< draft-ietf-oauth-v2-11.txt		draft-ietf-oauth-v2-12.txt >
	Network Working Group E. Hammer-Lahav, Ed.		Network Working Group E. Hammer-Lahav, Ed.
	Internet-Draft Yahoo!		Internet-Draft Yahoo!
	Obsoletes: 5849 (if approved) D. Recordon		Obsoletes: 5849 (if approved) D. Recordon
	Intended status: Standards Track Facebook		Intended status: Standards Track Facebook
	Expires: June 4, 2011 D. Hardt		Expires: July 25, 2011 D. Hardt
	Microsoft		Microsoft
	December 1, 2010		January 21, 2011
	The OAuth 2.0 Protocol Framework		The OAuth 2.0 Authorization Protocol
	draft-ietf-oauth-v2-11		draft-ietf-oauth-v2-12
	Abstract		Abstract
	This specification describes the OAuth 2.0 protocol framework.		This specification describes the OAuth 2.0 authorization protocol.
	Status of this Memo		Status of this Memo
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	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
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	Copyright Notice		Copyright Notice
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	document authors. All rights reserved.		document authors. All rights reserved.
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	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
	1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 5		1.1. Roles . . . . . . . . . . . . . . . . . . . . . . . . . . 3
	1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5		1.2. Access Token . . . . . . . . . . . . . . . . . . . . . . . 5
	1.3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . 7		1.3. Authorization Grant . . . . . . . . . . . . . . . . . . . 6
	1.4. Access Grants . . . . . . . . . . . . . . . . . . . . . . 8		1.4. Refresh Token . . . . . . . . . . . . . . . . . . . . . . 7
	1.4.1. Authorization Code . . . . . . . . . . . . . . . . . . 8		1.5. Notational Conventions . . . . . . . . . . . . . . . . . . 9
	1.4.2. Resource Owner Password Credentials . . . . . . . . . 10		2. Client Authentication . . . . . . . . . . . . . . . . . . . . 9
	1.4.3. Client Credentials . . . . . . . . . . . . . . . . . . 10		2.1. Client Password Authentication . . . . . . . . . . . . . . 9
	1.4.4. Refresh Token . . . . . . . . . . . . . . . . . . . . 11		2.2. Other Client Authentication Methods . . . . . . . . . . . 10
	1.4.5. Assertion . . . . . . . . . . . . . . . . . . . . . . 12		3. Protocol Endpoints . . . . . . . . . . . . . . . . . . . . . . 11
	2. Client Profiles . . . . . . . . . . . . . . . . . . . . . . . 12		3.1. Authorization Endpoint . . . . . . . . . . . . . . . . . . 11
	2.1. Web Server . . . . . . . . . . . . . . . . . . . . . . . . 12		3.2. Token Endpoint . . . . . . . . . . . . . . . . . . . . . . 12
	2.2. User-Agent . . . . . . . . . . . . . . . . . . . . . . . . 14		4. Requesting an Access Token . . . . . . . . . . . . . . . . . . 13
	2.3. Native Application . . . . . . . . . . . . . . . . . . . . 15		4.1. Authorization Code . . . . . . . . . . . . . . . . . . . . 13
	2.4. Autonomous . . . . . . . . . . . . . . . . . . . . . . . . 16		4.2. Implicit Grant . . . . . . . . . . . . . . . . . . . . . . 19
	3. Client Credentials . . . . . . . . . . . . . . . . . . . . . . 17		4.3. Resource Owner Password Credentials . . . . . . . . . . . 24
	3.1. Client Password Credentials . . . . . . . . . . . . . . . 17		4.4. Client Credentials . . . . . . . . . . . . . . . . . . . . 26
	3.2. Client Assertion Credentials . . . . . . . . . . . . . . . 18		4.5. Extensions . . . . . . . . . . . . . . . . . . . . . . . . 28
	4. Obtaining End-User Authorization . . . . . . . . . . . . . . . 20		5. Issuing an Access Token . . . . . . . . . . . . . . . . . . . 28
	4.1. Authorization Request . . . . . . . . . . . . . . . . . . 20		5.1. Successful Response . . . . . . . . . . . . . . . . . . . 28
	4.2. Authorization Response . . . . . . . . . . . . . . . . . . 22		5.2. Error Response . . . . . . . . . . . . . . . . . . . . . . 30
	4.3. Error Response . . . . . . . . . . . . . . . . . . . . . . 24		6. Refreshing an Access Token . . . . . . . . . . . . . . . . . . 31
	4.3.1. Error Codes . . . . . . . . . . . . . . . . . . . . . 25		7. Accessing Protected Resources . . . . . . . . . . . . . . . . 32
	5. Obtaining an Access Token . . . . . . . . . . . . . . . . . . 25		7.1. Access Token Types . . . . . . . . . . . . . . . . . . . . 33
	5.1. Access Grant Types . . . . . . . . . . . . . . . . . . . . 27		8. Extensibility . . . . . . . . . . . . . . . . . . . . . . . . 33
	5.1.1. Authorization Code . . . . . . . . . . . . . . . . . . 27		8.1. Defining Access Token Types . . . . . . . . . . . . . . . 33
	5.1.2. Resource Owner Password Credentials . . . . . . . . . 27		8.2. Defining New Endpoint Parameters . . . . . . . . . . . . . 34
	5.1.3. Client Credentials . . . . . . . . . . . . . . . . . . 28		8.3. Defining New Authorization Grant Types . . . . . . . . . . 34
	5.1.4. Refresh Token . . . . . . . . . . . . . . . . . . . . 28		9. Security Considerations . . . . . . . . . . . . . . . . . . . 34
	5.1.5. Assertion . . . . . . . . . . . . . . . . . . . . . . 29		10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35
	5.2. Access Token Response . . . . . . . . . . . . . . . . . . 30		10.1. The OAuth Access Token Type Registry . . . . . . . . . . . 35
	5.3. Error Response . . . . . . . . . . . . . . . . . . . . . . 31		10.2. The OAuth Parameters Registry . . . . . . . . . . . . . . 36
	5.3.1. Error Codes . . . . . . . . . . . . . . . . . . . . . 32		Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 39
	6. Accessing a Protected Resource . . . . . . . . . . . . . . . . 33		Appendix B. Contributors . . . . . . . . . . . . . . . . . . . . 39
	6.1. Access Token Types . . . . . . . . . . . . . . . . . . . . 33
	6.2. The WWW-Authenticate Response Header Field . . . . . . . . 33
	6.2.1. Error Codes . . . . . . . . . . . . . . . . . . . . . 35
	7. Extensibility . . . . . . . . . . . . . . . . . . . . . . . . 36
	7.1. Defining New Client Credentials Types . . . . . . . . . . 36
	7.2. Defining New Endpoint Parameters . . . . . . . . . . . . . 36
	7.3. Defining New Header Field Parameters . . . . . . . . . . . 36
	7.4. Defining New Access Grant Types . . . . . . . . . . . . . 37
	8. Security Considerations . . . . . . . . . . . . . . . . . . . 37
	9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 37
	9.1. The OAuth Parameters Registry . . . . . . . . . . . . . . 37
	9.1.1. Registration Template . . . . . . . . . . . . . . . . 37
	9.1.2. Example . . . . . . . . . . . . . . . . . . . . . . . 38
	Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 38
	Appendix B. Contributors . . . . . . . . . . . . . . . . . . . . 38
	Appendix C. Acknowledgements . . . . . . . . . . . . . . . . . . 39		Appendix C. Acknowledgements . . . . . . . . . . . . . . . . . . 39
	Appendix D. Document History . . . . . . . . . . . . . . . . . . 39		Appendix D. Document History . . . . . . . . . . . . . . . . . . 39
	10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 44		11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 43
	10.1. Normative References . . . . . . . . . . . . . . . . . . . 44		11.1. Normative References . . . . . . . . . . . . . . . . . . . 43
	10.2. Informative References . . . . . . . . . . . . . . . . . . 45		11.2. Informative References . . . . . . . . . . . . . . . . . . 45
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 46		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 45
	1. Introduction		1. Introduction
	With the increasing use of distributed web services and cloud
	computing, third-party applications require access to server-hosted
	resources. These resources are usually protected and require
	authentication using the resource owner's credentials (typically a
	username and password).
	In the traditional client-server authentication model, the client		In the traditional client-server authentication model, the client
	accesses a protected resource on the server by authenticating with		accesses a protected resource on the server by authenticating with
	the server using the resource owner's credentials. In order to		the server using the resource owner's credentials. In order to
	provide third-party applications access to protected resources, the		provide third-party applications access to protected resources, the
	resource owner shares its credentials with the third-party. This		resource owner shares its credentials with the third-party. This
	creates several problems and limitations:		creates several problems and limitations:
	o Third-party applications are required to store the resource-		o Third-party applications are required to store the resource-
	owner's credentials for future use, typically a password in clear-		owner's credentials for future use, typically a password in clear-
	text.		text.
	skipping to change at page 4, line 23 ¶		skipping to change at page 3, line 17 ¶
	In the traditional client-server authentication model, the client		In the traditional client-server authentication model, the client
	accesses a protected resource on the server by authenticating with		accesses a protected resource on the server by authenticating with
	the server using the resource owner's credentials. In order to		the server using the resource owner's credentials. In order to
	provide third-party applications access to protected resources, the		provide third-party applications access to protected resources, the
	resource owner shares its credentials with the third-party. This		resource owner shares its credentials with the third-party. This
	creates several problems and limitations:		creates several problems and limitations:
	o Third-party applications are required to store the resource-		o Third-party applications are required to store the resource-
	owner's credentials for future use, typically a password in clear-		owner's credentials for future use, typically a password in clear-
	text.		text.
	o Servers are required to support password authentication, despite		o Servers are required to support password authentication, despite
	the security weaknesses created by passwords.		the security weaknesses created by passwords.
	o Third-party applications gain overly broad access to the resource-		o Third-party applications gain overly broad access to the resource-
	owner's protected resources, leaving resource owners without any		owner's protected resources, leaving resource owners without any
	ability to restrict access to a limited subset of resources, to		ability to restrict duration or access to a limited subset of
	limit access duration, or to limit access to the methods supported		resources.
	by these resources.
	o Resource owners cannot revoke access to an individual third-party		o Resource owners cannot revoke access to an individual third-party
	without revoking access to all third-parties, and must do so by		without revoking access to all third-parties, and must do so by
	changing their password.		changing their password.
	OAuth addresses these issues by separating the role of the client		OAuth addresses these issues by introducing an authorization layer
	from that of the resource owner. In OAuth, the client (which is		and separating the role of the client from that of the resource
	usually not the resource owner, but is acting on the resource owner's		owner. In OAuth, the client requests access to resources controlled
	behalf) requests access to resources controlled by the resource owner		by the resource owner and hosted by the resource server, and is
	and hosted by the resource server, and is issued a different set of		issued a different set of credentials than those of the resource
	credentials than those of the resource owner.		owner.
	Instead of using the resource owner's credentials to access protected		Instead of using the resource owner's credentials to access protected
	resources, the client obtains an access token - a string which		resources, the client obtains an access token - a string denoting a
	denotes a specific scope, duration, and other attributes. Access		specific scope, duration, and other access attributes. Access tokens
	tokens are issued to third-party clients by an authorization server		are issued to third-party clients by an authorization server with the
	with the approval of the resource owner. The client uses the access		approval of the resource owner. The client uses the access token to
	token to access the protected resources hosted by the resource		access the protected resources hosted by the resource server.
	server.
	For example, a web user (resource owner) can grant a printing service		For example, a web user (resource owner) can grant a printing service
	(client) access to her protected photos stored at a photo sharing		(client) access to her protected photos stored at a photo sharing
	service (resource server), without sharing her username and password		service (resource server), without sharing her username and password
	with the printing service. Instead, she authenticates directly with		with the printing service. Instead, she authenticates directly with
	an authentication service trusted by the photo sharing service		a server trusted by the photo sharing service (authorization server)
	(authorization server) which issues the printing service delegation-		which issues the printing service delegation-specific credentials
	specific credentials (token).		(access token).
	Access tokens can have different formats, structures, and methods of
	utilization (e.g. cryptographic properties), based on the resource
	server security requirements. Access token attributes and the
	methods used to access protected resources are beyond the scope of
	this specification and are defined by companion specifications. The
	interaction between the authorization server and resource server is
	beyond the scope of this specification.
	1.1. Notational Conventions
	The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT',
	'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and 'OPTIONAL' in this
	document are to be interpreted as described in [RFC2119].
	This document uses the Augmented Backus-Naur Form (ABNF) notation of
	[I-D.ietf-httpbis-p1-messaging]. Additionally, the following rules
	are included from [RFC3986]: URI-reference; and from
	[I-D.ietf-httpbis-p1-messaging]: OWS, RWS, and quoted-string.
	Unless otherwise noted, all the protocol parameter names and values
	are case sensitive.
	1.2. Terminology		1.1. Roles
	protected resource		OAuth includes four roles working together to grant and provide
	An access-restricted resource which can be obtained using an		access to protected resources - access restricted resources which
	OAuth-authenticated request.		require authentication to access:
			resource owner
			An entity capable of granting access to a protected resource.
			When the resource owner is a person, it is referred to as an end-
			user.
	resource server		resource server
	A server capable of accepting and responding to protected		The server hosting the protected resources, capable of accepting
	resource requests.		and responding to protected resource requests using access tokens.
	client		client
	An application obtaining authorization and making protected		An application making protected resource requests on behalf of the
	resource requests.		resource owner and with its authorization.
	resource owner
	An entity capable of granting access to a protected resource.
	end-user
	A human resource owner.
	token
	A string representing an access authorization issued to the
	client. The string is usually opaque to the client. Tokens
	represent specific scopes and durations of access, granted by
	the resource owner, and enforced by the resource server and
	authorization servers. The token may denote an identifier used
	to retrieve the authorization information, or self-contain the
	authorization information in a verifiable manner (i.e. a token
	string consisting of some data and a signature). Tokens may be
	pure capabilities. Specific additional authentication
	credentials may be required in order for a client to use a
	token.
	access token
	A token used by the client to make authenticated requests on
	behalf of the resource owner.
	refresh token
	A token used by the client to obtain a new access token without
	having to involve the resource owner.
	authorization code A short-lived token representing the
	authorization provided by the end-user. The authorization code
	is used to obtain an access token and a refresh token.
	access grant A general term used to describe the intermediate
	credentials (such as an end-user password or authorization
	code) representing the resource owner authorization. Access
	grants are used by the client to obtain an access token. By
	exchanging access grants of different types for an access
	token, the resource server is only required to support a single
	authentication scheme.
	authorization server		authorization server
	A server capable of issuing tokens after successfully		The server issuing access tokens to the client after successfully
	authenticating the resource owner and obtaining authorization.		authenticating the resource owner and obtaining authorization.
