draft-ietf-ace-oscore-profile-05.txt		draft-ietf-ace-oscore-profile-06.txt
	ACE Working Group F. Palombini		ACE Working Group F. Palombini
	Internet-Draft Ericsson AB		Internet-Draft Ericsson AB
	Intended status: Standards Track L. Seitz		Intended status: Standards Track L. Seitz
	Expires: May 11, 2019 RISE SICS AB		Expires: July 7, 2019 RISE SICS AB
	G. Selander		G. Selander
	Ericsson AB		Ericsson AB
	M. Gunnarsson		M. Gunnarsson
	RISE SICS AB		RISE SICS AB
	November 7, 2018		January 3, 2019
	OSCORE profile of the Authentication and Authorization for Constrained		OSCORE profile of the Authentication and Authorization for Constrained
	Environments Framework		Environments Framework
	draft-ietf-ace-oscore-profile-05		draft-ietf-ace-oscore-profile-06
	Abstract		Abstract
	This memo specifies a profile for the Authentication and		This memo specifies a profile for the Authentication and
	Authorization for Constrained Environments (ACE) framework. It		Authorization for Constrained Environments (ACE) framework. It
	utilizes Object Security for Constrained RESTful Environments		utilizes Object Security for Constrained RESTful Environments
	(OSCORE) to provide communication security, server authentication,		(OSCORE) to provide communication security, server authentication,
	and proof-of-possession for a key owned by the client and bound to an		and proof-of-possession for a key owned by the client and bound to an
	OAuth 2.0 access token.		OAuth 2.0 access token.
	skipping to change at page 1, line 41 ¶		skipping to change at page 1, line 41 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at https://datatracker.ietf.org/drafts/current/.		Drafts is at https://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on May 11, 2019.		This Internet-Draft will expire on July 7, 2019.
	Copyright Notice		Copyright Notice
	Copyright (c) 2018 IETF Trust and the persons identified as the		Copyright (c) 2019 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
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	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
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	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3		1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 3		2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 3
	3. Client-AS Communication . . . . . . . . . . . . . . . . . . . 5		3. Client-AS Communication . . . . . . . . . . . . . . . . . . . 5
	3.1. C-to-AS: POST to token endpoint . . . . . . . . . . . . . 6		3.1. C-to-AS: POST to token endpoint . . . . . . . . . . . . . 6
	3.2. AS-to-C: Access Token . . . . . . . . . . . . . . . . . . 7		3.2. AS-to-C: Access Token . . . . . . . . . . . . . . . . . . 7
	3.2.1. OSCORE_Security_Context Object . . . . . . . . . . . 10		3.2.1. OSCORE_Security_Context Object . . . . . . . . . . . 11
	4. Client-RS Communication . . . . . . . . . . . . . . . . . . . 13		4. Client-RS Communication . . . . . . . . . . . . . . . . . . . 14
	4.1. C-to-RS: POST to authz-info endpoint . . . . . . . . . . 13		4.1. C-to-RS: POST to authz-info endpoint . . . . . . . . . . 15
	4.2. RS-to-C: 2.01 (Created) . . . . . . . . . . . . . . . . . 14		4.2. RS-to-C: 2.01 (Created) . . . . . . . . . . . . . . . . . 16
	4.3. OSCORE Setup . . . . . . . . . . . . . . . . . . . . . . 15		4.3. OSCORE Setup . . . . . . . . . . . . . . . . . . . . . . 17
	4.4. Access rights verification . . . . . . . . . . . . . . . 16		4.4. Access rights verification . . . . . . . . . . . . . . . 18
	5. Secure Communication with AS . . . . . . . . . . . . . . . . 17		5. Secure Communication with AS . . . . . . . . . . . . . . . . 19
	6. Discarding the Security Context . . . . . . . . . . . . . . . 17		6. Discarding the Security Context . . . . . . . . . . . . . . . 19
	7. Security Considerations . . . . . . . . . . . . . . . . . . . 18		7. Security Considerations . . . . . . . . . . . . . . . . . . . 20
	8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 18		8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 21
	9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19		9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
	9.1. ACE OAuth Profile Registry . . . . . . . . . . . . . . . 19		9.1. ACE OAuth Profile Registry . . . . . . . . . . . . . . . 21
	9.2. OSCORE Security Context Parameters Registry . . . . . . . 19		9.2. OSCORE Security Context Parameters Registry . . . . . . . 22
	9.3. CWT Confirmation Methods Registry . . . . . . . . . . . . 20		9.3. CWT Confirmation Methods Registry . . . . . . . . . . . . 22
	9.4. JWT Confirmation Methods Registry . . . . . . . . . . . . 20		9.4. JWT Confirmation Methods Registry . . . . . . . . . . . . 23
	9.5. Expert Review Instructions . . . . . . . . . . . . . . . 20		9.5. Expert Review Instructions . . . . . . . . . . . . . . . 23
	10. References . . . . . . . . . . . . . . . . . . . . . . . . . 21		10. References . . . . . . . . . . . . . . . . . . . . . . . . . 24
	10.1. Normative References . . . . . . . . . . . . . . . . . . 21		10.1. Normative References . . . . . . . . . . . . . . . . . . 24
	10.2. Informative References . . . . . . . . . . . . . . . . . 22		10.2. Informative References . . . . . . . . . . . . . . . . . 24
	Appendix A. Profile Requirements . . . . . . . . . . . . . . . . 23		Appendix A. Profile Requirements . . . . . . . . . . . . . . . . 25
	Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 23		Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 26
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26
	1. Introduction		1. Introduction
	This memo specifies a profile of the ACE framework		This memo specifies a profile of the ACE framework
	[I-D.ietf-ace-oauth-authz]. In this profile, a client and a resource		[I-D.ietf-ace-oauth-authz]. In this profile, a client and a resource
	server use CoAP [RFC7252] to communicate. The client uses an access		server use CoAP [RFC7252] to communicate. The client uses an access
	token, bound to a key (the proof-of-possession key) to authorize its		token, bound to a key (the proof-of-possession key) to authorize its
	access to the resource server. In order to provide communication		access to the resource server. In order to provide communication
	security, proof of possession, and server authentication they use		security, proof of possession, and server authentication they use
	Object Security for Constrained RESTful Environments (OSCORE)		Object Security for Constrained RESTful Environments (OSCORE)
	skipping to change at page 4, line 14 ¶		skipping to change at page 4, line 14 ¶
	To determine the AS in charge of a resource hosted at the RS, the		To determine the AS in charge of a resource hosted at the RS, the
	client C MAY send an initial Unauthorized Resource Request message to		client C MAY send an initial Unauthorized Resource Request message to
	the RS. The RS then denies the request and sends the address of its		the RS. The RS then denies the request and sends the address of its
	AS back to the client C as specified in section 5.1 of		AS back to the client C as specified in section 5.1 of
	[I-D.ietf-ace-oauth-authz]. The access token request and response		[I-D.ietf-ace-oauth-authz]. The access token request and response
	MUST be confidentiality-protected and ensure authenticity. This		MUST be confidentiality-protected and ensure authenticity. This
	profile RECOMMENDS the use of OSCORE between client and AS, but TLS		profile RECOMMENDS the use of OSCORE between client and AS, but TLS
	or DTLS MAY be used additionally or instead.		or DTLS MAY be used additionally or instead.
	Once the client has retrieved the access token, it posts it to the RS		Once the client has retrieved the access token, it generates a nonce
	using the authz-info endpoint and mechanisms specified in section 5.8		N1 and posts both the token and N1 to the RS using the authz-info
	of [I-D.ietf-ace-oauth-authz]. If the access token is valid, the RS		endpoint and mechanisms specified in section 5.8 of
	replies to this request with a 2.01 (Created) response, which		[I-D.ietf-ace-oauth-authz] and Content-Format = application/ace+cbor.
	contains a nonce N1.
	After receiving the nonce N1, the client generates a nonce N2,		If the access token is valid, the RS replies to this request with a
	concatenates it with N1 and sets the ID Context in its Security		2.01 (Created) response with Content-Format = application/ace+cbor,
			which contains a nonce N2 in a CBOR map. Moreover, the server
			concatenates N1 with N2 and sets the ID Context in the Security
	Context (see section 3 of [I-D.ietf-core-object-security]) to N1		Context (see section 3 of [I-D.ietf-core-object-security]) to N1
	concatenated with N2. The client then derives the complete Security		concatenated with N2. The RS then derives the complete Security
	Context from the ID Context plus the parameters received from the AS.		Context associated with the received token from it plus the
			parameters received in the AS, following section 3.2 of
			[I-D.ietf-core-object-security].
