< draft-ietf-ace-oauth-authz-02.txt		draft-ietf-ace-oauth-authz-03.txt >
	ACE Working Group L. Seitz		ACE Working Group L. Seitz
	Internet-Draft SICS		Internet-Draft SICS
	Intended status: Standards Track G. Selander		Intended status: Standards Track G. Selander
	Expires: December 12, 2016 Ericsson		Expires: April 15, 2017 Ericsson
	E. Wahlstroem		E. Wahlstroem
	Nexus Technology
	S. Erdtman		S. Erdtman
	Spotify AB		Spotify AB
	H. Tschofenig		H. Tschofenig
	ARM Ltd.		ARM Ltd.
	June 10, 2016		October 12, 2016
	Authentication and Authorization for Constrained Environments (ACE)		Authentication and Authorization for Constrained Environments (ACE)
	draft-ietf-ace-oauth-authz-02		draft-ietf-ace-oauth-authz-03
	Abstract		Abstract
	This specification defines the ACE framework for authentication and		This specification defines a framework for authentication and
	authorization in Internet of Things (IoT) deployments. The ACE		authorization in Internet of Things (IoT) environments. The
	framework is based on a set of building blocks including OAuth 2.0		framework is based on a set of building blocks including OAuth 2.0
	and CoAP, thus making a well-known and widely used authorization		and CoAP, thus making a well-known and widely used authorization
	solution suitable for IoT devices. Existing specifications are used		solution suitable for IoT devices. Existing specifications are used
	where possible, but where the limitations of IoT devices require it,		where possible, but where the constraints of IoT devices require it,
	profiles and extensions are provided.		extensions are added and profiles are defined.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	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 http://datatracker.ietf.org/drafts/current/.		Drafts is at http://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 December 12, 2016.		This Internet-Draft will expire on April 15, 2017.
	Copyright Notice		Copyright Notice
	Copyright (c) 2016 IETF Trust and the persons identified as the		Copyright (c) 2016 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
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://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 24 ¶		skipping to change at page 2, line 24 ¶
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4		2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
	3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 5		3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 5
	3.1. OAuth 2.0 . . . . . . . . . . . . . . . . . . . . . . . . 6		3.1. OAuth 2.0 . . . . . . . . . . . . . . . . . . . . . . . . 6
	3.2. CoAP . . . . . . . . . . . . . . . . . . . . . . . . . . 8		3.2. CoAP . . . . . . . . . . . . . . . . . . . . . . . . . . 8
	4. Protocol Interactions . . . . . . . . . . . . . . . . . . . . 9		4. Protocol Interactions . . . . . . . . . . . . . . . . . . . . 9
	5. Framework . . . . . . . . . . . . . . . . . . . . . . . . . . 13		5. Framework . . . . . . . . . . . . . . . . . . . . . . . . . . 13
	6. The 'Token' Resource . . . . . . . . . . . . . . . . . . . . 14		6. The 'Token' Endpoint . . . . . . . . . . . . . . . . . . . . 14
	6.1. Client-to-AS Request . . . . . . . . . . . . . . . . . . 14		6.1. Client-to-AS Request . . . . . . . . . . . . . . . . . . 14
	6.2. AS-to-Client Response . . . . . . . . . . . . . . . . . . 17		6.2. AS-to-Client Response . . . . . . . . . . . . . . . . . . 17
	6.3. Error Response . . . . . . . . . . . . . . . . . . . . . 18		6.3. Error Response . . . . . . . . . . . . . . . . . . . . . 18
	6.4. New Request and Response Parameters . . . . . . . . . . . 18		6.4. New Request and Response Parameters . . . . . . . . . . . 18
	6.4.1. Grant Type . . . . . . . . . . . . . . . . . . . . . 19		6.4.1. Audience . . . . . . . . . . . . . . . . . . . . . . 18
	6.4.2. Token Type and Algorithms . . . . . . . . . . . . . . 19		6.4.2. Grant Type . . . . . . . . . . . . . . . . . . . . . 19
	6.4.3. Profile . . . . . . . . . . . . . . . . . . . . . . . 20		6.4.3. Token Type . . . . . . . . . . . . . . . . . . . . . 19
	6.4.4. Confirmation . . . . . . . . . . . . . . . . . . . . 20		6.4.4. Profile . . . . . . . . . . . . . . . . . . . . . . . 19
	6.5. Mapping parameters to CBOR . . . . . . . . . . . . . . . 22		6.4.5. Confirmation . . . . . . . . . . . . . . . . . . . . 20
	7. The 'Introspect' Resource . . . . . . . . . . . . . . . . . . 22		6.5. Mapping parameters to CBOR . . . . . . . . . . . . . . . 21
			7. The 'Introspect' Endpoint . . . . . . . . . . . . . . . . . . 22
	7.1. RS-to-AS Request . . . . . . . . . . . . . . . . . . . . 23		7.1. RS-to-AS Request . . . . . . . . . . . . . . . . . . . . 23
	7.2. AS-to-RS Response . . . . . . . . . . . . . . . . . . . . 23		7.2. AS-to-RS Response . . . . . . . . . . . . . . . . . . . . 23
	7.3. Error Response . . . . . . . . . . . . . . . . . . . . . 24		7.3. Error Response . . . . . . . . . . . . . . . . . . . . . 24
	7.4. Client Token . . . . . . . . . . . . . . . . . . . . . . 25		7.4. Client Token . . . . . . . . . . . . . . . . . . . . . . 25
	7.5. Mapping Introspection parameters to CBOR . . . . . . . . 26		7.5. Mapping Introspection parameters to CBOR . . . . . . . . 26
	8. The Access Token . . . . . . . . . . . . . . . . . . . . . . 27		8. The Access Token . . . . . . . . . . . . . . . . . . . . . . 27
	8.1. The 'Authorization Information' Resource . . . . . . . . 27		8.1. The 'Authorization Information' Endpoint . . . . . . . . 28
	8.2. Token Expiration . . . . . . . . . . . . . . . . . . . . 28		8.2. Token Expiration . . . . . . . . . . . . . . . . . . . . 28
	9. Security Considerations . . . . . . . . . . . . . . . . . . . 28		9. Security Considerations . . . . . . . . . . . . . . . . . . . 29
	10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29		10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30
	10.1. OAuth Introspection Response Parameter Registration . . 29		10.1. OAuth Introspection Response Parameter Registration . . 30
	10.2. OAuth Parameter Registration . . . . . . . . . . . . . . 30		10.2. OAuth Parameter Registration . . . . . . . . . . . . . . 31
	10.3. OAuth Access Token Types . . . . . . . . . . . . . . . . 30		10.3. OAuth Access Token Types . . . . . . . . . . . . . . . . 31
	10.4. Token Type Mappings . . . . . . . . . . . . . . . . . . 30		10.4. Token Type Mappings . . . . . . . . . . . . . . . . . . 32
	10.4.1. Registration Template . . . . . . . . . . . . . . . 30		10.4.1. Registration Template . . . . . . . . . . . . . . . 32
	10.4.2. Initial Registry Contents . . . . . . . . . . . . . 31		10.4.2. Initial Registry Contents . . . . . . . . . . . . . 32
	10.5. JSON Web Token Claims . . . . . . . . . . . . . . . . . 31		10.5. CBOR Web Token Claims . . . . . . . . . . . . . . . . . 32
	10.6. ACE Profile Registry . . . . . . . . . . . . . . . . . . 31		10.6. ACE Profile Registry . . . . . . . . . . . . . . . . . . 33
	10.6.1. Registration Template . . . . . . . . . . . . . . . 31		10.6.1. Registration Template . . . . . . . . . . . . . . . 33
	10.7. OAuth Parameter Mappings Registry . . . . . . . . . . . 32		10.7. OAuth Parameter Mappings Registry . . . . . . . . . . . 33
	10.7.1. Registration Template . . . . . . . . . . . . . . . 32		10.7.1. Registration Template . . . . . . . . . . . . . . . 33
	10.7.2. Initial Registry Contents . . . . . . . . . . . . . 32		10.7.2. Initial Registry Contents . . . . . . . . . . . . . 34
	10.8. Introspection Resource CBOR Mappings Registry . . . . . 34		10.8. Introspection Endpoint CBOR Mappings Registry . . . . . 36
	10.8.1. Registration Template . . . . . . . . . . . . . . . 35		10.8.1. Registration Template . . . . . . . . . . . . . . . 36
	10.8.2. Initial Registry Contents . . . . . . . . . . . . . 35		10.8.2. Initial Registry Contents . . . . . . . . . . . . . 36
	10.9. CoAP Option Number Registration . . . . . . . . . . . . 37		10.9. CoAP Option Number Registration . . . . . . . . . . . . 38
	11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 37		11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 39
	12. References . . . . . . . . . . . . . . . . . . . . . . . . . 38		12. References . . . . . . . . . . . . . . . . . . . . . . . . . 39
	12.1. Normative References . . . . . . . . . . . . . . . . . . 38		12.1. Normative References . . . . . . . . . . . . . . . . . . 39
	12.2. Informative References . . . . . . . . . . . . . . . . . 38		12.2. Informative References . . . . . . . . . . . . . . . . . 40
	Appendix A. Design Justification . . . . . . . . . . . . . . . . 40		Appendix A. Design Justification . . . . . . . . . . . . . . . . 42
	Appendix B. Roles and Responsibilites . . . . . . . . . . . . . 42		Appendix B. Roles and Responsibilites . . . . . . . . . . . . . 44
	Appendix C. Deployment Examples . . . . . . . . . . . . . . . . 44		Appendix C. Requirements on Profiles . . . . . . . . . . . . . . 46
	C.1. Local Token Validation . . . . . . . . . . . . . . . . . 44		Appendix D. Deployment Examples . . . . . . . . . . . . . . . . 46
	C.2. Introspection Aided Token Validation . . . . . . . . . . 48		D.1. Local Token Validation . . . . . . . . . . . . . . . . . 47
	Appendix D. Document Updates . . . . . . . . . . . . . . . . . . 51		D.2. Introspection Aided Token Validation . . . . . . . . . . 50
	D.1. Version -01 to -02 . . . . . . . . . . . . . . . . . . . 52		Appendix E. Document Updates . . . . . . . . . . . . . . . . . . 54
	D.2. Version -00 to -01 . . . . . . . . . . . . . . . . . . . 52		E.1. Version -02 to -03 . . . . . . . . . . . . . . . . . . . 54
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 53		E.2. Version -01 to -02 . . . . . . . . . . . . . . . . . . . 54
			E.3. Version -00 to -01 . . . . . . . . . . . . . . . . . . . 55
			Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 56
	1. Introduction		1. Introduction
	Authorization is the process for granting approval to an entity to		Authorization is the process for granting approval to an entity to
	access a resource [RFC4949]. The authorization task itself can best		access a resource [RFC4949]. The authorization task itself can best
	be described as granting access to a requesting client, for a		be described as granting access to a requesting client, for a
	resource hosted on a device, the resource server (RS). This exchange		resource hosted on a device, the resource server (RS). This exchange
	is mediated by one or multiple authorization servers (AS). Managing		is mediated by one or multiple authorization servers (AS). Managing
	authorization for a large number of devices and users is a complex		authorization for a large number of devices and users is a complex
	task.		task.
	We envision that end consumers and enterprises will manage access to
	resources on, or produced by, Internet of Things (IoT) devices in the
	same style as they do today with data, services and applications on
	the Web or with their mobile devices. This desire will increase with
	the number of exposed services and capabilities provided by
	applications hosted on the IoT devices.
	While prior work on authorization solutions for the Web and for the		While prior work on authorization solutions for the Web and for the
	mobile environment also applies to the IoT environment many IoT		mobile environment also applies to the IoT environment many IoT
	devices are constrained, for example in terms of processing		devices are constrained, for example in terms of processing
	capabilities, available memory, etc. For web applications on		capabilities, available memory, etc. For web applications on
	constrained nodes this specification makes use of CoAP [RFC7252].		constrained nodes this specification makes use of CoAP [RFC7252].
	A detailed treatment of constraints can be found in [RFC7228], and		A detailed treatment of constraints can be found in [RFC7228], and
	the different IoT deployments present a continuous range of device		the different IoT deployments present a continuous range of device
	and network capabilities. Taking energy consumption as an example:		and network capabilities. Taking energy consumption as an example:
	At one end there are energy-harvesting or battery powered devices		At one end there are energy-harvesting or battery powered devices
	which have a tight power budget, on the other end there are mains-		which have a tight power budget, on the other end there are mains-
	powered devices, and all levels in between.		powered devices, and all levels in between.
	Hence, IoT devices may be very different in terms of available		Hence, IoT devices may be very different in terms of available
	processing and message exchange capabilities and there is a need to		processing and message exchange capabilities and there is a need to
	support many different authorization use cases [RFC7744].		support many different authorization use cases [RFC7744].
	This specification describes a framework for authentication and		This specification describes a framework for authentication and
	authorization in constrained environments (ACE) built on re-use of		authorization in constrained environments (ACE) built on re-use of
	skipping to change at page 5, line 9 ¶		skipping to change at page 5, line 7 ¶
	is not used in this memo.		is not used in this memo.
	Since this specification focuses on the problem of access control to		Since this specification focuses on the problem of access control to
	resources, we simplify the actors by assuming that the client		resources, we simplify the actors by assuming that the client
	authorization server (CAS) functionality is not stand-alone but		authorization server (CAS) functionality is not stand-alone but
	subsumed by either the authorization server or the client (see		subsumed by either the authorization server or the client (see
	section 2.2 in [I-D.ietf-ace-actors]).		section 2.2 in [I-D.ietf-ace-actors]).
	3. Overview		3. Overview
	This specification describes the ACE framework for authorization in		This specification defines the ACE framework for authorization in the
	the Internet of Things consisting of a set of building blocks.		Internet of Things environment. It consists of a set of building
			blocks.
	The basic block is the OAuth 2.0 [RFC6749] framework, which enjoys		The basic block is the OAuth 2.0 [RFC6749] framework, which enjoys
	widespread deployment. Many IoT devices can support OAuth 2.0		widespread deployment. Many IoT devices can support OAuth 2.0
	without any additional extensions, but for certain constrained		without any additional extensions, but for certain constrained
	settings additional profiling is needed.		settings additional profiling is needed.
	Another building block is the lightweight web transfer protocol CoAP		Another building block is the lightweight web transfer protocol CoAP
	[RFC7252] for those communication environments where HTTP is not		[RFC7252] for those communication environments where HTTP is not
	appropriate. CoAP typically runs on top of UDP which further reduces		appropriate. CoAP typically runs on top of UDP which further reduces
	overhead and message exchanges. While this specification defines		overhead and message exchanges. While this specification defines
	extensions for the use of OAuth over CoAP, we do envision further		extensions for the use of OAuth over CoAP, we do envision further
	underlying protocols to be supported in the future, such as MQTT or		underlying protocols to be supported in the future, such as HTTP/2,
	QUIC.		MQTT and QUIC.
	A third building block is CBOR [RFC7049] for encodings where JSON		A third building block is CBOR [RFC7049] for encodings where JSON
	[RFC7159] is not sufficiently compact. CBOR is a binary encoding		[RFC7159] is not sufficiently compact. CBOR is a binary encoding
	designed for small code and message size, which may be used for		designed for small code and message size, which may be used for
	encoding of self contained tokens, and also for encoding CoAP POST		encoding of self contained tokens, and also for encoding CoAP POST
	parameters and CoAP responses.		parameters and CoAP responses.
	A fourth building block is the compact CBOR-based secure message		A fourth building block is the compact CBOR-based secure message
	format COSE [I-D.ietf-cose-msg], which enables application layer		format COSE [I-D.ietf-cose-msg], which enables application layer
	security as an alternative or complement to transport layer security		security as an alternative or complement to transport layer security
	(DTLS [RFC6347] or TLS [RFC5246]). COSE is used to secure self		(DTLS [RFC6347] or TLS [RFC5246]). COSE is used to secure self
	contained tokens such as proof-of-possession (PoP) tokens		contained tokens such as proof-of-possession (PoP) tokens, which is
	[I-D.ietf-oauth-pop-architecture], which is an extension to the OAuth		an extension to the OAuth access tokens, and "client tokens" which
	access tokens, and "client tokens" which are defined in this		are defined in this framework (see Section 7.4). The default access
	framework (see Section 7.4). The default access token format is		token format is defined in CBOR web token (CWT)
	defined in CBOR web token (CWT) [I-D.ietf-ace-cbor-web-token].		[I-D.ietf-ace-cbor-web-token]. Application layer security for CoAP
	Application layer security for CoAP using COSE can be provided with		using COSE can be provided with OSCOAP
	OSCOAP [I-D.selander-ace-object-security].		[I-D.selander-ace-object-security].
	With the building blocks listed above, solutions satisfying various		With the building blocks listed above, solutions satisfying various
	IoT device and network constraints are possible. A list of		IoT device and network constraints are possible. A list of
	constraints is described in detail in RFC 7228 [RFC7228] and a		constraints is described in detail in RFC 7228 [RFC7228] and a
	description of how the building blocks mentioned above relate to the		description of how the building blocks mentioned above relate to the
	various constraints can be found in Appendix A.		various constraints can be found in Appendix A.
	Luckily, not every IoT device suffers from all constraints. The ACE		Luckily, not every IoT device suffers from all constraints. The ACE
	framework nevertheless takes all these aspects into account and		framework nevertheless takes all these aspects into account and
	allows several different deployment variants to co-exist rather than		allows several different deployment variants to co-exist rather than
	skipping to change at page 7, line 9 ¶		skipping to change at page 7, line 7 ¶
	client.		client.
	Access tokens can have different formats, and various methods of		Access tokens can have different formats, and various methods of
	utilization (e.g., cryptographic properties) based on the security		utilization (e.g., cryptographic properties) based on the security
	requirements of the given deployment.		requirements of the given deployment.