	The authorization server may be the same server as the resource
	server, or a separate entity. A single authorization server
	may issue tokens for multiple resource servers.
	end-user authorization endpoint
	The authorization server's HTTP endpoint capable of
	authenticating the end-user and obtaining authorization. The
	end-user authorization endpoint is described in Section 4.
	token endpoint
	The authorization server's HTTP endpoint capable of issuing
	tokens and refreshing expired tokens. The token endpoint is
	described in Section 5.
	client identifier
	A unique identifier issued to the client to identify itself to
	the authorization server. Client identifiers may have a
	matching secret. The client identifier is described in
	Section 3.
	1.3. Overview
	OAuth provides a method for clients to access a protected resource on		The interaction between the authorization server and resource server
	behalf of a resource owner. Before a client can access a protected		is beyond the scope of this specification. The authorization server
	resource, it must first obtain authorization (access grant) from the		may be the same server as the resource server or a separate entity.
	resource owner, then exchange the access grant for an access token		A single authorization server may issue access tokens accepted by
	(representing the grant's scope, duration, and other attributes).		multiple resource servers.
	The client accesses the protected resource by presenting the access
	token to the resource server.
	The access token provides an abstraction layer, replacing different		When interacting with the authorization server, the client identifies
	authorization constructs (e.g. username and password, assertion) for		itself using a set of client credentials which include a client
	a single token understood by the resource server. This abstraction		identifier and other authentication attributes. The means through
	enables issuing access tokens valid for a short time period, as well		which the client obtains its credentials are beyond the scope of this
	as removing the resource server's need to understand a wide range of		specification, but typically involve registration with the
	authentication schemes.		authorization server.
	+--------+ +---------------+		+--------+ +---------------+
	| |--(A)- Authorization Request ->| Resource |		| |--(A)- Authorization Request ->| Resource |
	| | | Owner |		| | | Owner |
	| |<-(B)----- Access Grant -------| |		| |<-(B)-- Authorization Grant ---| |
	| | +---------------+		| | +---------------+
	| |		| |
	| | Access Grant & +---------------+		| | Authorization Grant & +---------------+
	| |--(C)--- Client Credentials -->| Authorization |		| |--(C)--- Client Credentials -->| Authorization |
	| Client | | Server |		| Client | | Server |
	| |<-(D)----- Access Token -------| |		| |<-(D)----- Access Token -------| |
	| | +---------------+		| | +---------------+
	| |		| |
	| | +---------------+		| | +---------------+
	| |--(E)----- Access Token ------>| Resource |		| |--(E)----- Access Token ------>| Resource |
	| | | Server |		| | | Server |
	| |<-(F)--- Protected Resource ---| |		| |<-(F)--- Protected Resource ---| |
	+--------+ +---------------+		+--------+ +---------------+
	Figure 1: Abstract Protocol Flow		Figure 1: Abstract Protocol Flow
	The abstract flow illustrated in Figure 1 describes the overall		The abstract flow illustrated in Figure 1 describes the interaction
	protocol architecture and includes the following steps:		between the four roles and includes the following steps:
	(A) The client requests authorization from the resource owner. The		(A) The client requests authorization from the resource owner. The
	authorization request can be made directly to the resource		authorization request can be made directly to the resource owner
	owner, or preferably indirectly via an intermediary such as an		(as shown), or preferably indirectly via an intermediary such as
	authorization server.		an authorization server.
			(B) The client receives an authorization grant which represents the
	(B) The client receives an access grant which represents the		authorization provided by the resource owner. The authorization
	authorization provided by the resource owner.		grant type depends on the method used by the client and
			supported by the authorization server to obtain it.
	(C) The client requests an access token by authenticating with the		(C) The client requests an access token by authenticating with the
	authorization server using its client credentials, and		authorization server using its client credentials (prearranged
	presenting the access grant.		between the client and authorization server) and presenting the
			authorization grant.
	(D) The authorization server validates the client credentials and		(D) The authorization server validates the client credentials and
	the access grant, and if valid issues an access token.		the authorization grant, and if valid issues an access token.
			(E) The client requests the protected resource from the resource
	(E) The client makes a protected resource request to the resource		server and authenticates by presenting the access token.
	server by presenting the access token.
	(F) The resource server validates the access token, and if valid,		(F) The resource server validates the access token, and if valid,
	serves the request.		serves the request.
	1.4. Access Grants		1.2. Access Token
	The access grant represents the authorization provided by the		An access token is a string representing an authorization issued to
	resource owner. The access grant type depends on the method used by		the client. The string is usually opaque to the client. Tokens
	the client and supported by the authorization server to obtain it.		represent specific scopes and durations of access, granted by the
			resource owner, and enforced by the resource server and authorization
			server.
	1.4.1. Authorization Code		The token may denote an identifier used to retrieve the authorization
			information, or self-contain the authorization information in a
			verifiable manner (i.e. a token string consisting of some data and a
			signature). Tokens may be pure capabilities. Additional
			authentication credentials may be required in order for the client to
			use a token.
	The authorization code is an access grant obtained by directing the		The access token provides an abstraction layer, replacing different
	end-user to an authorization server. The authorization server		authorization constructs (e.g. username and password) with a single
	authenticates the end-user, obtains authorization, and issues the an		token understood by the resource server. This abstraction enables
	authorization code to the client. Because the end-user only		issuing access tokens more restrictive than the authorization grant
	authenticates with the authorization server, the end-user's password		used to obtain them, as well as removing the resource server's need
	is never shared with the client.		to understand a wide range of authentication methods.
	The authorization code access grant is suitable when the client is		Access tokens can have different formats, structures, and methods of
	interacting with an end-user via a user-agent.		utilization (e.g. cryptographic properties) based on the resource
			server security requirements. Access token attributes and the
			methods used to access protected resources are beyond the scope of
			this specification and are defined by companion specifications.
	+----------+		1.3. Authorization Grant
	| |
	| End-User |
	| |
	+----------+
	^
	|
	(B)
	+----|-----+ Client Identifier +---------------+
	| -+--(A)--- & Redirect URI ----->| |
	| User- | | Authorization |
	| Agent -|--(B)-- User authenticates -->| Server |
	| | | |
	| -+--(C)-- Authorization Code --<| |
	+-|----|---+ +---------------+
	(A) (C)
	| |
	^ v
	+---------+
	| |
	| Client |
	| |
	+---------+
	Figure 2: Obtaining an Authorization Code		An authorization grant is a general term used to describe the
			intermediate credentials representing the resource owner
			authorization, and serves as an abstraction layer. An authorization
			grant is used by the client to obtain an access token.
	The authorization code flow illustrated in Figure 2 includes the		1.3.1. Authorization Code
	following steps:
	(A) The client initiates the flow by directing the end-user's user-		The authorization code is obtained by using an authorization server
	agent to the authorization server's end-user authorization		as an intermediary between the client and resource owner. Instead of
	endpoint. The client includes its client identifier, requested		requesting authorization directly from the resource owner, the client
	scope, local state, and a redirection URI (to which the		directs the resource owner to an authorization server (via its user-
	authorization server will send the user-agent back once access		agent), which in turns directs the resource owner back to the client
	is granted or denied).		with the authorization code.
	(B) The authorization server authenticates the end-user (via the		Before directing the resource owner back to the client with the
	user-agent) and establishes whether the end-user grants or		authorization code, the authorization server authenticates the
	denies the client's access request.		resource owner and obtains authorization. Because the resource owner
			only authenticates with the authorization server, the resource
			owner's credentials are never shared with the client.
	(C) If access is granted, the authorization server directs the user-		The authorization code provides a few important security benefits
	agent back to the client using the redirection URI provided.		such as the ability to authenticate the client and issuing the access
	The authorization server includes an authorization code for the		token directly to the client without potentially exposing it to
	client to use to obtain an access token.		others, including the resource owner.
	Once the client obtains an authorization code, it requests an access		1.3.2. Implicit
	token by authenticating with the authorization server (using its
	client credentials) and presenting the authorization code (access
	grant).
	In cases where the client is incapable of maintaining its client		An implicit grant is issued when the resource owner's authorization
	credentials secret (such as native applications or an application		is expressed directly as an access token, without using an
	implemented as a user-agent script), the authorization server issues		intermediate credential. The implicit grant is issued in a similar
	an access token directly to the client in step (C), instead of		manner as an authorization code, but instead of the resource owner
	issuing an authorization code.		being redirected back to the client with the authorization code, it
			is redirected back with an access token and its related attributes.
	Obtaining an authorization code is described in Section 4.		When issuing an implicit grant, the authorization server cannot
			verify the identity of the client, and the access token may be
			exposed to the resource owner or other applications with access to
			the resource owner's user-agent.
	1.4.2. Resource Owner Password Credentials		Implicit grants improve the responsiveness and efficiency of some
			clients (such as a client implemented as an in-browser application)
			since it reduces the number of round trip required to obtain an
			access token.
			1.3.3. Resource Owner Password Credentials
	The resource owner password credentials (e.g. a username and		The resource owner password credentials (e.g. a username and
	password) can be used directly as an access grant to obtain an access		password) can be used directly as an authorization grant to obtain an
	token. The credentials should only be used when there is a high		access token. The credentials should only be used when there is a
	degree of trust between the resource owner and the client (e.g. its		high degree of trust between the resource owner and the client (e.g.
	computer operating system or a highly privileged application), and		its computer operating system or a highly privileged application),
	when other access grant types are not available (such as an		and when other authorization grant types are not available (such as
	authorization code).		an authorization code).
	Even though this grant type requires direct client access to the		Even though this grant type requires direct client access to the
	resource owner's credentials, the resource owner's credentials are		resource owner credentials, the resource owner credentials are used
	used for a single request and are exchanged for an access token.		for a single request and are exchanged for an access token. Unlike
	Unlike the HTTP Basic authentication scheme defined in [RFC2617],		the HTTP Basic authentication scheme defined in [RFC2617], this grant
	this grant type eliminates the need for the client to store the		type eliminates the need for the client to store the resource-owner
	resource-owner's credentials for future use.		credentials for future use.
	In Figure 3, the client requests authorization from the resource		1.3.4. Client Credentials
	owner directly. When the resource owner is an end-user, the client
	typically prompts the end-user for the username and password.
	+--------+ +----------+		The client credentials can be used as an authorization grant when the
	| |--(A)- Authorization Request ->| Resource |		authorization scope is limited to the protected resources under the
	| Client | | Owner |		control of the client, or to protected resources previously arranged
	| |<-(B)-- Username & Password ---| |		with the authorization server. Client credentials are used as an
	+--------+ +----------+		authorization grant typically when the client is acting on its own
			behalf (the client is also the resource owner).
	Figure 3: Obtaining Resource Owner Password Credentials		1.3.5. Extensions
	1.4.3. Client Credentials		Additional grant types may be defined to provide a bridge between
			OAuth and other trust frameworks. For example,
			[I-D.ietf-oauth-saml2-bearer] defines a SAML 2.0
			[OASIS.saml-core-2.0-os] bearer assertion grant type, which can be
			used to obtain an access token.
	The client credentials can be used as an access grant when the		1.4. Refresh Token
	authorization scope is limited to the protected resources under the
	control of the client, or other protected resources previously
	arranged with the authorization server. Client credentials are used
	as an access grant typically when the client is acting on its own
	behalf (the client is also the resource owner).
	1.4.4. Refresh Token		A refresh token is optionally issued by the authorization server to
			the client together with an access token. The client can use the
			refresh token to request another access token based on the same
			authorization, without having to involve the resource owner again, or
			having to retain the original authorization grant used to obtain the
			initial access token.
	Access tokens usually have a shorter lifetime than authorized by the		A refresh token is a string representing the authorization granted to
	resource owner. When issuing an access token, the authorization		the client by the resource owner. The string is usually opaque to
	server can include a refresh token which is used by the client to		the client. The token may denote an identifier used to retrieve the
	obtain a new access token when the current access token expires.		authorization information, or self-contain the authorization
	When requesting a new access token, the refresh token acts as an		information in a verifiable manner.
	access grant. Using a refresh token removes the need to interact
	with the resource owner again, or to store the original access grant
	used to obtain the access token and refresh token.
	+--------+ Access Grant & +---------------+		The refresh token can be used to obtain a new access token when the
	| |--(A)-- Client Credentials -->| Authorization |		current access token expires (access tokens may have a shorter
	| | | Server |		lifetime than authorized by the resource owner), or to obtain
	| |<-(B)---- Access Token -------| |		additional access tokens with identical or narrower scope.
	| | & Refresh Token +---------------+
	| |
	| | +---------------+
	| |--(C)----- Access Token ----->| |
	| | | |
	| |<-(D)-- Protected Resource ---| Resource |
	| Client | | Server |
	| |--(E)----- Access Token ----->| |
	| | | |
	| |<-(F)-- Invalid Token Error --| |
	| | +---------------+
	| |
	| | Refresh Token & +---------------+
	| |--(G)-- Client Credentials -->| Authorization |
	| | | Server |
	| |<-(H)----- Access Token ------| |
	+--------+ & Optional Refresh Token +---------------+
	Figure 4: Refreshing an Access Token		+--------+ Access Grant & +---------------+
			| |--(A)-------- Client Credentials --------->| |
			| | | |
			| |<-(B)----------- Access Token -------------| |
			| | & Refresh Token | |
			| | | |
			| | +----------+ | |
			| |--(C)---- Access Token ---->| | | |
			| | | | | |
			| |<-(D)- Protected Resource --| Resource | | Authorization |
			| Client | | Server | | Server |
			| |--(E)---- Access Token ---->| | | |
			| | | | | |
			| |<-(F)- Invalid Token Error -| | | |
			| | +----------+ | |
			| | | |
			| | Refresh Token & | |
			| |--(G)-------- Client Credentials --------->| |
			| | | |
			| |<-(H)----------- Access Token -------------| |
			+--------+ & Optional Refresh Token +---------------+
	The refresh token flow illustrated in Figure 4 includes the following		Figure 2: Refreshing an Expired Access Token
	steps:
			The flow illustrated in Figure 2 includes the following steps:
	(A) The client requests an access token by authenticating with the		(A) The client requests an access token by authenticating with the
	authorization server using its client credentials, and		authorization server using its client credentials, and
	presenting an access grant.		presenting an authorization grant.
	(B) The authorization server validates the client credentials and		(B) The authorization server validates the client credentials and
	the access grant, and if valid issues an access token and a		the authorization grant, and if valid issues an access token and
	refresh token.		a refresh token.
	(C) The client makes a protected resource requests to the resource		(C) The client makes a protected resource requests to the resource
	server by presenting the access token.		server by presenting the access token.
	(D) The resource server validates the access token, and if valid,		(D) The resource server validates the access token, and if valid,
	serves the request.		serves the request.
