ID
	o JWT Claim Name: "jti"		o JWT Claim Name: jti
	o Claim Key: 7		o Claim Key: 7
	o Claim Value Type(s): byte string		o Claim Value Type(s): byte string
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): Section 3.1.7 of [[ this specification		o Specification Document(s): Section 3.1.7 of [RFC8392]
	]]
	9.2. Media Type Registration		9.2. Media Type Registration
	This section registers the "application/cwt" media type in the "Media		IANA has registered the "application/cwt" media type in the "Media
	Types" registry [IANA.MediaTypes] in the manner described in RFC 6838		Types" registry [IANA.MediaTypes] in the manner described in RFC 6838
	[RFC6838], which can be used to indicate that the content is a CWT.		[RFC6838], which can be used to indicate that the content is a CWT.
	9.2.1. Registry Contents		9.2.1. Registry Contents
	o Type name: application		o Type name: application
	o Subtype name: cwt		o Subtype name: cwt
	o Required parameters: N/A		o Required parameters: N/A
	o Optional parameters: N/A		o Optional parameters: N/A
	o Encoding considerations: binary		o Encoding considerations: binary
	o Security considerations: See the Security Considerations section		o Security considerations: See the Security Considerations section
	of [[ this specification ]]		of [RFC8392]
	o Interoperability considerations: N/A		o Interoperability considerations: N/A
	o Published specification: [[ this specification ]]		o Published specification: [RFC8392]
	o Applications that use this media type: IoT applications sending		o Applications that use this media type: IoT applications sending
	security tokens over HTTP(S), CoAP(S), and other transports.		security tokens over HTTP(S), CoAP(S), and other transports.
	o Fragment identifier considerations: N/A		o Fragment identifier considerations: N/A
	o Additional information:		o Additional information:
	Magic number(s): N/A		Magic number(s): N/A
	File extension(s): N/A		File extension(s): N/A
	Macintosh file type code(s): N/A		Macintosh file type code(s): N/A
	o Person & email address to contact for further information:		o Person & email address to contact for further information:
	IESG, iesg@ietf.org		IESG, iesg@ietf.org
	o Intended usage: COMMON		o Intended usage: COMMON
	o Restrictions on usage: none		o Restrictions on usage: none
	o Author: Michael B. Jones, mbj@microsoft.com		o Author: Michael B. Jones, mbj@microsoft.com
	o Change controller: IESG		o Change controller: IESG
	o Provisional registration? No		o Provisional registration? No
	9.3. CoAP Content-Formats Registration		9.3. CoAP Content-Formats Registration
	This section registers the CoAP Content-Format ID for the		IANA has registered the CoAP Content-Format ID for the "application/
	"application/cwt" media type in the "CoAP Content-Formats" registry		cwt" media type in the "CoAP Content-Formats" registry
	[IANA.CoAP.Content-Formats].		[IANA.CoAP.Content-Formats].
	9.3.1. Registry Contents		9.3.1. Registry Contents
	o Media Type: application/cwt		o Media Type: application/cwt
	o Encoding: -		o Encoding: -
	o Id: TBD (maybe 61)		o Id: 61
	o Reference: [[ this specification ]]		o Reference: [RFC8392]
	9.4. CBOR Tag registration		9.4. CBOR Tag registration
	This section registers the CWT CBOR tag in the "CBOR Tags" registry		IANA has registered the CWT CBOR tag in the "CBOR Tags" registry
	[IANA.CBOR.Tags].		[IANA.CBOR.Tags].
	9.4.1. Registry Contents		9.4.1. Registry Contents
	o CBOR Tag: TBD (maybe 61 to use the same value as the Content-		o CBOR Tag: 61
	Format)
	o Data Item: CBOR Web Token (CWT)		o Data Item: CBOR Web Token (CWT)
	o Semantics: CBOR Web Token (CWT), as defined in [[ this		o Semantics: CBOR Web Token (CWT), as defined in [RFC8392]
	specification ]]		o Reference: [RFC8392]
	o Description of Semantics: [[ this specification ]]
	o Point of Contact: Michael B. Jones, mbj@microsoft.com		o Point of Contact: Michael B. Jones, mbj@microsoft.com
	10. References		10. References
	10.1. Normative References		10.1. Normative References
	[IANA.CBOR.Tags]		[IANA.CBOR.Tags]
	IANA, "Concise Binary Object Representation (CBOR) Tags",		IANA, "Concise Binary Object Representation (CBOR) Tags",
	<http://www.iana.org/assignments/cbor-tags/		<http://www.iana.org/assignments/cbor-tags/>.
	cbor-tags.xhtml>.