	Proof of Possession Tokens:		Proof of Possession Tokens:
	An access token may be bound to a cryptographic key, which is then		An access token may be bound to a cryptographic key, which is then
	used by an RS to authenticate requests from a client. Such tokens		used by an RS to authenticate requests from a client. Such tokens
	are called proof-of-possession tokens (or PoP tokens)		are called proof-of-possession tokens (or PoP tokens).
	[I-D.ietf-oauth-pop-architecture].
	The proof-of-possession (PoP) security concept assumes that the AS		The proof-of-possession (PoP) security concept assumes that the AS
	acts as a trusted third party that binds keys to access tokens.		acts as a trusted third party that binds keys to access tokens.
	These so called PoP keys are then used by the client to		These so called PoP keys are then used by the client to
	demonstrate the possession of the secret to the RS when accessing		demonstrate the possession of the secret to the RS when accessing
	the resource. The RS, when receiving an access token, needs to		the resource. The RS, when receiving an access token, needs to
	verify that the key used by the client matches the one included in		verify that the key used by the client matches the one bound to
	the access token. When this specification uses the term "access		the access token. When this specification uses the term "access
	token" it is assumed to be a PoP token unless specifically stated		token" it is assumed to be a PoP token unless specifically stated
	otherwise.		otherwise.
	The key bound to the access token (aka PoP key) may be based on		The key bound to the access token (aka PoP key) may be based on
	symmetric as well as on asymmetric cryptography. The appropriate		symmetric as well as on asymmetric cryptography. The appropriate
	choice of security depends on the constraints of the IoT devices		choice of security depends on the constraints of the IoT devices
	as well as on the security requirements of the use case.		as well as on the security requirements of the use case.
	Symmetric PoP key: The AS generates a random symmetric PoP key,		Symmetric PoP key: The AS generates a random symmetric PoP key.
	encrypts it for the RS and includes it inside an access token.		The key is either stored to be returned on introspection calls
	The PoP key is also encrypted for the client and sent together		or encrypted and included in the access token. The PoP key is
	with the access token to the client.>		also encrypted for the client and sent together with the access
			token to the client.
	Asymmetric PoP key: An asymmetric key pair is generated on the		Asymmetric PoP key: An asymmetric key pair is generated on the
	client and the public key is sent to the AS (if it does not		client and the public key is sent to the AS (if it does not
	already have knowledge of the client's public key).		already have knowledge of the client's public key).
	Information about the public key, which is the PoP key in this		Information about the public key, which is the PoP key in this
	case, is then included inside the access token and sent back to		case, is either stored to be returned on introspection calls or
	the requesting client. The RS can identify the client's public		included inside the access token and sent back to the
	key from the information in the token, which allows the client		requesting client. The RS can identify the client's public key
	to use the corresponding private key for the proof of		from the information in the token, which allows the client to
	possession.		use the corresponding private key for the proof of possession.
	The access token is protected against modifications using a MAC or		The access token is protected against modifications using a MAC or
	a digital signature, which is added by the AS. The choice of PoP		a digital signature, which is added by the AS. The choice of PoP
	key does not necessarily imply a specific credential type for the		key does not necessarily imply a specific credential type for the
	integrity protection of the token. More information about PoP		integrity protection of the token.
	tokens can be found in [I-D.ietf-oauth-pop-architecture].
	Scopes and Permissions:		Scopes and Permissions:
	In OAuth 2.0, the client specifies the type of permissions it is		In OAuth 2.0, the client specifies the type of permissions it is
	seeking to obtain (via the scope parameter) in the access request.		seeking to obtain (via the scope parameter) in the access token
	In turn, the AS may use the scope response parameter to inform the		request. In turn, the AS may use the scope response parameter to
	client of the scope of the access token issued. As the client		inform the client of the scope of the access token issued. As the
	could be a constrained device as well, this specification uses		client could be a constrained device as well, this specification
	CBOR encoded messages for CoAP, defined in Section 5, to request		uses CBOR encoded messages for CoAP, defined in Section 5, to
	scopes and to be informed what scopes the access token was		request scopes and to be informed what scopes the access token was
	actually authorized for by the AS.		actually authorized for by the AS.
	The values of the scope parameter are expressed as a list of		The values of the scope parameter are expressed as a list of
	space- delimited, case-sensitive strings, with a semantic that is		space- delimited, case-sensitive strings, with a semantic that is
	well-known to the AS and the RS. More details about the concept		well-known to the AS and the RS. More details about the concept
	of scopes is found under Section 3.3 in [RFC6749].		of scopes is found under Section 3.3 in [RFC6749].
	Claims:		Claims:
	Information carried in the access token, called claims, is in the		Information carried in the access token or returned from
	form of type-value pairs. An access token may, for example,		introspection, called claims, is in the form of type-value pairs.
	include a claim identifying the AS that issued the token (via the		An access token may, for example, include a claim identifying the
	"iss" claim) and what audience the access token is intended for		AS that issued the token (via the "iss" claim) and what audience
	(via the "aud" claim). The audience of an access token can be a		the access token is intended for (via the "aud" claim). The
	specific resource or one or many resource servers. The resource		audience of an access token can be a specific resource or one or
	owner policies influence what claims are put into the access token		many resource servers. The resource owner policies influence what
	by the authorization server.		claims are put into the access token by the authorization server.
	While the structure and encoding of the access token varies		While the structure and encoding of the access token varies
	throughout deployments, a standardized format has been defined		throughout deployments, a standardized format has been defined
	with the JSON Web Token (JWT) [RFC7519] where claims are encoded		with the JSON Web Token (JWT) [RFC7519] where claims are encoded
	as a JSON object. In [I-D.ietf-ace-cbor-web-token] an equivalent		as a JSON object. In [I-D.ietf-ace-cbor-web-token] an equivalent
	format using CBOR encoding (CWT) has been defined.		format using CBOR encoding (CWT) has been defined.
	Introspection:		Introspection:
	Introspection is a method for a resource server to query the		Introspection is a method for a resource server to query the
	skipping to change at page 9, line 10 ¶		skipping to change at page 9, line 6 ¶
	specifically designed for constrained environments. CoAP typically		specifically designed for constrained environments. CoAP typically
	uses datagram-oriented transport, such as UDP, where reordering and		uses datagram-oriented transport, such as UDP, where reordering and
	loss of packets can occur. A security solution need to take the		loss of packets can occur. A security solution need to take the
	latter aspects into account.		latter aspects into account.
	While HTTP uses headers and query-strings to convey additional		While HTTP uses headers and query-strings to convey additional
	information about a request, CoAP encodes such information in so-		information about a request, CoAP encodes such information in so-
	called 'options'.		called 'options'.
	CoAP supports application-layer fragmentation of the CoAP payloads		CoAP supports application-layer fragmentation of the CoAP payloads
	through blockwise transfers [I-D.ietf-core-block]. However, block-		through blockwise transfers [RFC7959]. However, block-wise transfer
	wise transfer does not increase the size limits of CoAP options,		does not increase the size limits of CoAP options, therefore data
	therefore data encoded in options has to be kept small.		encoded in options has to be kept small.
	Transport layer security for CoAP can be provided by DTLS 1.2		Transport layer security for CoAP can be provided by DTLS 1.2
	[RFC6347] or TLS 1.2 [RFC5246]. CoAP defines a number of proxy		[RFC6347] or TLS 1.2 [RFC5246]. CoAP defines a number of proxy
	operations which requires transport layer security to be terminated		operations which requires transport layer security to be terminated
	at the proxy. One approach for protecting CoAP communication end-to-		at the proxy. One approach for protecting CoAP communication end-to-
	end through proxies, and also to support security for CoAP over		end through proxies, and also to support security for CoAP over
	different transport in a uniform way, is to provide security on		different transport in a uniform way, is to provide security on
	application layer using an object-based security mechanism such as		application layer using an object-based security mechanism such as
	CBOR Encoded Message Syntax [I-D.ietf-cose-msg].		COSE [I-D.ietf-cose-msg].
	One application of COSE is OSCOAP [I-D.selander-ace-object-security],		One application of COSE is OSCOAP [I-D.selander-ace-object-security],
	which provides end-to-end confidentiality, integrity and replay		which provides end-to-end confidentiality, integrity and replay
	protection, and a secure binding between CoAP request and response		protection, and a secure binding between CoAP request and response
	messages. In OSCOAP, the CoAP messages are wrapped in COSE objects		messages. In OSCOAP, the CoAP messages are wrapped in COSE objects
	and sent using CoAP.		and sent using CoAP.
	4. Protocol Interactions		4. Protocol Interactions
	The ACE framework is based on the OAuth 2.0 protocol interactions		The ACE framework is based on the OAuth 2.0 protocol interactions
	using the /token and /introspect endpoints. A client obtains an		using the /token and /introspect endpoints. A client obtains an
	access token from an AS using the /token endpoint and subsequently		access token from an AS using the /token endpoint and subsequently
	presents the access token to a RS to gain access to a protected		presents the access token to a RS to gain access to a protected
	resource. The RS, after receiving an access token, may present it to		resource. The RS, after receiving an access token, may present it to
	the AS via the /introspect endpoint to get information about the		the AS via the /introspect endpoint to get information about the
	access token. In other deployments the RS may process the access		access token. In other deployments the RS may process the access
	token locally without the need to contact an AS. These interactions		token locally without the need to contact an AS. These interactions
	are shown in Figure 1. An overview of various OAuth concepts is		are shown in Figure 1. An overview of various OAuth concepts is
	provided in Section 3.1.		provided in Section 3.1.
			The OAuth 2.0 framework defines a number of "protocol flows" via
			grant types, which have been extended further with extensions to
			OAuth 2.0 (such as RFC 7521 [RFC7521] and
			[I-D.ietf-oauth-device-flow]). What grant types works best depends
			on the usage scenario and RFC 7744 [RFC7744] describes many different
			IoT use cases but there two preferred grant types, namely the
			Authorization Code Grant (described in Section 4.1 of RFC 7521) and
			the Client Credentials Grant (described in Section 4.4 of RFC 7521).
			The Authorization Code Grant is a good fit for use with apps running
			on smart phones and tablets that request access to IoT devices, a
			common scenario in the smart home environment, where users need to go
			through an authentication and authorization phase (at least during
			the initial setup phase). The native apps guidelines described in
			[I-D.ietf-oauth-native-apps] are applicable to this use case. The
			Client Credential Grant is a good fit for use with IoT devices where
			the OAuth client itself is constraint. In such a case the resource
			owner or another person on his or her behalf have arranged with the
			authorization server out-of-band, which is often accomplished using
			an commissioning tool.
	The consent of the resource owner, for giving a client access to a		The consent of the resource owner, for giving a client access to a
	protected resource, can be pre-configured authorization policies or		protected resource, can be provided dynamically as in the traditional
	dynamically at the time when the request is sent. The resource owner		OAuth flows, or it could be pre-configured by the resource owner as
	and the requesting party (i.e. client owner) are not shown in		authorization policies at the AS, which the AS evaluates when a token
	Figure 1.		request arrives. The resource owner and the requesting party (i.e.
			client owner) are not shown in Figure 1.
	This framework supports a wide variety of communication security		This framework supports a wide variety of communication security
	mechanisms between the ACE entities, such as client, AS, and RS. We		mechanisms between the ACE entities, such as client, AS, and RS. We
	assume that the client has been registered (also called enrolled or		assume that the client has been registered (also called enrolled or
	onboarded) to an AS using a mechanism defined outside the scope of		onboarded) to an AS using a mechanism defined outside the scope of
	this document. In practice, various techniques for onboarding have		this document. In practice, various techniques for onboarding have
	been used, such as factory-based provisioning or the use of		been used, such as factory-based provisioning or the use of
	commissioning tools. Regardless of the onboarding technique, this		commissioning tools. Regardless of the onboarding technique, this
	registration procedure implies that the client and the AS share		registration procedure implies that the client and the AS share
	credentials, and configuration parameters. These credentials are		credentials, and configuration parameters. These credentials are
	skipping to change at page 10, line 32 ¶		skipping to change at page 10, line 49 ¶
	At the start of the protocol there is an optional discovery step		At the start of the protocol there is an optional discovery step
	where the client discovers the resource server and the resources this		where the client discovers the resource server and the resources this
	server hosts. In this step the client might also determine what		server hosts. In this step the client might also determine what
	permissions are needed to access the protected resource. The		permissions are needed to access the protected resource. The
	detailed procedures for this discovery process may be defined in an		detailed procedures for this discovery process may be defined in an
	ACE profile and depend on the protocols being used and the specific		ACE profile and depend on the protocols being used and the specific
	deployment environment.		deployment environment.
	In Bluetooth Low Energy, for example, advertisements are broadcasted		In Bluetooth Low Energy, for example, advertisements are broadcasted
	by a peripheral, including information about the primary services.		by a peripheral, including information about the primary services.
	In CoAP, as a second example, a client can makes a request to		In CoAP, as a second example, a client can make a request to "/.well-
	"/.well-known/core" to obtain information about available resources,		known/core" to obtain information about available resources, which
	which are returned in a standardized format as described in		are returned in a standardized format as described in [RFC6690].
	[RFC6690].
	+--------+ +---------------+		+--------+ +---------------+
	| |---(A)-- Token Request ------->| |		| |---(A)-- Token Request ------->| |
	| | | Authorization |		| | | Authorization |
	| |<--(B)-- Access Token ---------| Server |		| |<--(B)-- Access Token ---------| Server |
	| | + Client Information | |		| | + RS Information | |
	| | +---------------+		| | +---------------+
	| | ^ |		| | ^ |
	| | Introspection Request (D)| |		| | Introspection Request (D)| |
	| Client | | |		| Client | | |
	| | Response + Client Token | |(E)		| | Response + Client Token | |(E)
	| | | v		| | | v
	| | +--------------+		| | +--------------+
	| |---(C)-- Token + Request ----->| |		| |---(C)-- Token + Request ----->| |
	| | | Resource |		| | | Resource |
	| |<--(F)-- Protected Resource ---| Server |		| |<--(F)-- Protected Resource ---| Server |
	skipping to change at page 11, line 39 ¶		skipping to change at page 11, line 39 ¶
	Section 3.1 for a short description) wherein the AS binds a key to		Section 3.1 for a short description) wherein the AS binds a key to
	an access token. The client may include permissions it seeks to		an access token. The client may include permissions it seeks to
	obtain, and information about the credentials it wants to use		obtain, and information about the credentials it wants to use
	(e.g., symmetric/asymmetric cryptography or a reference to a		(e.g., symmetric/asymmetric cryptography or a reference to a
	specific credential).		specific credential).
	Access Token Response (B):		Access Token Response (B):
	If the AS successfully processes the request from the client, it		If the AS successfully processes the request from the client, it
	returns an access token. It also returns various parameters,		returns an access token. It also returns various parameters,
	referred as "Client Information". In addition to the response		referred as "RS Information". In addition to the response
	parameters defined by OAuth 2.0 and the PoP token extension,		parameters defined by OAuth 2.0 and the PoP token extension,
	further response parameters, such as information on which profile		further response parameters, such as information on which profile
	the client should use with the resource server(s). More		the client should use with the resource server(s). More
	information about these parameters can be found in in Section 6.4.		information about these parameters can be found in in Section 6.4.
	Resource Request (C):		Resource Request (C):
	The client interacts with the RS to request access to the		The client interacts with the RS to request access to the
	protected resource and provides the access token. The protocol to		protected resource and provides the access token. The protocol to
	use between the client and the RS is not restricted to CoAP.		use between the client and the RS is not restricted to CoAP.
	HTTP, HTTP/2, QUIC, MQTT, Bluetooth Low Energy, etc., are also		HTTP, HTTP/2, QUIC, MQTT, Bluetooth Low Energy, etc., are also
	viable candidates.		viable candidates.
	Depending on the device limitations and the selected protocol this		Depending on the device limitations and the selected protocol this
	exchange may be split up into two parts:		exchange may be split up into two parts:
	(1) the client sends the access token containing, or		(1) the client sends the access token containing, or
	referencing, the authorization information to the RS, that may		referencing, the authorization information to the RS, that may
	be used for subsequent resource requests by the client, and		be used for subsequent resource requests by the client, and
	(2) the client makes the resource access request, using the		(2) the client makes the resource access request, using the
	communication security protocol and other client information		communication security protocol and other RS Information
	obtained from the AS.		obtained from the AS.
	The Client and the RS mutually authenticate using the security		The Client and the RS mutually authenticate using the security
	protocol specified in the profile (see step B) and the keys		protocol specified in the profile (see step B) and the keys
	obtained in the access token or the client information or the		obtained in the access token or the RS Information or the client
	client token. The RS verifies that the token is integrity		token. The RS verifies that the token is integrity protected by
	protected by the AS and compares the claims contained in the		the AS and compares the claims contained in the access token with
	access token with the resource request. If the RS is online,		the resource request. If the RS is online, validation can be
	validation can be handed over to the AS using token introspection		handed over to the AS using token introspection (see messages D
	(see messages D and E) over HTTP or CoAP, in which case the		and E) over HTTP or CoAP, in which case the different parts of
	different parts of step C may be interleaved with introspection.		step C may be interleaved with introspection.
	Token Introspection Request (D):		Token Introspection Request (D):
	A resource server may be configured to introspect the access token		A resource server may be configured to introspect the access token
	by including it in a request to the /introspect endpoint at that		by including it in a request to the /introspect endpoint at that
	AS. Token introspection over CoAP is defined in Section 7 and for		AS. Token introspection over CoAP is defined in Section 7 and for
	HTTP in [RFC7662].		HTTP in [RFC7662].
	Note that token introspection is an optional step and can be		Note that token introspection is an optional step and can be
	omitted if the token is self-contained and the resource server is		omitted if the token is self-contained and the resource server is
	skipping to change at page 13, line 22 ¶		skipping to change at page 13, line 22 ¶
	For IoT we cannot generally assume that the client and RS are part		For IoT we cannot generally assume that the client and RS are part
	of a common key infrastructure, so the AS provisions credentials		of a common key infrastructure, so the AS provisions credentials
	or associated information to allow mutual authentication. These		or associated information to allow mutual authentication. These
	credentials need to be provided to the parties before or during		credentials need to be provided to the parties before or during
	the authentication protocol is executed, and may be re-used for		the authentication protocol is executed, and may be re-used for
	subsequent token requests.		subsequent token requests.