	(E) Steps (C) and (D) repeat until the access token expires. If the		(E) Steps (C) and (D) repeat until the access token expires. If the
	client does not know the access token expired, it makes another		client knows the access token expired, it skips to step (G),
	protected resource request. Otherwise, it skips to step (G).		otherwise it makes another protected resource request.
	(F) Since the access token is invalid (expired), the resource server		(F) Since the access token is invalid (expired), the resource server
	returns an invalid token error.		returns an invalid token error.
	(G) The client requests a new access token by authenticating with		(G) The client requests a new access token by authenticating with
	the authorization server using its client credentials, and		the authorization server using its client credentials, and
	presenting the refresh token (as the access grant).		presenting the refresh token.
	(H) The authorization server validates the client credentials and		(H) The authorization server validates the client credentials and
	the refresh token, and if valid issues a new access token (and		the refresh token, and if valid issues a new access token (and
	optionally, a new refresh token).		optionally, a new refresh token).
	1.4.5. Assertion		1.5. Notational Conventions
	Assertions provide a bridge between OAuth and other trust frameworks.		The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT',
	They enable the client to utilize existing trust relationships in		'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and 'OPTIONAL' in this
	order to obtain an access token. The access grant represented by an		specification are to be interpreted as described in [RFC2119].
	assertion depends on the assertion type, its content, and how it was
	issued, which are beyond the scope of this specification.
	Assertions are used as part of the protocol extensibility model,		This specification uses the Augmented Backus-Naur Form (ABNF)
	providing a way for authorization servers to support additional		notation of [I-D.ietf-httpbis-p1-messaging]. Additionally, the
	access grant types.		following rules are included from [RFC3986]: URI-reference; and from
			[I-D.ietf-httpbis-p1-messaging]: OWS, RWS, and quoted-string.
	2. Client Profiles		Unless otherwise noted, all the protocol parameter names and values
			are case sensitive.
	[[ add intro and find new names for the profiles. this section will		2. Client Authentication
	have normative language in future drafts, similar to -05 and earlier.
	]]
	2.1. Web Server		Client credentials are used to identify and authenticate the client.
			The client credentials include a client identified - a unique string
			issued to the client to identify itself to the authorization server.
			The methods through which the client obtains its client credentials
			are beyond the scope of this specification.
	The web server profile is suitable for clients capable of interacting		Due to the nature of some clients, the authorization server SHOULD
	with the end-user's user-agent (typically a web browser) and capable		NOT make assumptions about the confidentiality of client credentials
	of receiving incoming requests (via redirection) from the		without establishing trust with the client. The authorization server
	authorization server (capable of acting as an HTTP server).		SHOULD NOT issue client credentials to clients incapable of keeping
			their secrets confidential.
	+----------+ Client Identifier +---------------+		2.1. Client Password Authentication
	| -+----(A)--- & Redirect URI ------>| |
	| End-user | | Authorization |
	| at |<---(B)-- User authenticates --->| Server |
	| Browser | | |
	| -+----(C)-- Authorization Code ---<| |
	+-|----|---+ +---------------+
	| | ^ v
	(A) (C) | |
	| | | |
	^ v | |
	+---------+ | |
	| |>---(D)-- Client Credentials, --------' |
	| Server | Authorization Code, |
	| -Based | & Redirect URI |
	| Client | |
	| |<---(E)----- Access Token -------------------'
	+---------+ (w/ Optional Refresh Token)
	Figure 5: Web Server Flow		The client password authentication uses a shared symmetric secret to
			authenticate the client. The client identifier and password are
			included in the request using the following parameters:
	The web server flow illustrated in Figure 5 includes the following		client_id
	steps:		REQUIRED. The client identifier.
			client_secret
			REQUIRED. The client password.
	(A) The web client initiates the flow by redirecting the end-user's		For example (line breaks are for display purposes only):
	user-agent to the end-user authorization endpoint as described
	in Section 4. The client includes its client identifier,
	requested scope, local state, and a redirect URI to which the
	authorization server will send the end-user back once access is
	granted (or denied).
	(B) The authorization server authenticates the end-user (via the		POST /token HTTP/1.1
	user-agent) and establishes whether the end-user grants or		Host: server.example.com
	denies the client's access request.		Content-Type: application/x-www-form-urlencoded
	(C) Assuming the end-user granted access, the authorization server		grant_type=authorization_code&client_id=s6BhdRkqt3&
	redirects the user-agent back to the client to the redirection		client_secret=gX1fBat3bV&code=i1WsRn1uB1&
	URI provided earlier. The authorization includes an		redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
	authorization code for the client to use to obtain an access
	token.
	(D) The client requests an access token from the authorization		2.2. Other Client Authentication Methods
	server by authenticating and including the authorization code
	received in the previous step as described in Section 5.
	(E) The authorization server validates the client credentials and		In cases where client password authentication is not suitable or
	the authorization code and responds back with the access token.		sufficient, the authorization server MAY support other existing HTTP
			authentication schemes or define new methods. In addition, the
			authorization server MAY allow unauthenticated access token requests
			when the client identity does not matter (e.g. anonymous client) or
			when the client identity is established via other means.
	2.2. User-Agent		For example, the authorization server MAY support using the HTTP
			Basic authentication scheme as defined in [RFC2617] to include the
			client identifier as the username and client password as the password
			(line breaks are for display purposes only):
	The user-agent profile is suitable for client applications residing		POST /token HTTP/1.1
	in a user-agent, typically implemented in a browser using a scripting		Host: server.example.com
	language such as JavaScript. These clients cannot keep client		Authorization: Basic czZCaGRSa3F0MzpnWDFmQmF0M2JW
	secrets confidential and the authentication of the client is based on		Content-Type: application/x-www-form-urlencoded
	the user-agent's same-origin policy.
	Unlike other profiles in which the client makes separate requests for		grant_type=authorization_code&code=i1WsRn1uB1&
	end-user authorization and access token, the client receives the		redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
	access token as a result of the end-user authorization request in the
	form of an HTTP redirection. The client requests the authorization
	server to redirect the user-agent to another web server or local
	resource accessible to the user-agent which is capable of extracting
	the access token from the response and passing it to the client.
	This user-agent profile does not utilize the client secret since the		When using a method other than client password authentication to
	client executables reside on the end-user's computer or device which		exchange an authorization code grant type, the authorization server
	makes the client secret accessible and exploitable. Because the		MUST define a method for mapping the client credentials to the client
	access token is encoded into the redirection URI, it may be exposed		identifier used to obtain the authorization code.
	to the end-user and other applications residing on the computer or
	device.
	+----------+ Client Identifier +----------------+		3. Protocol Endpoints
	| |>---(A)-- & Redirection URI --->| |
	| | | |
	End <--+ - - - +----(B)-- User authenticates -->| Authorization |
	User | | | Server |
	| |<---(C)--- Redirect URI -------<| |
	| Client | with Access Token | |
	| in | in Fragment +----------------+
	| Browser |
	| | +----------------+
	| |>---(D)--- Redirect URI ------->| |
	| | without Fragment | Web Server |
	| | | with Client |
	| (F) |<---(E)--- Web Page with ------<| Resource |
	| Access | Script | |
	| Token | +----------------+
	+----------+
	Figure 6: User-Agent Flow
	The user-agent flow illustrated in Figure 6 includes the following		The authorization process utilizes two endpoints:
	steps:
	(A) The client sends the user-agent to the end-user authorization		o Authorization endpoint - used to obtain authorization from the
	endpoint as described in Section 4. The client includes its		resource owner via user-agent redirection.
	client identifier, requested scope, local state, and a redirect		o Token endpoint - used to exchange an authorization grant for an
	URI to which the authorization server will send the end-user		access token, typically with client authentication.
	back once authorization is granted (or denied).
	(B) The authorization server authenticates the end-user (via the		Not every authorization grant flow utilizes both endpoints.
	user-agent) and establishes whether the end-user grants or		Extension grant types MAY define additional endpoints as needed.
	denies the client's access request.
	(C) If the end-user granted access, the authorization server		3.1. Authorization Endpoint
	redirects the user-agent to the redirection URI provided
	earlier. The redirection URI includes the access token in the
	URI fragment.
	(D) The user-agent follows the redirection instructions by making a		The authorization endpoint is used to interact with the resource
	request to the web server which does not include the fragment.		owner and obtain authorization which is expressed explicitly as an
	The user-agent retains the fragment information locally.		authorization code (exchanged for an access token), or implicitly by
			direct issuance of an access token.
	(E) The web server returns a web page (typically an HTML page with		The authorization server MUST first verify the identity of the
	an embedded script) capable of accessing the full redirection		resource owner. The way in which the authorization server
	URI including the fragment retained by the user-agent, and		authenticates the resource owner (e.g. username and password login,
	extracting the access token (and other parameters) contained in		session cookies) is beyond the scope of this specification.
	the fragment.
	(F) The user-agent executes the script provided by the web server		The location of the authorization endpoint can be found in the
	locally, which extracts the access token and passes it to the		service documentation. The endpoint URI MAY include a query
	client.		component as defined by [RFC3986] section 3, which MUST be retained
			when adding additional query parameters.
	2.3. Native Application		Requests to the authorization endpoint result in user authentication
			and the transmission of sensitive information. If the response
			includes an access token, the authorization server MUST require TLS
			1.2 as defined in [RFC5246] and MAY support additional transport-
			layer mechanisms meeting its security requirements. If the response
			does not include an access token, the authorization server SHOULD
			require TLS 1.2 and any additional transport-layer mechanism meeting
			its security requirements.
	Native applications are clients running as native code on the end-		The authorization server MUST support the use of the HTTP "GET"
	user's computer or device (i.e. executing outside a user-agent or as		method for the authorization endpoint, and MAY support the use of the
	a desktop program). These clients are often capable of interacting		"POST" method as well.
	with (or embedding) the end-user's user-agent but are limited in how
	such interaction affects their end-user experience. In many cases,
	native applications are incapable of receiving direct callback
	requests from the server (e.g. firewall, operating system
	restrictions).
	Native application clients can be implemented in different ways based		Parameters sent without a value MUST be treated as if they were
	on their requirements and desired end-user experience. Native		omitted from the request. The authorization server SHOULD ignore
	application clients can:		unrecognized request parameters.
	o Utilize the end-user authorization endpoint as described in		3.1.1. Redirection URI
	Section 4 by launching an external user-agent. The client can
	capture the response by providing a redirection URI with a custom
	URI scheme (registered with the operating system to invoke the
	client application), or by providing a redirection URI pointing to
	a server-hosted resource under the client's control which makes
	the response available to the client (e.g. using the window title
	or other locations accessible from outside the user-agent).
	o Utilize the end-user authorization endpoint as described in		The client directs the resource owner's user-agent to the
	Section 4 by using an embedded user-agent. The client obtains the		authorization endpoint and includes a redirection URI to which the
	response by directly communicating with the embedded user-agent.		authorization server will redirect the user-agent back once
			authorization has been obtained (or denied). The client MAY omit the
			redirection URI if one has been established between the client and
			authorization server via other means, such as during the client
			registration process.
	o Prompt end-users for their password and use them directly to		The redirection URI MUST be an absolute URI and MAY include a query
	obtain an access token. This is generally discouraged, as it		component, which MUST be retained by the authorization server when
	hands the end-user's password directly to the third-party client		adding additional query parameters.
	which in turn has to store it in clear-text. It also requires the
	server to support password-based authentication.
	When choosing between launching an external browser and an embedded		The authorization server SHOULD require the client to pre-register
	user-agent, developers should consider the following:		their redirection URI or at least certain components such as the
			scheme, host, port and path. If a redirection URI was registered,
			the authorization server MUST compare any redirection URI received at
			the authorization endpoint with the registered URI.
	o External user-agents may improve completion rate as the end-user		The authorization server SHOULD NOT redirect the user-agent to
	may already be logged-in and not have to re-authenticate.		unregistered or untrusted URIs to prevent the endpoint from being
			used as an open redirector. If no valid redirection URI is
			available, the authorization server SHOULD inform the resource owner
			directly of the error.
	o Embedded user-agents often offer a better end-user flow, as they		3.2. Token Endpoint
	remove the need to switch context and open new windows.
	o Embedded user-agents pose a security challenge because users are		The token endpoint is used by the client to obtain an access token by
	authenticating in an unidentified window without access to the		authenticating with the authorization server and presenting its
	visual protections offered by many user-agents.		authorization grant. The token endpoint is used with every
			authorization grant except for the implicit grant type (since an
			access token is issued directly).
	2.4. Autonomous		The location of the token endpoint can be found in the service
			documentation. The endpoint URI MAY include a query component, which
			MUST be retained when adding additional query parameters.
	Autonomous clients utilize an existing trust relationship or		Since requests to the token endpoint result in the transmission of
	framework to establish authorization. Autonomous clients can be		clear-text credentials (in the HTTP request and response), the
	implemented in different ways based on their requirements and the		authorization server MUST require the use of a transport-layer
	existing trust framework they rely upon. Autonomous clients can:		security mechanism when sending requests to the token endpoints. The
			authorization server MUST support TLS 1.2 as defined in [RFC5246],
			and MAY support additional transport-layer mechanisms meeting its
			security requirements.
	o Obtain an access token by authenticating with the authorization		The token endpoint requires client authentication as described in
	server using their client credentials. The scope of the access		Section 2 . The authorization server MAY accept any form of client
	token is limited to the protected resources under the control of		authentication meeting its security requirements. The client MUST
	the client, or that of another resource owner previously arranged		NOT use more than one authentication method in each request.
	with the authorization server.
	o Use an existing access grant expressed as an assertion using an		The client MUST use the HTTP "POST" method when making access token
	assertion format supported by the authorization server. Using		requests.
	assertions requires the client to obtain an assertion (such as a
	SAML [OASIS.saml-core-2.0-os] assertion) from an assertion issuer
	or to self-issue an assertion. The assertion format, the process
	by which the assertion is obtained, and the method of validating
	the assertion are defined by the assertion issuer and the
	authorization server, and are beyond the scope of this
	specification.
	3. Client Credentials		Parameters sent without a value MUST be treated as if they were
			omitted from the request. The authorization server SHOULD ignore
			unrecognized request parameters.
	When interacting with the authorization server, the client identifies		4. Requesting an Access Token
	itself using a set of client credentials which include a client
	identifier and other properties for client authentication. The means
	through which the client obtains its credentials are beyond the scope
	of this specification, but typically involve registration with the
	authorization server.
	Due to the nature of some clients, authorization servers SHOULD NOT		The client obtains an access token by requesting authorization from
	make assumptions about the confidentiality of client secrets without		the resource owner. The authorization is expressed in the form of an
	establishing trust with the client. Authorization servers SHOULD NOT		authorization grant which the client exchanges for an access token.
	issue client secrets to clients incapable of keeping their secrets		OAuth defines four grant types: authorization code, implicit,
	confidential.		resource owner password credentials, and client credentials, as well
			as an extension mechanism for defining additional grant types.