	[IANA.CoAP.Content-Formats]		[IANA.CoAP.Content-Formats]
	IANA, "CoAP Content-Formats",		IANA, "CoAP Content-Formats",
	<http://www.iana.org/assignments/core-parameters/		<https://www.iana.org/assignments/core-parameters/>.
	core-parameters.xhtml#content-formats>.
			[IANA.CWT.Claims]
			IANA, "CBOR Web Token (CWT) Claims",
			<http://www.iana.org/assignments/cwt>.
	[IANA.MediaTypes]		[IANA.MediaTypes]
	IANA, "Media Types",		IANA, "Media Types",
	<http://www.iana.org/assignments/media-types>.		<http://www.iana.org/assignments/media-types>.
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<https://www.rfc-editor.org/info/rfc2119>.		<https://www.rfc-editor.org/info/rfc2119>.
	skipping to change at page 16, line 29 ¶		skipping to change at page 17, line 29 ¶
	A.1. Example CWT Claims Set		A.1. Example CWT Claims Set
	The CWT Claims Set used for the different examples displays usage of		The CWT Claims Set used for the different examples displays usage of
	all the defined claims. For signed and MACed examples, the CWT		all the defined claims. For signed and MACed examples, the CWT
	Claims Set is the CBOR encoding as a byte string.		Claims Set is the CBOR encoding as a byte string.
	a70175636f61703a2f2f61732e6578616d706c652e636f6d02656572696b7703		a70175636f61703a2f2f61732e6578616d706c652e636f6d02656572696b7703
	7818636f61703a2f2f6c696768742e6578616d706c652e636f6d041a5612aeb0		7818636f61703a2f2f6c696768742e6578616d706c652e636f6d041a5612aeb0
	051a5610d9f0061a5610d9f007420b71		051a5610d9f0061a5610d9f007420b71
	Figure 2: Example CWT Claims Set as hex string		Figure 2: Example CWT Claims Set as Hex String
	{		{
	/ iss / 1: "coap://as.example.com",		/ iss / 1: "coap://as.example.com",
	/ sub / 2: "erikw",		/ sub / 2: "erikw",
	/ aud / 3: "coap://light.example.com",		/ aud / 3: "coap://light.example.com",
	/ exp / 4: 1444064944,		/ exp / 4: 1444064944,
	/ nbf / 5: 1443944944,		/ nbf / 5: 1443944944,
	/ iat / 6: 1443944944,		/ iat / 6: 1443944944,
	/ cti / 7: h'0b71'		/ cti / 7: h'0b71'
	}		}
	Figure 3: Example CWT Claims Set in CBOR diagnostic notation		Figure 3: Example CWT Claims Set in CBOR Diagnostic Notation
	A.2. Example keys		A.2. Example Keys
	This section contains the keys used to sign, MAC, and encrypt the		This section contains the keys used to sign, MAC, and encrypt the
	messages in this appendix. Line breaks are for display purposes		messages in this appendix. Line breaks are for display purposes
	only.		only.