			After receiving the nonce N2, the client concatenates it with N1 and
			sets the ID Context in its Security Context (see section 3 of
			[I-D.ietf-core-object-security]) to N1 concatenated with N2. The
			client then derives the complete Security Context from the ID Context
			plus the parameters received from the AS.
	Finally, the client sends a request protected with OSCORE to the RS.		Finally, the client sends a request protected with OSCORE to the RS.
	This message contains the ID Context value. When receiving this		This message may contain the ID Context value. If the request
	request after the 2.01 (Created) response, the server extract the ID		verifies, then this Security Context is stored in the server, and
	Context from it, verifies that the first part is equal to the nonce		used in the response, and in further communications with the client,
	N1 it previously sent, and if so, sets its own ID Context and derives		until token expiration. This Security Context is discarded if the
	the complete Security Context from it plus the parameters received in		same token is re-used to successfully derive a new Security Context.
	the AS, following section 3.2 of [I-D.ietf-core-object-security]. If		Once the client receives a valid response, it does not continue to
	the request verifies, then this Security Context is stored in the		include the ID Context value in further requests.
	server, and used in the response, and in further communications with
	the client, until token expiration. Once the client receives a valid
	response, it does not continue to include the ID Context value in
	further requests.
	The use of random nonces during the exchange prevents the reuse of		The use of random nonces during the exchange prevents the reuse of
	AEAD nonces and keys with different messages, in case of re-		AEAD nonces and keys with different messages, in case of re-
	derivation of the Security Context both for Clients and Resource		derivation of the Security Context both for Clients and Resource
	Servers from an old non-expired access token, e.g. in case of re-boot		Servers from an old non-expired access token, e.g. in case of re-boot
	of either the client or RS. In fact, by using random nonces as ID		of either the client or RS. In fact, by using random nonces as ID
	Context, the request to the authz-info endpoint posting the same		Context, the request to the authz-info endpoint posting the same
	token results in a different Security Context, since Master Secret,		token results in a different Security Context, since Master Secret,
	Sender ID and Recipient ID are the same but ID Context is different.		Sender ID and Recipient ID are the same but ID Context is different.
	Therefore, the main requirement for the nonces is that they have a		Therefore, the main requirement for the nonces is that they have a
	skipping to change at page 5, line 18 ¶		skipping to change at page 5, line 22 ¶
	C RS AS		C RS AS
	| [-- Resource Request --->] | |		| [-- Resource Request --->] | |
	| | |		| | |
	| [<----- AS Information --] | |		| [<----- AS Information --] | |
	| | |		| | |
	| ----- POST /token ----------------------------> |		| ----- POST /token ----------------------------> |
	| | |		| | |
	| <---------------------------- Access Token ----- |		| <---------------------------- Access Token ----- |
	| + RS Information |		| + RS Information |
	| ---- POST /authz-info ---> | |		| ---- POST /authz-info ---> | |
			| (access_token, N1) | |
	| | |		| | |
	| <--- 2.01 Created (N1) --- | |		| <--- 2.01 Created (N2) --- | |
	| | |		| | |
	/Sec Context Derivation/ | |		/Sec Context /Sec Context |
			Derivation/ Derivation/ |
	| | |		| | |
	| ---- OSCORE Request -----> | |		| ---- OSCORE Request -----> | |
	| (N1, N2) | |		| ?(N1, N2) | |
	| | |
	| /Sec Context Derivation/ |
	| | |		| | |
	| <--- OSCORE Response ----- | |		| <--- OSCORE Response ----- | |
	| | |		| | |
	| ---- OSCORE Request -----> | |		| ---- OSCORE Request -----> | |
	| | |		| | |
	| <--- OSCORE Response ----- | |		| <--- OSCORE Response ----- | |
	| ... | |		| ... | |
	Figure 1: Protocol Overview		Figure 1: Protocol Overview
	skipping to change at page 6, line 23 ¶		skipping to change at page 6, line 23 ¶
	An example of such a request, in CBOR diagnostic notation without the		An example of such a request, in CBOR diagnostic notation without the
	tag and value abbreviations is reported in Figure 2		tag and value abbreviations is reported in Figure 2
	Header: POST (Code=0.02)		Header: POST (Code=0.02)
	Uri-Host: "as.example.com"		Uri-Host: "as.example.com"
	Uri-Path: "token"		Uri-Path: "token"
	Content-Format: "application/ace+cbor"		Content-Format: "application/ace+cbor"
	Payload:		Payload:
	{		{
	"grant_type" : "client_credentials",
	"client_id" : "myclient",
	"req_aud" : "tempSensor4711",		"req_aud" : "tempSensor4711",
	"scope" : "read"		"scope" : "read"
	}		}
	Figure 2: Example C-to-AS POST /token request for an access token		Figure 2: Example C-to-AS POST /token request for an access token
	bound to a symmetric key.		bound to a symmetric key.
	If the client wants to update its access rights without changing an		If the client wants to update its access rights without changing an
	existing OSCORE Security Context, it MUST include in its POST request		existing OSCORE Security Context, it MUST include in its POST request
	to the token endpoint a req_cnf object carrying the client's		to the token endpoint a req_cnf object carrying the client's
	skipping to change at page 7, line 10 ¶		skipping to change at page 7, line 10 ¶
	Section 5.6.3 of [I-D.ietf-ace-oauth-authz].		Section 5.6.3 of [I-D.ietf-ace-oauth-authz].
	An example of such a request, in CBOR diagnostic notation without the		An example of such a request, in CBOR diagnostic notation without the
	tag and value abbreviations is reported in Figure 3		tag and value abbreviations is reported in Figure 3
	Header: POST (Code=0.02)		Header: POST (Code=0.02)
	Uri-Host: "as.example.com"		Uri-Host: "as.example.com"
	Uri-Path: "token"		Uri-Path: "token"
	Content-Format: "application/ace+cbor"		Content-Format: "application/ace+cbor"
	Payload:		Payload:
	{		{
	"grant_type" : "client_credentials",
	"client_id" : "myclient",
	"req_aud" : "tempSensor4711",		"req_aud" : "tempSensor4711",
	"scope" : "write",		"scope" : "write",
	"req_cnf" : {		"req_cnf" : {
	"kid" : b64'Qg'		"kid" : "myclient"
	}		}
	Figure 3: Example C-to-AS POST /token request for updating rights to		Figure 3: Example C-to-AS POST /token request for updating rights to
	an access token bound to a symmetric key.		an access token bound to a symmetric key.
	3.2. AS-to-C: Access Token		3.2. AS-to-C: Access Token
	After verifying the POST request to the token endpoint and that the		After verifying the POST request to the token endpoint and that the
	client is authorized to obtain an access token corresponding to its		client is authorized to obtain an access token corresponding to its
	access token request, the AS responds as defined in section 5.6.2 of		access token request, the AS responds as defined in section 5.6.2 of
	[I-D.ietf-ace-oauth-authz]. If the client request was invalid, or		[I-D.ietf-ace-oauth-authz]. If the client request was invalid, or
	not authorized, the AS returns an error response as described in		not authorized, the AS returns an error response as described in
	section 5.6.3 of [I-D.ietf-ace-oauth-authz].		section 5.6.3 of [I-D.ietf-ace-oauth-authz].
	The AS signals that the use of OSCORE is REQUIRED for a specific		The AS can signal that the use of OSCORE is REQUIRED for a specific
	access token by including the "profile" parameter with the value		access token by including the "profile" parameter with the value
	"coap_oscore" in the access token response. This means that the		"coap_oscore" in the access token response. This means that the
	client MUST use OSCORE towards all resource servers for which this		client MUST use OSCORE towards all resource servers for which this
	access token is valid, and follow Section 4.3 to derive the security		access token is valid, and follow Section 4.3 to derive the security
	context to run OSCORE.		context to run OSCORE. Usually it is assumed that constrained
			devices will be pre-configured with the necessary profile, so that
			this kind of profile negotiation can be omitted.