	The authorization server MAY authenticate the client using any		4.1. Authorization Code
	appropriate set of credentials and authentication schemes. The
	client MUST NOT include more than one set of credentials or
	authentication mechanism with each request.
	3.1. Client Password Credentials		The authorization code flow is suitable for clients capable of
			maintaining their client credentials confidential (for authenticating
			with the authorization server) such as a client implemented on a
			secure server. As a redirection-based profile, the client must be
			capable of interacting with the resource owner's user-agent
			(typically a web browser) and capable of receiving incoming requests
			(via redirection) from the authorization server.
	The client password credentials use a shared symmetric secret to		+----------+
	authenticate the client. The client identifier and password are		| resource |
	included in the request using the HTTP Basic authentication scheme as		| owner |
	defined in [RFC2617] by including the client identifier as the		| |
	username and client password as the password.		+----------+
			^
			|
			(B)
			+----|-----+ Client Identifier +---------------+
			| -+----(A)--- & Redirect URI ------>| |
			| User- | | Authorization |
			| Agent -+----(B)-- User authenticates --->| Server |
			| | | |
			| -+----(C)-- Authorization Code ---<| |
			+-|----|---+ +---------------+
			| | ^ v
			(A) (C) | |
			| | | |
			^ v | |
			+---------+ | |
			| |>---(D)-- Client Credentials, --------' |
			| | Authorization Code, |
			| Client | & Redirect URI |
			| | |
			| |<---(E)----- Access Token -------------------'
			+---------+ (w/ Optional Refresh Token)
	For example (line breaks are for display purposes only):		Figure 3: Authorization Code Flow
	POST /token HTTP/1.1		The flow illustrated in Figure 3 includes the following steps:
	Host: server.example.com
	Authorization: Basic czZCaGRSa3F0MzpnWDFmQmF0M2JW
	Content-Type: application/x-www-form-urlencoded
	grant_type=authorization_code&code=i1WsRn1uB1&		(A) The client initiates the flow by directing the resource owner's
	redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb		user-agent to the authorization endpoint. The client includes
			its client identifier, requested scope, local state, and a
			redirection URI to which the authorization server will send the
			user-agent back once access is granted (or denied).
			(B) The authorization server authenticates the resource owner (via
			the user-agent) and establishes whether the resource owner
			grants or denies the client's access request.
			(C) Assuming the resource owner grants access, the authorization
			server redirects the user-agent back to the client using the
			redirection URI provided earlier. The redirection URI includes
			an authorization code.
	Alternatively, the client MAY include the password in the request		(D) The client requests an access token from the authorization
	body using the following parameters:		server's token endpoint by authenticating using its client
			credentials, and includes the authorization code received in the
			previous step.
			(E) The authorization server validates the client credentials and
			the authorization code and if valid, responds back with an
			access token.
			4.1.1. Authorization Request
			The client constructs the request URI by adding the following
			parameters to the query component of the authorization endpoint URI
			using the "application/x-www-form-urlencoded" format as defined by
			[W3C.REC-html401-19991224]:
			response_type
			REQUIRED. Value MUST be set to "code".
	client_id		client_id
	REQUIRED. The client identifier.		REQUIRED. The client identifier as described in Section 2.
			redirect_uri
			REQUIRED, unless a redirection URI has been established between
			the client and authorization server via other means. Described
			in Section 3.1.1.
			scope
			OPTIONAL. The scope of the access request expressed as a list
			of space-delimited strings. The value is defined by the
			authorization server. If the value contains multiple space-
			delimited strings, their order does not matter, and each string
			adds an additional access range to the requested scope.
			state
			OPTIONAL. An opaque value used by the client to maintain state
			between the request and callback. The authorization server
			includes this value when redirecting the user-agent back to the
			client.
	client_secret REQUIRED. The client password.		The client directs the resource owner to the constructed URI using an
			HTTP redirection response, or by other means available to it via the
			user-agent.
	For example (line breaks are for display purposes only):		For example, the client directs the user-agent to make the following
			HTTP request using transport-layer security (line breaks are for
			display purposes only):
	POST /token HTTP/1.1		GET /authorize?response_type=code&client_id=s6BhdRkqt3&
			redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb HTTP/1.1
	Host: server.example.com		Host: server.example.com
	Content-Type: application/x-www-form-urlencoded
	grant_type=authorization_code&client_id=s6BhdRkqt3&		The authorization server validates the request to ensure all required
	client_secret=gX1fBat3bV&code=i1WsRn1uB1&		parameters are present and valid. If the request is valid, the
	redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb		authorization server authenticates the resource owner and obtains an
			authorization decision (by asking the resource owner or by
			establishing approval via other means).
	The authorization server MUST accept the client credentials using		When a decision is established, the authorization server directs the
	both the request parameter, and the HTTP Basic authentication scheme.		user-agent to the provided client redirection URI using an HTTP
	The authorization server MAY support additional authentication		redirection response, or by other means available to it via the user-
	schemes suitable for the transmission of password credentials.		agent.
	3.2. Client Assertion Credentials		4.1.2. Authorization Response
	The client assertion credentials are used in cases where a password		If the resource owner grants the access request, the authorization
	(clear-text shared symmetric secret) is unsuitable or does not		server issues an authorization code and delivers it to the client by
	provide sufficient security for client authentication. In such cases		adding the following parameters to the query component of the
	it is common to use other mechanisms such as HMAC or digital		redirection URI using the "application/x-www-form-urlencoded" format:
	signatures that do not require sending clear-text secrets. The
	client assertion credentials provide an extensible mechanism to use
	an assertion format supported by the authorization server for
	authentication the client.
	Using assertions requires the client to obtain an assertion (such as		code
	a SAML [OASIS.saml-core-2.0-os] assertion) from an assertion issuer		REQUIRED. The authorization code generated by the
	or to self-issue an assertion. The assertion format, the process by		authorization server. The authorization code SHOULD expire
	which the assertion is obtained, and the method of validating the		shortly after it is issued to minimize the risk of leaks. The
	assertion are defined by the assertion issuer and the authorization		client MUST NOT reuse the authorization code. If an
	server, and are beyond the scope of this specification.		authorization code is used more than once, the authorization
			server MAY revoke all tokens previously issued based on that
			authorization code. The authorization code is bound to the
			client identifier and redirection URI.
			state
			REQUIRED if the "state" parameter was present in the client
			authorization request. Set to the exact value received from
			the client.
	When using a client assertion, the client includes the following		For example, the authorization server redirects the user-agent by
	parameters:		sending the following HTTP response:
	client_assertion_type REQUIRED. The format of the assertion as		HTTP/1.1 302 Found
	defined by the authorization server. The value MUST be an		Location: https://client.example.com/cb?code=i1WsRn1uB1
	absolute URI.
	client_assertion REQUIRED. The client assertion.		The client SHOULD ignore unrecognized response parameters. The
			authorization code string size is left undefined by this
			specification. The clients should avoid making assumptions about
			code value sizes. The authorization server should document the size
			of any value is issues.
	For example, the client sends the following access token request		4.1.2.1. Error Response
	using a SAML 2.0 assertion to authenticate itself (line breaks are
	for display purposes only):		If the request fails due to a missing, invalid, or mismatching
			redirection URI, the authorization server SHOULD inform the resource
			owner of the error, and MUST NOT redirect the user-agent to the
			invalid redirection URI.
			If the resource owner denies the access request or if the request
			fails for reasons other than a missing or invalid redirection URI,
			the authorization server informs the client by adding the following
			parameters to the query component of the redirection URI using the
			"application/x-www-form-urlencoded" format:
			error
			REQUIRED. A single error code from the following:
			invalid_request
			The request is missing a required parameter, includes an
			unsupported parameter or parameter value, or is otherwise
			malformed.
			invalid_client
			The client identifier provided is invalid.
			unauthorized_client
			The client is not authorized to request an authorization
			code using this method.
			access_denied
			The resource owner or authorization server denied the
			request.
			unsupported_response_type
			The authorization server does not support obtaining an
			authorization code using this method.
			invalid_scope
			The requested scope is invalid, unknown, or malformed.
			error_description
			OPTIONAL. A human-readable text providing additional
			information, used to assist in the understanding and resolution
			of the error occurred.
			error_uri
			OPTIONAL. A URI identifying a human-readable web page with
			information about the error, used to provide the resource owner
			with additional information about the error.
			state
			REQUIRED if the "state" parameter was present in the client
			authorization request. Set to the exact value received from
			the client.
			For example, the authorization server redirects the user-agent by
			sending the following HTTP response:
			HTTP/1.1 302 Found
			Location: https://client.example.com/cb?error=access_denied
			4.1.3. Access Token Request
			The client makes a request to the token endpoint by adding the
			following parameter using the "application/x-www-form-urlencoded"
			format in the HTTP request entity-body:
			grant_type
			REQUIRED. Value MUST be set to "authorization_code".
			code
			REQUIRED. The authorization code received from the
			authorization server.
			redirect_uri
			REQUIRED. The redirection URI used in the initial request.
			The client includes its authentication credentials as described in
			Section 2
			For example, the client makes the following HTTP request by including
			its client credentials via the "client_id" and "client_secret"
			parameters, and using transport-layer security (line breaks are for
			display purposes only):
	POST /token HTTP/1.1		POST /token HTTP/1.1
	Host: server.example.com		Host: server.example.com
	Content-Type: application/x-www-form-urlencoded		Content-Type: application/x-www-form-urlencoded
	grant_type=authorization_code&code=i1WsRn1uB1&		grant_type=authorization_code&client_id=s6BhdRkqt3&
	client_assertion=PHNhbWxwOl[...omitted for brevity...]ZT4%3D&		client_secret=gX1fBat3bV&code=i1WsRn1uB1&
	client_assertion_type=
	urn%3Aoasis%3Anames%sAtc%3ASAML%3A2.0%3Aassertion&
	redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb		redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
	When obtaining an access token using a client assertion together with		The authorization server MUST:
	an authorization code (as described in Section 5.1.1), a mechanism is
	needed to map between the value of "client_id" parameter used to
	obtain the authorization code, and the client assertion. Such
	mechanism is beyond the out of scope for this specification, but MUST
	be specified for any client assertion type used in combination with
	an authorization code.
	The authorization server MUST reject access token requests using		o Validate the client credentials and ensure they match the
	client assertion credentials that do not contain HMAC or signed		authorization code.
	values that:		o Verify that the authorization code and redirection URI are valid
			and match its stored association.
	o State the assertion was specifically issued to be consumed by the		If the request is valid and authorized, the authorization server
	receiving endpoint (typically via an audience or recipient value		issues an access token and optional refresh token, and responds as
	containing the receiving endpoint's identifier).		described in Section 5.
	o Identify the entity that issued the assertion (typically via an		4.2. Implicit Grant
	issuer value).
	o Identify when the assertion expires as an absolute time (typically		The implicit grant flow is suitable for clients incapable of
	via an expiration value containing a UTC date/time value). The		maintaining their client credentials confidential (for authenticating
	authorization server MUST reject expired assertions.		with the authorization server) such as client applications residing
			in a user-agent, typically implemented in a browser using a scripting
			language such as JavaScript, or native applications. These clients
			cannot keep client secrets confidential and the authentication of the
			client is based on the user-agent's same-origin policy.
	4. Obtaining End-User Authorization		As a redirection-based profile, the client must be capable of
			interacting with the resource owner's user-agent (typically a web
			browser) and capable of receiving incoming requests (via redirection)
			from the authorization server.
	Before the client can access a protect resource, it MUST first obtain		Unlike the authorization code flow in which the client makes separate
	authorization from the end-user. To obtain an end-user		requests for authorization and access token, the client receives the
	authorization, the client sends the end-user to the end-user		access token as the result of the authorization request.
	authorization endpoint. Once obtained, the end-user access grant is
	expressed as an authorization code which the client uses to obtain an
	access token.
	At the end-user authorization endpoint, the end-user first		The implicit grant flow does not utilize the client credentials since
	authenticates with the authorization server, and then grants or		the client is unable to maintain their confidentiality (the client
	denies the access request. The way in which the authorization server		resides on the resource owner's computer or device which makes the
	authenticates the end-user (e.g. username and password login, OpenID,		client credentials accessible and exploitable). Because the access
	session cookies) and in which the authorization server obtains the		token is encoded into the redirection URI, it may be exposed to the
	end-user's authorization, including whether it uses a secure channel		resource owner and other applications residing on its computer or
	such as TLS, is beyond the scope of this specification. However, the		device.
	authorization server MUST first verify the identity of the end-user.
	The location of the end-user authorization endpoint can be found in		+----------+
	the service documentation. The end-user authorization endpoint URI		| Resource |
	MAY include a query component as defined by [RFC3986] section 3,		| Owner |
	which must be retained when adding additional query parameters.		| |
			+----------+
			^
			|
			(B)
			+----|-----+ Client Identifier +---------------+
			| -+----(A)--- & Redirect URI ----->| |
			| User- | | Authorization |
			| Agent -|----(B)-- User authenticates -->| Server |
			| | | |
			| |<---(C)---- Redirect URI ------<| |
			| | with Access Token +---------------+
			| | in Fragment
			| | +---------------+
			| |----(D)---- Redirect URI ------>| Web Server |
			| | without Fragment | with Client |
			| | | Resource |
			| (F) |<---(E)------- Script ---------<| |
			| | +---------------+
			+-|--------+
			| |
			(A) (G) Access Token
			| |
			^ v
			+---------+
			| |
			| Client |
			| |
			+---------+
	Since requests to the end-user authorization endpoint result in user		Figure 4: Implicit Grant Flow
	authentication and the transmission of sensitive information, the
	authorization server SHOULD require the use of a transport-layer
	security mechanism such as TLS when sending requests to the end-user
	authorization endpoint.
	4.1. Authorization Request		The flow illustrated in Figure 4 includes the following steps:
	In order to direct the end-user's user-agent to the authorization		(A) The client initiates the flow by directing the resource owner's
	server, the client constructs the request URI by adding the following		user-agent to the authorization endpoint. The client includes
	parameters to the end-user authorization endpoint URI query component		its client identifier, requested scope, local state, and a
	using the "application/x-www-form-urlencoded" format as defined by		redirection URI to which the authorization server will send the
	[W3C.REC-html401-19991224]:		user-agent back once access is granted (or denied).
			(B) The authorization server authenticates the resource owner (via
			the user-agent) and establishes whether the resource owner
			grants or denies the client's access request.
	response_type		(C) Assuming the resource owner grants access, the authorization
	REQUIRED. The requested response: an access token, an		server redirects the user-agent back to the client using the
	authorization code, or both. The parameter value MUST be set		redirection URI provided earlier. The redirection URI includes
	to "token" for requesting an access token, "code" for		the access token in the URI fragment.
	requesting an authorization code, or "code_and_token" to		(D) The user-agent follows the redirection instructions by making a
	request both. The authorization server MAY decline to provide		request to the web server (does not include the fragment). The
	one or more of these response types.		user-agent retains the fragment information locally.