	A.2.1. 128-bit Symmetric Key		A.2.1. 128-Bit Symmetric Key
	a42050231f4c4d4d3051fdc2ec0a3851d5b3830104024c53796d6d6574726963		a42050231f4c4d4d3051fdc2ec0a3851d5b3830104024c53796d6d6574726963
	313238030a		313238030a
	Figure 4: 128-bit symmetric COSE_Key as hex string		Figure 4: 128-Bit Symmetric COSE_Key as Hex String
	{		{
	/ k / -1: h'231f4c4d4d3051fdc2ec0a3851d5b383'		/ k / -1: h'231f4c4d4d3051fdc2ec0a3851d5b383'
	/ kty / 1: 4 / Symmetric /,		/ kty / 1: 4 / Symmetric /,
	/ kid / 2: h'53796d6d6574726963313238' / 'Symmetric128' /,		/ kid / 2: h'53796d6d6574726963313238' / 'Symmetric128' /,
	/ alg / 3: 10 / AES-CCM-16-64-128 /		/ alg / 3: 10 / AES-CCM-16-64-128 /
	}		}
	Figure 5: 128-bit symmetric COSE_Key in CBOR diagnostic notation		Figure 5: 128-Bit Symmetric COSE_Key in CBOR Diagnostic Notation
	A.2.2. 256-bit Symmetric Key		A.2.2. 256-Bit Symmetric Key
	a4205820403697de87af64611c1d32a05dab0fe1fcb715a86ab435f1ec99192d		a4205820403697de87af64611c1d32a05dab0fe1fcb715a86ab435f1ec99192d
	795693880104024c53796d6d6574726963323536030a		795693880104024c53796d6d6574726963323536030a
	Figure 6: 256-bit symmetric COSE_Key as hex string		Figure 6: 256-Bit Symmetric COSE_Key as Hex String
	{		{
	/ k / -1: h'403697de87af64611c1d32a05dab0fe1fcb715a86ab435f1		/ k / -1: h'403697de87af64611c1d32a05dab0fe1fcb715a86ab435f1
	ec99192d79569388'		ec99192d79569388'
	/ kty / 1: 4 / Symmetric /,		/ kty / 1: 4 / Symmetric /,
	/ kid / 4: h'53796d6d6574726963323536' / 'Symmetric256' /,		/ kid / 4: h'53796d6d6574726963323536' / 'Symmetric256' /,
	/ alg / 3: 4 / HMAC 256/64 /		/ alg / 3: 4 / HMAC 256/64 /
	}		}
	Figure 7: 256-bit symmetric COSE_Key in CBOR diagnostic notation		Figure 7: 256-Bit Symmetric COSE_Key in CBOR Diagnostic Notation
	A.2.3. ECDSA P-256 256-bit COSE Key		A.2.3. Elliptic Curve Digital Signature Algorithm (ECDSA) P-256 256-Bit
			COSE Key
	a72358206c1382765aec5358f117733d281c1c7bdc39884d04a45a1e6c67c858		a72358206c1382765aec5358f117733d281c1c7bdc39884d04a45a1e6c67c858
	bc206c1922582060f7f1a780d8a783bfb7a2dd6b2796e8128dbbcef9d3d168db		bc206c1922582060f7f1a780d8a783bfb7a2dd6b2796e8128dbbcef9d3d168db
	9529971a36e7b9215820143329cce7868e416927599cf65a34f3ce2ffda55a7e		9529971a36e7b9215820143329cce7868e416927599cf65a34f3ce2ffda55a7e
	ca69ed8919a394d42f0f2001010202524173796d6d6574726963454344534132		ca69ed8919a394d42f0f2001010202524173796d6d6574726963454344534132
	35360326		35360326
	Figure 8: ECDSA 256-bit COSE Key as hex string		Figure 8: ECDSA 256-Bit COSE Key as Hex String
	{		{
	/ d / -4: h'6c1382765aec5358f117733d281c1c7bdc39884d04a45a1e		/ d / -4: h'6c1382765aec5358f117733d281c1c7bdc39884d04a45a1e
	6c67c858bc206c19',		6c67c858bc206c19',
	/ y / -3: h'60f7f1a780d8a783bfb7a2dd6b2796e8128dbbcef9d3d168		/ y / -3: h'60f7f1a780d8a783bfb7a2dd6b2796e8128dbbcef9d3d168
	db9529971a36e7b9',		db9529971a36e7b9',
	/ x / -2: h'143329cce7868e416927599cf65a34f3ce2ffda55a7eca69		/ x / -2: h'143329cce7868e416927599cf65a34f3ce2ffda55a7eca69
	ed8919a394d42f0f',		ed8919a394d42f0f',
	/ crv / -1: 1 / P-256 /,		/ crv / -1: 1 / P-256 /,
	/ kty / 1: 2 / EC2 /,		/ kty / 1: 2 / EC2 /,
	/ kid / 2: h'4173796d6d657472696345434453413		/ kid / 2: h'4173796d6d657472696345434453413
	23536' / 'AsymmetricECDSA256' /,		23536' / 'AsymmetricECDSA256' /,
	/ alg / 3: -7 / ECDSA 256 /		/ alg / 3: -7 / ECDSA 256 /
	}		}
	Figure 9: ECDSA 256-bit COSE Key in CBOR diagnostic notation		Figure 9: ECDSA 256-Bit COSE Key in CBOR Diagnostic Notation
	A.3. Example Signed CWT		A.3. Example Signed CWT
	This section shows a signed CWT with a single recipient and a full		This section shows a signed CWT with a single recipient and a full
	CWT Claims Set.		CWT Claims Set.