	Moreover, the AS MUST provision the following data:		Moreover, the AS MUST provision the following data:
	o a master secret		o a master secret
	o a client identifier
	o a server identifier		o a server identifier
	Additionally, the AS MAY provision the following data, in the same		Additionally, the AS MAY provision the following data, in the same
	response.		response.
			o a client identifier
	o an AEAD algorithm		o an AEAD algorithm
	o an HKDF algorithm		o an HKDF algorithm
	o a salt		o a salt
	o a replay window type and size		o a replay window type and size
	The master secret MUST be communicated as the 'ms' field in the		The master secret MUST be communicated as the 'ms' field in the
	OSCORE_Security_Context in the 'cnf' parameter of the access token		OSCORE_Security_Context in the 'cnf' parameter of the access token
	response as defined in Section 3.2 of [I-D.ietf-ace-oauth-params].		response as defined in Section 3.2 of [I-D.ietf-ace-oauth-params].
	The OSCORE_Security_Context is a CBOR map object, defined in		The OSCORE_Security_Context is a CBOR map object, defined in
	Section 3.2.1. The AEAD algorithm MAY be included as the 'alg'		Section 3.2.1. The AEAD algorithm MAY be included as the 'alg'
	parameter in the OSCORE_Security_Context; the HKDF algorithm MAY be		parameter in the OSCORE_Security_Context; the HKDF algorithm MAY be
	included as the 'hkdf' parameter of the OSCORE_Security_Context, the		included as the 'hkdf' parameter of the OSCORE_Security_Context, the
	salt MAY be included as the 'salt' parameter of the		salt MAY be included as the 'salt' parameter of the
	COSCORE_Security_Context and the replay window type and size MAY be		COSCORE_Security_Context, and the replay window type and size MAY be
	included as the 'rpl' of the OSCORE_Security_Context, as defined in		included as the 'rpl' of the OSCORE_Security_Context, as defined in
	Section 3.2.1.		Section 3.2.1.
	The same parameters MUST be included as metadata of the access token.		The same parameters MUST be included as metadata of the access token.
	This profile RECOMMENDS the use of CBOR web token (CWT) as specified		This profile RECOMMENDS the use of CBOR web token (CWT) as specified
	in [RFC8392]. If the token is a CWT, the same		in [RFC8392]. If the token is a CWT, the same
	OSCORE_Security_Context structure defined above MUST be placed in the		OSCORE_Security_Context structure defined above MUST be placed in the
	'cnf' claim of this token.		'cnf' claim of this token.
	The AS MUST also assign identifiers to both client and RS, which are		The AS MUST also assign an identifier to the RS, and MAY assign an
	then used as Sender ID and Recipient ID in the OSCORE context as		identifier to the client. These identifiers are then used as Sender
	described in section 3.1 of [I-D.ietf-core-object-security]. The		ID and Recipient ID in the OSCORE context as described in section 3.1
	client identifiers MUST be unique in the set of all clients on a		of [I-D.ietf-core-object-security]. The client identifiers MUST be
	single RS, and RS identifiers MUST be unique in the set of all RS for		unique in the set of all clients on a single RS, and RS identifiers
	any given client. Moreover, these MUST be included in the		MUST be unique in the set of all RS for any given client. Moreover,
	OSCORE_Security_Context, as defined in Section 3.2.1.		when assigned, these MUST be included in the OSCORE_Security_Context,
			as defined in Section 3.2.1.
	We assume in this document that a resource is associated to one		We assume in this document that a resource is associated to one
	single AS, which makes it possible to assume unique identifiers for		single AS, which makes it possible to assume unique identifiers for
	each client requesting a particular resource to a RS. If this is not		each client requesting a particular resource to a RS. If this is not
	the case, collisions of identifiers may appear in the RS, in which		the case, collisions of identifiers may appear in the RS, in which
	case the RS needs to have a mechanism in place to disambiguate		case the RS needs to have a mechanism in place to disambiguate
	identifiers or mitigate their effect.		identifiers or mitigate their effect.
	Note that in Section 4.3 C sets the Sender ID of its Security Context		Note that in Section 4.3 C sets the Sender ID of its Security Context
	to the clientId value received and the Recipient ID to the serverId		to the clientId value received and the Recipient ID to the serverId
	value, and RS does the opposite.		value, and RS does the opposite.
	Figure 4 shows an example of such an AS response, in CBOR diagnostic		Figure 4 shows an example of such an AS response, in CBOR diagnostic
	notation without the tag and value abbreviations.		notation without the tag and value abbreviations.
	Header: Created (Code=2.01)		Header: Created (Code=2.01)
	Content-Type: "application/cose+cbor"		Content-Type: "application/ace+cbor"
	Payload:		Payload:
	{		{
	"access_token" : b64'SlAV32hkKG ...		"access_token" : h'a5037674656d7053656e73 ...'
	(remainder of access token omitted for brevity)',		(remainder of access token omitted for brevity)',
	"profile" : "coap_oscore",		"profile" : "coap_oscore",
	"expires_in" : "3600",		"expires_in" : "3600",
	"cnf" : {		"cnf" : {
	"OSCORE_Security_Context" : {		"OSCORE_Security_Context" : {
	"alg" : "AES-CCM-16-64-128",		"alg" : "AES-CCM-16-64-128",
	"clientId" : b64'qA',		"clientId" : b64'qA',
	"serverId" : b64'Qg',		"serverId" : b64'Qg',
	"ms" : b64'+a+Dg2jjU+eIiOFCa9lObw'		"ms" : h'f9af838368e353e78888e1426bd94e6f'
	}		}
	}		}
	}		}
	Figure 4: Example AS-to-C Access Token response with OSCORE profile.		Figure 4: Example AS-to-C Access Token response with OSCORE profile.
	Figure 5 shows an example CWT, containing the necessary OSCORE		Figure 5 shows an example CWT, containing the necessary OSCORE
	parameters in the 'cnf' claim, in CBOR diagnostic notation without		parameters in the 'cnf' claim, in CBOR diagnostic notation without
	tag and value abbreviations.		tag and value abbreviations.
	{		{
	"aud" : "tempSensorInLivingRoom",		"aud" : "tempSensorInLivingRoom",
	"iat" : "1360189224",		"iat" : "1360189224",
	"exp" : "1360289224",		"exp" : "1360289224",
	"scope" : "temperature_g firmware_p",		"scope" : "temperature_g firmware_p",
	"cnf" : {		"cnf" : {
	"OSCORE_Security_Context" : {		"OSCORE_Security_Context" : {
	"alg" : "AES-CCM-16-64-128",		"alg" : "AES-CCM-16-64-128",
	"clientId" : b64'Qg',		"clientId" : "client",
	"serverId" : b64'qA',		"serverId" : "server",
	"ms" : b64'+a+Dg2jjU+eIiOFCa9lObw'		"ms" : h'f9af838368e353e78888e1426bd94e6f'
	}		}
	}		}
	Figure 5: Example CWT with OSCORE parameters.		Figure 5: Example CWT with OSCORE parameters.
			The same CWT token as in Figure 5, using the value abbreviations
			defined in [I-D.ietf-ace-oauth-authz] and
			[I-D.ietf-ace-cwt-proof-of-possession] and encoded in CBOR is shown
			in Figure 6.
			NOTE TO THE RFC EDITOR: before publishing, it should be checked (and
			in case fixed) that the values used below (which are not yet
			registered) are the final values registered in IANA.
			A5 # map(5)
			03 # unsigned(3)
			76 # text(22)
			74656D7053656E736F72496E4C6976696E67526F6F6D
			# "tempSensorInLivingRoom"
			06 # unsigned(6)
			1A 5112D728 # unsigned(1360189224)
			04 # unsigned(4)
			1A 51145DC8 # unsigned(1360289224)
			09 # unsigned(9)
			78 18 # text(24)
			74656D70657261747572655F67206669726D776172655F70
			# "temperature_g firmware_p"
			08 # unsigned(8)
			A1 # map(1)
			04 # unsigned(4)
			A4 # map(4)
			05 # unsigned(5)
			0A # unsigned(10)
			02 # unsigned(2)
			66 # text(6)
			636C69656E74 # "client"
			03 # unsigned(3)
			66 # text(6)
			736572766572 # "server"
			01 # unsigned(1)
			50 # bytes(16)
			F9AF838368E353E78888E1426BD94E6F
			Figure 6: Example CWT with OSCORE parameters.