			(E) The web server returns a web page (typically an HTML document
			with an embedded script) capable of accessing the full
			redirection URI including the fragment retained by the user-
			agent, and extracting the access token (and other parameters)
			contained in the fragment.
			(F) The user-agent executes the script provided by the web server
			locally, which extracts the access token and passes it to the
			client.
	client_id		4.2.1. Authorization Request
	REQUIRED. The client identifier as described in Section 3.
			The client constructs the request URI by adding the following
			parameters to the query component of the authorization endpoint URI
			using the "application/x-www-form-urlencoded" format:
			response_type
			REQUIRED. Value MUST be set to "token".
			client_id
			REQUIRED. The client identifier as described in Section 2.
			Due to lack of client authentication, the client identifier
			alone MUST NOT be relied upon for client identification.
	redirect_uri		redirect_uri
	REQUIRED, unless a redirection URI has been established between		REQUIRED, unless a redirection URI has been established between
	the client and authorization server via other means. An		the client and authorization server via other means. Described
	absolute URI to which the authorization server will redirect		in Section 3.1.1.
	the user-agent to when the end-user authorization step is
	completed. The authorization server SHOULD require the client
	to pre-register their redirection URI.
	scope		scope
	OPTIONAL. The scope of the access request expressed as a list		OPTIONAL. The scope of the access request expressed as a list
	of space-delimited strings. The value of the "scope" parameter		of space-delimited strings. The value is defined by the
	is defined by the authorization server. If the value contains		authorization server. If the value contains multiple space-
	multiple space-delimited strings, their order does not matter,		delimited strings, their order does not matter, and each string
	and each string adds an additional access range to the		adds an additional access range to the requested scope.
	requested scope.
	state		state
	OPTIONAL. An opaque value used by the client to maintain state		OPTIONAL. An opaque value used by the client to maintain state
	between the request and callback. The authorization server		between the request and callback. The authorization server
	includes this value when redirecting the user-agent back to the		includes this value when redirecting the user-agent back to the
	client.		client.
	The client directs the end-user to the constructed URI using an HTTP		The client directs the resource owner to the constructed URI using an
	redirection response, or by other means available to it via the end-		HTTP redirection response, or by other means available to it via the
	user's user-agent. The authorization server MUST support the use of		user-agent.
	the HTTP "GET" method for the end-user authorization endpoint, and
	MAY support the use of the "POST" method as well.
	For example, the client directs the end-user's user-agent to make the		For example, the client directs the user-agent to make the following
	following HTTP request using transport-layer security (line breaks		HTTP request using transport-layer security (line breaks are for
	are for display purposes only):		display purposes only):
	GET /authorize?response_type=code&client_id=s6BhdRkqt3&		GET /authorize?response_type=token&client_id=s6BhdRkqt3&
	redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb HTTP/1.1		redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb HTTP/1.1
	Host: server.example.com		Host: server.example.com
	If the client has previously registered a redirection URI with the
	authorization server, the authorization server MUST verify that the
	redirection URI received matches the registered URI associated with
	the client identifier. The authorization server SHOULD NOT redirect
	the user-agent to unregistered or untrusted URIs to prevent the
	endpoint from being used as an open redirector. If no valid
	redirection URI is available, the authorization server SHOULD inform
	the end-user of the error occured. [[ provide guidance on how to
	perform matching ]]
	Parameters sent without a value MUST be treated as if they were
	omitted from the request. The authorization server SHOULD ignore
	unrecognized request parameters.
	The authorization server validates the request to ensure all required		The authorization server validates the request to ensure all required
	parameters are present and valid. If the request is invalid, the		parameters are present and valid. If the request is valid, the
	authorization server redirects the user-agent back to the client		authorization server authenticates the resource owner and obtains an
	using the redirection URI provided with the appropriate error code as		authorization decision (by asking the resource owner or by
	described in Section 4.3.		establishing approval via other means).
	The authorization server authenticates the end-user and obtains an
	authorization decision (by asking the end-user or by establishing
	approval via other means). When a decision has been established, the
	authorization server directs the end-user's user-agent to the
	provided client redirection URI using an HTTP redirection response,
	or by other means available to it via the end-user's user-agent.
	4.2. Authorization Response		When a decision is established, the authorization server directs the
			user-agent to the provided client redirection URI using an HTTP
			redirection response, or by other means available to it via the user-
			agent.
	If the end-user grants the access request, the authorization server		4.2.2. Access Token Response
	issues an access token, an authorization code, or both, and delivers
	them to the client by adding the following parameters to the
	redirection URI (as described below):
	code		If the resource owner grants the access request, the authorization
	REQUIRED if the response type is "code" or "code_and_token",		server issues an access token and delivers it to the client by adding
	otherwise MUST NOT be included. The authorization code		the following parameters to the fragment component of the redirection
	generated by the authorization server. The authorization code		URI using the "application/x-www-form-urlencoded" format:
	SHOULD expire shortly after it is issued to minimize the risk
	of leaks. The client MUST NOT reuse the authorization code.
	If an authorization code is used more than once, the
	authorization server MAY revoke all tokens previously issued
	based on that authorization code. The authorization code is
	bound to the client identifier and redirection URI.
	access_token		access_token
	REQUIRED if the response type is "token" or "code_and_token",		REQUIRED. The access token issued by the authorization server.
	otherwise MUST NOT be included. The access token issued by the
	authorization server.
	token_type		token_type
	REQUIRED if the response includes an access token. The type of		REQUIRED. The type of the token issued as described in
	the token issued. The token type informs the client how the		Section 7.1. Value is case insensitive.
	access token is to be used when accessing a protected resource
	as described in Section 6.1.
	expires_in		expires_in
	OPTIONAL. The duration in seconds of the access token lifetime		OPTIONAL. The duration in seconds of the access token
	if an access token is included. For example, the value "3600"		lifetime. For example, the value "3600" denotes that the
	denotes that the access token will expire in one hour from the		access token will expire in one hour from the time the response
	time the response was generated by the authorization server.		was generated.
	scope		scope
	OPTIONAL. The scope of the access token as a list of space-		OPTIONAL. The scope of the access request expressed as a list
	delimited strings if an access token is included. The value of		of space-delimited strings. The value is defined by the
	the "scope" parameter is defined by the authorization server.		authorization server. If the value contains multiple space-
	If the value contains multiple space-delimited strings, their		delimited strings, their order does not matter, and each string
	order does not matter, and each string adds an additional		adds an additional access range to the requested scope. The
	access range to the requested scope. The authorization server		authorization server SHOULD include the parameter if the
	SHOULD include the parameter if the requested scope is		requested scope is different from the one requested by the
	different from the one requested by the client.		client.
	state		state
	REQUIRED if the "state" parameter was present in the client		REQUIRED if the "state" parameter was present in the client
	authorization request. Set to the exact value received from		authorization request. Set to the exact value received from
	the client.		the client.
	The method in which the authorization server adds the parameter to		For example, the authorization server redirects the user-agent by
	the redirection URI is determined by the response type requested by		sending the following HTTP response (URI line breaks are for display
	the client in the authorization request using the "response_type"		purposes only):
	parameter.
	If the response type is "code", the authorization server adds the
	parameters to the redirection URI query component using the
	"application/x-www-form-urlencoded" format as defined by
	[W3C.REC-html401-19991224].
	For example, the authorization server redirects the end-user's user-
	agent by sending the following HTTP response:
	HTTP/1.1 302 Found
	Location: https://client.example.com/cb?code=i1WsRn1uB1
	If the response type is "token" or "code_and_token", the
	authorization server adds the parameters to the redirection URI
	fragment component using the "application/x-www-form-urlencoded"
	format as defined by [W3C.REC-html401-19991224].
	For example, the authorization server redirects the end-user's user-
	agent by sending the following HTTP response (URI line breaks are for
	display purposes only):
	HTTP/1.1 302 Found		HTTP/1.1 302 Found
	Location: http://example.com/rd#access_token=FJQbwq9&		Location: http://example.com/rd#access_token=FJQbwq9&
	token_type=example&expires_in=3600		token_type=example&expires_in=3600
	Clients SHOULD ignore unrecognized response parameters. The sizes of		The client SHOULD ignore unrecognized response parameters. The
	tokens and other values received from the authorization server, are		access token string size is left undefined by this specification.
	left undefined by this specification. Clients should avoid making		The client should avoid making assumptions about value sizes. The
	assumptions about value sizes. Servers should document the expected		authorization server should document the size of any value it issues.
	size of any value they issue.
	4.3. Error Response		4.2.2.1. Error Response
	If the end-user denies the access request or if the request fails for		If the request fails due to a missing, invalid, or mismatching
	reasons other than a missing or invalid redirection URI, the		redirection URI, the authorization server SHOULD inform the resource
	authorization server informs the client by adding the following		owner of the error, and MUST NOT redirect the user-agent to the
	parameters to the redirection URI query component using the		invalid redirection URI.
	"application/x-www-form-urlencoded" format as defined by
	[W3C.REC-html401-19991224]:
	error		If the resource owner denies the access request or if the request
	REQUIRED. A single error code as described in Section 4.3.1.		fails for reasons other than a missing or invalid redirection URI,
			the authorization server informs the client by adding the following
			parameters to the fragment component of the redirection URI using the
			"application/x-www-form-urlencoded" format:
	error_description OPTIONAL. A human-readable text providing		error
	additional information, used to assist in the understanding and		REQUIRED. A single error code from the following:
	resolution of the error occurred.		invalid_request
			The request is missing a required parameter, includes an
			unsupported parameter or parameter value, or is otherwise
			malformed.
			invalid_client
			The client identifier provided is invalid.
			unauthorized_client
			The client is not authorized to request an access token
			using this method.
	error_uri OPTIONAL. A URI identifying a human-readable web page		access_denied
	with information about the error, used to provide the end-user		The resource owner or authorization server denied the
			request.
			unsupported_response_type
			The authorization server does not support obtaining an
			access token using this method.
			invalid_scope
			The requested scope is invalid, unknown, or malformed.
			error_description
			OPTIONAL. A human-readable text providing additional
			information, used to assist in the understanding and resolution
			of the error occurred.
			error_uri
			OPTIONAL. A URI identifying a human-readable web page with
			information about the error, used to provide the resource owner
	with additional information about the error.		with additional information about the error.
	state		state
	REQUIRED if the "state" parameter was present in the client		REQUIRED if the "state" parameter was present in the client
	authorization request. Set to the exact value received from		authorization request. Set to the exact value received from
	the client.		the client.
	For example, the authorization server redirects the end-user's user-		For example, the authorization server redirects the user-agent by
	agent by sending the following HTTP response:		sending the following HTTP response:
	HTTP/1.1 302 Found		HTTP/1.1 302 Found
	Location: https://client.example.com/cb?error=access_denied		Location: https://client.example.com/cb#error=access_denied
	If the request fails due to a missing or invalid redirection URI, the
	authorization server SHOULD inform the end-user of the error, and
	MUST NOT redirect the end-user's user-agent to the invalid
	redirection URI.
	4.3.1. Error Codes
	The authorization server includes one of the following error codes
	with the error response:
	invalid_request
	The request is missing a required parameter, includes an
	unsupported parameter or parameter value, or is otherwise
	malformed.
	invalid_client
	The client identifier provided is invalid.
	unauthorized_client
	The client is not authorized to use the requested response
	type.
	redirect_uri_mismatch
	The redirection URI provided does not match a pre-registered
	value.
	access_denied		4.3. Resource Owner Password Credentials
	The end-user or authorization server denied the request.
	unsupported_response_type		The resource owner password credentials flow is suitable in cases
	The requested response type is not supported by the		where the resource owner has a trust relationship with the client,
	authorization server.		such as its computer operating system or a highly privileged
			application. The authorization server should take special care when
			enabling the flow, and only when other flows are not viable.
	invalid_scope		The flow is suitable for clients capable of obtaining the resource
	The requested scope is invalid, unknown, or malformed.		owner credentials (username and password, typically using an
			interactive form). It is also used to migrate existing clients using
			direct authentication schemes such as HTTP Basic or Digest
			authentication to OAuth by converting the stored credentials with an
			access token.
	[[ Add mechanism for extending error codes ]]		The method through which the client obtains the resource owner
			credentials is beyond the scope of this specification. The client
			MUST discard the credentials once an access token has been obtained.
	5. Obtaining an Access Token		+----------+
			| Resource |
			| Owner |
			| |
			+----------+
			v
			|
			(A) Password Credentials
			|
			v
			+---------+ +---------------+
			| | Client Credentials | |
			| |>--(B)---- & Resource Owner ----->| |
			| Client | Password Credentials | Authorization |
			| | | Server |
			| |<--(C)---- Access Token ---------<| |
			| | (w/ Optional Refresh Token) | |
			+---------+ +---------------+
	The client obtains an access token by authenticating with the		Figure 5: Resource Owner Password Credentials Flow
	authorization server and presenting its access grant (in the form of
	an authorization code, resource owner credentials, an assertion, or a
	refresh token).
	Since requests to the token endpoint result in the transmission of		The flow illustrated in Figure 5 includes the following steps:
	clear-text credentials in the HTTP request and response, the
	authorization server MUST require the use of a transport-layer
	security mechanism when sending requests to the token endpoints.
	Servers MUST support TLS 1.2 as defined in [RFC5246], and MAY support
	additional transport-layer security mechanisms.
	The client requests an access token by making an HTTP "POST" request		(A) The resource owner provides the client with its username and
	to the token endpoint. The location of the token endpoint can be		password.
	found in the service documentation. The token endpoint URI MAY		(B) The client requests an access token from the authorization
	include a query component.		server's token endpoint by authenticating using its client
			credentials, and includes the credentials received from the
			resource owner.
			(C) The authorization server validates the resource owner
			credentials and the client credentials and issues an access
			token.
	The client authenticates with the authorization server by adding its		4.3.1. Access Token Request
	client credentials to the request as described in Section 3. The
	authorization server MAY allow unauthenticated access token requests
	when the client identity does not matter (e.g. anonymous client) or
	when the client identity is established via other means (e.g. using
	an assertion access grant).
	The client constructs the request by including the following		The client makes a request to the token endpoint by adding the
	parameters using the "application/x-www-form-urlencoded" format in		following parameter using the "application/x-www-form-urlencoded"
	the HTTP request entity-body:		format in the HTTP request entity-body:
	grant_type		grant_type
	REQUIRED. The access grant type included in the request.		REQUIRED. Value MUST be set to "password".