	The signature is generated using the private key listed in		The signature is generated using the private key listed in
	Appendix A.2.3 and it can be validated using the public key from		Appendix A.2.3, and it can be validated using the public key from
	Appendix A.2.3. Line breaks are for display purposes only.		Appendix A.2.3. Line breaks are for display purposes only.
	d28443a10126a104524173796d6d657472696345434453413235365850a701756		d28443a10126a104524173796d6d657472696345434453413235365850a701756
	36f61703a2f2f61732e6578616d706c652e636f6d02656572696b77037818636f		36f61703a2f2f61732e6578616d706c652e636f6d02656572696b77037818636f
	61703a2f2f6c696768742e6578616d706c652e636f6d041a5612aeb0051a5610d		61703a2f2f6c696768742e6578616d706c652e636f6d041a5612aeb0051a5610d
	9f0061a5610d9f007420b7158405427c1ff28d23fbad1f29c4c7c6a555e601d6f		9f0061a5610d9f007420b7158405427c1ff28d23fbad1f29c4c7c6a555e601d6f
	a29f9179bc3d7438bacaca5acd08c8d4d4f96131680c429a01f85951ecee743a5		a29f9179bc3d7438bacaca5acd08c8d4d4f96131680c429a01f85951ecee743a5
	2b9b63632c57209120e1c9e30		2b9b63632c57209120e1c9e30
	Figure 10: Signed CWT as hex string		Figure 10: Signed CWT as Hex String
	18(		18(
	[		[
	/ protected / << {		/ protected / << {
	/ alg / 1: -7 / ECDSA 256 /		/ alg / 1: -7 / ECDSA 256 /
	} >>,		} >>,
	/ unprotected / {		/ unprotected / {
	/ kid / 4: h'4173796d6d657472696345434453413		/ kid / 4: h'4173796d6d657472696345434453413
	23536' / 'AsymmetricECDSA256' /		23536' / 'AsymmetricECDSA256' /
	},		},
	skipping to change at page 19, line 30 ¶		skipping to change at page 20, line 30 ¶
	/ iat / 6: 1443944944,		/ iat / 6: 1443944944,
	/ cti / 7: h'0b71'		/ cti / 7: h'0b71'
	} >>,		} >>,
	/ signature / h'5427c1ff28d23fbad1f29c4c7c6a555e601d6fa29f		/ signature / h'5427c1ff28d23fbad1f29c4c7c6a555e601d6fa29f
	9179bc3d7438bacaca5acd08c8d4d4f96131680c42		9179bc3d7438bacaca5acd08c8d4d4f96131680c42
	9a01f85951ecee743a52b9b63632c57209120e1c9e		9a01f85951ecee743a52b9b63632c57209120e1c9e
	30'		30'
	]		]
	)		)
	Figure 11: Signed CWT in CBOR diagnostic notation		Figure 11: Signed CWT in CBOR Diagnostic Notation
	A.4. Example MACed CWT		A.4. Example MACed CWT
	This section shows a MACed CWT with a single recipient, a full CWT		This section shows a MACed CWT with a single recipient, a full CWT
	Claims Set, and a CWT tag.		Claims Set, and a CWT tag.
	The MAC is generated using the 256-bit symmetric key from		The MAC is generated using the 256-bit symmetric key from
	Appendix A.2.2 with a 64-bit truncation. Line breaks are for display		Appendix A.2.2 with a 64-bit truncation. Line breaks are for display
	purposes only.		purposes only.