	If the client has requested an update to its access rights using the		If the client has requested an update to its access rights using the
	same OSCORE Security Context, which is valid and authorized, the AS		same OSCORE Security Context, which is valid and authorized, the AS
	MUST omit the 'cnf' parameter in the response, and MUST carry the		MUST omit the 'cnf' parameter in the response, and MUST carry the
	client identifier in the 'kid' field in the 'cnf' parameter of the		client identifier in the 'kid' field in the 'cnf' parameter of the
	token. The client identifier needs to be provisioned, in order for		token. The client identifier needs to be provisioned, in order for
	the RS to identify the previously generated Security Context.		the RS to identify the previously generated Security Context.
	Figure 6 shows an example of such an AS response, in CBOR diagnostic		Figure 7 shows an example of such an AS response, in CBOR diagnostic
	notation without the tag and value abbreviations.		notation without the tag and value abbreviations.
	Header: Created (Code=2.01)		Header: Created (Code=2.01)
	Content-Type: "application/cose+cbor"		Content-Type: "application/ace+cbor"
	Payload:		Payload:
	{		{
	"access_token" : b64'SlAV32hkKG ...		"access_token" : h'a5037674656d7053656e73 ...'
	(remainder of access token omitted for brevity)',		(remainder of access token omitted for brevity)',
	"profile" : "coap_oscore",		"profile" : "coap_oscore",
	"expires_in" : "3600"		"expires_in" : "3600"
	}		}
	Figure 6: Example AS-to-C Access Token response with OSCORE profile,		Figure 7: Example AS-to-C Access Token response with OSCORE profile,
	for update of access rights.		for update of access rights.
	Figure 7 shows an example CWT, containing the necessary OSCORE		Figure 8 shows an example CWT, containing the necessary OSCORE
	parameters in the 'cnf' claim for update of access rights, in CBOR		parameters in the 'cnf' claim for update of access rights, in CBOR
	diagnostic notation without tag and value abbreviations.		diagnostic notation without tag and value abbreviations.
	{		{
	"aud" : "tempSensorInLivingRoom",		"aud" : "tempSensorInLivingRoom",
	"iat" : "1360189224",		"iat" : "1360189224",
	"exp" : "1360289224",		"exp" : "1360289224",
	"scope" : "temperature_h",		"scope" : "temperature_h",
	"cnf" : {		"cnf" : {
	"kid" : b64'Qg'		"kid" : b64'Qg'
	}		}
	}		}
	Figure 7: Example CWT with OSCORE parameters for update of access		Figure 8: Example CWT with OSCORE parameters for update of access
	rights.		rights.
	3.2.1. OSCORE_Security_Context Object		3.2.1. OSCORE_Security_Context Object
	An OSCORE_Security_Context is an object that represents part or all		An OSCORE_Security_Context is an object that represents part or all
	of an OSCORE Security Context (Section 3.1 of		of an OSCORE Security Context (Section 3.1 of
	[I-D.ietf-core-object-security]). The OSCORE_Security_Context object		[I-D.ietf-core-object-security]). The OSCORE_Security_Context object
	can either be encoded as JSON or as CBOR. In both cases, the set of		can either be encoded as JSON or as CBOR. In both cases, the set of
	common parameters that can appear in an OSCORE_Security_Context		common parameters that can appear in an OSCORE_Security_Context
	object can be found in the IANA "OSCORE Security Context Parameters"		object can be found in the IANA "OSCORE Security Context Parameters"
	registry (Section Section 9.2) and is defined below. All parameters		registry (Section Section 9.2) and is defined below. All parameters
	are optional. Table 1 provides a summary of the		are optional. Table 1 provides a summary of the
	OSCORE_Security_Context parameters defined in this section.		OSCORE_Security_Context parameters defined in this section.
	+----------+-------+----------------+--------------+----------------+		+-----------+-------+----------------+--------------+---------------+
	| name | CBOR | CBOR type | registry | description |		| name | CBOR | CBOR type | registry | description |
	| | label | | | |		| | label | | | |
	+----------+-------+----------------+--------------+----------------+		+-----------+-------+----------------+--------------+---------------+
	| ms | 1 | bstr | | OSCORE Master |		| ms | 1 | bstr | | OSCORE Master |
	| | | | | Secret value |		| | | | | Secret value |
	| | | | | |		| | | | | |
	| clientId | 2 | bstr | | OSCORE Sender |		| clientId | 2 | bstr | | OSCORE Sender |
	| | | | | ID value of |		| | | | | ID value of |
	| | | | | the client, |		| | | | | the client, |
	| | | | | OSCORE |		| | | | | OSCORE |
	| | | | | Recipient ID |		| | | | | Recipient ID |
	| | | | | value of the |		| | | | | value of the |
	| | | | | server |		| | | | | server |
	| | | | | |		| | | | | |
	| serverId | 3 | bstr | | OSCORE Sender |		| serverId | 3 | bstr | | OSCORE Sender |
	| | | | | ID value of |		| | | | | ID value of |
	| | | | | the server, |		| | | | | the server, |
	| | | | | OSCORE |		| | | | | OSCORE |
	| | | | | Recipient ID |		| | | | | Recipient ID |
	| | | | | value of the |		| | | | | value of the |
	| | | | | client |		| | | | | client |
	| | | | | |		| | | | | |
	| hkdf | 4 | bstr / int | COSE | OSCORE HKDF |		| hkdf | 4 | bstr / int | COSE | OSCORE HKDF |
	| | | | Algorithm | value |		| | | | Algorithm | value |
	| | | | Values | |		| | | | Values | |
	| | | | (HMAC-based) | |		| | | | (HMAC-based) | |
	| | | | | |		| | | | | |
	| alg | 5 | tstr / int | COSE | OSCORE AEAD |		| alg | 5 | tstr / int | COSE | OSCORE AEAD |
	| | | | Algorithm | Algorithm |		| | | | Algorithm | Algorithm |
	| | | | Values | value |		| | | | Values | value |
	| | | | (AEAD) | |		| | | | (AEAD) | |
	| | | | | |		| | | | | |
	| salt | 6 | bstr | | OSCORE Master |		| salt | 6 | bstr | | OSCORE Master |
	| | | | | Salt value |		| | | | | Salt value |
	| | | | | |		| | | | | |
	| rpl | 7 | bstr / int | | OSCORE Replay |		| contextId | 7 | bstr | | OSCORE ID |
	| | | | | Window Type |		| | | | | Context value |
	| | | | | and Size |		| | | | | |
	+----------+-------+----------------+--------------+----------------+		| rpl | 8 | bstr / int | | OSCORE Replay |
			| | | | | Window Type |
			| | | | | and Size |
			+-----------+-------+----------------+--------------+---------------+
	Table 1: OSCORE_Security_Context Parameters		Table 1: OSCORE_Security_Context Parameters
	ms: This parameter identifies the OSCORE Master Secret value, which		ms: This parameter identifies the OSCORE Master Secret value, which
	is a byte string. For more information about this field, see		is a byte string. For more information about this field, see
	section 3.1 of [I-D.ietf-core-object-security]. In JSON, the "ms"		section 3.1 of [I-D.ietf-core-object-security]. In JSON, the "ms"
	value is a Base64 encoded byte string. In CBOR, the "ms" type is		value is a Base64 encoded byte string. In CBOR, the "ms" type is
	bstr, and has label 1.		bstr, and has label 1.
	clientId: This parameter identifies a client identifier as a byte		clientId: This parameter identifies a client identifier as a byte
	string. This identifier is used as OSCORE Sender ID in the client		string. This identifier is used as OSCORE Sender ID in the client
	and OSCORE Recipient ID in the server. For more information about		and OSCORE Recipient ID in the server. For more information about
	this field, see section 3.1 of [I-D.ietf-core-object-security].		this field, see section 3.1 of [I-D.ietf-core-object-security].