	Proof-of-Possession		Proof-of-Possession
	The ACE framework by default implements proof-of-possession for		The ACE framework by default implements proof-of-possession for
	access tokens, i.e. that the authenticated token holder is bound		access tokens, i.e. that the token holder can prove being a holder
	to the token. The binding is provided by the "cnf" claim		of the key bound to the token. The binding is provided by the
	indicating what key is used for mutual authentication. If clients		"cnf" claim indicating what key is used for mutual authentication.
	need to update a token, e.g. to get additional rights, they can		If clients need to update a token, e.g. to get additional rights,
	request that the AS binds the new access token to the same		they can request that the AS binds the new access token to the
	credential as the previous token.		same credential as the previous token.
	ACE Profile Negotiation		ACE Profiles
	The client or RS may be limited in the encodings or protocols it		The client or RS may be limited in the encodings or protocols it
	supports. To support a variety of different deployment settings,		supports. To support a variety of different deployment settings,
	specific interactions between client and RS are defined in an ACE		specific interactions between client and RS are defined in an ACE
	profile. The ACE framework supports the negotiation of different		profile. In ACE framework the AS is expected to manage the
	ACE profiles between client and AS using the "profile" parameter		matching of compatible profile choices between a client and an RS.
	in the token request and token response.		The AS informs the client of the selected profile using the
			"profile" parameter in the token request and token response.
	OAuth 2.0 requires the use of TLS both to protect the communication		OAuth 2.0 requires the use of TLS both to protect the communication
	between AS and client when requesting an access token and between AS		between AS and client when requesting an access token; between client
	and RS for introspection. In constrained settings TLS is not always		and RS when accessing a resource and between AS and RS for
	feasible, or desirable. Nevertheless it is REQUIRED that the data		introspection. In constrained settings TLS is not always feasible,
	exchanged with the AS is encrypted and integrity protected. It is		or desirable. Nevertheless it is REQUIRED that the data exchanged
	furthermore REQUIRED that the AS and the endpoint communicating with		with the AS is encrypted and integrity protected. It is furthermore
	it (client or RS) perform mutual authentication.		REQUIRED that the AS and the endpoint communicating with it (client
			or RS) perform mutual authentication.
	Profiles are expected to specify the details of how this is done,		Profiles are expected to specify the details of how this is done,
	depending e.g. on the communication protocol and the credentials used		depending e.g. on the communication protocol and the credentials used
	by the client or the RS.		by the client or the RS.
	In OAuth 2.0 the communication with the Token and the Introspection		In OAuth 2.0 the communication with the Token and the Introspection
	resources at the AS is assumed to be via HTTP and may use Uri-query		endpoints at the AS is assumed to be via HTTP and may use Uri-query
	parameters. This framework RECOMMENDS to use CoAP instead and		parameters. This framework RECOMMENDS to use CoAP instead and
	RECOMMENDS the use of the following alternative instead of Uri-query		RECOMMENDS the use of the following alternative instead of Uri-query
	parameters: The sender (client or RS) encodes the parameters of its		parameters: The sender (client or RS) encodes the parameters of its
	request as a CBOR map and submits that map as the payload of the POST		request as a CBOR map and submits that map as the payload of the POST
	request. The Content-format MUST be "application/cbor" in that case.		request. The Content-format depends on the security applied to the
			content and must be specified by the corresponding profile.
	The OAuth 2.0 AS uses a JSON structure in the payload of its		The OAuth 2.0 AS uses a JSON structure in the payload of its
	responses both to client and RS. This framework RECOMMENDS the use		responses both to client and RS. This framework RECOMMENDS the use
	of CBOR [RFC7049] instead. The requesting device can explicitly		of CBOR [RFC7049] instead. The requesting device can explicitly
	request this encoding by setting the CoAP Accept option in the		request this encoding by setting the CoAP Accept option in the
	request to "application/cbor".		request to "application/cbor". Depending on the profile, the content
			may arrive in a different format wrapping a CBOR payload.
	6. The 'Token' Resource		6. The 'Token' Endpoint
	In plain OAuth 2.0 the AS provides the /token resource for submitting		In plain OAuth 2.0 the AS provides the /token endpoint for submitting
	access token requests. This framework extends the functionality of		access token requests. This framework extends the functionality of
	the /token resource, giving the AS the possibility to help client and		the /token endpoint, giving the AS the possibility to help client and
	RS to establish shared keys or to exchange their public keys.		RS to establish shared keys or to exchange their public keys.
			Furthermore this framework defines encodings using CoAP and CBOR,
			instead of HTTP and JSON.
	Communication between the client and the token resource at the AS		Communication between the client and the /token endpoint at the AS
	MUST be integrity protected and encrypted. Furthermore AS and client		MUST be integrity protected and encrypted. Furthermore AS and client
	MUST perform mutual authentication. Profiles of this framework are		MUST perform mutual authentication. Profiles of this framework are
	expected to specify how authentication and communication security is		expected to specify how authentication and communication security is
	implemented.		implemented.
	The figures of this section uses CBOR diagnostic notation without the		The figures of this section uses CBOR diagnostic notation without the
	integer abbreviations for the parameters or their values for better		integer abbreviations for the parameters or their values for better
	readability.		readability.
	6.1. Client-to-AS Request		6.1. Client-to-AS Request
	When requesting an access token from the AS, the client MAY include		The client sends a CoAP POST request to the token endpoint at the AS,
	the following parameters in the request in addition to the ones		the profile is expected to specify the Content-Type and wrapping of
	required or optional according to the OAuth 2.0 specification		the payload. The content of the request consists of the parameters
	[RFC6749]:		specified in section 4 of the OAuth 2.0 specification [RFC6749]
			encoded as a CBOR map.
	token_type
	OPTIONAL. See Section 6.4 for more details.
	alg		In addition to these parameters, this framework defines the following
	OPTIONAL. See Section 6.4 for more details.		parameters for requesting an access token from a /token endpoint:
	profile		aud
	OPTIONAL. This indicates the profile that the client would like		OPTIONAL. Specifies the audience for which the client is
	to use with the RS. See Section 6.4 for more details on the		requesting an access token. If this parameter is missing it is
	formatting of this parameter. If the RS cannot support the		assumed that the client and the AS have a pre-established
	requested profile, the AS MUST reply with an error message.		understanding of the audience that an access token should address.
			If a client submits a request for an access token without
			specifying an "aud" parameter, and the AS does not have a default
			"aud" value for this client, then the AS MUST respond with an
			error message with the CoAP response code 4.00 (Bad Request).
	cnf		cnf
	OPTIONAL. This field contains information about a public key the		OPTIONAL. This field contains information about the key the
	client would like to bind to the access token. If the client		client would like to bind to the access token for proof-of-
	requests an asymmetric proof-of-possession algorithm, but does not		possession. It is NOT RECOMMENDED that a client submits a
	provide a public key, the AS MUST respond with an error message.		symmetric key value to the AS using this parameter. See
	See Section 6.4 for more details on the formatting of the 'cnf'		Section 6.4.5 for more details on the formatting of the 'cnf'
	parameter.		parameter.
	These new parameters are optional in the case where the AS has prior
	knowledge of the capabilities of the client, otherwise these
	parameters are required. This prior knowledge may, for example, be
	set by the use of a dynamic client registration protocol exchange
	[RFC7591].
	The following examples illustrate different types of requests for		The following examples illustrate different types of requests for
	proof-of-possession tokens.		proof-of-possession tokens.
	Figure 2 shows a request for a token with a symmetric proof-of-		Figure 2 shows a request for a token with a symmetric proof-of-
	possession key.		possession key. Note that in this example we assume a DTLS-based
			communication security profile, therefore the Content-Type is
			"application/cbor".
	Header: POST (Code=0.02)		Header: POST (Code=0.02)
	Uri-Host: "server.example.com"		Uri-Host: "server.example.com"
	Uri-Path: "token"		Uri-Path: "token"
	Content-Type: "application/cbor"		Content-Type: "application/cbor"
	Payload:		Payload:
	{		{
	"grant_type" : "client_credentials",		"grant_type" : "client_credentials",
	"aud" : "tempSensor4711",		"aud" : "tempSensor4711",
	"client_id" : "myclient",		}
	"client_secret" : b64'FWRUVGZUZmZFRkWSRlVGhA',
	"token_type" : "pop",
	"alg" : "HS256",
	"profile" : "coap_dtls"
	}
	Figure 2: Example request for an access token bound to a symmetric		Figure 2: Example request for an access token bound to a symmetric
	key.		key.
	Figure 3 shows a request for a token with an asymmetric proof-of-		Figure 3 shows a request for a token with an asymmetric proof-of-
	possession key.		possession key. Note that in this example we assume an object
			security-based profile, therefore the Content-Type is "application/
			cose+cbor".
	Header: POST (Code=0.02)		Header: POST (Code=0.02)
	Uri-Host: "server.example.com"		Uri-Host: "server.example.com"
	Uri-Path: "token"		Uri-Path: "token"
	Content-Type: "application/cbor"		Content-Type: "application/cose+cbor"
	Payload:		Payload:
	{		{
	"grant_type" : "token",		"grant_type" : "client_credentials",
	"aud" : "lockOfDoor0815",
	"client_id" : "myclient",
	"token_type" : "pop",
	"alg" : "ES256",
	"profile" : "coap_oscoap"
	"cnf" : {		"cnf" : {
	"COSE_Key" : {		"COSE_Key" : {
	"kty" : "EC",		"kty" : "EC",
	"kid" : h'11',		"kid" : h'11',
	"crv" : "P-256",		"crv" : "P-256",
	"x" : b64'usWxHK2PmfnHKwXPS54m0kTcGJ90UiglWiGahtagnv8',		"x" : b64'usWxHK2PmfnHKwXPS54m0kTcGJ90UiglWiGahtagnv8',
	"y" : b64'IBOL+C3BttVivg+lSreASjpkttcsz+1rb7btKLv8EX4'		"y" : b64'IBOL+C3BttVivg+lSreASjpkttcsz+1rb7btKLv8EX4'
	}		}
	}		}
	}		}
	Figure 3: Example request for an access token bound to an asymmetric		Figure 3: Example request for an access token bound to an asymmetric
	key.		key.
	Figure 4 shows a request for a token where a previously communicated		Figure 4 shows a request for a token where a previously communicated
	proof-of-possession key is only referenced.		proof-of-possession key is only referenced. Note that we assume a
			DTLS-based communication security profile for this example, therefore
			the Content-Type is "application/cbor". Also note that the client
			performs a password based authentication in this example by
			submitting its client_secret.
	Header: POST (Code=0.02)		Header: POST (Code=0.02)
	Uri-Host: "server.example.com"		Uri-Host: "server.example.com"
	Uri-Path: "token"		Uri-Path: "token"
	Content-Type: "application/cbor"		Content-Type: "application/cbor"
	Payload:		Payload:
	{		{
	"grant_type" : "client_credentials",		"grant_type" : "client_credentials",
			"client_id" : "myclient",
			"client_secret" : "mysecret234",
	"aud" : "valve424",		"aud" : "valve424",
	"scope" : "read",		"scope" : "read",
	"client_id" : "myclient",
	"token_type" : "pop",
	"alg" : "ES256",
	"profile" : "coap_oscoap"
	"cnf" : {		"cnf" : {
	"kid" : b64'6kg0dXJM13U'		"kid" : b64'6kg0dXJM13U'
	}		}
	}		}
	Figure 4: Example request for an access token bound to a key		Figure 4: Example request for an access token bound to a key
	reference.		reference.
	6.2. AS-to-Client Response		6.2. AS-to-Client Response
	If the access token request has been successfully verified by the AS		If the access token request has been successfully verified by the AS
	and the client is authorized to obtain a PoP token for the indicated		and the client is authorized to obtain an access token corresponding
	audience and scopes (if any), the AS issues an access token. If		to its access token request, the AS sends a response with the CoAP
	client authentication failed or is invalid, the authorization server		response code 2.01 (Created). If client request was invalid, or not
	returns an error response as described in Section 6.3.		authorized, the AS returns an error response as described in
			Section 6.3.
	The following parameters may also be part of a successful response in		Note that the AS decides which token type and profile to use when
	addition to those defined in section 5.1 of [RFC6749]:		issuing a successful response. It is assumed that the AS has prior
			knowledge of the capabilities of the client, and the RS. This prior
			knowledge may, for example, be set by the use of a dynamic client
			registration protocol exchange [RFC7591].
			The content of the successful reply MUST be encoded as CBOR map,
			containing paramters as speficied in section 5.1 of [RFC6749]. In
			addition to these parameters, the following parameters are also part
			of a successful response:
	profile		profile
	REQUIRED. This indicates the profile that the client MUST use		REQUIRED. This indicates the profile that the client MUST use
	towards the RS. See Section 6.4 for the formatting of this		towards the RS. See Section 6.4.4 for the formatting of this
	parameter.		parameter.
	cnf		cnf
	REQUIRED. This field contains information about the proof-of		REQUIRED if the token type is 'pop'. OPTIONAL otherwise. If a
	possession key for this access token. See Section 6.4 for the		symmetric proof-of-possession algorithms was selected, this field
			contains the proof-of-possession key. If an asymmetric algorithm
			was selected, this field contains information about the public key
			used by the RS to authenticate. See Section 6.4.5 for the
	formatting of this parameter.		formatting of this parameter.
			token_type
			OPTIONAL. By default implementations of this framework SHOULD
			assume that the token_type is 'pop'. If a specific use case
			requires another token_type (e.g. 'Bearer') to be used then this
			parameter is REQUIRED.
	Note that the access token can also contains a 'cnf' claim, however,		Note that if CBOR Web Tokens [I-D.ietf-ace-cbor-web-token] are used,
	these two values are consumed by different parties. The access token		the access token can also contain a 'cnf' claim. This claim is
	is created by the AS and processed by the RS (and opaque to the		however consumed by a different party. The access token is created
	client) whereas the Client Information is created by the AS and		by the AS and processed by the RS (and opaque to the client) whereas
	processed by the client; it is never forwarded to the resource		the RS Information is created by the AS and processed by the client;
	server.		it is never forwarded to the resource server.
	The following examples illustrate different types of responses for		The following examples illustrate different types of responses for
	proof-of-possession tokens.		proof-of-possession tokens.
	Figure 5 shows a response containing a token and a 'cnf' parameter		Figure 5 shows a response containing a token and a 'cnf' parameter
	with a symmetric proof-of-possession key.		with a symmetric proof-of-possession key. Note that we assume a
			DTLS-based communication security profile for this example, therefore
			the Content-Type is "application/cbor".
	Header: Created (Code=2.01)		Header: Created (Code=2.01)
	Content-Type: "application/cbor"		Content-Type: "application/cbor"
	Payload:		Payload:
	{		{
	"access_token" : b64'SlAV32hkKG ...		"access_token" : b64'SlAV32hkKG ...
	(remainder of CWT omitted for brevity;		(remainder of CWT omitted for brevity;
	CWT contains COSE_Key in the 'cnf' claim)',		CWT contains COSE_Key in the 'cnf' claim)',
	"token_type" : "pop",
	"alg" : "HS256",
	"expires_in" : "3600",		"expires_in" : "3600",
	"profile" : "coap_dtls"
	"cnf" : {		"cnf" : {
	"COSE_Key" : {		"COSE_Key" : {
	"kty" : "Symmetric",		"kty" : "Symmetric",
	"kid" : b64'39Gqlw',		"kid" : b64'39Gqlw',
	"k" : b64'hJtXhkV8FJG+Onbc6mxCcQh'		"k" : b64'hJtXhkV8FJG+Onbc6mxCcQh'
	}		}
	}		}
	}		}
	Figure 5: Example AS response with an access token bound to a		Figure 5: Example AS response with an access token bound to a
	symmetric key.		symmetric key.
	6.3. Error Response		6.3. Error Response
	The error responses for CoAP-based interactions with the AS are		The error responses for CoAP-based interactions with the AS are
	equivalent to the ones for HTTP-based interactions as defined in		equivalent to the ones for HTTP-based interactions as defined in
	section 5.2 of [RFC6749], with the following differences: The		section 5.2 of [RFC6749], with the following differences: The
	Content-Type MUST be set to "application/cbor", the payload MUST be		Content-Type is specified by the communication security profile used
	encoded in a CBOR map and the CoAP response code 4.00 Bad Request		between client and AS. The raw payload before being processed by the
	MUST be used unless specified otherwise.		communication security protocol MUST be encoded as a CBOR map and the
			CoAP response code 4.00 (Bad Request) MUST be used unless specified
			otherwise.
	6.4. New Request and Response Parameters		6.4. New Request and Response Parameters
	This section defines parameters that can be used in access token		This section provides more detail about the new parameters that can
	requests and responses, as well as abbreviations for more compact		be used in access token requests and responses, as well as
	encoding of existing parameters and common values.		abbreviations for more compact encoding of existing parameters and
			common parameter values.
	6.4.1. Grant Type		6.4.1. Audience
			This parameter specifies for which audience the client is requesting
			a token. It should be encoded as CBOR text string (major type 3).
			The formatting and semantics of these strings are application
			specific.
			6.4.2. Grant Type
	The abbreviations in Figure 6 MAY be used in CBOR encodings instead		The abbreviations in Figure 6 MAY be used in CBOR encodings instead
	of the string values defined in [RFC6749].		of the string values defined in [RFC6749].