	d83dd18443a10104a1044c53796d6d65747269633235365850a70175636f6170		d83dd18443a10104a1044c53796d6d65747269633235365850a70175636f6170
	3a2f2f61732e6578616d706c652e636f6d02656572696b77037818636f61703a		3a2f2f61732e6578616d706c652e636f6d02656572696b77037818636f61703a
	2f2f6c696768742e6578616d706c652e636f6d041a5612aeb0051a5610d9f006		2f2f6c696768742e6578616d706c652e636f6d041a5612aeb0051a5610d9f006
	1a5610d9f007420b7148093101ef6d789200		1a5610d9f007420b7148093101ef6d789200
	Figure 12: MACed CWT with CWT tag as hex string		Figure 12: MACed CWT with CWT Tag as Hex String
	61(		61(
	17(		17(
	[		[
	/ protected / << {		/ protected / << {
	/ alg / 1: 4 / HMAC-256-64 /		/ alg / 1: 4 / HMAC-256-64 /
	} >>,		} >>,
	/ unprotected / {		/ unprotected / {
	/ kid / 4: h'53796d6d6574726963323536' / 'Symmetric256' /		/ kid / 4: h'53796d6d6574726963323536' / 'Symmetric256' /
	},		},
	skipping to change at page 20, line 28 ¶		skipping to change at page 21, line 28 ¶
	/ exp / 4: 1444064944,		/ exp / 4: 1444064944,
	/ nbf / 5: 1443944944,		/ nbf / 5: 1443944944,
	/ iat / 6: 1443944944,		/ iat / 6: 1443944944,
	/ cti / 7: h'0b71'		/ cti / 7: h'0b71'
	} >>,		} >>,
	/ tag / h'093101ef6d789200'		/ tag / h'093101ef6d789200'
	]		]
	)		)
	)		)
	Figure 13: MACed CWT with CWT tag in CBOR diagnostic notation		Figure 13: MACed CWT with CWT Tag in CBOR Diagnostic Notation
	A.5. Example Encrypted CWT		A.5. Example Encrypted CWT
	This section shows an encrypted CWT with a single recipient and a		This section shows an encrypted CWT with a single recipient and a
	full CWT Claims Set.		full CWT Claims Set.
	The encryption is done with AES-CCM mode using the 128-bit symmetric		The encryption is done with AES-CCM mode using the 128-bit symmetric
	key from Appendix A.2.1 with a 64-bit tag and 13-byte nonce, i.e.,		key from Appendix A.2.1 with a 64-bit tag and 13-byte nonce, i.e.,
	COSE AES-CCM-16-64-128. Line breaks are for display purposes only.		COSE AES-CCM-16-64-128. Line breaks are for display purposes only.
	d08343a1010aa2044c53796d6d6574726963313238054d99a0d7846e762c49ff		d08343a1010aa2044c53796d6d6574726963313238054d99a0d7846e762c49ff
	e8a63e0b5858b918a11fd81e438b7f973d9e2e119bcb22424ba0f38a80f27562		e8a63e0b5858b918a11fd81e438b7f973d9e2e119bcb22424ba0f38a80f27562
	f400ee1d0d6c0fdb559c02421fd384fc2ebe22d7071378b0ea7428fff157444d		f400ee1d0d6c0fdb559c02421fd384fc2ebe22d7071378b0ea7428fff157444d
	45f7e6afcda1aae5f6495830c58627087fc5b4974f319a8707a635dd643b		45f7e6afcda1aae5f6495830c58627087fc5b4974f319a8707a635dd643b
	Figure 14: Encrypted CWT as hex string		Figure 14: Encrypted CWT as Hex String
	16(		16(
	[		[
	/ protected / << {		/ protected / << {
	/ alg / 1: 10 / AES-CCM-16-64-128 /		/ alg / 1: 10 / AES-CCM-16-64-128 /
	} >>,		} >>,
	/ unprotected / {		/ unprotected / {
	/ kid / 4: h'53796d6d6574726963313238' / 'Symmetric128' /,		/ kid / 4: h'53796d6d6574726963313238' / 'Symmetric128' /,
	/ iv / 5: h'99a0d7846e762c49ffe8a63e0b'		/ iv / 5: h'99a0d7846e762c49ffe8a63e0b'
	},		},
	/ ciphertext / h'b918a11fd81e438b7f973d9e2e119bcb22424ba0f38		/ ciphertext / h'b918a11fd81e438b7f973d9e2e119bcb22424ba0f38
	a80f27562f400ee1d0d6c0fdb559c02421fd384fc2e		a80f27562f400ee1d0d6c0fdb559c02421fd384fc2e
	be22d7071378b0ea7428fff157444d45f7e6afcda1a		be22d7071378b0ea7428fff157444d45f7e6afcda1a
	ae5f6495830c58627087fc5b4974f319a8707a635dd		ae5f6495830c58627087fc5b4974f319a8707a635dd
	643b'		643b'
	]		]
	)		)
	Figure 15: Encrypted CWT in CBOR diagnostic notation		Figure 15: Encrypted CWT in CBOR Diagnostic Notation
	A.6. Example Nested CWT		A.6. Example Nested CWT
	This section shows a Nested CWT, signed and then encrypted, with a		This section shows a Nested CWT, signed and then encrypted, with a
	single recipient and a full CWT Claims Set.		single recipient and a full CWT Claims Set.