	Value MUST be one of "authorization_code", "password",		username
	"refresh_token", "client_credentials", or an absolute URI		REQUIRED. The resource owner username.
	identifying an assertion format supported by the authorization
	server.
			password
			REQUIRED. The resource owner password.
	scope		scope
	OPTIONAL. The scope of the access request expressed as a list		OPTIONAL. The scope of the access request expressed as a list
	of space-delimited strings. The value of the "scope" parameter		of space-delimited strings. The value is defined by the
	is defined by the authorization server. If the value contains		authorization server. If the value contains multiple space-
	multiple space-delimited strings, their order does not matter,		delimited strings, their order does not matter, and each string
	and each string adds an additional access range to the		adds an additional access range to the requested scope.
	requested scope. If the access grant being used already
	represents an approved scope (e.g. authorization code,
	assertion), the requested scope MUST be equal or lesser than
	the scope previously granted, and if omitted is treated as
	equal to the previously approved scope.
	In addition, the client MUST include the appropriate parameters
	listed for the selected access grant type as described in
	Section 5.1.
	Parameters sent without a value MUST be treated as if they were
	omitted from the request. The authorization server SHOULD ignore
	unrecognized request parameters.
	5.1. Access Grant Types
	The client requests an access token using an authorization code,
	resource owner password credentials, client credentials, refresh
	token, or assertion.
	5.1.1. Authorization Code
	The client includes the authorization code using the
	"authorization_code" access grant type and the following parameters:
	code		The client includes its authentication credentials as described in
	REQUIRED. The authorization code received from the		Section 2
	authorization server.
	redirect_uri		[[ add internationalization consideration for username and password
	REQUIRED. The redirection URI used in the initial request.		]]
	For example, the client makes the following HTTP request by including		For example, the client makes the following HTTP request by including
	its client credentials via the "client_secret" parameter described in		its client credentials via the "client_id" and "client_secret"
	Section 3 and using transport-layer security (line breaks are for		parameters, and using transport-layer security (line breaks are for
	display purposes only):		display purposes only):
	POST /token HTTP/1.1		POST /token HTTP/1.1
	Host: server.example.com		Host: server.example.com
	Content-Type: application/x-www-form-urlencoded		Content-Type: application/x-www-form-urlencoded
	grant_type=authorization_code&client_id=s6BhdRkqt3&		grant_type=password&client_id=s6BhdRkqt3&
	client_secret=gX1fBat3bV&code=i1WsRn1uB1&		client_secret=47HDu8s&username=johndoe&password=A3ddj3w
	redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
	The authorization server MUST:		The authorization server MUST:
	o Validate the client credentials (if present) and ensure they match		o Validate the client credentials.
	the authorization code.		o Validate the resource owner password credentials.
	o Verify that the authorization code and redirection URI are all
	valid and match its stored association.
	If the request is valid, the authorization server issues a successful
	response as described in Section 5.2.
	5.1.2. Resource Owner Password Credentials
	The client includes the resource owner credentials using the
	"password" access grant type and the following parameters: [[ add
	internationalization consideration for username and password ]]
	username		If the request is valid and authorized, the authorization server
	REQUIRED. The resource owner's username.		issues an access token and optional refresh token, and responds as
			described in Section 5.
	password		4.4. Client Credentials
	REQUIRED. The resource owner's password.
	For example, the client makes the following HTTP request by including		The client can request an access token using only its client
	its client credentials via the "client_secret" parameter described in		credentials when the client is requesting access to the protected
	Section 3 and using transport-layer security (line breaks are for		resources under its control, or those of another resource owner which
	display purposes only):		has been previously arranged with the authorization server (the
			method of which is beyond the scope of this specification).
	POST /token HTTP/1.1		+---------+ +---------------+
	Host: server.example.com		| | | |
	Content-Type: application/x-www-form-urlencoded		| |>--(A)--- Client Credentials ---->| Authorization |
			| Client | | Server |
			| |<--(B)---- Access Token ---------<| |
			| | (w/ Optional Refresh Token) | |
			+---------+ +---------------+
	grant_type=password&client_id=s6BhdRkqt3&		Figure 6: Client Credentials Flow
	client_secret=47HDu8s&username=johndoe&password=A3ddj3w
	The authorization server MUST validate the client credentials (if		The flow illustrated in Figure 6 includes the following steps:
	present) and end-user credentials and if valid issue an access token
	response as described in Section 5.2.
	5.1.3. Client Credentials		(A) The client requests an access token from the token endpoint by
			authenticating using its client credentials.
			(B) The authorization server validates the client credentials and
			issues an access token.
	The client can request an access token using only its client		4.4.1. Access Token Request
	credentials using the "client_credentials" access grant type. When
	omitting an explicit access grant, the client is requesting access to
	the protected resources under its control, or those of another
	resource owner which has been previously arranged with the
	authorization server (the method of which is beyond the scope of this
	specification).
	5.1.4. Refresh Token		The client makes a request to the token endpoint by adding the
			following parameter using the "application/x-www-form-urlencoded"
			format in the HTTP request entity-body:
	The client includes the refresh token using the "refresh_token"		grant_type
	access grant type and the following parameter:		REQUIRED. Value MUST be set to "client_credentials".
			scope
			OPTIONAL. The scope of the access request expressed as a list
			of space-delimited strings. The value is defined by the
			authorization server. If the value contains multiple space-
			delimited strings, their order does not matter, and each string
			adds an additional access range to the requested scope.
	refresh_token		The client includes its authentication credentials as described in
	REQUIRED. The refresh token associated with the access token		Section 2
	to be refreshed.
	For example, the client makes the following HTTP request by including		For example, the client makes the following HTTP request by including
	its client credentials via the "client_secret" parameter described in		its client credentials via the "client_id" and "client_secret"
	Section 3 and using transport-layer security (line breaks are for		parameters, and using transport-layer security (line breaks are for
	display purposes only):		display purposes only):
	POST /token HTTP/1.1		POST /token HTTP/1.1
	Host: server.example.com		Host: server.example.com
	Content-Type: application/x-www-form-urlencoded		Content-Type: application/x-www-form-urlencoded
	grant_type=refresh_token&client_id=s6BhdRkqt3&		grant_type=client_credentials&client_id=s6BhdRkqt3&
	client_secret=8eSEIpnqmM&refresh_token=n4E9O119d		client_secret=47HDu8s
	The authorization server MUST verify the client credentials (if		The authorization server MUST validate the client credentials.
	present), the validity of the refresh token, and that the resource
	owner's authorization is still valid. If the request is valid, the
	authorization server issues an access token response as described in
	Section 5.2. The authorization server MAY issue a new refresh token,
	in which case, the client MUST discard the old refresh token and
	replace it with the new refresh token.
	5.1.5. Assertion		If the request is valid and authorized, the authorization server
			issues an access token and optional refresh token, and responds as
			described in Section 5.
	The client includes an assertion by specifying the assertion format		4.5. Extensions
	using an absolute URI (as defined by the authorization server) as the
	value of the "grant_type" parameter and by adding the following
	parameter:
	assertion		The client uses an extension grant type by specifying the grant type
	REQUIRED. The assertion.		using an absolute URI (defined by the authorization server) as the
			value of the "grant_type" parameter of the token endpoint, and by
			adding any additional parameters necessary.
	For example, the client makes the following HTTP request using		For example, to request an access token using a SAML 2.0 assertion
	transport-layer security, and client authentication is achieved via		grant type, the client makes the following HTTP request using
	the assertion (line breaks are for display purposes only):		transport-layer security (line breaks are for display purposes only):
	POST /token HTTP/1.1		POST /token HTTP/1.1
	Host: server.example.com		Host: server.example.com
	Content-Type: application/x-www-form-urlencoded		Content-Type: application/x-www-form-urlencoded
	grant_type=urn%3Aoasis%3Anames%3Atc%3ASAML%3A2.0%3Aassertion&		grant_type=http%3A%2F%2Foauth.net%2Fgrant_type%2Fassertion%2F
	assertion=PHNhbWxwOl[...omitted for brevity...]ZT4%3D		saml%2F2.0%2Fbearer&assertion=PEFzc2VydGlvbiBJc3N1ZUluc3RhbnQ
			[...omitted for brevity...]V0aG5TdGF0ZW1lbnQ-PC9Bc3NlcnRpb24-
	The authorization server MUST validate the client credentials (if		Client authentication and the scope of the grant are obtained via the
	present) and the assertion and if valid issues an access token		assertion as defined by [I-D.ietf-oauth-saml2-bearer].
	response as described in Section 5.2. The authorization server
	SHOULD NOT issue a refresh token (instead, it should require the
	client to use the same or new assertion).
	Authorization servers SHOULD issue access tokens with a limited		5. Issuing an Access Token
	lifetime and require clients to refresh them by requesting a new
	access token using the same assertion if it is still valid.
	Otherwise the client MUST obtain a new valid assertion.
	5.2. Access Token Response		If the access token request is valid and authorized, the
			authorization server issues an access token and optional refresh
			token as described in Section 5.1. If the request failed client
			authentication or is invalid, the authorization server return an
			error response as described in Section 5.2.
	After receiving and verifying a valid and authorized access token		5.1. Successful Response
	request from the client, the authorization server issues the access
	token and optional refresh token, and constructs the response by
	adding the following parameters to the entity body of the HTTP
	response with a 200 (OK) status code:
	The token response contains the following parameters:		The authorization server issues an access token and optional refresh
			token, and constructs the response by adding the following parameters
			to the entity body of the HTTP response with a 200 (OK) status code:
	access_token		access_token
	REQUIRED. The access token issued by the authorization server.		REQUIRED. The access token issued by the authorization server.
	token_type		token_type
	REQUIRED. The type of the token issued. The token type		REQUIRED. The type of the token issued as described in
	informs the client how the access token is to be used when		Section 7.1. Value is case insensitive.
	accessing a protected resource as described in Section 6.1.
	expires_in		expires_in
	OPTIONAL. The duration in seconds of the access token		OPTIONAL. The duration in seconds of the access token
	lifetime. For example, the value "3600" denotes that the		lifetime. For example, the value "3600" denotes that the
	access token will expire in one hour from the time the response		access token will expire in one hour from the time the response
	was generated by the authorization server.		was generated.
	refresh_token		refresh_token
	OPTIONAL. The refresh token used to obtain new access tokens		OPTIONAL. The refresh token which can be used to obtain new
	using the same end-user access grant as described in		access tokens using the same authorization grant as described
	Section 5.1.4. The authorization server SHOULD NOT issue a		in Section 6.
	refresh token when the access grant type is an assertion or a
	set of client credentials.
	scope		scope
	OPTIONAL. The scope of the access token as a list of space-		OPTIONAL. The scope of the access request expressed as a list
	delimited strings. The value of the "scope" parameter is		of space-delimited strings. The value is defined by the
	defined by the authorization server. If the value contains		authorization server. If the value contains multiple space-
	multiple space-delimited strings, their order does not matter,		delimited strings, their order does not matter, and each string
	and each string adds an additional access range to the		adds an additional access range to the requested scope. The
	requested scope. The authorization server SHOULD include the		authorization server SHOULD include the parameter if the
	parameter if the requested scope is different from the one		requested scope is different from the one requested by the
	requested by the client.		client.
	The parameters are including in the entity body of the HTTP response		The parameters are including in the entity body of the HTTP response
	using the "application/json" media type as defined by [RFC4627]. The		using the "application/json" media type as defined by [RFC4627]. The
	parameters are serialized into a JSON structure by adding each		parameters are serialized into a JSON structure by adding each
	parameter at the highest structure level. Parameter names and string		parameter at the highest structure level. Parameter names and string
	values are included as JSON strings. Numerical values are included		values are included as JSON strings. Numerical values are included
	as JSON numbers.		as JSON numbers.
	The authorization server MUST include the HTTP "Cache-Control"		The authorization server MUST include the HTTP "Cache-Control"
	response header field with a value of "no-store" in any response		response header field with a value of "no-store" in any response
	skipping to change at page 31, line 26 ¶		skipping to change at page 29, line 50 ¶
	For example:		For example:
	HTTP/1.1 200 OK		HTTP/1.1 200 OK
	Content-Type: application/json		Content-Type: application/json
	Cache-Control: no-store		Cache-Control: no-store
	{		{
	"access_token":"SlAV32hkKG",		"access_token":"SlAV32hkKG",
	"token_type":"example",		"token_type":"example",
	"expires_in":3600,		"expires_in":3600,
	"refresh_token":"8xLOxBtZp8"		"refresh_token":"8xLOxBtZp8",
			"example_parameter":"example-value"
	}		}
	Clients SHOULD ignore unrecognized response parameters. The sizes of		The client SHOULD ignore unrecognized response parameters. The sizes
	tokens and other values received from the authorization server, are		of tokens and other values received from the authorization server are
	left undefined by this specification. Clients should avoid making		left undefined. The client should avoid making assumptions about
	assumptions about value sizes. Servers should document the expected		value sizes. The authorization server should document the size of
	size of any value they issue.		any value it issues.
	5.3. Error Response		5.2. Error Response
	If the token request is invalid or unauthorized, the authorization		If the client provided invalid credentials using an HTTP
	server constructs the response by adding the following parameter to		authentication scheme via the "Authorization" request header field,
	the entity body of the HTTP response using the "application/json"		the authorization server MUST respond with a HTTP 401 (Unauthorized)
	media type:		status code, and include the "WWW-Authenticate" response header field
			matching the authentication scheme used by the client. Otherwise,
			the authorization server MUST respond with the HTTP 400 (Bad Request)
			status code.
	error		The authorization server constructs the response by adding the
	REQUIRED. A single error code as described in Section 5.3.1.		following parameter to the response:
	error_description OPTIONAL. A human-readable text providing		error
	additional information, used to assist in the understanding and		REQUIRED. A single error code from the following:
	resolution of the error occurred.		invalid_request
			The request is missing a required parameter, includes an
			unsupported parameter or parameter value, repeats a
			parameter, includes multiple credentials, utilizes more
			than one mechanism for authenticating the client, or is
			otherwise malformed.
			invalid_client
			Client authentication failed (e.g. unknown client, no
			client credentials included, multiple client credentials
			included, or unsupported credentials type).
			invalid_grant
			The provided authorization grant is invalid, expired,
			revoked, or does not match the redirection URI used in
			the authorization request.
			unauthorized_client
			The authenticated client is not authorized to use this
			authorization grant type.
			unsupported_grant_type
			The authorization grant type is not supported by the
			authorization server.
	error_uri OPTIONAL. A URI identifying a human-readable web page		invalid_scope
	with information about the error, used to provide the end-user		The requested scope is invalid, unknown, malformed, or
			exceeds the previously granted scope.
			error_description
			OPTIONAL. A human-readable text providing additional
			information, used to assist in the understanding and resolution
			of the error occurred.
			error_uri
			OPTIONAL. A URI identifying a human-readable web page with
			information about the error, used to provide the resource owner
	with additional information about the error.		with additional information about the error.