	/--------------------+----------+--------------\		/--------------------+----------+--------------\
	| grant_type | CBOR Key | Major Type |		| grant_type | CBOR Key | Major Type |
	|--------------------+----------+--------------|		|--------------------+----------+--------------|
	| password | 0 | 0 (uint) |		| password | 0 | 0 (uint) |
	| authorization_code | 1 | 0 |		| authorization_code | 1 | 0 |
	| client_credentials | 2 | 0 |		| client_credentials | 2 | 0 |
	| refresh_token | 3 | 0 |		| refresh_token | 3 | 0 |
	\--------------------+----------+--------------/		\--------------------+----------+--------------/
	Figure 6: CBOR abbreviations for common grant types		Figure 6: CBOR abbreviations for common grant types
	6.4.2. Token Type and Algorithms		6.4.3. Token Type
	To allow clients to indicate support for specific token types and
	respective algorithms they need to interact with the AS. They can
	either provide this information out-of-band or via the 'token_type'
	and 'alg' parameter in the client request.
	The value in the 'alg' parameter together with value from the		The 'token_type' parameter allows the AS to indicate to the client
	'token_type' parameter allow the client to indicate the supported		which type of access token it is receiving (e.g. a bearer token).
	algorithms for a given token type. The token type refers to the		The 'pop' token type MUST be assumed by default if the AS does not
	specification used by the client to interact with the resource server		provide a different value.
	to demonstrate possession of the key. The 'alg' parameter provides
	further information about the algorithm, such as whether a symmetric
	or an asymmetric crypto-system is used. Hence, a client supporting a
	specific token type also knows how to populate the values to the
	'alg' parameter.
	This document registers the new value "pop" for the OAuth Access		This document registers the new value "pop" for the OAuth Access
	Token Types registry, specifying a Proof-of-Possession token. How		Token Types registry, specifying a Proof-of-Possession token. How
	the proof-of-possession is performed is specified by the 'alg'		the proof-of-possession is performed is specified by the profiles.
	parameter. Profiles of this framework are responsible for defining
	values for the 'alg' parameter together with the corresponding proof-
	of-possession mechanisms.
	The values in the 'alg' parameter are case-sensitive. If the client
	supports more than one algorithm then each individual value MUST be
	separated by a space.
	6.4.3. Profile
	The "profile" parameter identifies the communication protocol and the		The values in the 'token_type' parameter are CBOR text strings (major
	communication security protocol between the client and the RS.		type 3).
	An initial set of profile identifiers and their CBOR encodings are		6.4.4. Profile
	specified in Figure 7. Profiles using other combinations of
	protocols are expected to define their own profile identifiers.
	/--------------------+----------+--------------\		Profiles of this framework are expected to define the communication
	| Profile identifier | CBOR Key | Major Type |		protocol and the communication security protocol between the client
	|--------------------+----------+--------------|		and the RS. Furthermore profiles are expected to define proof-of-
	| http_tls | 0 | 0 (uint) |		possession methods, if they support proof-of-possession tokens.
	| coap_dtls | 1 | 0 |
	| coap_oscoap | 2 | 0 |
	\--------------------+----------+--------------/
	Figure 7: Profile identifiers and their CBOR mappings		A profile should specify an identifier that is used to uniquely
			identify itself in the 'profile' parameter.
	Profiles MAY define additional parameters for both the token request		Profiles MAY define additional parameters for both the token request
	and the client information in the access token response in order to		and the RS Information in the access token response in order to
	support negotioation or signalling of profile specific parameters.		support negotioation or signalling of profile specific parameters.
	6.4.4. Confirmation		6.4.5. Confirmation
	The "cnf" parameter identifies or provides the key used for proof-of-		The "cnf" parameter identifies or provides the key used for proof-of-
	possession. This framework extends the definition of 'cnf' from		possession or for authenticating the RS depending on the proof-of-
	[RFC7800] by defining CBOR/COSE encodings and the use of 'cnf' for		possession algorithm and the context cnf is used in. This framework
	transporting keys in the client information.		extends the definition of 'cnf' from [RFC7800] by adding CBOR/COSE
			encodings and the use of 'cnf' for transporting keys in the RS
			Information.
	A CBOR encoded payload MAY contain the 'cnf' parameter with the		A CBOR encoded payload MAY contain the 'cnf' parameter with the
	following contents:		following contents:
	COSE_Key In this case the 'cnf' parameter contains the proof-of-		COSE_Key In this case the 'cnf' parameter contains the proof-of-
	possession key to be used by the client. An example is shown in		possession key to be used by the client. An example is shown in
	Figure 8.		Figure 7.
	"cnf" : {		"cnf" : {
	"COSE_Key" : {		"COSE_Key" : {
	"kty" : "EC",		"kty" : "EC",
	"kid" : h'11',		"kid" : h'11',
	"crv" : "P-256",		"crv" : "P-256",
	"x" : b64'usWxHK2PmfnHKwXPS54m0kTcGJ90UiglWiGahtagnv8',		"x" : b64'usWxHK2PmfnHKwXPS54m0kTcGJ90UiglWiGahtagnv8',
	"y" : b64'IBOL+C3BttVivg+lSreASjpkttcsz+1rb7btKLv8EX4'		"y" : b64'IBOL+C3BttVivg+lSreASjpkttcsz+1rb7btKLv8EX4'
	}		}
	}		}
	Figure 8: Confirmation parameter containing a public key		Figure 7: Confirmation parameter containing a public key
			Note that the COSE_Key structure may contain an "alg" or "key_ops"
			parameter. If such parameters are present, a client MUST NOT use
			a key that is not compatible with the profile or proof-of-
			possession algorithm according to those parameters.
	COSE_Encrypted In this case the 'cnf' parameter contains an		COSE_Encrypted In this case the 'cnf' parameter contains an
	encrypted symmetriic key destined for the client. The client is		encrypted symmetric key destined for the client. The client is
	assumed to be able to decrypt the cihpertext of this parameter.		assumed to be able to decrypt the cihpertext of this parameter.
	The parameter is encoded as COSE_Encrypted object wrapping a		The parameter is encoded as COSE_Encrypted object wrapping a
	COSE_Key object. Figure 9 shows an example of this type of		COSE_Key object. Figure 8 shows an example of this type of
	encoding.		encoding.
	"cnf" : {		"cnf" : {
	"COSE_Encrypted" : {		"COSE_Encrypted" : {
	993(		993(
	[ h'a1010a' # protected header : {"alg" : "AES-CCM-16-64-128"}		[ h'a1010a' # protected header : {"alg" : "AES-CCM-16-64-128"}
	"iv" : b64'ifUvZaHFgJM7UmGnjA', # unprotected header		"iv" : b64'ifUvZaHFgJM7UmGnjA', # unprotected header
	b64'WXThuZo6TMCaZZqi6ef/8WHTjOdGk8kNzaIhIQ' # ciphertext		b64'WXThuZo6TMCaZZqi6ef/8WHTjOdGk8kNzaIhIQ' # ciphertext
	]		]
	)		)
	}		}
	}		}
	Figure 9: Confirmation paramter containing an encrypted symmetric key		Figure 8: Confirmation paramter containing an encrypted symmetric key
	The ciphertext here could e.g. contain a symmetric key as in		The ciphertext here could e.g. contain a symmetric key as in
	Figure 10.		Figure 9.
	{		{
	"kty" : "Symmetric",		"kty" : "Symmetric",
	"kid" : b64'39Gqlw',		"kid" : b64'39Gqlw',
	"k" : b64'hJtXhkV8FJG+Onbc6mxCcQh'		"k" : b64'hJtXhkV8FJG+Onbc6mxCcQh'
	}		}
	Figure 10: Example plaintext of an encrypted cnf parameter		Figure 9: Example plaintext of an encrypted cnf parameter
	Key Identifier In this case the 'cnf' parameter references a key		Key Identifier In this case the 'cnf' parameter references a key
	that is assumed to be previously known by the recipient. This		that is assumed to be previously known by the recipient. This
	allows clients that perform repeated requests for an access token		allows clients that perform repeated requests for an access token
	for the same audience but e.g. with different scopes to omit key		for the same audience but e.g. with different scopes to omit key
	transport in the access token, token request and token response.		transport in the access token, token request and token response.
	Figure 11 shows such an example.		Figure 10 shows such an example.
	"cnf" : {		"cnf" : {
	"kid" : b64'39Gqlw'		"kid" : b64'39Gqlw'
	}		}
	Figure 11: A Confirmation parameter with just a key identifier		Figure 10: A Confirmation parameter with just a key identifier
	6.5. Mapping parameters to CBOR		6.5. Mapping parameters to CBOR
	All OAuth parameters in access token requests and responses are		All OAuth parameters in access token requests and responses are
	mapped to CBOR types as follows and are given an integer key value to		mapped to CBOR types as follows and are given an integer key value to
	save space.		save space.
	/-------------------+----------+-----------------\		/-------------------+----------+-----------------\
	| Parameter name | CBOR Key | Major Type |		| Parameter name | CBOR Key | Major Type |
	|-------------------+----------+-----------------|		|-------------------+----------+-----------------|
	| client_id | 1 | 3 (text string) |		| aud | 3 | 3 |
	| client_secret | 2 | 2 (byte string) |		| client_id | 8 | 3 (text string) |
	| response_type | 3 | 3 |		| client_secret | 9 | 2 (byte string) |
	| redirect_uri | 4 | 3 |		| response_type | 10 | 3 |
	| scope | 5 | 3 |		| redirect_uri | 11 | 3 |
	| state | 6 | 3 |		| scope | 12 | 3 |
	| code | 7 | 2 |		| state | 13 | 3 |
	| error_description | 8 | 3 |		| code | 14 | 2 |
	| error_uri | 9 | 3 |		| error_description | 15 | 3 |
	| grant_type | 10 | 0 (unit) |		| error_uri | 16 | 3 |
	| access_token | 11 | 3 |		| grant_type | 17 | 0 (unit) |
	| token_type | 12 | 0 |		| access_token | 18 | 3 |
	| expires_in | 13 | 0 |		| token_type | 19 | 0 |
	| username | 14 | 3 |		| expires_in | 20 | 0 |
	| password | 15 | 3 |		| username | 21 | 3 |
	| refresh_token | 16 | 3 |		| password | 22 | 3 |
	| alg | 17 | 3 |		| refresh_token | 23 | 3 |
	| cnf | 18 | 5 (map) |		| cnf | 24 | 5 (map) |
	| aud | 19 | 3 |		| profile | 25 | 3 |
	| profile | 20 | 0 |		\-------------------+----------+-----------------/
	\---------------+--------------+-----------------/
	Figure 12: CBOR mappings used in token requests		Figure 11: CBOR mappings used in token requests
	7. The 'Introspect' Resource		7. The 'Introspect' Endpoint
	Token introspection [RFC7662] is used by the RS and potentially the		Token introspection [RFC7662] is used by the RS and potentially the
	client to query the AS for metadata about a given token e.g. validity		client to query the AS for metadata about a given token e.g. validity
	or scope. Analogous to the protocol defined in RFC 7662 [RFC7662]		or scope. Analogous to the protocol defined in RFC 7662 [RFC7662]
	for HTTP and JSON, this section defines adaptations to more		for HTTP and JSON, this section defines adaptations to more
	constrained environments using CoAP and CBOR.		constrained environments using CoAP and CBOR.
	Communication between the RS and the introspection resource at the AS		Communication between the RS and the introspection endpoint at the AS
	MUST be integrity protected and encrypted. Furthermore AS and RS		MUST be integrity protected and encrypted. Furthermore AS and RS
	MUST perform mutual authentication. Finally the AS SHOULD to verify		MUST perform mutual authentication. Finally the AS SHOULD verify
	that the RS has the right to access introspection information about		that the RS has the right to access introspection information about
	the provided token. Profiles of this framework are expected to		the provided token. Profiles of this framework are expected to
	specify how authentication and communication security is implemented.		specify how authentication and communication security is implemented.
	The figures of this section uses CBOR diagnostic notation without the		The figures of this section uses CBOR diagnostic notation without the
	integer abbreviations for the parameters or their values for better		integer abbreviations for the parameters or their values for better
	readability.		readability.
	7.1. RS-to-AS Request		7.1. RS-to-AS Request
	The RS sends a CoAP POST request to the introspection resource at the		The RS sends a CoAP POST request to the introspection endpoint at the
	AS, with payload sent as "application/cbor" data. The payload is a		AS, the profile is expected to specify the Content-Type and wrapping
	CBOR map with a 'token' parameter containing the access token along		of the payload. The payload MUST be encoded as a CBOR map with a
	with optional parameters representing additional context that is		'token' parameter containing the access token along with optional
	known by the RS to aid the AS in its response.		parameters representing additional context that is known by the RS to
			aid the AS in its response.
	The same parameters are required and optional as in section 2.1 of		The same parameters are required and optional as in section 2.1 of
	RFC 7662 [RFC7662].		RFC 7662 [RFC7662].
	For example, Figure 13 shows a RS calling the token introspection		For example, Figure 12 shows a RS calling the token introspection
	resource at the AS to query about an OAuth 2.0 proof-of-possession		endpoint at the AS to query about an OAuth 2.0 proof-of-possession
	token.		token. Note that we assume a object security-based communication
			security profile for this example, therefore the Content-Type is
			"application/cose+cbor".
	Header: POST (Code=0.02)		Header: POST (Code=0.02)
	Uri-Host: "server.example.com"		Uri-Host: "server.example.com"
	Uri-Path: "introspect"		Uri-Path: "introspect"
	Content-Type: "application/cbor"		Content-Type: "application/cose+cbor"
	Payload:		Payload:
	{		{
	"token" : b64'7gj0dXJQ43U',		"token" : b64'7gj0dXJQ43U',
	"token_type_hint" : "pop"		"token_type_hint" : "pop"
	}		}
	Figure 13: Example introspection request.		Figure 12: Example introspection request.
	7.2. AS-to-RS Response		7.2. AS-to-RS Response
	The AS responds with a CBOR object in "application/cbor" format with		If the introspection request is authorized and successfully
	the same required and optional parameters as in section 2.2. of RFC		processed, the AS sends a response with the CoAP response code 2.01
	7662 [RFC7662] with the following additions:		(Created). If the introspection request was invalid, not authorized
			or couldn't be processed the AS returns an error response as
			described in Section 7.3.
	alg		In a successful response, the AS encodes the response parameters in a
	OPTIONAL. See Section 6.4 for more details.		CBOR map including with the same required and optional parameters as
			in section 2.2. of RFC 7662 [RFC7662] with the following additions:
	cnf		cnf
	OPTIONAL. This field contains information about the proof-of-		OPTIONAL. This field contains information about the proof-of-
	possession key that binds the client to the access token. See		possession key that binds the client to the access token. See
	Section 6.4 for more details on the formatting of the 'cnf'		Section 6.4.5 for more details on the formatting of the 'cnf'
	parameter.		parameter.
	profile		profile
	OPTIONAL. This indicates the profile that the RS MUST use with		OPTIONAL. This indicates the profile that the RS MUST use with
	the client. See Section 6.4 for more details on the formatting of		the client. See Section 6.4.4 for more details on the formatting
	this parameter.		of this parameter.
	client_token		client_token
	OPTIONAL. This parameter contains information that the RS MUST		OPTIONAL. This parameter contains information that the RS MUST
	pass on to the client. See Section 7.4 for more details.		pass on to the client. See Section 7.4 for more details.
	For example, Figure 14 shows an AS response to the introspection		For example, Figure 13 shows an AS response to the introspection
	request in Figure 13.		request in Figure 12. Note that we assume a DTLS-based communication
			security profile for this example, therefore the Content-Type is
			"application/cbor".
	Header: Created Code=2.01)		Header: Created Code=2.01)
	Content-Type: "application/cbor"		Content-Type: "application/cbor"
	Payload:		Payload:
	{		{
	"active" : true,		"active" : true,
	"scope" : "read",		"scope" : "read",
	"token_type" : "pop",
	"alg" : "HS256",
	"profile" : "coap_dtls",		"profile" : "coap_dtls",
	"client_token" : b64'2QPhg0OhAQo ...		"client_token" : b64'2QPhg0OhAQo ...
	(remainder of client token omitted for brevity)',		(remainder of client token omitted for brevity)',
	"cnf" : {		"cnf" : {
	"COSE_Key" : {		"COSE_Key" : {
	"kty" : "Symmetric",		"kty" : "Symmetric",
	"kid" : b64'39Gqlw',		"kid" : b64'39Gqlw',
	"k" : b64'hJtXhkV8FJG+Onbc6mxCcQh'		"k" : b64'hJtXhkV8FJG+Onbc6mxCcQh'
	}		}
	}		}
	}		}
	Figure 14: Example introspection response.		Figure 13: Example introspection response.
	7.3. Error Response		7.3. Error Response
	The error responses for CoAP-based interactions with the AS are		The error responses for CoAP-based interactions with the AS are
	equivalent to the ones for HTTP-based interactions as defined in		equivalent to the ones for HTTP-based interactions as defined in
	section 2.3 of [RFC7662], with the following differences:		section 2.3 of [RFC7662], with the following differences:
	o If content is sent, the Content-Type MUST be set to "application/		o If content is sent, the Content-Type MUST be set according to the
	cbor", and the payload MUST be encoded in a CBOR map.		specification of the communication security profile, and the
			content payload MUST be encoded as a CBOR map.
	o If the credentials used by the RS are invalid the AS MUST respond		o If the credentials used by the RS are invalid the AS MUST respond
	with the CoAP response code code 4.01 (Unauthorized) and use the		with the CoAP response code 4.01 (Unauthorized) and use the
	required and optional parameters from section 5.2 in RFC 6749		required and optional parameters from section 5.2 in RFC 6749
	[RFC6749].		[RFC6749].
	o If the RS does not have the right to perform this introspection		o If the RS does not have the right to perform this introspection
	request, the AS MUST respond with the CoAP response code 4.03		request, the AS MUST respond with the CoAP response code 4.03
	(Forbidden). In this case no payload is returned.		(Forbidden). In this case no payload is returned.