	The signature is generated using the private ECDSA key from		The signature is generated using the private ECDSA key from
	Appendix A.2.3 and it can be validated using the public ECDSA parts		Appendix A.2.3, and it can be validated using the public ECDSA parts
	from Appendix A.2.3. The encryption is done with AES-CCM mode using		from Appendix A.2.3. The encryption is done with AES-CCM mode using
	the 128-bit symmetric key from Appendix A.2.1 with a 64-bit tag and		the 128-bit symmetric key from Appendix A.2.1 with a 64-bit tag and
	13-byte nonce, i.e., COSE AES-CCM-16-64-128. The content type is set		13-byte nonce, i.e., COSE AES-CCM-16-64-128. The content type is set
	to CWT to indicate that there are multiple layers of COSE protection		to CWT to indicate that there are multiple layers of COSE protection
	before finding the CWT Claims Set. The decrypted ciphertext will be a		before finding the CWT Claims Set. The decrypted ciphertext will be a
	COSE_sign1 structure. In this example, it is the same one as in		COSE_sign1 structure. In this example, it is the same one as in
	Appendix A.3, i.e., a Signed CWT Claims Set. Note that there is no		Appendix A.3, i.e., a Signed CWT Claims Set. Note that there is no
	limitation to the number of layers; this is an example with two		limitation to the number of layers; this is an example with two
	layers. Line breaks are for display purposes only.		layers. Line breaks are for display purposes only.
	d08343a1010aa2044c53796d6d6574726963313238054d4a0694c0e69ee6b595		d08343a1010aa2044c53796d6d6574726963313238054d4a0694c0e69ee6b595
	6655c7b258b7f6b0914f993de822cc47e5e57a188d7960b528a747446fe12f0e		6655c7b258b7f6b0914f993de822cc47e5e57a188d7960b528a747446fe12f0e
	7de05650dec74724366763f167a29c002dfd15b34d8993391cf49bc91127f545		7de05650dec74724366763f167a29c002dfd15b34d8993391cf49bc91127f545
	dba8703d66f5b7f1ae91237503d371e6333df9708d78c4fb8a8386c8ff09dc49		dba8703d66f5b7f1ae91237503d371e6333df9708d78c4fb8a8386c8ff09dc49
	af768b23179deab78d96490a66d5724fb33900c60799d9872fac6da3bdb89043		af768b23179deab78d96490a66d5724fb33900c60799d9872fac6da3bdb89043
	d67c2a05414ce331b5b8f1ed8ff7138f45905db2c4d5bc8045ab372bff142631		d67c2a05414ce331b5b8f1ed8ff7138f45905db2c4d5bc8045ab372bff142631
	610a7e0f677b7e9b0bc73adefdcee16d9d5d284c616abeab5d8c291ce0		610a7e0f677b7e9b0bc73adefdcee16d9d5d284c616abeab5d8c291ce0
	Figure 16: Signed and Encrypted CWT as hex string		Figure 16: Signed and Encrypted CWT as Hex String
	16(		16(
	[		[
	/ protected / << {		/ protected / << {
	/ alg / 1: 10 / AES-CCM-16-64-128 /		/ alg / 1: 10 / AES-CCM-16-64-128 /
	} >>,		} >>,
	/ unprotected / {		/ unprotected / {
	/ kid / 4: h'53796d6d6574726963313238' / 'Symmetric128' /,		/ kid / 4: h'53796d6d6574726963313238' / 'Symmetric128' /,
	/ iv / 5: h'4a0694c0e69ee6b5956655c7b2'		/ iv / 5: h'4a0694c0e69ee6b5956655c7b2'
	},		},
	skipping to change at page 22, line 26 ¶		skipping to change at page 23, line 26 ¶
	fd15b34d8993391cf49bc91127f545dba8703d66f5b		fd15b34d8993391cf49bc91127f545dba8703d66f5b
	7f1ae91237503d371e6333df9708d78c4fb8a8386c8		7f1ae91237503d371e6333df9708d78c4fb8a8386c8
	ff09dc49af768b23179deab78d96490a66d5724fb33		ff09dc49af768b23179deab78d96490a66d5724fb33
	900c60799d9872fac6da3bdb89043d67c2a05414ce3		900c60799d9872fac6da3bdb89043d67c2a05414ce3
	31b5b8f1ed8ff7138f45905db2c4d5bc8045ab372bf		31b5b8f1ed8ff7138f45905db2c4d5bc8045ab372bf
	f142631610a7e0f677b7e9b0bc73adefdcee16d9d5d		f142631610a7e0f677b7e9b0bc73adefdcee16d9d5d
	284c616abeab5d8c291ce0'		284c616abeab5d8c291ce0'
	]		]
	)		)
	Figure 17: Signed and Encrypted CWT in CBOR diagnostic notation		Figure 17: Signed and Encrypted CWT in CBOR Diagnostic Notation
	A.7. Example MACed CWT with a floating-point value		A.7. Example MACed CWT with a Floating-Point Value
	This section shows a MACed CWT with a single recipient and a simple		This section shows a MACed CWT with a single recipient and a simple
	CWT Claims Set. The CWT Claims Set with a floating-point 'iat' value.		CWT Claims Set. The CWT Claims Set with a floating-point 'iat' value.