			The parameters are including in the entity body of the HTTP response
			using the "application/json" media type as defined by [RFC4627]. The
			parameters are serialized into a JSON structure by adding each
			parameter at the highest structure level. Parameter names and string
			values are included as JSON strings. Numerical values are included
			as JSON numbers.
	For example:		For example:
	HTTP/1.1 400 Bad Request		HTTP/1.1 400 Bad Request
	Content-Type: application/json		Content-Type: application/json
	Cache-Control: no-store		Cache-Control: no-store
	{		{
	"error":"invalid_request"		"error":"invalid_request"
	}		}
	If the client provided invalid credentials using an HTTP		6. Refreshing an Access Token
	authentication scheme via the "Authorization" request header field,
	the authorization server MUST respond with the HTTP 401
	(Unauthorized) status code. Otherwise, the authorization server
	SHALL respond with the HTTP 400 (Bad Request) status code.
	5.3.1. Error Codes
	The authorization server includes one of the following error codes		The client makes a request to the token endpoint by adding the
	with the error response:		following parameter using the "application/x-www-form-urlencoded"
			format in the HTTP request entity-body:
	invalid_request		grant_type
	The request is missing a required parameter, includes an		REQUIRED. Value MUST be set to "refresh_token".
	unsupported parameter or parameter value, repeats a parameter,		refresh_token
	includes multiple credentials, utilizes more than one mechanism		REQUIRED. The refresh token issued along the access token
	for authenticating the client, or is otherwise malformed.		being refreshed.
			scope
			OPTIONAL. The scope of the access request expressed as a list
			of space-delimited strings. The value is defined by the
			authorization server. If the value contains multiple space-
			delimited strings, their order does not matter, and each string
			adds an additional access range to the requested scope. The
			requested scope MUST be equal or lesser than the scope
			originally granted by the resource owner, and if omitted is
			treated as equal to the previously approved scope.
	invalid_client		The client includes its authentication credentials as described in
	The client identifier provided is invalid, the client failed to		Section 2
	authenticate, the client did not include its credentials,
	provided multiple client credentials, or used unsupported
	credentials type.
	unauthorized_client		For example, the client makes the following HTTP request by including
	The authenticated client is not authorized to use the access		its client credentials via the "client_id" and "client_secret"
	grant type provided.		parameters, and using transport-layer security (line breaks are for
			display purposes only):
	invalid_grant		POST /token HTTP/1.1
	The provided access grant is invalid, expired, or revoked (e.g.		Host: server.example.com
	invalid assertion, expired authorization token, bad end-user		Content-Type: application/x-www-form-urlencoded
	password credentials, or mismatching authorization code and
	redirection URI).
	unsupported_grant_type		grant_type=refresh_token&client_id=s6BhdRkqt3&
	The access grant included - its type or another attribute - is		client_secret=8eSEIpnqmM&refresh_token=n4E9O119d
	not supported by the authorization server.
	invalid_scope		The authorization server MUST validate the client credentials, the
	The requested scope is invalid, unknown, malformed, or exceeds		refresh token, and verify that the resource owner's authorization is
	the previously granted scope.		still valid. If valid, the authorization server issues an access
			token response as described in Section 5.
	[[ Add mechanism for extending error codes ]]		The authorization server MAY issue a new refresh token, in which
			case, the client MUST discard the old refresh token and replace it
			with the new refresh token.
	6. Accessing a Protected Resource		7. Accessing Protected Resources
	Clients access protected resources by presenting an access token to		The client accesses protected resources by presenting the access
	the resource server. The resource server MUST validate the access		token to the resource server. The resource server MUST validate the
	token and ensure it has not expired and that its scope covers the		access token and ensure it has not expired and that its scope covers
	requested resource. The methods used by the resource server to		the requested resource. The methods used by the resource server to
	validate the access token are beyond the scope of this specification,		validate the access token are beyond the scope of this specification,
	but generally involve an interaction or coordination between the		but generally involve an interaction or coordination between the
	resource server and authorization server.		resource server and the authorization server.
	The method in which the client utilized the access token to		The method in which the client utilized the access token to
	authenticate with the resource server depends on the type of access		authenticate with the resource server depends on the type of access
	token issued by the authorization server.		token issued by the authorization server. Typically, it involves
			using the HTTP "Authorization" request header field with an
	6.1. Access Token Types		authentication scheme defined by the access token type specification.
	[[ add token type explanation, maybe with links to other token specs
	]]
	6.2. The WWW-Authenticate Response Header Field
	If the protected resource request does not include authentication
	credentials, contains an invalid access token, or is malformed, the
	resource server MUST include the HTTP "WWW-Authenticate" response
	header field. The "WWW-Authenticate" header field uses the framework
	defined by [RFC2617] as follows:
	challenge = "OAuth2" [ RWS 1#param ]
	param = scope /
	error / error-desc / error-uri /
	( token "=" ( token / quoted-string ) )
	scope = "scope" "=" <"> scope-v *( SP scope-v ) <">
	scope-v = 1*quoted-char
	quoted-char = ALPHA / DIGIT /
	"!" / "#" / "$" / "%" / "&" / "'" / "(" / ")" /
	"*" / "+" / "-" / "." / "/" / ":" / "<" / "=" /
	">" / "?" / "@" / "[" / "]" / "^" / "_" / "`" /
	"{" / "|" / "}" / "~" / "\" / "," / ";"
	error = "error" "=" quoted-string
	error-desc = "error_description" "=" quoted-string
	error-uri = "error_uri" = <"> URI-reference <">
	The "scope" attribute is a space-delimited list of scope values
	indicating the required scope of the access token for accessing the
	requested resource. The "scope" attribute MUST NOT appear more than
	once.
	If the protected resource request included an access token and failed
	authentication, the resource server SHOULD include the "error"
	attribute to provide the client with the reason why the access
	request was declined. The parameter value is described in
	Section 6.2.1. In addition, the resource server MAY include the
	"error_description" attribute to provide a human-readable
	explanation, and the "error-uri" attribute with an absolute URI
	identifying a human-readable web page explaining the error. The
	"error", "error_description", and "error_uri" attribute MUST NOT
	appear more than once.
	For example, in response to a protected resource request without
	authentication:
	HTTP/1.1 401 Unauthorized
	WWW-Authenticate: OAuth2
	And in response to a protected resource request with an
	authentication attempt using an expired access token:
	HTTP/1.1 401 Unauthorized		7.1. Access Token Types
	WWW-Authenticate: OAuth2
	error="invalid_token",
	error_description="The access token expired"
	6.2.1. Error Codes		The access token type provides the client with the information
			required to successfully utilize the access token to make a protected
			resource request (along with type-specific attributes).
	When a request fails, the resource server responds using the		For example, the "bearer" token type defined in
	appropriate HTTP status code (typically, 400, 401, or 403), and		[I-D.ietf-oauth-v2-bearer] is utilized by simply including the access
	includes one of the following error codes in the response:		token string in the request:
	invalid_request		GET /resource/1 HTTP/1.1
	The request is missing a required parameter, includes an		Host: example.com
	unsupported parameter or parameter value, repeats the same		Authorization: BEARER h480djs93hd8
	parameter, uses more than one method for including an access
	token, or is otherwise malformed. The resource server SHOULD
	respond with the HTTP 400 (Bad Request) status code.
	invalid_token		while the "mac" token type defined in [I-D.hammer-oauth-v2-mac-token]
	The access token provided is expired, revoked, malformed, or		is utilized by issuing a token secret together with the access token
	invalid for other reasons. The resource SHOULD respond with		which is used to sign certain components of the HTTP requests:
	the HTTP 401 (Unauthorized) status code. The client MAY
	request a new access token and retry the protected resource
	request.
	insufficient_scope		GET /resource/1 HTTP/1.1
	The request requires higher privileges than provided by the		Host: example.com
	access token. The resource server SHOULD respond with the HTTP		Authorization: MAC token="h480djs93hd8",
	403 (Forbidden) status code and MAY include the "scope"		timestamp="137131200",
	attribute with the scope necessary to access the protected		nonce="dj83hs9s",
	resource.		signature="kDZvddkndxvhGRXZhvuDjEWhGeE="
	[[ Add mechanism for extending error codes ]]		Each access token type definition specifies the additional attributes
			(if any) sent to the client together with the "access_token" response
			parameter. It also defines the HTTP authentication method used to
			include the access token when making a protected resource request.
	If the request lacks any authentication information (i.e. the client		8. Extensibility
	was unaware authentication is necessary or attempted using an
	unsupported authentication method), the resource server SHOULD not
	include an error code or other error information.
	For example:		8.1. Defining Access Token Types
	HTTP/1.1 401 Unauthorized		Access token types can be defined in one of two ways: registered in
	WWW-Authenticate: OAuth2		the access token type registry (following the procedures in
			Section 10.1), or use the "x_" type name prefix.
	7. Extensibility		Types utilizing the "x_" name prefix MUST be limited to vendor-
			specific implementations that are not commonly applicable, and are
			specific to the implementation details of the resource server where
			they are used. If a vendor-specific type requires additional vendor-
			specific token response parameters, they MUST also use the "x_" name
			prefix.
	7.1. Defining New Client Credentials Types		All other types MUST be registered, and MUST NOT use the "x_" type
			name prefix. Type names MUST conform to the type-name ABNF. If the
			type definition includes a new HTTP authentication scheme, the type
			name SHOULD be identical to the authentication scheme name (as
			defined by [RFC2617]).
	[[ TBD ]]		type-name = 1*name-char
			name-char = "-" / "." / "_" / DIGIT / ALPHA
	7.2. Defining New Endpoint Parameters		8.2. Defining New Endpoint Parameters
	Applications that wish to define new request or response parameters		New request or response parameters for use with the authorization
	for use with the end-user authorization endpoint or the token		endpoint or the token endpoint can be added in one of two ways:
	endpoint SHALL do so in one of two ways: register them in the		registered in the parameters registry (following the procedures in
	parameters registry (following the procedures in Section 9.1), or use		Section 10.2), or use the "x_" parameter name prefix.
	the "x_" parameter name prefix.
	Parameters utilizing the "x_" parameter name prefix MUST be limited		Parameters utilizing the "x_" parameter name prefix MUST be limited
	to vendor-specific extensions that are not commonly applicable, and		to vendor-specific extensions that are not commonly applicable, and
	are specific to the implementation details of the authorization		are specific to the implementation details of the authorization
	server where they are used. All other new parameters MUST be		server where they are used. All other new parameters MUST be
	registered, and MUST NOT use the "x_" parameter name prefix.		registered, and MUST NOT use the "x_" parameter name prefix.
	Parameter names MUST conform to the param-name ABNF, and parameter		Parameter names MUST conform to the param-name ABNF, and parameter
	values syntax MUST be well-defined (e.g., using ABNF, or a reference		values syntax MUST be well-defined (e.g., using ABNF, or a reference
	to the syntax of an existing parameter).		to the syntax of an existing parameter).
	param-name = 1*name-char		param-name = 1*name-char
	name-char = "-" / "." / "_" / DIGIT / ALPHA		name-char = "-" / "." / "_" / DIGIT / ALPHA
	7.3. Defining New Header Field Parameters		8.3. Defining New Authorization Grant Types
	Applications that wish to define new parameters for use in the OAuth		New authorization grant types can be defined by assigning them a
	"WWW-Authenticate" header field MUST register them in the parameters		unique URI for use with the "grant_type" parameter. If the extension
	registry, following the procedures in Section 9.1.		grant type requires additional token endpoint parameters, they MUST
			be registered in the OAuth parameters registry as described by
			Section 10.2.
	Parameter names MUST conform to the param-name ABNF and MUST NOT		9. Security Considerations
	begin with "x_". Parameter values MUST conform to the param-value
	ABNF and their syntax MUST be well-defined (e.g., using ABNF, or a
	reference to the syntax of an existing parameter).
	param-value = quoted-value | quoted-string		[[ TBD ]]
	7.4. Defining New Access Grant Types		10. IANA Considerations
	The assertion access grant type allows the authorization server to		10.1. The OAuth Access Token Type Registry
	accept additional access grants not specified. Applications that
	wish to define additional access grant types can do so by utilizing a
	new or existing assertion type and format.
	8. Security Considerations		This specification establishes the OAuth access token type registry.
	[[ TBD ]]		Access token types are registered on the advice of one or more
			Designated Experts (appointed by the IESG or their delegate), with a
			Specification Required (using terminology from [RFC5226]). However,
			to allow for the allocation of values prior to publication, the
			Designated Expert(s) may approve registration once they are satisfied
			that such a specification will be published.
	9. IANA Considerations		Registration requests should be sent to the [TBD]@ietf.org mailing
			list for review and comment, with an appropriate subject (e.g.,
			"Request for access toke type: example"). [[ Note to RFC-EDITOR: The
			name of the mailing list should be determined in consultation with
			the IESG and IANA. Suggested name: oauth-ext-review. ]]
	9.1. The OAuth Parameters Registry		Before a period of 14 days has passed, the Designated Expert(s) will
			either approve or deny the registration request, communicating this
			decision both to the review list and to IANA. Denials should include
			an explanation and, if applicable, suggestions as to how to make the
			request successful. Registration requests that are undetermined for
			a period longer than 21 days can be brought to the IESG's attention
			(using the iesg@iesg.org mailing list) for resolution.
	This document establishes the OAuth parameters registry.		10.1.1. Registration Template
	Additional parameters to be use in the end-user authorization		Type name:
	endpoint request, the end-user authorization endpoint response, the		The name requested (e.g., "example").
	token endpoint request, the token endpoint response, or the		Additional Token Endpoint Response Parameters:
	"WWW-Authenticate" header field, are registered on the advice of one		Additional response parameters returned together with the
	or more Designated Experts (appointed by the IESG or their delegate),		"access_token" parameter. New parameters MUST be separately
	with a Specification Required (using terminology from [RFC5226]).		registered in the OAuth parameters registry as described by
	However, to allow for the allocation of values prior to publication,		Section 10.2.
	the Designated Expert(s) may approve registration once they are		HTTP Authentication Scheme(s):
	satisfied that such a specification will be published.		The HTTP authentication scheme name(s), if any, used to
			authenticate protected resources requests using access token of
			this type.
			Change controller:
			For standards-track RFCs, state "IETF". For others, give the name
			of the responsible party. Other details (e.g., postal address,
			e-mail address, home page URI) may also be included.
			Specification document(s):
			Reference to document that specifies the parameter, preferably
			including a URI that can be used to retrieve a copy of the
			document. An indication of the relevant sections may also be
			included, but is not required.
			10.2. The OAuth Parameters Registry
			This specification establishes the OAuth parameters registry.
			Additional parameters for inclusion in the authorization endpoint
			request, the authorization endpoint response, the token endpoint
			request, or the token endpoint response, are registered on the advice
			of one or more Designated Experts (appointed by the IESG or their
			delegate), with a Specification Required (using terminology from
			[RFC5226]). However, to allow for the allocation of values prior to
			publication, the Designated Expert(s) may approve registration once
			they are satisfied that such a specification will be published.