	In JSON, the "clientID" value is a Base64 encoded byte string. In		In JSON, the "clientId" value is a Base64 encoded byte string. In
	CBOR, the "clientID" type is bstr, and has label 2.		CBOR, the "clientId" type is bstr, and has label 2.
	serverId: This parameter identifies a server identifier as a byte		serverId: This parameter identifies a server identifier as a byte
	string. This identifier is used as OSCORE Sender ID in the client		string. This identifier is used as OSCORE Sender ID in the client
	and OSCORE Recipient ID in the server. For more information about		and OSCORE Recipient ID in the server. For more information about
	this field, see section 3.1 of [I-D.ietf-core-object-security].		this field, see section 3.1 of [I-D.ietf-core-object-security].
	In JSON, the "serverID" value is a Base64 encoded byte string. In		In JSON, the "serverId" value is a Base64 encoded byte string. In
	CBOR, the "serverID" type is bstr, and has label 3.		CBOR, the "serverId" type is bstr, and has label 3.
	hkdf: This parameter identifies the OSCORE HKDF Algorithm. For more		hkdf: This parameter identifies the OSCORE HKDF Algorithm. For more
	information about this field, see section 3.1 of		information about this field, see section 3.1 of
	[I-D.ietf-core-object-security]. The values used MUST be		[I-D.ietf-core-object-security]. The values used MUST be
	registered in the IANA "COSE Algorithms" registry and MUST be		registered in the IANA "COSE Algorithms" registry and MUST be
	HMAC-based HKDF algorithms. The value can either be the integer		HMAC-based HKDF algorithms. The value can either be the integer
	or the text string value of the HMAC-based HKDF algorithm in the		or the text string value of the HMAC-based HKDF algorithm in the
	"COSE Algorithms" registry. In JSON, the "hkdf" value is a case-		"COSE Algorithms" registry. In JSON, the "hkdf" value is a case-
	sensitive ASCII string or an integer. In CBOR, the "hkdf" type is		sensitive ASCII string or an integer. In CBOR, the "hkdf" type is
	tstr or int, and has label 4.		tstr or int, and has label 4.
	skipping to change at page 12, line 45 ¶		skipping to change at page 13, line 48 ¶
	Algorithms" registry. In JSON, the "alg" value is a case-		Algorithms" registry. In JSON, the "alg" value is a case-
	sensitive ASCII string or an integer. In CBOR, the "alg" type is		sensitive ASCII string or an integer. In CBOR, the "alg" type is
	tstr or int, and has label 5.		tstr or int, and has label 5.
	salt: This parameter identifies the OSCORE Master Salt value, which		salt: This parameter identifies the OSCORE Master Salt value, which
	is a byte string. For more information about this field, see		is a byte string. For more information about this field, see
	section 3.1 of [I-D.ietf-core-object-security]. In JSON, the		section 3.1 of [I-D.ietf-core-object-security]. In JSON, the
	"salt" value is a Base64 encoded byte string. In CBOR, the "salt"		"salt" value is a Base64 encoded byte string. In CBOR, the "salt"
	type is bstr, and has label 6.		type is bstr, and has label 6.
			contextId: This parameter identifies the security context as a byte
			string. This identifier is used as OSCORE ID Context. For more
			information about this field, see section 3.1 of
			[I-D.ietf-core-object-security]. In JSON, the "contextID" value
			is a Base64 encoded byte string. In CBOR, the "contextID" type is
			bstr, and has label 7.
	repl: This parameter is used to carry the OSCORE value, encoded as a		repl: This parameter is used to carry the OSCORE value, encoded as a
	bstr. This parameter identifies the OSCORE Replay Window Size and		bstr. This parameter identifies the OSCORE Replay Window Size and
	Type value, which is a byte string. For more information about		Type value, which is a byte string. For more information about
	this field, see section 3.1 of [I-D.ietf-core-object-security].		this field, see section 3.1 of [I-D.ietf-core-object-security].
	In JSON, the "repl" value is a Base64 encoded byte string. In		In JSON, the "repl" value is a Base64 encoded byte string. In
	CBOR, the "repl" type is bstr, and has label 7.		CBOR, the "repl" type is bstr, and has label 8.
	An example of JSON OSCORE_Security_Context is given in Figure 8.		An example of JSON OSCORE_Security_Context is given in Figure 9.
	"OSCORE_Security_Context" : {		"OSCORE_Security_Context" : {
	"alg" : "AES-CCM-16-64-128",		"alg" : "AES-CCM-16-64-128",
	"clientId" : b64'qA',		"clientId" : b64'qA',
	"serverId" : b64'Qg',		"serverId" : b64'Qg',
	"ms" : b64'+a+Dg2jjU+eIiOFCa9lObw'		"ms" : b64'+a+Dg2jjU+eIiOFCa9lObw'
	}		}
	Figure 8: Example JSON OSCORE_Security_Context object		Figure 9: Example JSON OSCORE_Security_Context object
	The CDDL grammar describing the CBOR OSCORE_Security_Context object		The CDDL grammar describing the CBOR OSCORE_Security_Context object
	is:		is:
	OSCORE_Security_Context = {		OSCORE_Security_Context = {
	? 1 => bstr, ; ms		? 1 => bstr, ; ms
	? 2 => bstr, ; clientId		? 2 => bstr, ; clientId
	? 3 => bstr, ; serverId		? 3 => bstr, ; serverId
	? 4 => tstr / int, ; hkdf		? 4 => tstr / int, ; hkdf
	? 5 => tstr / int, ; alg		? 5 => tstr / int, ; alg
	? 6 => bstr, ; salt		? 6 => bstr, ; salt
	? 7 => bstr / tstr ; rpl		? 7 => bstr, ; contextId
			? 8 => bstr / tstr, ; rpl
			* int / tstr => any
	}		}
	4. Client-RS Communication		4. Client-RS Communication
	The following subsections describe the details of the POST request		The following subsections describe the details of the POST request
	and response to the authz-info endpoint between client and RS. The		and response to the authz-info endpoint between client and RS. The
	client posts the token that includes the materials provisioned by the		client generates a nonce N1 and posts it together with the token that
	AS to the RS, which can then use Section 3.2 of		includes the materials provisioned by the AS to the RS. The RS then
			derives a nonce N2 and use Section 3.2 of
	[I-D.ietf-core-object-security] to derive a security context based on		[I-D.ietf-core-object-security] to derive a security context based on
	a shared master secret and a set of other parameters, established		a shared master secret and the two nonces, established between client
	between client and server.		and server.
	Note that the proof-of-possession required to bind the access token		Note that the proof-of-possession required to bind the access token
	to the client is implicitly performed by generating the shared OSCORE		to the client is implicitly performed by generating the shared OSCORE
	Security Context using the pop-key as master secret, for both client		Security Context using the pop-key as master secret, for both client
	and RS. An attacker using a stolen token will not be able to		and RS. An attacker using a stolen token will not be able to
	generate a valid OSCORE context and thus not be able to prove		generate a valid OSCORE context and thus not be able to prove
	possession of the pop-key.		possession of the pop-key.
	4.1. C-to-RS: POST to authz-info endpoint		4.1. C-to-RS: POST to authz-info endpoint
	The client MUST use CoAP and the Authorization Information resource		The client MUST generate a nonce N1 very unlikely to have been
	as described in section 5.8.1 of [I-D.ietf-ace-oauth-authz] to		previously used with the same input keying material. This profile
	transport the token to the RS.		RECOMMENDS to use a 64-bit long random number as nonce. The client
			MUST store this nonce as long as the response from the RS is not
			received and the access token related to it is still valid. The
			client MUST use CoAP and the Authorization Information resource as
			described in section 5.8.1 of [I-D.ietf-ace-oauth-authz] to transport
			the token and N1 to the RS. The client MUST use the Content-Format
			"application/ace+cbor" defined in section 8.14 of
			[I-D.ietf-ace-oauth-authz]. The client MUST include the access token
			using the correct CBOR label (e.g., "cwt" for CWT, "jwt" for JWT) and
			N1 using the 'nonce' parameter defined in section 5.1.2 of
			[I-D.ietf-ace-oauth-authz].
	The authz-info endpoint is not protected, nor are the responses from		The authz-info endpoint is not protected, nor are the responses from
	this resource.		this resource.
	The access token MUST be encrypted, since it is transferred from the		The access token MUST be encrypted, since it is transferred from the
	client to the RS over an unprotected channel.		client to the RS over an unprotected channel.