	The MAC is generated using the 256-bit symmetric key from		The MAC is generated using the 256-bit symmetric key from
	Appendix A.2.2 with a 64-bit truncation. Line breaks are for display		Appendix A.2.2 with a 64-bit truncation. Line breaks are for display
	purposes only.		purposes only.
	d18443a10104a1044c53796d6d65747269633235364ba106fb41d584367c2000		d18443a10104a1044c53796d6d65747269633235364ba106fb41d584367c2000
	0048b8816f34c0542892		0048b8816f34c0542892
	Figure 18: MACed CWT with a floating-point value as hex string		Figure 18: MACed CWT with a Floating-Point Value as Hex String
	17(		17(
	[		[
	/ protected / << {		/ protected / << {
	/ alg / 1: 4 / HMAC-256-64 /		/ alg / 1: 4 / HMAC-256-64 /
	} >>,		} >>,
	/ unprotected / {		/ unprotected / {
	/ kid / 4: h'53796d6d6574726963323536' / 'Symmetric256' /,		/ kid / 4: h'53796d6d6574726963323536' / 'Symmetric256' /,
	},		},
	/ payload / << {		/ payload / << {
	/ iat / 6: 1443944944.5		/ iat / 6: 1443944944.5
	} >>,		} >>,
	/ tag / h'b8816f34c0542892'		/ tag / h'b8816f34c0542892'
	]		]
	)		)
	Figure 19: MACed CWT with a floating-point value in CBOR diagnostic		Figure 19: MACed CWT with a Floating-Point Value
	notation		in CBOR Diagnostic Notation
	Appendix B. Acknowledgements		Acknowledgements
	This specification is based on JSON Web Token (JWT) [RFC7519], the		This specification is based on JSON Web Token (JWT) [RFC7519], the
	authors of which also include Nat Sakimura and John Bradley. It also		authors of which also include Nat Sakimura and John Bradley. It also
	incorporates suggestions made by many people, including Carsten		incorporates suggestions made by many people, including Carsten
	Bormann, Alissa Cooper, Esko Dijk, Benjamin Kaduk, Warren Kumari,		Bormann, Alissa Cooper, Esko Dijk, Benjamin Kaduk, Warren Kumari,
	Carlos Martinez, Alexey Melnikov, Kathleen Moriarty, Eric Rescorla,		Carlos Martinez, Alexey Melnikov, Kathleen Moriarty, Eric Rescorla,
	Dan Romascanu, Adam Roach, Kyle Rose, Jim Schaad, Ludwig Seitz, and		Dan Romascanu, Adam Roach, Kyle Rose, Jim Schaad, Ludwig Seitz, and
	Goeran Selander.		Goeran Selander.
	[[ RFC Editor: Is it possible to preserve the non-ASCII spellings of
	the names Erik Wahlstroem and Goeran Selander in the final
	specification? ]]
	Appendix C. Document History
	[[ to be removed by the RFC Editor before publication as an RFC ]]
	-15
	o Added section references when the terms "NumericDate" and
	"StringOrURI" are used, as suggested by Adam Roach.