	Note that a properly formed and authorized query for an inactive or		Note that a properly formed and authorized query for an inactive or
	otherwise invalid token does not warrant an error response by this		otherwise invalid token does not warrant an error response by this
	specification. In these cases, the authorization server MUST instead		specification. In these cases, the authorization server MUST instead
	respond with an introspection response with the "active" field set to		respond with an introspection response with the "active" field set to
	"false".		"false".
	skipping to change at page 25, line 23 ¶		skipping to change at page 25, line 27 ¶
	EDITORIAL NOTE: We have tentatively introduced this concept and would		EDITORIAL NOTE: We have tentatively introduced this concept and would
	specifically like feedback if this is viewed as a useful addition to		specifically like feedback if this is viewed as a useful addition to
	the framework.		the framework.
	In cases where the client has limited connectivity and is requesting		In cases where the client has limited connectivity and is requesting
	access to a previously unknown resource servers, using a long term		access to a previously unknown resource servers, using a long term
	token, there are situations where it would be beneficial to relay the		token, there are situations where it would be beneficial to relay the
	proof-of-possession key and other relevant information from the AS to		proof-of-possession key and other relevant information from the AS to
	the client through the RS. The client_token parameter is designed to		the client through the RS. The client_token parameter is designed to
	carry such information, and is intended to be used as described in		carry such information, and is intended to be used as described in
	Figure 15.		Figure 14.
	Resource Authorization		Resource Authorization
	Client Server Server		Client Server Server
	| | |		| | |
	| | |		| | |
	A: +--------------->| |		C: +--------------->| |
	| POST | |		| POST | |
	| Access Token | |		| Access Token | |
	| B: +--------------->|		| D: +--------------->|
	| | Introspection |		| | Introspection |
	| | Request |		| | Request |
	| | |		| | |
	| C: +<---------------+		| E: +<---------------+
	| | Introspection |		| | Introspection |
	| | Response |		| | Response |
	| | + Client Token |		| | + Client Token |
	D: |<---------------+ |		|<---------------+ |
	| 2.01 Created | |		| 2.01 Created | |
	| + Client Token |		| + Client Token |
	Figure 15: Use of the client_token parameter.		Figure 14: Use of the client_token parameter.
	The client token is a COSE_Encrytped object, containing as payload a		The client token is a COSE_Encrytped object, containing as payload a
	CBOR map with the following claims:		CBOR map with the following claims:
	cnf		cnf
	REQUIRED. Contains information about the proof-of-possession key		REQUIRED if the token type is 'pop', OPTIONAL otherwise. Contains
	the client is to use with its access token. See Section 6.4.4.		information about the proof-of-possession key the client is to use
			with its access token. See Section 6.4.5.
	token_type		token_type
	OPTIONAL. See Section 6.4.2.		OPTIONAL. See Section 6.4.3.
	alg
	OPTIONAL. See Section 6.4.2.
	profile		profile
	REQUIRED. See Section 6.4.3.		REQUIRED. See Section 6.4.4.
	rs_cnf		rs_cnf
	OPTIONAL. Contains information about the key that the RS uses to		OPTIONAL. Contains information about the key that the RS uses to
	authenticate towards the client. If the key is symmetric then		authenticate towards the client. If the key is symmetric then
	this claim MUST NOT be part of the Client Token, since this is the		this claim MUST NOT be part of the Client Token, since this is the
	same key as the one specified through the 'cnf' claim. This claim		same key as the one specified through the 'cnf' claim. This claim
	uses the same encoding as the 'cnf' parameter. See Section 6.4.3.		uses the same encoding as the 'cnf' parameter. See Section 6.4.4.
	The AS encrypts this token using a key shared between the AS and the		The AS encrypts this token using a key shared between the AS and the
	client, so that only the client can decrypt it and access its		client, so that only the client can decrypt it and access its
	payload. How this key is established is out of scope of this		payload. How this key is established is out of scope of this
	framework.		framework.
	7.5. Mapping Introspection parameters to CBOR		7.5. Mapping Introspection parameters to CBOR
	The introspection request and response parameters are mapped to CBOR		The introspection request and response parameters are mapped to CBOR
	types as follows and are given an integer key value to save space.		types as follows and are given an integer key value to save space.
	/----------------+----------+-----------------\		/-----------------+----------+-----------------\
	| Parameter name | CBOR Key | Major Type |		| Parameter name | CBOR Key | Major Type |
	|----------------+----------+-----------------|		|-----------------+----------+-----------------|
	| active | 1 | 0 (uint) |		| iss | 1 | 3 (text string) |
	| username | 2 | 3 (text string) |		| sub | 2 | 3 |
	| client_id | 3 | 3 |		| aud | 3 | 3 |
	| scope | 4 | 3 |		| exp | 4 | 6 tag value 1 |
	| token_type | 5 | 3 |		| nbf | 5 | 6 tag value 1 |
	| exp | 6 | 6 tag value 1 |		| iat | 6 | 6 tag value 1 |
	| iat | 7 | 6 tag value 1 |		| cti | 7 | 2 (byte string) |
	| nbf | 8 | 6 tag value 1 |		| client_id | 8 | 3 |
	| sub | 9 | 3 |		| scope | 12 | 3 |
	| aud | 10 | 3 |		| token_type | 19 | 3 |
	| iss | 11 | 3 |		| username | 21 | 3 |
	| jti | 12 | 3 |		| cnf | 24 | 5 (map) |
	| alg | 13 | 3 |		| profile | 25 | 0 (uint) |
	| cnf | 14 | 5 (map) |		| token | 26 | 3 |
	| aud | 15 | 3 |		| token_type_hint | 27 | 3 |
	| client_token | 16 | 3 |		| active | 28 | 0 |
	| rs_cnf | 17 | 5 |		| client_token | 29 | 3 |
	\----------------+----------+-----------------/		| rs_cnf | 30 | 5 |
			\-----------------+----------+-----------------/
	Figure 16: CBOR Mappings to Token Introspection Parameters.		Figure 15: CBOR Mappings to Token Introspection Parameters.
	8. The Access Token		8. The Access Token
	This framework RECOMMENDS the use of CBOR web token (CWT) as		This framework RECOMMENDS the use of CBOR web token (CWT) as
	specified in [I-D.ietf-ace-cbor-web-token].		specified in [I-D.ietf-ace-cbor-web-token].
	In order to facilitate offline processing of access tokens, this		In order to facilitate offline processing of access tokens, this
	draft specfifies the "scope" claim for access tokens that explicitly		draft specifies the "cnf" and "scope" claims for CBOR web tokens.
	encodes the scope of a given access token. This claim follows the
	same encoding rules as defined in section 3.3 of [RFC6749]. The
	meaning of a specific scope value is application specific and
	expected to be known to the RS running that application.
	8.1. The 'Authorization Information' Resource		The "scope" claim explicitly encodes the scope of a given access
			token. This claim follows the same encoding rules as defined in
			section 3.3 of [RFC6749]. The meaning of a specific scope value is
			application specific and expected to be known to the RS running that
			application.
			The "cnf" claim follows the same rules as specified for JSON web
			token in RFC7800 [RFC7800], except that it is encoded in CBOR in the
			same way as specified for the "cnf" parameter in section
			Section 6.4.5.
			8.1. The 'Authorization Information' Endpoint
	The access token, containing authorization information and		The access token, containing authorization information and
	information of the key used by the client, is transported to the RS		information of the key used by the client, needs to be transported to
	so that the RS can authenticate and authorize the client request.		the RS so that the RS can authenticate and authorize the client
			request.
	This section defines a method for transporting the access token to		This section defines a method for transporting the access token to
	the RS using CoAP that MAY be used. An ACE profile MAY define other		the RS using CoAP. Profiles of this framework MAY define other
	methods for token transport.		methods for token transport. Implementations conforming to this
			framework MUST implement this method of token transportation.
	This method REQUIRES the RS to implement an /authz-info resource. A		The method consists of a /authz-info endpoint, implemented by the RS.
	client using this method MUST make a POST request to /authz-info on		A client using this method MUST make a POST request to /authz-info at
	the RS with the access token in the payload. The RS receiving the		the RS with the access token in the payload. The RS receiving the
	token MUST verify the validity of the token. If the token is valid,		token MUST verify the validity of the token. If the token is valid,
	the RS MUST respond to the POST request with 2.04 (Changed).		the RS MUST respond to the POST request with 2.04 (Changed).
	If the token is not valid, the RS MUST respond with error code 4.01		If the token is not valid, the RS MUST respond with the CoAP response
	(Unauthorized). If the token is valid but the audience of the token		code 4.01 (Unauthorized). If the token is valid but the audience of
	does not match the RS, the RS MUST respond with error code 4.03		the token does not match the RS, the RS MUST respond with the CoAP
	(Forbidden).		response code 4.03 (Forbidden).
	The RS MAY make an introspection request to validate the token before		The RS MAY make an introspection request to validate the token before
	responding to the POST /authz-info request. If the introspection		responding to the POST /authz-info request. If the introspection
	response contains a client token (Section 7.4) then this token SHALL		response contains a client token (Section 7.4) then this token SHALL
	be included in the payload of the 2.04 (Changed) response.		be included in the payload of the 2.04 (Changed) response.
			Profiles are expected to specify how the /authz-info endpoint is
			protected. Note that since the token contains information that allow
			the client and the RS to establish a security context in the first
			place, mutual authentication may not be possible at this point.
	8.2. Token Expiration		8.2. Token Expiration
	Depending on the capabilities of the RS, there are various ways in		Depending on the capabilities of the RS, there are various ways in
	which it can verify the validity of a received access token. We list		which it can verify the validity of a received access token. We list
	the possibilities here including what functionality they require of		the possibilities here including what functionality they require of
	the RS.		the RS.
	o The token is a CWT/JWT and includes a 'exp' claim and possibly the		o The token is a CWT/JWT and includes a 'exp' claim and possibly the
	'nbf' claim. The RS verifies these by comparing them to values		'nbf' claim. The RS verifies these by comparing them to values
	from its internal clock as defined in [RFC7519]. In this case the		from its internal clock as defined in [RFC7519]. In this case the
	RS must have a real time chip (RTC) or some other way of reliably		RS's internal clock must reflect the current date and time, or at
	measuring time.		least be synchronized with the AS's clock. How this clock
			synchronization would be performed is out of scope for this memo.
	o The RS verifies the validity of the token by performing an		o The RS verifies the validity of the token by performing an
	introspection request as specified in Section 7. This requires		introspection request as specified in Section 7. This requires
	the RS to have a reliable network connection to the AS and to be		the RS to have a reliable network connection to the AS and to be
	able to handle two secure sessions in parallel (C to RS and AS to		able to handle two secure sessions in parallel (C to RS and AS to
	RS).		RS).
	o The RS and the AS both store a sequence number linked to their		o The RS and the AS both store a sequence number linked to their
	common security association. The AS increments this number for		common security association. The AS increments this number for
	each access token it issues and includes it in the access token,		each access token it issues and includes it in the access token,
	which is a CWT/JWT. The RS keeps track of the most recently		which is a CWT/JWT. The RS keeps track of the most recently
	received sequence number, and only accepts tokens as valid, that		received sequence number, and only accepts tokens as valid, that
	skipping to change at page 29, line 6 ¶		skipping to change at page 29, line 27 ¶
	means of reliably measuring time, this is the best that can be		means of reliably measuring time, this is the best that can be
	achieved.		achieved.
	9. Security Considerations		9. Security Considerations
	The entire document is about security. Security considerations		The entire document is about security. Security considerations
	applicable to authentication and authorization in RESTful		applicable to authentication and authorization in RESTful
	environments provided in OAuth 2.0 [RFC6749] apply to this work, as		environments provided in OAuth 2.0 [RFC6749] apply to this work, as
	well as the security considerations from [I-D.ietf-ace-actors].		well as the security considerations from [I-D.ietf-ace-actors].
	Furthermore [RFC6819] provides additional security considerations for		Furthermore [RFC6819] provides additional security considerations for
	OAuth which apply to IoT deployments as well. Finally		OAuth which apply to IoT deployments as well.
	[I-D.ietf-oauth-pop-architecture] discusses security and privacy
	threats as well as mitigation measures for Proof-of-Possession		A large range of threats can be mitigated by protecting the contents
	tokens.		of the access token by using a digital signature or a keyed message
			digest. Consequently, the token integrity protection MUST be applied
			to prevent the token from being modified, particularly since it
			contains a reference to the symmetric key or the asymmetric key. If
			the access token contains the symmetric key, this symmetric key MUST
			be encrypted by the authorization server with a long-term key shared
			with the resource server.
			It is important for the authorization server to include the identity
			of the intended recipient (the audience), typically a single resource
			server (or a list of resource servers), in the token. Using a single
			shared secret with multiple authorization server to simplify key
			management is NOT RECOMMENDED since the benefit from using the proof-
			of-possession concept is significantly reduced.
			Token replay is also not possible since an eavesdropper will also
			have to obtain the corresponding private key or shared secret that is
			bound to the access token. Nevertheless, it is good practice to
			limit the lifetime of the access token and therefore the lifetime of
			associated key.
			The authorization server MUST offer confidentiality protection for
			any interactions with the client. This step is extremely important
			since the client will obtain the session key from the authorization
			server for use with a specific access token. Not using
			confidentiality protection exposes this secret (and the access token)
			to an eavesdropper thereby making the proof-of-possession security
			model completely insecure. This framework relies on profiles to
			define how confidentiality protection is provided, and additional
			protection can be applied by encrypting the CWT as specified in
			section 5.1 of [I-D.ietf-ace-cbor-web-token] to provide an additional
			layer of protection for cases where keying material is conveyed, for
			example, to a hardware security module.
			Developers MUST ensure that the ephemeral credentials (i.e., the
			private key or the session key) is not leaked to third parties. An
			adversary in possession of the ephemeral credentials bound to the
			access token will be able to impersonate the client. Be aware that
			this is a real risk with many constrained environments, since
			adversaries can often easily get physical access to the devices.
			Clients can at any time request a new proof-of-possession capable
			access token. Using a refresh token to regularly request new access
			tokens that are bound to fresh and unique keys is important if the
			client has this capability. Keeping the lifetime of the access token
			short allows the authorization server to use shorter key sizes, which
			translate to a performance benefit for the client and for the
			resource server. Shorter keys also lead to shorter messages
			(particularly with asymmetric keying material).
			When authorization servers bind symmetric keys to access tokens then
			they SHOULD scope these access tokens to a specific permissions.
	10. IANA Considerations		10. IANA Considerations
	This specification registers new parameters for OAuth and establishes		This specification registers new parameters for OAuth and establishes
	registries for mappings to CBOR.		registries for mappings to CBOR.
	10.1. OAuth Introspection Response Parameter Registration		10.1. OAuth Introspection Response Parameter Registration
	This specification registers the following parameters in the OAuth		This specification registers the following parameters in the OAuth
	introspection response parameters		introspection response parameters
	o Name: "alg"
	o Description: Algorithm to use with PoP key, as defined in PoP
	token specification,
	o Change Controller: IESG
	o Specification Document(s): this document
	o Name: "cnf"		o Name: "cnf"
	o Description: Key to use to prove the right to use an access token,		o Description: Key to use to prove the right to use an access token,
	as defined in [RFC7800].		as defined in [RFC7800].
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Name: "aud"		o Name: "aud"
	o Description: reference to intended receiving RS, as defined in PoP		o Description: reference to intended receiving RS, as defined in PoP
	token specification.		token specification.
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Name: "profile"		o Name: "profile"
	o Description: The communication and communication security profile		o Description: The communication and communication security profile
	used between client and RS, as defined in ACE profiles.		used between client and RS, as defined in ACE profiles.
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Name: "client_token"		o Name: "client_token"
	o Description: Information that the RS MUST pass to the client e.g.		o Description: Information that the RS MUST pass to the client e.g.
	about the proof-of-possession keys.		about the proof-of-possession keys.
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
			o Name: "rs_cnf"
			o Description: Describes the public key the RS uses to authenticate.
			o Change Controller: IESG
			o Specification Document(s): this document
	10.2. OAuth Parameter Registration		10.2. OAuth Parameter Registration
	This specification registers the following parameters in the OAuth		This specification registers the following parameters in the OAuth
	Parameters Registry		Parameters Registry
	o Name: "alg"
	o Description: Algorithm to use with PoP key, as defined in PoP
	token specification,
	o Change Controller: IESG
	o Specification Document(s): this document
	o Parameter name: "profile"		o Parameter name: "profile"
	o Parameter usage location: token request, and token response		o Parameter usage location: token request, and token response
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Name: "cnf"		o Name: "cnf"
	o Description: Key to use to prove the right to use an access token,		o Description: Key to use to prove the right to use an access token,
	as defined in [RFC7800].		as defined in [RFC7800].
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	skipping to change at page 31, line 26 ¶		skipping to change at page 32, line 40 ¶
	o Parameter name: "Bearer"		o Parameter name: "Bearer"
	o Mapped value: 1		o Mapped value: 1
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "pop"		o Parameter name: "pop"
	o Mapped value: 2		o Mapped value: 2
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	10.5. JSON Web Token Claims		10.5. CBOR Web Token Claims
	This specification registers the following new claim in the JSON Web		This specification registers the following new claims in the CBOR Web
	Token (JWT) registry.		Token (CWT) registry:
	o Claim Name: "scope"		o Claim Name: "scope"
	o Claim Description: The scope of an access token as defined in		o Claim Description: The scope of an access token as defined in
	[RFC6749].		[RFC6749].
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
			o Claim Name: "cnf"
			o Claim Description: The proof-of-possession key of an access token
			as defined in [RFC7800].
			o Change Controller: IESG
			o Specification Document(s): this document
	10.6. ACE Profile Registry		10.6. ACE Profile Registry
	A new registry will be requested from IANA, entitled "ACE Profile		A new registry will be requested from IANA, entitled "ACE Profile
	Registry". The registry is to be created as Expert Review Required.		Registry". The registry is to be created as Expert Review Required.