	Note that a client may be required to re-POST the access token, since		Note that a client may be required to re-POST the access token, since
	an RS may delete a stored access token, due to lack of memory.		an RS may delete a stored access token, due to lack of memory.
	Figure 9 shows an example of the request sent from the client to the		Figure 10 shows an example of the request sent from the client to the
	RS.		RS, in CBOR diagnostic notation without the tag and value
			abbreviations.
	Header: POST (Code=0.02)		Header: POST (Code=0.02)
	Uri-Host: "rs.example.com"		Uri-Host: "rs.example.com"
	Uri-Path: "authz-info"		Uri-Path: "authz-info"
	Content-Format: "application/cwt"		Content-Format: "application/ace+cbor"
	Payload:		Payload:
	b64'SlAV32hkKG ...		{
	(remainder of access token omitted for brevity)',		"access_token": h'a5037674656d7053656e73 ...'
			(remainder of access token omitted for brevity)',
			"nonce": h'018a278f7faab55a'
			}
	Figure 9: Example C-to-RS POST /authz-info request using CWT		Figure 10: Example C-to-RS POST /authz-info request using CWT
	4.2. RS-to-C: 2.01 (Created)		4.2. RS-to-C: 2.01 (Created)
	The RS MUST follow the procedures defined in section 5.8.1 of		The RS MUST follow the procedures defined in section 5.8.1 of
	[I-D.ietf-ace-oauth-authz]: the RS MUST verify the validity of the		[I-D.ietf-ace-oauth-authz]: the RS MUST verify the validity of the
	token. If the token is valid, the RS MUST respond to the POST		token. If the token is valid, the RS MUST respond to the POST
	request with 2.01 (Created). If the token is valid but is associated		request with 2.01 (Created). If the token is valid but is associated
	to claims that the RS cannot process (e.g., an unknown scope) the RS		to claims that the RS cannot process (e.g., an unknown scope), or if
			any of the expected parameters in the OSCORE_Security_Context is
			missing (e.g. any of the mandatory parameters from the AS), the RS
	MUST respond with a response code equivalent to the CoAP code 4.00		MUST respond with a response code equivalent to the CoAP code 4.00
	(Bad Request). In the latter case the RS MAY provide additional		(Bad Request). In the latter case the RS MAY provide additional
	information in the error response, in order to clarify what went		information in the error response, in order to clarify what went
	wrong. The RS MAY make an introspection request to validate the		wrong. The RS MAY make an introspection request to validate the
	token before responding to the POST request to the authz-info		token before responding to the POST request to the authz-info
	endpoint.		endpoint.
	Additionally, the RS MUST generate a nonce (N1) with a good amount of		Additionally, the RS MUST generate a nonce N2 very unlikely to have
	randomness, and include it in the payload of the 2.01 (Created)		been previously used with the same input keying material, and send it
	response as a CBOR byte string. This profile RECOMMENDS to use a		within the 2.01 (Created) response. The payload of the 2.01
	nonce of 64 bits. The RS MUST store this nonce as long as the access		(Created) response MUST be a CBOR map containing the 'nonce'
	token related to it is still valid.		parameter defined in section 5.1.2 of [I-D.ietf-ace-oauth-authz], set
			to N2. This profile RECOMMENDS to use a 64-bit long random number as
	Note that, when using this profile, an identifier of the token (e.g.,		nonce. Moreover, if the OSCORE_Security_Context in the token did not
	the cti for a CWT) is not transported in the payload of this request,		contain a 'clientId' parameter, the RS MUST generate an identifier,
	as section 5.8.1 of [I-D.ietf-ace-oauth-authz] allows.		unique in the set of all its existing client identifiers, and send it
			in a 'clientId' parameter in the CBOR map as a CBOR bstr. The RS MAY
			generate and send a 'ClientId' identifier even though the
			OSCORE_Security_Context contained such a parameter, in order to
			guarantee the uniqueness of the client identifier. The RS MUST use
			the Content-Format "application/ace+cbor" defined in section 8.14 of
			[I-D.ietf-ace-oauth-authz].
	Figure 10 shows an example of the response sent from the RS to the		Figure 11 shows an example of the response sent from the RS to the
	client.		client, in CBOR diagnostic notation without the tag and value
			abbreviations.
	Header: Created (Code=2.01)		Header: Created (Code=2.01)
	Content-Format: "application/cbor"		Content-Format: "application/ace+cbor"
	Payload:		Payload:
	h'018a278f7faab55a',		{
			"nonce": h'25a8991cd700ac01'
			}
	Figure 10: Example RS-to-C 2.01 (Created) response		Figure 11: Example RS-to-C 2.01 (Created) response
	When receiving an updated access token with updated authorization		When receiving an updated access token with updated authorization
	information from the client (see section Section 3.1), it is		information from the client (see section Section 3.1), it is
	RECOMMENDED that the RS overwrites the previous token, that is only		RECOMMENDED that the RS overwrites the previous token, that is only
	the latest authorization information in the token received by the RS		the latest authorization information in the token received by the RS
	is valid. This simplifies for the RS to keep track of authorization		is valid. This simplifies for the RS to keep track of authorization
	information for a given client.		information for a given client.
	As specified in section 5.8.3 of [I-D.ietf-ace-oauth-authz], the RS		As specified in section 5.8.3 of [I-D.ietf-ace-oauth-authz], the RS
	MUST notify the client with an error response with code 4.01		MUST notify the client with an error response with code 4.01
	(Unauthorized) for any long running request before terminating the		(Unauthorized) for any long running request before terminating the
	session, when the access token expires.		session, when the access token expires.
	4.3. OSCORE Setup		4.3. OSCORE Setup
	Once receiving the 2.01 (Created) response from the RS, following the		Once receiving the 2.01 (Created) response from the RS, following the
	POST request to authz-info endpoint, the client MUST extract the		POST request to authz-info endpoint, the client MUST extract the
	nonce N1 from the CBOR byte string in the payload of the response.		nonce N2 from the 'nonce' parameter and the client identifier from
	The client MUST generate itself a nonce (N2) with a good amount of		the 'clientId' in the CBOR map in the payload of the response. Then,
	randomness. This profile RECOMMENDS to use a nonce of 64 bits.		the client MUST set the ID Context of the Security Context created to
	Then, the client MUST set the ID Context of the Security Context		communicate with the RS to the concatenation of N1 and N2, in this
	created to communicate with the RS to the concatenation of N1 and N2,		order: ID Context = N1 | N2, where | denotes byte string
	in this order: ID Context = N1 | N2, where | denotes byte string		concatenation. The client MUST set the Master Secret and Recipient
	concatenation. The client MUST set the Master Secret, Sender ID and		ID from the parameters received from the AS in Section 3.2. The
	Recipient ID from the parameters received from the AS in Section 3.2.		client MUST set the AEAD Algorithm, Master Salt, HKDF, and Replay
	The client MUST set the AEAD Algorithm, Master Salt, HKDF and Replay
	Window from the parameters received from the AS in Section 3.2, if		Window from the parameters received from the AS in Section 3.2, if
	present. In case these parameters are omitted, the default values		present. In case these parameters are omitted, the default values
	are used as described in section 3.2 of		are used as described in section 3.2 of
	[I-D.ietf-core-object-security]. After that, the client MUST derive		[I-D.ietf-core-object-security]. The client MUST set the Sender ID
	the complete Security Context following section 3.2.1 of		from the 'clientId in the 2.01 (Created) response, if present;
			otherwise, the client MUST set the Sender ID from the parameters
			received from the AS in Section 3.2. After that, the client MUST
			derive the complete Security Context following section 3.2.1 of
	[I-D.ietf-core-object-security]. From this point on, the client MUST		[I-D.ietf-core-object-security]. From this point on, the client MUST
	use this Security Context to communicate with the RS when accessing		use this Security Context to communicate with the RS when accessing
	the resources as specified by the authorization information.		the resources as specified by the authorization information.
			If any of the expected parameters is missing (e.g. any of the
			mandatory parameters from the AS, or the 'clientId', either received
			from the AS or in the 2.01 (Created) response from the RS), the
			client MUST stop the exchange, and MUST NOT derive the Security
			Context. The client MAY restart the exchange, to get the correct
			security material.