	-14
	o Cleaned up the descriptions of the numeric ranges of claim keys
	being registered in the registration template for the "CBOR Web
	Token (CWT) Claims" registry, as suggested by Adam Roach.
	o Clarified the relationships between the JWT and CWT "NumericDate"
	and "StringOrURI" terms, as suggested by Adam Roach.
	o Eliminated unnecessary uses of the word "type", as suggested by
	Adam Roach.
	o Added the text "IANA must only accept registry updates from the
	Designated Experts and should direct all requests for registration
	to the review mailing list" from RFC 7519, as suggested by Amanda
	Baber of IANA, which is also intended to address Alexey Melnikov's
	comment.
	o Removed a superfluous comma, as suggested by Warren Kumari.
	o Acknowledged additional reviewers.
	-13
	o Clarified the registration criteria applied to different ranges of
	Claim Key values, as suggested by Kathleen Moriarty and Dan
	Romascanu.
	o No longer describe the syntax of CWT claims as being the same as
	that of the corresponding JWT claims, as suggested by Kyle Rose.
	o Added guidance about the selection of the Designated Experts, as
	suggested by Benjamin Kaduk.
	o Acknowledged additional reviewers.
	-12
	o Updated the RFC 5226 reference to RFC 8126.
	o Made the IANA registration criteria consistent across sections.
	o Stated that registrations for the limited set of values between
	-256 and 255 and strings of length 1 are to be restricted to
	claims with general applicability.
	o Changed the "Reference" field name to "Description of Semantics"
	in the CBOR Tag registration request.
	o Asked the RFC Editor whether it is possible to preserve the non-
	ASCII spellings of the names Erik Wahlstroem and Goeran Selander
	in the final specification.
	-11
	o Corrected the "iv" value in the signed and encrypted CWT example.
	o Mention CoAP in the "application/cwt" media type registration.
	o Changed references of the form "Section 4.1.1 of JWT <xref
	target="RFC7519"/>" to "Section 4.1.1 of <xref target="RFC7519"/>"
	so that rfcmarkup will generate correct external section reference
	links.
	o Updated Acknowledgements.
	-10
	o Clarified that the audience claim value can be a single audience
	value or an array of audience values, just as is the case for the
	JWT "aud" claim.
	o Clarified the nested CWT description.
	o Changed uses of "binary string" to "byte string".
	-09
	o Added key ID values to the examples.
	o Key values for the examples are now represented in COSE_Key format
	using CBOR diagnostic notation.
	-08
	o Updated the diagnostic notation for embedded objects in the
	examples, addressing feedback by Carsten Bormann.
	-07
	o Updated examples for signing and encryption. Signatures are now
	deterministic as recommended by COSE specification.
	-06
	o Addressed review comments by Carsten Bormann and Jim Schaad. All
	changes were editorial in nature.
	-05
	o Addressed working group last call comments with the following
	changes:
	o Say that CWT is derived from JWT, rather than CWT is a profile of
	JWT.
	o Used CBOR type names in descriptions, rather than major/minor type
	numbers.
	o Clarified the NumericDate and StringOrURI descriptions.
	o Changed to allow CWT claim names to use values of any legal CBOR
	map key type.
	o Changed to use the CWT tag to identify nested CWTs instead of the
	CWT content type.
	o Added an example using a floating-point date value.
	o Acknowledged reviewers.
	-04
	o Specified that the use of CBOR tags to prefix any of the claim
	values defined in this specification is NOT RECOMMENDED.
	-03
	o Reworked the examples to include signed, MACed, encrypted, and
	nested CWTs.
	o Defined the CWT CBOR tag and explained its usage.
	-02
	o Added IANA registration for the application/cwt media type.
	o Clarified the nested CWT language.
	o Corrected nits identified by Ludwig Seitz.
	-01
	o Added IANA registration for CWT Claims.
	o Added IANA registration for the application/cwt CoAP content-
	format type.
	o Added Samuel Erdtman as an editor.
	o Changed Erik's e-mail address.
	-00
	o Created the initial working group version based on draft-
	wahlstroem-ace-cbor-web-token-00.
	Authors' Addresses		Authors' Addresses
	Michael B. Jones		Michael B. Jones
	Microsoft		Microsoft
	Email: mbj@microsoft.com		Email: mbj@microsoft.com
	URI: http://self-issued.info/		URI: http://self-issued.info/
	Erik Wahlstroem		Erik Wahlstroem
	Sweden		Sweden
End of changes. 86 change blocks.
	342 lines changed or deleted		160 lines changed or added
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