	10.6.1. Registration Template		10.6.1. Registration Template
	Profile name:		Profile name:
	Name of the profile to be included in the profile attribute.		Name of the profile to be included in the profile attribute.
	Profile description:		Profile description:
	skipping to change at page 32, line 4 ¶		skipping to change at page 33, line 25 ¶
	Profile name:		Profile name:
	Name of the profile to be included in the profile attribute.		Name of the profile to be included in the profile attribute.
	Profile description:		Profile description:
	Text giving an over view of the profile and the context it is		Text giving an over view of the profile and the context it is
	developed for.		developed for.
	Profile ID:		Profile ID:
	Integer value to identify the profile. The value MUST be an		Integer value to identify the profile. The value MUST be an
	integer in the range of 1 to 65536.		integer in the range of 1 to 65536.
	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):
	Reference to the document or documents that specify the		Reference to the document or documents that specify the
	parameter,preferably including URIs that can be used to retrieve		parameter,preferably including URIs that can be used to retrieve
	copies of the documents. An indication of the relevant sections		copies of the documents. An indication of the relevant sections
	may also be included but is not required.		may also be included but is not required.
	10.7. OAuth Parameter Mappings Registry		10.7. OAuth Parameter Mappings Registry
	A new registry will be requested from IANA, entitled "Token Resource		A new registry will be requested from IANA, entitled "Token Endpoint
	CBOR Mappings Registry". The registry is to be created as Expert		CBOR Mappings Registry". The registry is to be created as Expert
	Review Required.		Review Required.
	10.7.1. Registration Template		10.7.1. Registration Template
	Parameter name:		Parameter name:
	OAuth Parameter name, refers to the name in the OAuth parameter		OAuth Parameter name, refers to the name in the OAuth parameter
	registry e.g. "client_id".		registry e.g. "client_id".
	CBOR key value:		CBOR key value:
	Key value for the claim. The key value MUST be an integer in the		Key value for the claim. The key value MUST be an integer in the
	skipping to change at page 32, line 32 ¶		skipping to change at page 34, line 4 ¶
	Parameter name:		Parameter name:
	OAuth Parameter name, refers to the name in the OAuth parameter		OAuth Parameter name, refers to the name in the OAuth parameter
	registry e.g. "client_id".		registry e.g. "client_id".
	CBOR key value:		CBOR key value:
	Key value for the claim. The key value MUST be an integer in the		Key value for the claim. The key value MUST be an integer in the
	range of 1 to 65536.		range of 1 to 65536.
	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):
	Reference to the document or documents that specify the		Reference to the document or documents that specify the
	parameter,preferably including URIs that can be used to retrieve		parameter,preferably including URIs that can be used to retrieve
	copies of the documents. An indication of the relevant sections		copies of the documents. An indication of the relevant sections
	may also be included but is not required.		may also be included but is not required.
	10.7.2. Initial Registry Contents		10.7.2. Initial Registry Contents
			o Parameter name: "aud"
			o CBOR key value: 3
			o Change Controller: IESG
			o Specification Document(s): this document
	o Parameter name: "client_id"		o Parameter name: "client_id"
	o CBOR key value: 1		o CBOR key value: 8
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "client_secret"		o Parameter name: "client_secret"
	o CBOR key value: 2		o CBOR key value: 9
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "response_type"		o Parameter name: "response_type"
	o CBOR key value: 3		o CBOR key value: 10
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "redirect_uri"		o Parameter name: "redirect_uri"
	o CBOR key value: 4		o CBOR key value: 11
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "scope"		o Parameter name: "scope"
	o CBOR key value: 5		o CBOR key value: 12
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "state"		o Parameter name: "state"
	o CBOR key value: 6		o CBOR key value: 13
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "code"		o Parameter name: "code"
	o CBOR key value: 7		o CBOR key value: 14
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "error_description"		o Parameter name: "error_description"
	o CBOR key value: 8		o CBOR key value: 15
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "error_uri"		o Parameter name: "error_uri"
	o CBOR key value: 9		o CBOR key value: 16
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "grant_type"		o Parameter name: "grant_type"
	o CBOR key value: 10		o CBOR key value: 17
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "access_token"		o Parameter name: "access_token"
	o CBOR key value: 11		o CBOR key value: 18
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "token_type"		o Parameter name: "token_type"
	o CBOR key value: 12		o CBOR key value: 19
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "expires_in"		o Parameter name: "expires_in"
	o CBOR key value: 13		o CBOR key value: 20
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "username"		o Parameter name: "username"
	o CBOR key value: 14		o CBOR key value: 21
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "password"		o Parameter name: "password"
	o CBOR key value: 15		o CBOR key value: 22
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "refresh_token"		o Parameter name: "refresh_token"
	o CBOR key value: 16		o CBOR key value: 23
	o Change Controller: IESG
	o Specification Document(s): this document
	o Parameter name: "alg"
	o CBOR key value: 17
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "cnf"		o Parameter name: "cnf"
	o CBOR key value: 18		o CBOR key value: 24
	o Change Controller: IESG
	o Specification Document(s): this document
	o Parameter name: "aud"
	o CBOR key value: 19
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "profile"		o Parameter name: "profile"
	o CBOR key value: 20		o CBOR key value: 25
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	10.8. Introspection Resource CBOR Mappings Registry		10.8. Introspection Endpoint CBOR Mappings Registry
	A new registry will be requested from IANA, entitled "Introspection		A new registry will be requested from IANA, entitled "Introspection
	Resource CBOR Mappings Registry". The registry is to be created as		Endpoint CBOR Mappings Registry". The registry is to be created as
	Expert Review Required.		Expert Review Required.
	10.8.1. Registration Template		10.8.1. Registration Template
	Response parameter name:		Response parameter name:
	Name of the response parameter as defined in the "OAuth Token		Name of the response parameter as defined in the "OAuth Token
	Introspection Response" registry e.g. "active".		Introspection Response" registry e.g. "active".
	CBOR key value:		CBOR key value:
	Key value for the claim. The key value MUST be an integer in the		Key value for the claim. The key value MUST be an integer in the
	range of 1 to 65536.		range of 1 to 65536.
	skipping to change at page 35, line 25 ¶		skipping to change at page 36, line 37 ¶
	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):
	Reference to the document or documents that specify the		Reference to the document or documents that specify the
	parameter,preferably including URIs that can be used to retrieve		parameter,preferably including URIs that can be used to retrieve
	copies of the documents. An indication of the relevant sections		copies of the documents. An indication of the relevant sections
	may also be included but is not required.		may also be included but is not required.
	10.8.2. Initial Registry Contents		10.8.2. Initial Registry Contents
	o Response parameter name: "active"		o Response parameter name: "iss"
	o CBOR key value: 1		o CBOR key value: 1
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Response parameter name: "username"		o Response parameter name: "sub"
	o CBOR key value: 2		o CBOR key value: 2
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Response parameter name: "client_id"		o Response parameter name: "aud"
	o CBOR key value: 3		o CBOR key value: 3
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
			o Response parameter name: "exp"
	o Response parameter name: "scope"
	o CBOR key value: 4		o CBOR key value: 4
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Response parameter name: "token_type"		o Response parameter name: "nbf"
	o CBOR key value: 5		o CBOR key value: 5
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Response parameter name: "exp"		o Response parameter name: "iat"
	o CBOR key value: 6		o CBOR key value: 6
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Response parameter name: "iat"		o Response parameter name: "cti"
	o CBOR key value: 7		o CBOR key value: 7
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Response parameter name: "nbf"		o Response parameter name: "client_id"
	o CBOR key value: 8		o CBOR key value: 8
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Response parameter name: "sub"		o Response parameter name: "scope"
	o CBOR key value: 9		o CBOR key value: 12
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Response parameter name: "aud"		o Response parameter name: "token_type"
	o CBOR key value: 10		o CBOR key value: 19
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Response parameter name: "iss"		o Response parameter name: "username"
	o CBOR key value: 11		o CBOR key value: 21
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Response parameter name: "jti"		o Parameter name: "cnf"
	o CBOR key value: 12		o CBOR key value: 24
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "alg"		o Parameter name: "profile"
	o CBOR key value: 13		o CBOR key value: 25
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "cnf"		o Response parameter name: "token"
	o CBOR key value: 14		o CBOR key value: 26
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	o Parameter name: "aud"		o Response parameter name: "token_type_hint"
	o CBOR key value: 15		o CBOR key value: 27
			o Change Controller: IESG
			o Specification Document(s): this document
			o Response parameter name: "active"
			o CBOR key value: 28
			o Change Controller: IESG
			o Specification Document(s): this document
			o Response parameter name: "client_token"
			o CBOR key value: 29
			o Change Controller: IESG
			o Specification Document(s): this document
			o Response parameter name: "rs_cnf"
			o CBOR key value: 30
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): this document		o Specification Document(s): this document
	10.9. CoAP Option Number Registration		10.9. CoAP Option Number Registration
	This section registers the "Access-Token" CoAP Option Number in the		This section registers the "Access-Token" CoAP Option Number in the
	"CoRE Parameters" sub-registry "CoAP Option Numbers" in the manner		"CoRE Parameters" sub-registry "CoAP Option Numbers" in the manner
	described in [RFC7252].		described in [RFC7252].
	Name		Name
	skipping to change at page 37, line 25 ¶		skipping to change at page 39, line 4 ¶
	TBD		TBD
	Reference		Reference
	[This document].		[This document].
	Meaning in Request		Meaning in Request
	Contains an Access Token according to [This document] containing		Contains an Access Token according to [This document] containing
	access permissions of the client.		access permissions of the client.
	Meaning in Response		Meaning in Response
	Not used in response		Not used in response
	Safe-to-Forward		Safe-to-Forward
	TBD		Yes
	Format		Format
	Based on the observer the format is perceived differently. Opaque		Based on the observer the format is perceived differently. Opaque
	data to the client and CWT or reference token to the RS.		data to the client and CWT or reference token to the RS.
	Length		Length
	Less then 255 bytes		Less then 255 bytes
	11. Acknowledgments		11. Acknowledgments
	We would like to thank Eve Maler for her contributions to the use of		We would like to thank Eve Maler for her contributions to the use of
	OAuth 2.0 and UMA in IoT scenarios, Robert Taylor for his discussion		OAuth 2.0 and UMA in IoT scenarios, Robert Taylor for his discussion
	input, and Malisa Vucinic for his input on the ACRE proposal		input, and Malisa Vucinic for his input on the ACRE proposal
	[I-D.seitz-ace-core-authz] which was one source of inspiration for		[I-D.seitz-ace-core-authz] which was one source of inspiration for
	this work. Finally, we would like to thank the ACE working group in		this work. Finally, we would like to thank the ACE working group in
	general for their feedback.		general for their feedback.
			We would like to thank the authors of draft-ietf-oauth-pop-key-
			distribution, from where we copied large parts of our security
			considerations.
	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 project CyberWI, with funding from Vinnova.		the CelticPlus project CyberWI, with funding from Vinnova.
	12. References		12. References
	12.1. Normative References		12.1. Normative References
	[I-D.ietf-ace-cbor-web-token]		[I-D.ietf-ace-cbor-web-token]
	Wahlstroem, E., Jones, M., and H. Tschofenig, "CBOR Web		Wahlstroem, E., Jones, M., Tschofenig, H., and S. Erdtman,
	Token (CWT)", draft-ietf-ace-cbor-web-token-00 (work in		"CBOR Web Token (CWT)", draft-ietf-ace-cbor-web-token-01
	progress), May 2016.		(work in progress), July 2016.
	[I-D.ietf-cose-msg]		[I-D.ietf-cose-msg]
	Schaad, J., "CBOR Encoded Message Syntax", draft-ietf-		Schaad, J., "CBOR Object Signing and Encryption (COSE)",
	cose-msg-12 (work in progress), May 2016.		draft-ietf-cose-msg-19 (work in progress), September 2016.
	[I-D.selander-ace-object-security]
	Selander, G., Mattsson, J., Palombini, F., and L. Seitz,
	"Object Security of CoAP (OSCOAP)", draft-selander-ace-
	object-security-04 (work in progress), March 2016.
	[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,
	<http://www.rfc-editor.org/info/rfc2119>.		<http://www.rfc-editor.org/info/rfc2119>.
	[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer		[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
	Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,		Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
	January 2012, <http://www.rfc-editor.org/info/rfc6347>.		January 2012, <http://www.rfc-editor.org/info/rfc6347>.
	skipping to change at page 38, line 51 ¶		skipping to change at page 40, line 28 ¶
	[RFC7800] Jones, M., Bradley, J., and H. Tschofenig, "Proof-of-		[RFC7800] Jones, M., Bradley, J., and H. Tschofenig, "Proof-of-
	Possession Key Semantics for JSON Web Tokens (JWTs)",		Possession Key Semantics for JSON Web Tokens (JWTs)",
	RFC 7800, DOI 10.17487/RFC7800, April 2016,		RFC 7800, DOI 10.17487/RFC7800, April 2016,
	<http://www.rfc-editor.org/info/rfc7800>.		<http://www.rfc-editor.org/info/rfc7800>.
	12.2. Informative References		12.2. Informative References
	[I-D.ietf-ace-actors]		[I-D.ietf-ace-actors]
	Gerdes, S., Seitz, L., Selander, G., and C. Bormann, "An		Gerdes, S., Seitz, L., Selander, G., and C. Bormann, "An
	architecture for authorization in constrained		architecture for authorization in constrained
	environments", draft-ietf-ace-actors-03 (work in		environments", draft-ietf-ace-actors-04 (work in
	progress), March 2016.		progress), September 2016.
	[I-D.ietf-core-block]		[I-D.ietf-oauth-device-flow]
	Bormann, C. and Z. Shelby, "Block-wise transfers in CoAP",		Denniss, W., Myrseth, S., Bradley, J., Jones, M., and H.
	draft-ietf-core-block-20 (work in progress), April 2016.		Tschofenig, "OAuth 2.0 Device Flow", draft-ietf-oauth-
			device-flow-03 (work in progress), July 2016.
	[I-D.ietf-oauth-pop-architecture]		[I-D.ietf-oauth-native-apps]
	Hunt, P., Richer, J., Mills, W., Mishra, P., and H.		Denniss, W. and J. Bradley, "OAuth 2.0 for Native Apps",
	Tschofenig, "OAuth 2.0 Proof-of-Possession (PoP) Security		draft-ietf-oauth-native-apps-03 (work in progress), July
	Architecture", draft-ietf-oauth-pop-architecture-07 (work		2016.
	in progress), December 2015.
	[I-D.seitz-ace-core-authz]		[I-D.seitz-ace-core-authz]
	Seitz, L., Selander, G., and M. Vucinic, "Authorization		Seitz, L., Selander, G., and M. Vucinic, "Authorization
	for Constrained RESTful Environments", draft-seitz-ace-		for Constrained RESTful Environments", draft-seitz-ace-
	core-authz-00 (work in progress), June 2015.		core-authz-00 (work in progress), June 2015.
			[I-D.selander-ace-object-security]
			Selander, G., Mattsson, J., Palombini, F., and L. Seitz,
			"Object Security of CoAP (OSCOAP)", draft-selander-ace-
			object-security-05 (work in progress), July 2016.
	[RFC4949] Shirey, R., "Internet Security Glossary, Version 2",		[RFC4949] Shirey, R., "Internet Security Glossary, Version 2",
	FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007,		FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007,
	<http://www.rfc-editor.org/info/rfc4949>.		<http://www.rfc-editor.org/info/rfc4949>.
	[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security		[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
	(TLS) Protocol Version 1.2", RFC 5246,		(TLS) Protocol Version 1.2", RFC 5246,
	DOI 10.17487/RFC5246, August 2008,		DOI 10.17487/RFC5246, August 2008,
	<http://www.rfc-editor.org/info/rfc5246>.		<http://www.rfc-editor.org/info/rfc5246>.
	[RFC6690] Shelby, Z., "Constrained RESTful Environments (CoRE) Link		[RFC6690] Shelby, Z., "Constrained RESTful Environments (CoRE) Link
	skipping to change at page 40, line 19 ¶		skipping to change at page 41, line 49 ¶
	[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer		[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
	Protocol (HTTP/1.1): Semantics and Content", RFC 7231,		Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
	DOI 10.17487/RFC7231, June 2014,		DOI 10.17487/RFC7231, June 2014,
	<http://www.rfc-editor.org/info/rfc7231>.		<http://www.rfc-editor.org/info/rfc7231>.
	[RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token		[RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
	(JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,		(JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
	<http://www.rfc-editor.org/info/rfc7519>.		<http://www.rfc-editor.org/info/rfc7519>.
			[RFC7521] Campbell, B., Mortimore, C., Jones, M., and Y. Goland,
			"Assertion Framework for OAuth 2.0 Client Authentication
			and Authorization Grants", RFC 7521, DOI 10.17487/RFC7521,
			May 2015, <http://www.rfc-editor.org/info/rfc7521>.
	[RFC7591] Richer, J., Ed., Jones, M., Bradley, J., Machulak, M., and		[RFC7591] Richer, J., Ed., Jones, M., Bradley, J., Machulak, M., and
	P. Hunt, "OAuth 2.0 Dynamic Client Registration Protocol",		P. Hunt, "OAuth 2.0 Dynamic Client Registration Protocol",
	RFC 7591, DOI 10.17487/RFC7591, July 2015,		RFC 7591, DOI 10.17487/RFC7591, July 2015,
	<http://www.rfc-editor.org/info/rfc7591>.		<http://www.rfc-editor.org/info/rfc7591>.
	[RFC7744] Seitz, L., Ed., Gerdes, S., Ed., Selander, G., Mani, M.,		[RFC7744] Seitz, L., Ed., Gerdes, S., Ed., Selander, G., Mani, M.,
	and S. Kumar, "Use Cases for Authentication and		and S. Kumar, "Use Cases for Authentication and
	Authorization in Constrained Environments", RFC 7744,		Authorization in Constrained Environments", RFC 7744,
	DOI 10.17487/RFC7744, January 2016,		DOI 10.17487/RFC7744, January 2016,
	<http://www.rfc-editor.org/info/rfc7744>.		<http://www.rfc-editor.org/info/rfc7744>.