	The client then uses this Security Context to send requests to RS		The client then uses this Security Context to send requests to RS
	using OSCORE. In the first request sent to the RS, the client MUST		using OSCORE. In the first request sent to the RS, the client MAY
	include the kid context, with value ID Context, i.e. N1 concatenated		include the kid context, with value ID Context, i.e. N1 concatenated
	with N2. The client needs to make sure the RS receives the kid		with N2.
	context, possibly adding the kid context to later requests, until it
	receives a valid OSCORE response from the RS using the same Security
	Context.
	When the RS receives this first OSCORE-protected request, it MUST		After sending the 2.01 (Created) response, the RS MUST set the ID
	extract the kid context from the message first. Then, it needs to		Context of the Security Context created to communicate with the
	verify that the first part of the kid context corresponds to the		client to the concatenation of N1 and N2, in this order: ID Context =
	nonce N1 it previously sent, and that it is followed by a non-zero-		N1 | N2, where | denotes byte string concatenation. The RS MUST set
	length byte string. If that is verified, the RS MUST set the ID		the Master Secret, Sender ID and Recipient ID from the parameters,
	Context to the kid context value. Then, the RS MUST set the Master		received from the client in the access token in Section 4.1 after
	Secret, Sender ID and Recipient ID from the parameters received from		validation of the token as specified in Section 4.2. The RS MUST set
	the client in the access token in Section 4.1. The RS MUST set the		the AEAD Algorithm, Master Salt, HKDF, and Replay Window from the
	AEAD Algorithm, Master Salt, HKDF and Replay Window from the
	parameters received from the client in the access token in		parameters received from the client in the access token in
	Section 4.1, if present. In case these parameters are omitted, the		Section 4.1 after validation of the token as specified in
			Section 4.2, if present. In case these parameters are omitted, the
	default values are used as described in section 3.2 of		default values are used as described in section 3.2 of
	[I-D.ietf-core-object-security]. After that, the RS MUST derive the		[I-D.ietf-core-object-security]. After that, the RS MUST derive the
	complete Security Context following section 3.2.1 of		complete Security Context following section 3.2.1 of
	[I-D.ietf-core-object-security], and MUST associate this Security		[I-D.ietf-core-object-security], and MUST associate this Security
	Context with the authorization information from the access token.		Context with the authorization information from the access token.
	Then, the RS MUST delete the nonce N1 from memory.
	The RS then uses this Security Context to verify the request and send		The RS then uses this Security Context to verify the request and send
	responses to RS using OSCORE. If OSCORE verification fails, error		responses to RS using OSCORE. If OSCORE verification fails, error
	responses are used, as specified in section 8 of		responses are used, as specified in section 8 of
	[I-D.ietf-core-object-security]. Additionally, if OSCORE		[I-D.ietf-core-object-security]. Additionally, if OSCORE
	verification succeeds, the verification of access rights is performed		verification succeeds, the verification of access rights is performed
	as described in section Section 4.4. The RS MUST NOT use the		as described in section Section 4.4. The RS MUST NOT use the
	Security Context after the related token has expired, and MUST		Security Context after the related token has expired, and MUST
	respond with a unprotected 4.01 (Unauthorized) error message.		respond with a unprotected 4.01 (Unauthorized) error message.
	4.4. Access rights verification		4.4. Access rights verification
	The RS MUST follow the procedures defined in section 5.8.2 of		The RS MUST follow the procedures defined in section 5.8.2 of
	[I-D.ietf-ace-oauth-authz]: if an RS receives an OSCORE-protected		[I-D.ietf-ace-oauth-authz]: if an RS receives an OSCORE-protected
	request from a client, then it processes according to		request from a client, then the RS processes it according to
	[I-D.ietf-core-object-security]. If OSCORE verification succeeds,		[I-D.ietf-core-object-security]. If OSCORE verification succeeds,
	and the target resource requires authorization, the RS retrieves the		and the target resource requires authorization, the RS retrieves the
	authorization information from the access token associated to the		authorization information from the access token associated to the
	Security Context. The RS then MUST verify that the authorization		Security Context. The RS then MUST verify that the authorization
	information covers the resource and the action requested.		information covers the resource and the action requested.
	The response code MUST be 4.01 (Unauthorized) in case the client has		The response code MUST be 4.01 (Unauthorized) in case the client has
	not used the Security Context associated with the access token, or if		not used the Security Context associated with the access token, or if
	RS has no valid access token for the client. If RS has an access		RS has no valid access token for the client. If RS has an access
	token for the client but not for the resource that was requested, RS		token for the client but not for the resource that was requested, RS
	skipping to change at page 17, line 41 ¶		skipping to change at page 20, line 5 ¶
	an RS when:		an RS when:
	o the Sequence Number space ends.		o the Sequence Number space ends.
	o the access token associated with the context expires.		o the access token associated with the context expires.
	o the client receives a number of 4.01 Unauthorized responses to		o the client receives a number of 4.01 Unauthorized responses to
	OSCORE requests using the same security context. The exact number		OSCORE requests using the same security context. The exact number
	needs to be specified by the application.		needs to be specified by the application.
	o the client receives a new nonce in the 2.01 Created response (see		o the client receives a new nonce in the 2.01 (Created) response
	Section 4.2) to a POST request to the authz-info endpoint, when		(see Section 4.2) to a POST request to the authz-info endpoint,
	re-posting a non-expired token associated to the existing context.		when re-posting a non-expired token associated to the existing
			context.
	The RS MUST discard the current security context associated with a		The RS MUST discard the current security context associated with a
	client when:		client when:
	o Sequence Number space ends.		o Sequence Number space ends.
	o Access token associated with the context expires.		o Access token associated with the context expires.
	7. Security Considerations		7. Security Considerations
	skipping to change at page 18, line 25 ¶		skipping to change at page 20, line 37 ¶
	OSCORE is designed to secure point-to-point communication, providing		OSCORE is designed to secure point-to-point communication, providing
	a secure binding between the request and the response(s). Thus the		a secure binding between the request and the response(s). Thus the
	basic OSCORE protocol is not intended for use in point-to-multipoint		basic OSCORE protocol is not intended for use in point-to-multipoint
	communication (e.g. multicast, publish-subscribe). Implementers of		communication (e.g. multicast, publish-subscribe). Implementers of
	this profile should make sure that their usecase corresponds to the		this profile should make sure that their usecase corresponds to the
	expected use of OSCORE, to prevent weakening the security assurances		expected use of OSCORE, to prevent weakening the security assurances
	provided by OSCORE.		provided by OSCORE.
	Since the use of nonces in the exchange guarantees uniqueness of AEAD		Since the use of nonces in the exchange guarantees uniqueness of AEAD
	keys and nonces even in case of re-boots, a good amount of randomness		keys and nonces, it is REQUIRED that nonces are not reused with the
	is required. If that is not guaranteed, nodes are still susceptible		same input keying material even in case of re-boots. This document
	to re-using nonces and keys, in case the Security Context is lost,		RECOMMENDS the use of 64 bit random nonces to guarantee non-reuse; if
	and on-path attacker replaying messages.		applications use something else, such as a counter, they need to
			guarantee that reboot and lost of state on either node does not
			provoke re-use. If that is not guaranteed, nodes are still
			susceptible to re-using AEAD nonces and keys, in case the Security
			Context is lost, and on-path attacker replay messages.
	This profiles recommends that the RS maintains a single access token		This profiles recommends that the RS maintains a single access token
	for a client. The use of multiple access tokens for a single client		for a client. The use of multiple access tokens for a single client
	increases the strain on the resource server as it must consider every		increases the strain on the resource server as it must consider every
	access token and calculate the actual permissions of the client.		access token and calculate the actual permissions of the client.