			[RFC7959] Bormann, C. and Z. Shelby, Ed., "Block-Wise Transfers in
			the Constrained Application Protocol (CoAP)", RFC 7959,
			DOI 10.17487/RFC7959, August 2016,
			<http://www.rfc-editor.org/info/rfc7959>.
	Appendix A. Design Justification		Appendix A. Design Justification
	This section provides further insight into the design decisions of		This section provides further insight into the design decisions of
	the solution documented in this document. Section 3 lists several		the solution documented in this document. Section 3 lists several
	building blocks and briefly summarizes their importance. The		building blocks and briefly summarizes their importance. The
	justification for offering some of those building blocks, as opposed		justification for offering some of those building blocks, as opposed
	to using OAuth 2.0 as is, is given below.		to using OAuth 2.0 as is, is given below.
	Common IoT constraints are:		Common IoT constraints are:
	skipping to change at page 42, line 14 ¶		skipping to change at page 44, line 4 ¶
	security reasons, e.g. to avoid an entry point for Denial-of-		security reasons, e.g. to avoid an entry point for Denial-of-
	Service attacks.		Service attacks.
	The communication interactions this framework builds upon (as		The communication interactions this framework builds upon (as
	shown graphically in Figure 1) may be accomplished using a variety		shown graphically in Figure 1) may be accomplished using a variety
	of different protocols, and not all parts of the message flow are		of different protocols, and not all parts of the message flow are
	used in all applications due to the communication constraints.		used in all applications due to the communication constraints.
	While we envision deployments to make use of CoAP we explicitly		While we envision deployments to make use of CoAP we explicitly
	want to support HTTP, HTTP/2 or specific protocols, such as		want to support HTTP, HTTP/2 or specific protocols, such as
	Bluetooth Smart communication, which does not necessarily use IP.		Bluetooth Smart communication, which does not necessarily use IP.
	The latter raises the need for application layer security over the		The latter raises the need for application layer security over the
	various interfaces.		various interfaces.
	Appendix B. Roles and Responsibilites		Appendix B. Roles and Responsibilites
	Resource Owner		Resource Owner
	* Make sure that the RS is registered at the AS.		* Make sure that the RS is registered at the AS. This includes
			making known to the AS which profiles, token_types, scopes, and
			key types (symmetric/asymmetric) the RS supports. Also making
			it known to the AS which audience(s) the RS identifies itself
			with.
	* Make sure that clients can discover the AS which is in charge		* Make sure that clients can discover the AS which is in charge
	of the RS.		of the RS.
	* Make sure that the AS has the necessary, up-to-date, access		* Make sure that the AS has the necessary, up-to-date, access
	control policies for the RS.		control policies for the RS.
	Requesting Party		Requesting Party
	* Make sure that the client is provisioned the necessary		* Make sure that the client is provisioned the necessary
	credentials to authenticate to the AS.		credentials to authenticate to the AS.
	* Make sure that the client is configured to follow the security		* Make sure that the client is configured to follow the security
	requirements of the Requesting Party, when issuing requests		requirements of the Requesting Party, when issuing requests
	(e.g. minimum communication security requirements, trust		(e.g. minimum communication security requirements, trust
	anchors).		anchors).
	* Register the client at the AS.		* Register the client at the AS. This includes making known to
			the AS which profiles, token_types, and key types (symmetric/
			asymmetric) the client.
	Authorization Server		Authorization Server
	* Register RS and manage corresponding security contexts.		* Register RS and manage corresponding security contexts.
	* Register clients and including authentication credentials.		* Register clients and including authentication credentials.
	* Allow Resource Owners to configure and update access control		* Allow Resource Owners to configure and update access control
	policies related to their registered RS'		policies related to their registered RS'
	* Expose a service that allows clients to request tokens.		* Expose the /token endpoint to allow clients to request tokens.
	* Authenticate clients that wishes to request a token.		* Authenticate clients that wish to request a token.
	* Process a token requests against the authorization policies		* Process a token request against the authorization policies
	configured for the RS.		configured for the RS.
	* Expose a service that allows RS's to submit token introspection		* Expose the /introspection endpoint that allows RS's to submit
	requests.		token introspection requests.
	* Authenticate RS's that wishes to get an introspection response.		* Authenticate RS's that wish to get an introspection response.
	* Process token introspection requests.		* Process token introspection requests.
	* Optionally: Handle token revocation.		* Optionally: Handle token revocation.
	Client		Client
	* Discover the AS in charge of the RS that is to be targeted with		* Discover the AS in charge of the RS that is to be targeted with
	a request.		a request.
	* Submit the token request (A).		* Submit the token request (A).
	+ Authenticate towards the AS.		+ Authenticate towards the AS.
	+ Specify which RS, which resource(s), and which action(s) the		+ Optionally (if not pre-configured): Specify which RS, which
	request(s) will target.		resource(s), and which action(s) the request(s) will target.
	+ Specify preferences for communication security
	+ If raw public key (rpk) or certificate is used, make sure		+ If raw public key (rpk) or certificate is used, make sure
	the AS has the right rpk or certificate for this client.		the AS has the right rpk or certificate for this client.
	* Process the access token and client information (B)		* Process the access token and RS Information (B)
	+ Check that the token has the right format (e.g. CWT).		+ Check that the RS Information provides the necessary
	+ Check that the client information provides the necessary
	security parameters (e.g. PoP key, information on		security parameters (e.g. PoP key, information on
	communication security protocols supported by the RS).		communication security protocols supported by the RS).
	* Send the token and request to the RS (C)		* Send the token and request to the RS (C)
	+ Authenticate towards the RS (this could coincide with the		+ Authenticate towards the RS (this could coincide with the
	proof of possession process).		proof of possession process).
	+ Transmit the token as specified by the AS (default is to an		+ Transmit the token as specified by the AS (default is to the
	authorization information resource, alternative options are		/authz-info endpoint, alternative options are specified by
	as a CoAP option or in the DTLS handshake).		profiles).
	+ Perform the proof-of-possession procedure as specified for		+ Perform the proof-of-possession procedure as specified by
	the type of used token (this may already have been taken		the profile in use (this may already have been taken care of
	care of through the authentication procedure).		through the authentication procedure).
	* Process the RS response (F) requirements of the Requesting		* Process the RS response (F) requirements of the Requesting
	Party, when issuing requests (e.g. minimum communication		Party, when issuing requests (e.g. minimum communication
	security requirements, trust anchors).		security requirements, trust anchors).
	* Register the client at the AS.		* Register the client at the AS.
	Resource Server		Resource Server
	* Expose a way to submit access tokens.		* Expose a way to submit access tokens. By default this is the
			/authz-info endpoint.
	* Process an access token.		* Process an access token.
	+ Verify the token is from the right AS.		+ Verify the token is from the right AS.
	+ Verify that the token applies to this RS.		+ Verify that the token applies to this RS.
	+ Check that the token has not expired (if the token provides		+ Check that the token has not expired (if the token provides
	expiration information).		expiration information).
	+ Check the token's integrity.		+ Check the token's integrity.
	+ Store the token so that it can be retrieved in the context		+ Store the token so that it can be retrieved in the context
	of a matching request.		of a matching request.
	* Process a request.		* Process a request.
	skipping to change at page 44, line 4 ¶		skipping to change at page 45, line 49 ¶
	+ Verify the token is from the right AS.		+ Verify the token is from the right AS.
	+ Verify that the token applies to this RS.		+ Verify that the token applies to this RS.
	+ Check that the token has not expired (if the token provides		+ Check that the token has not expired (if the token provides
	expiration information).		expiration information).
	+ Check the token's integrity.		+ Check the token's integrity.
	+ Store the token so that it can be retrieved in the context		+ Store the token so that it can be retrieved in the context
	of a matching request.		of a matching request.
	* Process a request.		* Process a request.
	+ Set up communication security with the client.		+ Set up communication security with the client.
	+ Authenticate the client.		+ Authenticate the client.
	+ Match the client against existing tokens.		+ Match the client against existing tokens.
	+ Check that tokens belonging to the client actually authorize		+ Check that tokens belonging to the client actually authorize
	the requested action.		the requested action.
	+ Optionally: Check that the matching tokens are still valid		+ Optionally: Check that the matching tokens are still valid
	(if this is possible.		(if this is possible.)
	* Send a response following the agreed upon communication		* Send a response following the agreed upon communication
	security.		security.
	Appendix C. Deployment Examples		Appendix C. Requirements on Profiles
			This section lists the requirements on profiles of this framework,
			for the convenience of a profile designer. All this information is
			also given in the appropriate sections of the main document, this is
			just meant as a checklist, to make it more easy to spot parts one
			might have missed.
			o Specify the discovery process of how the client finds the right AS
			for an RS it wants to send a request to.
			o Specify the communication protocol the client and RS the must use
			(e.g. CoAP).
			o Specify the security protocol the client and RS must use to
			protect their communication (e.g. OSCOAP or DTLS over CoAP).
			This must provide encryption and integrity protection.
			o Specify how the client and the RS mutually authenticate
			o Specify the Content-format of the protocol messages (e.g.
			"application/cbor" or "application/cose+cbor").
			o Specify the proof-of-possession protocol(s) and how to select one,
			if several are available. Also specify which key types (e.g.
			symmetric/asymmetric) are supported by a specific proof-of-
			possession protocol.
			o Specify a unique profile identifier.
			o Optionally specify how the RS talks to the AS for introspection.
			o Optionally specify how the client talks to the AS for requesting a
			token.
			o Specify how/if the /authz-info endpoint is protected.
			o Optionally define other methods of token transport than the
			/authz-info endpoint.
			Appendix D. Deployment Examples
	There is a large variety of IoT deployments, as is indicated in		There is a large variety of IoT deployments, as is indicated in
	Appendix A, and this section highlights a few common variants. This		Appendix A, and this section highlights a few common variants. This
	section is not normative but illustrates how the framework can be		section is not normative but illustrates how the framework can be
	applied.		applied.
	For each of the deployment variants there are a number of possible		For each of the deployment variants there are a number of possible
	security setups between clients, resource servers and authorization		security setups between clients, resource servers and authorization
	servers. The main focus in the following subsections is on how		servers. The main focus in the following subsections is on how
	authorization of a client request for a resource hosted by a RS is		authorization of a client request for a resource hosted by a RS is
	performed. This requires the the security of the requests and		performed. This requires the the security of the requests and
	responses between the clients and the RS to consider.		responses between the clients and the RS to consider.
	Note: CBOR diagnostic notation is used for examples of requests and		Note: CBOR diagnostic notation is used for examples of requests and
	responses.		responses.
	C.1. Local Token Validation		D.1. Local Token Validation
	In this scenario we consider the case where the resource server is		In this scenario we consider the case where the resource server is
	offline, i.e. it is not connected to the AS at the time of the access		offline, i.e. it is not connected to the AS at the time of the access
	request. This access procedure involves steps A, B, C, and F of		request. This access procedure involves steps A, B, C, and F of
	Figure 1.		Figure 1.
	Since the resource server must be able to verify the access token		Since the resource server must be able to verify the access token
	locally, self-contained access tokens must be used.		locally, self-contained access tokens must be used.
	This example shows the interactions between a client, the		This example shows the interactions between a client, the
	authorization server and a temperature sensor acting as a resource		authorization server and a temperature sensor acting as a resource
	server. Message exchanges A and B are shown in Figure 17.		server. Message exchanges A and B are shown in Figure 16.
	A: The client first generates a public-private key pair used for		A: The client first generates a public-private key pair used for
	communication security with the RS.		communication security with the RS.
	The client sends the POST request to /token at the AS. The		The client sends the POST request to /token at the AS. The
	request contains the public key of the client and the Audience		security of this request can be transport or application layer, it
	parameter set to "tempSensorInLivingRoom", a value that the		is up the the comunication security profile to define. In the
	temperature sensor identifies itself with. The AS evaluates the		example trasport layer identification of the AS is done and the
	request and authorizes the client to access the resource.		client identifies with client_id and client_secret as in classic
			OAuth. The request contains the public key of the client and the
	B: The AS responds with a PoP token and client information. The		Audience parameter set to "tempSensorInLivingRoom", a value that
	PoP token contains the public key of the client, and the client		the temperature sensor identifies itself with. The AS evaluates
	information contains the public key of the RS. For communication		the request and authorizes the client to access the resource.
			B: The AS responds with a PoP token and RS Information. The PoP
			token contains the public key of the client, and the RS
			Information contains the public key of the RS. For communication
	security this example uses DTLS RawPublicKey between the client		security this example uses DTLS RawPublicKey between the client
	and the RS. The issued token will have a short validity time,		and the RS. The issued token will have a short validity time,
	i.e. 'exp' close to 'iat', to protect the RS from replay attacks		i.e. 'exp' close to 'iat', to protect the RS from replay attacks.
	since it, that cannot do introspection to check the tokens current		The token includes the claim such as "scope" with the authorized
	validity. The token includes the claim "aif" with the authorized		access that an owner of the temperature device can enjoy. In this
	access that an owner of the temperature device can enjoy. The		example, the 'scope' claim, issued by the AS, informs the RS that
	'aif' claim, issued by the AS, informs the RS that the owner of		the owner of the token, that can prove the possession of a key is
	the token, that can prove the possession of a key is authorized to		authorized to make a GET request against the /temperature resource
	make a GET request against the /temperature resource and a POST		and a POST request on the /firmware resource. Note that the
	request on the /firmware resource.		syntax and semantics of the scope claim are application specific.
	Note: In this example we assume that the client knows what		Note: In this example we assume that the client knows what
	resource it wants to access, and is therefore able to request		resource it wants to access, and is therefore able to request
	specific audience and scope claims for the access token.		specific audience and scope claims for the access token.
	Authorization		Authorization
	Client Server		Client Server
	| |		| |
			|<=======>| DTLS Connection Establishment
			| | to identify the AS
	| |		| |
	A: +-------->| Header: POST (Code=0.02)		A: +-------->| Header: POST (Code=0.02)
	| POST | Uri-Path:"token"		| POST | Uri-Path:"token"
	| | Content-Type: application/cbor		| | Content-Type: application/cbor
	| | Payload: <Request-Payload>		| | Payload: <Request-Payload>
	| |		| |
	B: |<--------+ Header: 2.05 Content		B: |<--------+ Header: 2.05 Content
	| 2.05 | Content-Type: application/cbor		| 2.05 | Content-Type: application/cbor
	| | Payload: <Response-Payload>		| | Payload: <Response-Payload>
	| |		| |
	Figure 17: Token Request and Response Using Client Credentials.		Figure 16: Token Request and Response Using Client Credentials.
	The information contained in the Request-Payload and the Response-		The information contained in the Request-Payload and the Response-
	Payload is shown in Figure 18.		Payload is shown in Figure 17. Note that we assume a DTLS-based
			communication security profile for this example, therefore the
			Content-Type is "application/cbor".
	Request-Payload :		Request-Payload :
	{		{
	"grant_type" : "client_credentials",		"grant_type" : "client_credentials",
	"aud" : "tempSensorInLivingRoom",		"aud" : "tempSensorInLivingRoom",
	"client_id" : "myclient",		"client_id" : "myclient",
	"client_secret" : "qwerty"		"client_secret" : "qwerty"
	}		}
	Response-Payload :		Response-Payload :
	skipping to change at page 46, line 29 ¶		skipping to change at page 48, line 52 ¶
	"COSE_Key" : {		"COSE_Key" : {
	"kid" : b64'c29tZSBwdWJsaWMga2V5IGlk',		"kid" : b64'c29tZSBwdWJsaWMga2V5IGlk',
	"kty" : "EC",		"kty" : "EC",
	"crv" : "P-256",		"crv" : "P-256",
	"x" : b64'MKBCTNIcKUSDii11ySs3526iDZ8AiTo7Tu6KPAqv7D4',		"x" : b64'MKBCTNIcKUSDii11ySs3526iDZ8AiTo7Tu6KPAqv7D4',
	"y" : b64'4Etl6SRW2YiLUrN5vfvVHuhp7x8PxltmWWlbbM4IFyM'		"y" : b64'4Etl6SRW2YiLUrN5vfvVHuhp7x8PxltmWWlbbM4IFyM'
	}		}
	}		}
	}		}
	Figure 18: Request and Response Payload Details.		Figure 17: Request and Response Payload Details.
	The content of the access token is shown in Figure 19.		The content of the access token is shown in Figure 18.
	{		{
	"aud" : "tempSensorInLivingRoom",		"aud" : "tempSensorInLivingRoom",
	"iat" : "1360189224",		"iat" : "1360189224",
	"exp" : "1360289224",		"exp" : "1360289224",
	"aif" : [["/temperature", 0], ["/firmware", 2]],		"scope" : "temperature_g firmware_p",
	"cnf" : {		"cnf" : {
	"jwk" : {		"jwk" : {
	"kid" : b64'1Bg8vub9tLe1gHMzV76e8',		"kid" : b64'1Bg8vub9tLe1gHMzV76e8',
	"kty" : "EC",		"kty" : "EC",
	"crv" : "P-256",		"crv" : "P-256",
	"x" : b64'f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU',		"x" : b64'f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU',
	"y" : b64'x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0'		"y" : b64'x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0'
	}		}
	}		}
	}		}
	Figure 19: Access Token including Public Key of the Client.		Figure 18: Access Token including Public Key of the Client.
	Messages C and F are shown in Figure 20 - Figure 21.		Messages C and F are shown in Figure 19 - Figure 20.
	C: The client then sends the PoP token to the /authz-info resource		C: The client then sends the PoP token to the /authz-info endpoint
	at the RS. This is a plain CoAP request, i.e. no transport or		at the RS. This is a plain CoAP request, i.e. no transport or
	application layer security between client and RS, since the token		application layer security between client and RS, since the token
	is integrity protected between AS and RS. The RS verifies that		is integrity protected between AS and RS. The RS verifies that
	the PoP token was created by a known and trusted AS, is valid, and		the PoP token was created by a known and trusted AS, is valid, and
	responds to the client. The RS caches the security context		responds to the client. The RS caches the security context
	together with authorization information about this client		together with authorization information about this client
	contained in the PoP token.		contained in the PoP token.
	Resource		Resource
	Client Server		Client Server
	| |		| |
	C: +-------->| Header: POST (Code=0.02)		C: +-------->| Header: POST (Code=0.02)
	| POST | Uri-Path:"authz-info"		| POST | Uri-Path:"authz-info"
	| | Payload: SlAV32hkKG ...		| | Payload: SlAV32hkKG ...
	| |		| |
	|<--------+ Header: 2.01 Created		|<--------+ Header: 2.04 Changed
	| 2.01 |		| 2.04 |
	| |		| |
	Figure 20: Access Token provisioning to RS		Figure 19: Access Token provisioning to RS
	The client and the RS runs the DTLS handshake using the raw public		The client and the RS runs the DTLS handshake using the raw public
	keys established in step B and C.		keys established in step B and C.
	The client sends the CoAP request GET to /temperature on RS over		The client sends the CoAP request GET to /temperature on RS over
	DTLS. The RS verifies that the request is authorized, based on		DTLS. The RS verifies that the request is authorized, based on
	previously established security context.		previously established security context.
	F: The RS responds with a resource representation over DTLS.		F: The RS responds with a resource representation over DTLS.
	Resource		Resource
	Client Server		Client Server
	| |		| |
	|<=======>| DTLS Connection Establishment		|<=======>| DTLS Connection Establishment
	| | using Raw Public Keys		| | using Raw Public Keys
	| |		| |
	+-------->| Header: GET (Code=0.01)		+-------->| Header: GET (Code=0.01)
	| GET | Uri-Path: "temperature"		| GET | Uri-Path: "temperature"
	| |		| |
	| |		| |
	| |		| |
	F: |<--------+ Header: 2.05 Content		F: |<--------+ Header: 2.05 Content
	| 2.05 | Payload: <sensor value>		| 2.05 | Payload: <sensor value>
	| |		| |
	Figure 21: Resource Request and Response protected by DTLS.		Figure 20: Resource Request and Response protected by DTLS.
	C.2. Introspection Aided Token Validation		D.2. Introspection Aided Token Validation
	In this deployment scenario we assume that a client is not be able to		In this deployment scenario we assume that a client is not able to
	access the AS at the time of the access request. Since the RS is,		access the AS at the time of the access request. Since the RS is,
	however, connected to the back-end infrastructure it can make use of		however, connected to the back-end infrastructure it can make use of
	token introspection. This access procedure involves steps A-F of		token introspection. This access procedure involves steps A-F of
	Figure 1, but assumes steps A and B have been carried out during a		Figure 1, but assumes steps A and B have been carried out during a
	phase when the client had connectivity to AS.		phase when the client had connectivity to AS.
	Since the client is assumed to be offline, at least for a certain		Since the client is assumed to be offline, at least for a certain
	period of time, a pre-provisioned access token has to be long-lived.		period of time, a pre-provisioned access token has to be long-lived.
	The resource server may use its online connectivity to validate the		The resource server may use its online connectivity to validate the
	access token with the authorization server, which is shown in the		access token with the authorization server, which is shown in the
	example below.		example below.
	In the example we show the interactions between an offline client		In the example interactions between an offline client (key fob), a RS
	(key fob), a resource server (online lock), and an authorization		(online lock), and an AS is shown. We assume that there is a
	server. We assume that there is a provisioning step where the client		provisioning step where the client has access to the AS. This
	has access to the AS. This corresponds to message exchanges A and B		corresponds to message exchanges A and B which are shown in
	which are shown in Figure 22.		Figure 21.
	Authorization consent from the resource owner can be pre-configured,		Authorization consent from the resource owner can be pre-configured,
	but it can also be provided via an interactive flow with the resource		but it can also be provided via an interactive flow with the resource
	owner. An example of this for the key fob case could be that the		owner. An example of this for the key fob case could be that the
	resource owner has a connected car, he buys a generic key that he		resource owner has a connected car, he buys a generic key that he
	wants to use with the car. To authorize the key fob he connects it		wants to use with the car. To authorize the key fob he connects it
	to his computer that then provides the UI for the device. After that		to his computer that then provides the UI for the device. After that
	OAuth 2.0 implicit flow can used to authorize the key for his car at		OAuth 2.0 implicit flow can used to authorize the key for his car at
	the the car manufacturers AS.		the the car manufacturers AS.
	skipping to change at page 48, line 46 ¶		skipping to change at page 51, line 19 ¶
	be used to access since the token request is not send at the time of		be used to access since the token request is not send at the time of
	access. So the scope and audience parameters is set quite wide to		access. So the scope and audience parameters is set quite wide to
	start with and new values different form the original once can be		start with and new values different form the original once can be
	returned from introspection later on.		returned from introspection later on.
	A: The client sends the request using POST to /token at AS. The		A: The client sends the request using POST to /token at AS. The
	request contains the Audience parameter set to "PACS1337" (PACS,		request contains the Audience parameter set to "PACS1337" (PACS,
	Physical Access System), a value the that the online door in		Physical Access System), a value the that the online door in
	question identifies itself with. The AS generates an access token		question identifies itself with. The AS generates an access token
	as on opaque string, which it can match to the specific client, a		as on opaque string, which it can match to the specific client, a
	targeted audience and a symmetric key.		targeted audience and a symmetric key. The security is provided
	B: The AS responds with the an access token and client		by identifying the AS on transport layer using a pre shared
	information, the latter containing a symmetric key. Communication		security context (psk, rpk or certificate) and then the client is
	security between C and RS will be DTLS and PreSharedKey. The PoP		identified using client_id and client_secret as in classic OAuth
	key being used as the PreSharedKey.		B: The AS responds with the an access token and RS Information,
			the latter containing a symmetric key. Communication security
			between C and RS will be DTLS and PreSharedKey. The PoP key being
			used as the PreSharedKey.
	Authorization		Authorization
	Client Server		Client Server
	| |		| |
	| |		| |
	A: +-------->| Header: POST (Code=0.02)		A: +-------->| Header: POST (Code=0.02)
	| POST | Uri-Path:"token"		| POST | Uri-Path:"token"
	| | Content-Type: application/cbor		| | Content-Type: application/cbor
	| | Payload: <Request-Payload>		| | Payload: <Request-Payload>
	| |		| |
	B: |<--------+ Header: 2.05 Content		B: |<--------+ Header: 2.05 Content
	| | Content-Type: application/cbor		| | Content-Type: application/cbor
	| 2.05 | Payload: <Response-Payload>		| 2.05 | Payload: <Response-Payload>
	| |		| |
	Figure 22: Token Request and Response using Client Credentials.		Figure 21: Token Request and Response using Client Credentials.
	The information contained in the Request-Payload and the Response-		The information contained in the Request-Payload and the Response-
	Payload is shown in Figure 23.		Payload is shown in Figure 22.
	Request-Payload:		Request-Payload:
	{		{
	"grant_type" : "client_credentials",		"grant_type" : "client_credentials",
	"aud" : "lockOfDoor4711",		"aud" : "lockOfDoor4711",
	"client_id" : "keyfob",		"client_id" : "keyfob",
	"client_secret" : "qwerty"		"client_secret" : "qwerty"
	}		}
	Response-Payload:		Response-Payload:
	skipping to change at page 49, line 47 ¶		skipping to change at page 52, line 28 ¶
	"cnf" : {		"cnf" : {
	"COSE_Key" : {		"COSE_Key" : {
	"kid" : b64'c29tZSBwdWJsaWMga2V5IGlk',		"kid" : b64'c29tZSBwdWJsaWMga2V5IGlk',
	"kty" : "oct",		"kty" : "oct",
	"alg" : "HS256",		"alg" : "HS256",
	"k": b64'ZoRSOrFzN_FzUA5XKMYoVHyzff5oRJxl-IXRtztJ6uE'		"k": b64'ZoRSOrFzN_FzUA5XKMYoVHyzff5oRJxl-IXRtztJ6uE'
	}		}
	}		}
	}		}
	Figure 23: Request and Response Payload for C offline		Figure 22: Request and Response Payload for C offline
	The access token in this case is just an opaque string referencing		The access token in this case is just an opaque string referencing
	the authorization information at the AS.		the authorization information at the AS.
	C: Next, the client POSTs the access token to the /authz-info		C: Next, the client POSTs the access token to the /authz-info
	resource in the RS. This is a plain CoAP request, i.e. no DTLS		endpoint in the RS. This is a plain CoAP request, i.e. no DTLS
	between client and RS. Since the token is an opaque string, the		between client and RS. Since the token is an opaque string, the
	RS cannot verify it on its own, and thus defers to respond the		RS cannot verify it on its own, and thus defers to respond the
	client with a status code until after step E.		client with a status code until after step E.
	D: The RS forwards the token to the /introspect resource on the		D: The RS forwards the token to the /introspect endpoint on the
	AS. Introspection assumes a secure connection between the AS and		AS. Introspection assumes a secure connection between the AS and
	the RS, e.g. using transport of application layer security, which		the RS, e.g. using transport of application layer security. In
	is not detailed in this example.		the example AS is identified using pre shared security context
			(psk, rpk or certificate) while RS is acting as client and is
			identified with client_id and client_secret.
	E: The AS provides the introspection response containing		E: The AS provides the introspection response containing
	parameters about the token. This includes the confirmation key		parameters about the token. This includes the confirmation key
	(cnf) parameter that allows the RS to verify the client's proof of		(cnf) parameter that allows the RS to verify the client's proof of
	possession in step F.		possession in step F.
	After receiving message E, the RS responds to the client's POST in		After receiving message E, the RS responds to the client's POST in
	step C with Code 2.01 Created.		step C with the CoAP response code 2.01 (Created).
	Resource		Resource
	Client Server		Client Server
	| |		| |
	C: +-------->| Header: POST (T=CON, Code=0.02)		C: +-------->| Header: POST (T=CON, Code=0.02)
	| POST | Uri-Path:"authz-info"		| POST | Uri-Path:"authz-info"
	| | Content-Type: "application/cbor"		| | Content-Type: "application/cbor"
	| | Payload: b64'SlAV32hkKG ...''		| | Payload: b64'SlAV32hkKG ...''
	| |		| |
	| | Authorization		| | Authorization
	| | Server		| | Server
	| | |		| | |
	D: | +--------->| Header: POST (Code=0.02)		| D: +--------->| Header: POST (Code=0.02)
	| | POST | Uri-Path: "introspect"		| | POST | Uri-Path: "introspect"
	| | | Content-Type: "application/cbor"		| | | Content-Type: "application/cbor"
	| | | Payload: <Request-Payload>		| | | Payload: <Request-Payload>
	| | |		| | |
	E: | |<---------+ Header: 2.05 Content		| E: |<---------+ Header: 2.05 Content
	| | 2.05 | Content-Type: "application/cbor"		| | 2.05 | Content-Type: "application/cbor"
	| | | Payload: <Response-Payload>		| | | Payload: <Response-Payload>
	| | |		| | |
	| |		| |
	C: |<--------+ Header: 2.01 Created		|<--------+ Header: 2.01 Created
	| 2.01 |		| 2.01 |
	| |		| |
	Figure 24: Token Introspection for C offline		Figure 23: Token Introspection for C offline
	The information contained in the Request-Payload and the Response-		The information contained in the Request-Payload and the Response-
	Payload is shown in Figure 25.		Payload is shown in Figure 24.
	Request-Payload:		Request-Payload:
	{		{
	"token" : b64'SlAV32hkKG...',		"token" : b64'SlAV32hkKG...',
	"client_id" : "FrontDoor",		"client_id" : "FrontDoor",
	"client_secret" : "ytrewq"		"client_secret" : "ytrewq"
	}		}
	Response-Payload:		Response-Payload:
	{		{
	"active" : true,		"active" : true,
	"aud" : "lockOfDoor4711",		"aud" : "lockOfDoor4711",
	"scope" : "open, close",		"scope" : "open, close",
	"iat" : 1311280970,		"iat" : 1311280970,
	"cnf" : {		"cnf" : {
	"kid" : b64'JDLUhTMjU2IiwiY3R5Ijoi ...'		"kid" : b64'JDLUhTMjU2IiwiY3R5Ijoi ...'
	}		}
	}		}
	Figure 25: Request and Response Payload for Introspection		Figure 24: Request and Response Payload for Introspection
	The client uses the symmetric PoP key to establish a DTLS		The client uses the symmetric PoP key to establish a DTLS
	PreSharedKey secure connection to the RS. The CoAP request PUT is		PreSharedKey secure connection to the RS. The CoAP request PUT is
	sent to the uri-path /state on RS changing state of the door to		sent to the uri-path /state on RS changing state of the door to
	locked.		locked.
	F: The RS responds with a appropriate over the secure DTLS		F: The RS responds with a appropriate over the secure DTLS
	channel.		channel.
	Resource		Resource
	Client Server		Client Server
	skipping to change at page 51, line 46 ¶		skipping to change at page 54, line 26 ¶
	| | using Pre Shared Key		| | using Pre Shared Key
	| |		| |
	+-------->| Header: PUT (Code=0.03)		+-------->| Header: PUT (Code=0.03)
	| PUT | Uri-Path: "state"		| PUT | Uri-Path: "state"
	| | Payload: <new state for the lock>		| | Payload: <new state for the lock>
	| |		| |
	F: |<--------+ Header: 2.04 Changed		F: |<--------+ Header: 2.04 Changed
	| 2.04 | Payload: <new state for the lock>		| 2.04 | Payload: <new state for the lock>
	| |		| |
	Figure 26: Resource request and response protected by OSCOAP		Figure 25: Resource request and response protected by OSCOAP
	Appendix D. Document Updates		Appendix E. Document Updates
	D.1. Version -01 to -02
			E.1. Version -02 to -03
			o Removed references to draft-ietf-oauth-pop-key-distribution since
			the status of this draft is unclear.
			o Copied and adapted security considerations from draft-ietf-oauth-
			pop-key-distribution.
			o Renamed "client information" to "RS information" since it is
			information about the RS.
			o Clarified the requirements on profiles of this framework.
			o Clarified the token endpoint protocol and removed negotiation of
			'profile' and 'alg' (section 6).
			o Renumbered the abbreviations for claims and parameters to get a
			consistent numbering across different endpoints.
			o Clarified the introspection endpoint.
			o Renamed token, introspection and authz-info to 'endpoint' instead
			of 'resource' to mirror the OAuth 2.0 terminology.
			o Updated the examples in the appendices.
			E.2. Version -01 to -02
	o Restructured to remove communication security parts. These shall		o Restructured to remove communication security parts. These shall
	now be defined in profiles.		now be defined in profiles.
	o Restructured section 5 to create new sections on the OAuth		o Restructured section 5 to create new sections on the OAuth
	endpoints /token, /introspect and /authz-info.		endpoints /token, /introspect and /authz-info.
	o Pulled in material from draft-ietf-oauth-pop-key-distribution in		o Pulled in material from draft-ietf-oauth-pop-key-distribution in
	order to define proof-of-possession key distribution.		order to define proof-of-possession key distribution.
	o Introduced the 'cnf' parameter as defined in RFC7800 to reference		o Introduced the 'cnf' parameter as defined in RFC7800 to reference
	or transport keys used for proof of posession.		or transport keys used for proof of posession.
	o Introduced the 'client-token' to transport client information from		o Introduced the 'client-token' to transport client information from
	the AS to the client via the RS in conjunction with introspection.		the AS to the client via the RS in conjunction with introspection.
	o Expanded the IANA section to define parameters for token request,		o Expanded the IANA section to define parameters for token request,
	introspection and CWT claims.		introspection and CWT claims.
	o Moved deployment scenarios to the appendix as examples.		o Moved deployment scenarios to the appendix as examples.
	D.2. Version -00 to -01		E.3. Version -00 to -01
	o Changed 5.1. from "Communication Security Protocol" to "Client		o Changed 5.1. from "Communication Security Protocol" to "Client
	Information".		Information".
	o Major rewrite of 5.1 to clarify the information exchanged between		o Major rewrite of 5.1 to clarify the information exchanged between
	C and AS in the PoP token request profile for IoT.		C and AS in the PoP token request profile for IoT.
	* Allow the client to indicate preferences for the communication		* Allow the client to indicate preferences for the communication
	security protocol.		security protocol.
	* Defined the term "Client Information" for the additional		* Defined the term "Client Information" for the additional
	information returned to the client in addition to the access		information returned to the client in addition to the access
	skipping to change at page 53, line 24 ¶		skipping to change at page 56, line 24 ¶
	Goeran Selander		Goeran Selander
	Ericsson		Ericsson
	Faroegatan 6		Faroegatan 6
	Kista 164 80		Kista 164 80
	SWEDEN		SWEDEN
	Email: goran.selander@ericsson.com		Email: goran.selander@ericsson.com
	Erik Wahlstroem		Erik Wahlstroem
	Nexus Technology
	Telefonvagen 26
	Hagersten 126 26
	Sweden		Sweden
	Email: erik.wahlstrom@nexusgroup.com		Email: erik@wahlstromtekniska.se
	Samuel Erdtman		Samuel Erdtman
	Spotify AB		Spotify AB
	Birger Jarlsgatan 61, 4tr		Birger Jarlsgatan 61, 4tr
	Stockholm 113 56		Stockholm 113 56
	Sweden		Sweden
	Email: erdtman@spotify.com		Email: erdtman@spotify.com
	Hannes Tschofenig		Hannes Tschofenig
End of changes. 242 change blocks.
	555 lines changed or deleted		735 lines changed or added
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