	Also, tokens may contradict each other which may lead the server to		Also, tokens may contradict each other which may lead the server to
	enforce wrong permissions. If one of the access tokens expires		enforce wrong permissions. If one of the access tokens expires
	earlier than others, the resulting permissions may offer insufficient		earlier than others, the resulting permissions may offer insufficient
	protection. Developers should avoid using multiple access tokens for		protection. Developers should avoid using multiple access tokens for
	a client.		a client.
	skipping to change at page 19, line 37 ¶		skipping to change at page 22, line 10 ¶
	and Authorization for Constrained Environments framework.		and Authorization for Constrained Environments framework.
	o Profile ID: TBD (value between 1 and 255)		o Profile ID: TBD (value between 1 and 255)
	o Change Controller: IESG		o Change Controller: IESG
	o Specification Document(s): [[this specification]]		o Specification Document(s): [[this specification]]
	9.2. OSCORE Security Context Parameters Registry		9.2. OSCORE Security Context Parameters Registry
	It is requested that IANA create a new registry entitled "OSCORE		It is requested that IANA create a new registry entitled "OSCORE
	Security Context Parameters" registry. The registry is to be created		Security Context Parameters" registry. The registry is to be created
	as Expert Review Required. Guidelines for the experts is provided		as Expert Review Required. Guidelines for the experts is provided
	Section 9.5. It should be noted that in additional to the expert		Section 9.5. It should be noted that in addition to the expert
	review, some portions of the registry require a specification,		review, some portions of the registry require a specification,
	potentially on standards track, be supplied as well.		potentially on standards track, be supplied as well.
	The columns of the registry are:		The columns of the registry are:
	name This is a descriptive name that enables easier reference to the		name The JSON name requested (e.g., "ms"). Because a core goal of
	item. It is not used in the CBOR encoding.		this specification is for the resulting representations to be
			compact, it is RECOMMENDED that the name be short. This name is
			case sensitive. Names may not match other registered names in a
			case-insensitive manner unless the Designated Experts state that
			there is a compelling reason to allow an exception. The name is
			not used in the CBOR encoding.
	CBOR label The value to be used to identify this algorithm. Key map		CBOR label The value to be used to identify this algorithm. Key map
	labels MUST be unique. The label can be a positive integer, a		labels MUST be unique. The label can be a positive integer, a
	negative integer or a string. Integer values between 0 and 255		negative integer or a string. Integer values between 0 and 255
	and strings of length 1 are designated as Standards Track Document		and strings of length 1 are designated as Standards Track Document
	required. Integer values from 256 to 65535 and strings of length		required. Integer values from 256 to 65535 and strings of length
	2 are designated as Specification Required. Integer values of		2 are designated as Specification Required. Integer values of
	greater than 65535 and strings of length greater than 2 are		greater than 65535 and strings of length greater than 2 are
	designated as expert review. Integer values less than -65536 are		designated as expert review. Integer values less than -65536 are
	marked as private use.		marked as private use.
	CBOR Type This field contains the CBOR type for the field.		CBOR Type This field contains the CBOR type for the field.
	skipping to change at page 21, line 38 ¶		skipping to change at page 24, line 15 ¶
	size.		size.
	10. References		10. References
	10.1. Normative References		10.1. Normative References
	[I-D.ietf-ace-oauth-authz]		[I-D.ietf-ace-oauth-authz]
	Seitz, L., Selander, G., Wahlstroem, E., Erdtman, S., and		Seitz, L., Selander, G., Wahlstroem, E., Erdtman, S., and
	H. Tschofenig, "Authentication and Authorization for		H. Tschofenig, "Authentication and Authorization for
	Constrained Environments (ACE) using the OAuth 2.0		Constrained Environments (ACE) using the OAuth 2.0
	Framework (ACE-OAuth)", draft-ietf-ace-oauth-authz-16		Framework (ACE-OAuth)", draft-ietf-ace-oauth-authz-17
	(work in progress), October 2018.		(work in progress), November 2018.
	[I-D.ietf-ace-oauth-params]		[I-D.ietf-ace-oauth-params]
	Seitz, L., "Additional OAuth Parameters for Authorization		Seitz, L., "Additional OAuth Parameters for Authorization
	in Constrained Environments (ACE)", draft-ietf-ace-oauth-		in Constrained Environments (ACE)", draft-ietf-ace-oauth-
	params-00 (work in progress), September 2018.		params-01 (work in progress), November 2018.
	[I-D.ietf-core-object-security]		[I-D.ietf-core-object-security]
	Selander, G., Mattsson, J., Palombini, F., and L. Seitz,		Selander, G., Mattsson, J., Palombini, F., and L. Seitz,
	"Object Security for Constrained RESTful Environments		"Object Security for Constrained RESTful Environments
	(OSCORE)", draft-ietf-core-object-security-15 (work in		(OSCORE)", draft-ietf-core-object-security-15 (work in
	progress), August 2018.		progress), August 2018.
	[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,
	skipping to change at page 22, line 29 ¶		skipping to change at page 25, line 9 ¶
	[RFC8392] Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig,		[RFC8392] Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig,
	"CBOR Web Token (CWT)", RFC 8392, DOI 10.17487/RFC8392,		"CBOR Web Token (CWT)", RFC 8392, DOI 10.17487/RFC8392,
	May 2018, <https://www.rfc-editor.org/info/rfc8392>.		May 2018, <https://www.rfc-editor.org/info/rfc8392>.
	10.2. Informative References		10.2. Informative References
	[I-D.ietf-ace-cwt-proof-of-possession]		[I-D.ietf-ace-cwt-proof-of-possession]
	Jones, M., Seitz, L., Selander, G., Erdtman, S., and H.		Jones, M., Seitz, L., Selander, G., Erdtman, S., and H.
	Tschofenig, "Proof-of-Possession Key Semantics for CBOR		Tschofenig, "Proof-of-Possession Key Semantics for CBOR
	Web Tokens (CWTs)", draft-ietf-ace-cwt-proof-of-		Web Tokens (CWTs)", draft-ietf-ace-cwt-proof-of-
	possession-04 (work in progress), November 2018.		possession-05 (work in progress), November 2018.
	[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,
	<https://www.rfc-editor.org/info/rfc4949>.		<https://www.rfc-editor.org/info/rfc4949>.
	[RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework",		[RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework",
	RFC 6749, DOI 10.17487/RFC6749, October 2012,		RFC 6749, DOI 10.17487/RFC6749, October 2012,
	<https://www.rfc-editor.org/info/rfc6749>.		<https://www.rfc-editor.org/info/rfc6749>.
	[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer		[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
	skipping to change at page 23, line 17 ¶		skipping to change at page 25, line 41 ¶
	This section lists the specifications on this profile based on the		This section lists the specifications on this profile based on the
	requirements on the framework, as requested in Appendix C of		requirements on the framework, as requested in Appendix C of
	[I-D.ietf-ace-oauth-authz].		[I-D.ietf-ace-oauth-authz].
	o (Optional) discovery process of how the client finds the right AS		o (Optional) discovery process of how the client finds the right AS
	for an RS it wants to send a request to: Not specified		for an RS it wants to send a request to: Not specified
	o communication protocol the client and the RS must use: CoAP		o communication protocol the client and the RS must use: CoAP
	o security protocol the client and RS must use: OSCORE		o security protocol the client and RS must use: OSCORE
	o how the client and the RS mutually authenticate: Implicitly by		o how the client and the RS mutually authenticate: Implicitly by
	possession of a common OSCORE security context		possession of a common OSCORE security context
	o Content-format of the protocol messages: "application/cose+cbor"		o Content-format of the protocol messages: "application/ace+cbor"
	o proof-of-possession protocol(s) and how to select one; which key		o proof-of-possession protocol(s) and how to select one; which key
	types (e.g. symmetric/asymmetric) supported: OSCORE algorithms;		types (e.g. symmetric/asymmetric) supported: OSCORE algorithms;
	pre-established symmetric keys		pre-established symmetric keys
	o profile identifier: coap_oscore		o profile identifier: coap_oscore
	o (Optional) how the RS talks to the AS for introspection: HTTP/CoAP		o (Optional) how the RS talks to the AS for introspection: HTTP/CoAP
	(+ TLS/DTLS/OSCORE)		(+ TLS/DTLS/OSCORE)
	o how the client talks to the AS for requesting a token: HTTP/CoAP		o how the client talks to the AS for requesting a token: HTTP/CoAP
	(+ TLS/DTLS/OSCORE)		(+ TLS/DTLS/OSCORE)
	o how/if the authz-info endpoint is protected: Security protocol		o how/if the authz-info endpoint is protected: Security protocol
	above		above
End of changes. 72 change blocks.
	200 lines changed or deleted		297 lines changed or added
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