	Registration requests should be sent to the [TBD]@ietf.org mailing		Registration requests should be sent to the [TBD]@ietf.org mailing
	list for review and comment, with an appropriate subject (e.g.,		list for review and comment, with an appropriate subject (e.g.,
	"Request for parameter: example"). [[ Note to RFC-EDITOR: The name of		"Request for parameter: example"). [[ Note to RFC-EDITOR: The name of
	the mailing list should be determined in consultation with the IESG		the mailing list should be determined in consultation with the IESG
	and IANA. Suggested name: oauth-ext-review. ]]		and IANA. Suggested name: oauth-ext-review. ]]
	Before a period of 14 days has passed, the Designated Expert(s) will		Before a period of 14 days has passed, the Designated Expert(s) will
	either approve or deny the registration request, communicating this		either approve or deny the registration request, communicating this
	decision both to the review list and to IANA. Denials should include		decision both to the review list and to IANA. Denials should include
	an explanation and, if applicable, suggestions as to how to make the		an explanation and, if applicable, suggestions as to how to make the
	request successful. Registration requests that are undetermined for		request successful. Registration requests that are undetermined for
	a period longer than 21 days can be brought to the IESG's attention		a period longer than 21 days can be brought to the IESG's attention
	(using the iesg@iesg.org mailing list) for resolution.		(using the iesg@iesg.org mailing list) for resolution.
	9.1.1. Registration Template		10.2.1. Registration Template
	Parameter name: The name requested (e.g., "example").
	Parameter usage location: The location(s) where parameter can be		Parameter name:
	used. The possible locations are: the end-user authorization		The name requested (e.g., "example").
	endpoint request, the end-user authorization endpoint response,		Parameter usage location:
	the token endpoint request, the token endpoint response, the or		The location(s) where parameter can be used. The possible
	the "WWW-Authenticate" header field.		locations are: authorization request, authorization response,
			token request, or token response.
			Change controller:
			For standards-track RFCs, state "IETF". For others, give the name
			of the responsible party. Other details (e.g., postal address,
			e-mail address, home page URI) may also be included.
	Change controller: For standards-track RFCs, state "IETF". For		Specification document(s):
	others, give the name of the responsible party. Other details		Reference to document that specifies the parameter, preferably
	(e.g., postal address, e-mail address, home page URI) may also be		including a URI that can be used to retrieve a copy of the
	included.		document. An indication of the relevant sections may also be
			included, but is not required.
	Specification document(s): Reference to document that specifies the		10.2.2. Initial Registry Contents
	parameter, preferably including a URI that can be used to retrieve
	a copy of the document. An indication of the relevant sections
	may also be included, but is not required.
	Related information: Optionally, citations to additional documents		The OAuth Parameters Registry's initial contents are:
	containing further relevant information.
	9.1.2. Example		o Parameter name: client_id
			o Parameter usage location: authorization request, token request
			o Change controller: IETF
			o Specification document(s): [[ this document ]]
	The following is the parameter registration request for the "scope"		o Parameter name: client_secret
	parameter as defined in this specification:		o Parameter usage location: token request
			o Change controller: IETF
			o Specification document(s): [[ this document ]]
	Parameter name: scope		o Parameter name: response_type
			o Parameter usage location: authorization request
			o Change controller: IETF
			o Specification document(s): [[ this document ]]
	Parameter usage location: The end-user authorization endpoint		o Parameter name: redirect_uri
	request, the end-user authorization endpoint response, the token		o Parameter usage location: authorization request, token request
	endpoint request, the token endpoint response, and the		o Change controller: IETF
	"WWW-Authenticate" header field.		o Specification document(s): [[ this document ]]
	Change controller: IETF		o Parameter name: scope
			o Parameter usage location: authorization request, authorization
			response, token request, token response
			o Change controller: IETF
			o Specification document(s): [[ this document ]]
	Specification document(s): [[ this document ]]		o Parameter name: state
			o Parameter usage location: authorization request, authorization
			response
			o Change controller: IETF
			o Specification document(s): [[ this document ]]
	Related information: None		o Parameter name: code
			o Parameter usage location: authorization response, token request
			o Change controller: IETF
			o Specification document(s): [[ this document ]]
			o Parameter name: error_description
			o Parameter usage location: authorization response, token response
			o Change controller: IETF
			o Specification document(s): [[ this document ]]
			o Parameter name: error_uri
			o Parameter usage location: authorization response, token response
			o Change controller: IETF
			o Specification document(s): [[ this document ]]
			o Parameter name: grant_type
			o Parameter usage location: token request
			o Change controller: IETF
			o Specification document(s): [[ this document ]]
			o Parameter name: access_token
			o Parameter usage location: authorization response, token response
			o Change controller: IETF
			o Specification document(s): [[ this document ]]
			o Parameter name: token_type
			o Parameter usage location: authorization response, token response
			o Change controller: IETF
			o Specification document(s): [[ this document ]]
			o Parameter name: expires_in
			o Parameter usage location: authorization response, token response
			o Change controller: IETF
			o Specification document(s): [[ this document ]]
			o Parameter name: username
			o Parameter usage location: token request
			o Change controller: IETF
			o Specification document(s): [[ this document ]]
			o Parameter name: password
			o Parameter usage location: token request
			o Change controller: IETF
			o Specification document(s): [[ this document ]]
			o Parameter name: refresh_token
			o Parameter usage location: token request, token response
			o Change controller: IETF
			o Specification document(s): [[ this document ]]
	Appendix A. Examples		Appendix A. Examples
	[[ TBD ]]		[[ TBD ]]
	Appendix B. Contributors		Appendix B. Contributors
	The following people contributed to preliminary versions of this		The following people contributed to preliminary versions of this
	document: Blaine Cook (BT), Brian Eaton (Google), Yaron Goland		document: Blaine Cook (BT), Brian Eaton (Google), Yaron Goland
	(Microsoft), Brent Goldman (Facebook), Raffi Krikorian (Twitter),		(Microsoft), Brent Goldman (Facebook), Raffi Krikorian (Twitter),
	Luke Shepard (Facebook), and Allen Tom (Yahoo!). The content and		Luke Shepard (Facebook), and Allen Tom (Yahoo!). The content and
	concepts within are a product of the OAuth community, WRAP community,		concepts within are a product of the OAuth community, WRAP community,
	and the OAuth Working Group.		and the OAuth Working Group.
	The OAuth Working Group has dozens of very active contributors who		The OAuth Working Group has dozens of very active contributors who
	proposed ideas and wording for this document, including: [[ If your		proposed ideas and wording for this document, including:
	name is missing or you think someone should be added here, please
	send Eran a note - don't be shy ]]
	Michael Adams, Andrew Arnott, Dirk Balfanz, Brian Campbell, Leah		Michael Adams, Andrew Arnott, Dirk Balfanz, Brian Campbell, Leah
	Culver, Bill de hOra, Brian Ellin, Igor Faynberg, George Fletcher,		Culver, Bill de hOra, Brian Ellin, Igor Faynberg, George Fletcher,
	Tim Freeman, Evan Gilbert, Kristoffer Gronowski, Justin Hart, Mike		Tim Freeman, Evan Gilbert, Kristoffer Gronowski, Justin Hart, Phil
	Jones, John Kemp, Chasen Le Hara, Torsten Lodderstedt, Alastair Mair,		Hunt, Mike Jones, John Kemp, Chasen Le Hara, Torsten Lodderstedt,
	Eve Maler, James Manger, Laurence Miao, Chuck Mortimore, Justin		Alastair Mair, Eve Maler, James Manger, Laurence Miao, Chuck
	Richer, Peter Saint-Andre, Nat Sakimura, Rob Sayre, Marius Scurtescu,		Mortimore, Justin Richer, Peter Saint-Andre, Nat Sakimura, Rob Sayre,
	Naitik Shah, Justin Smith, Jeremy Suriel, Christian Stuebner, Paul		Marius Scurtescu, Naitik Shah, Justin Smith, Jeremy Suriel, Christian
	Tarjan, Franklin Tse, and Nick Walker.		Stuebner, Paul Tarjan, Franklin Tse, and Nick Walker.
	Appendix C. Acknowledgements		Appendix C. Acknowledgements
	[[ Add OAuth 1.0a authors + WG contributors ]]		[[ Add OAuth 1.0a authors + WG contributors ]]
	Appendix D. Document History		Appendix D. Document History
	[[ to be removed by RFC editor before publication as an RFC ]]		[[ to be removed by RFC editor before publication as an RFC ]]
			-12
			o Complete restructure with lots of new prose.
			o Removed terminology and expanded terms in overview.
			o Changed assertions to extensions and added informative reference
			to the SAML 2.0 extension.
			o Renamed access grant to authorization grant.
			o Clarified 'token_type' as case insensitive.
			o Authorization endpoint requires TLS when an access token is
			issued.
			o Removed client assertion credentials, mandatory HTTP Basic
			authentication support for client credentials, WWW-Authenticate
			header, and the OAuth2 authentication scheme.
			o Changed implicit grant (aka user-agent flow) error response from
			query to fragment.
			o Removed the 'redirect_uri_mismatch' error code since in such a
			case, the authorization server must not send the error back to the
			client.
			o Added parameter registration for all parameters in this
			specification.
			o Defined access token type registry.
	-11		-11
	o Many editorial changes. Fixed user authorization section		o Many editorial changes. Fixed user authorization section
	structure. Removed unused normative references. Adjusted		structure. Removed unused normative references. Adjusted
	language regarding single use of authorization codes.		language regarding single use of authorization codes.
	o Fixed header ABNF.		o Fixed header ABNF.
	o Change access token description from shared symmetric secret to		o Change access token description from shared symmetric secret to
	password.		password.
	o Moved access grant 'none' to a separate section, renamed to		o Moved access grant 'none' to a separate section, renamed to
	'client_credentials'.		'client_credentials'.
	o Demoted the HTTP status code requirement from MUST to SHOULD in		o Demoted the HTTP status code requirement from MUST to SHOULD in
	protected resource response error.		protected resource response error.
	o Removed 'expired_token' error code.		o Removed 'expired_token' error code.
	o Moved all the 'code_and_token' parameter to the fragment (from		o Moved all the 'code_and_token' parameter to the fragment (from
	code being in the query).		code being in the query).
	o Removed 'assertion_type' parameter (moved to 'grant_type').		o Removed 'assertion_type' parameter (moved to 'grant_type').
	o Added note about redirecting to invalid redirection URIs (open		o Added note about redirecting to invalid redirection URIs (open
	redirectors).		redirectors).
	o Removed bearer token section, added new required 'token_type'		o Removed bearer token section, added new required 'token_type'
	parameter with extensibility.		parameter with extensibility.
	o 'error-uri' parameter value changed to absolute URI.		o 'error-uri' parameter value changed to absolute URI.
	o OAuth 2.0 HTTP authentication scheme name changed to 'OAuth2'.		o OAuth 2.0 HTTP authentication scheme name changed to 'OAuth2'.
	o Dropped the 'WWW-Authenticate' header field 'realm' parameter.		o Dropped the 'WWW-Authenticate' header field 'realm' parameter.
	o Removed definition of access token characters.		o Removed definition of access token characters.
	o Added instructions for dealing with error and an invalid		o Added instructions for dealing with error and an invalid
	redirection URI.		redirection URI.
	-10		-10
	o Fixed typos. Many editorial changes. Rewrote introduction.		o Fixed typos. Many editorial changes. Rewrote introduction.
	removed terminology grouping.		removed terminology grouping.
			o Allowed POST for resource owner authorization endpoint.
	o Allowed POST for end-user authorization endpoint.
	o Fixed token endpoint to not require client authentication.		o Fixed token endpoint to not require client authentication.
	o Made URI query and POST body 'oauth_token' parameter optional.		o Made URI query and POST body 'oauth_token' parameter optional.
	o Moved all parameter names and values to use underscores.		o Moved all parameter names and values to use underscores.
	o Changed 'basic_credentials' to 'password',		o Changed 'basic_credentials' to 'password',
	'invalid_client_credentials' and 'invalid_client_id' to		'invalid_client_credentials' and 'invalid_client_id' to
	'invalid_client'.		'invalid_client'.
	o Added note that access token requests without an access grant		o Added note that access token requests without an access grant
	should not include a refresh token.		should not include a refresh token.
	o Changed scheme name from 'Token' to 'OAuth', simplified request		o Changed scheme name from 'Token' to 'OAuth', simplified request
	format to simple string for token instead of key=value pair (still		format to simple string for token instead of key=value pair (still
	supported for extensions).		supported for extensions).
	o Defined permitted access token string characters (suitable for		o Defined permitted access token string characters (suitable for
	inclusion in an HTTP header).		inclusion in an HTTP header).
	o Added a note about conflicts with previous versions.		o Added a note about conflicts with previous versions.
	o Moved 'client_id' definition from client authentication to access		o Moved 'client_id' definition from client authentication to access
	token endpoint.		token endpoint.
	o Added definition for 'access grant'.		o Added definition for 'access grant'.
	-09		-09
	o Fixed typos, editorial changes.		o Fixed typos, editorial changes.
	o Added token expiration example.		o Added token expiration example.
			o Added scope parameter to resource owner authorization endpoint
	o Added scope parameter to end-user authorization endpoint response.		response.
	o Added note about parameters with empty values (same as omitted).		o Added note about parameters with empty values (same as omitted).
	o Changed parameter values to use '-' instead of '_'. Parameter		o Changed parameter values to use '-' instead of '_'. Parameter
	names still use '_'.		names still use '_'.
	o Changed authorization endpoint client type to response type with		o Changed authorization endpoint client type to response type with
	values: code, token, and both.		values: code, token, and both.
	o Complete cleanup of error codes. Added support for error		o Complete cleanup of error codes. Added support for error
	description and URI.		description and URI.
	o Add initial extensibility support.		o Add initial extensibility support.
	-08		-08
	o Renamed verification code to authorization code.		o Renamed verification code to authorization code.
	o Revised terminology, structured section, added new terms.		o Revised terminology, structured section, added new terms.
	o Changed flows to profiles and moved to introduction.		o Changed flows to profiles and moved to introduction.
	o Added support for access token rescoping.		o Added support for access token rescoping.
	o Cleaned up client credentials section.		o Cleaned up client credentials section.
	o New introduction overview.		o New introduction overview.
	o Added error code for invalid username and password, and renamed		o Added error code for invalid username and password, and renamed
	error code to be more consistent.		error code to be more consistent.
	o Added access grant type parameter to token endpoint.		o Added access grant type parameter to token endpoint.
	-07		-07
	o Major rewrite of entire document structure.		o Major rewrite of entire document structure.
	o Removed device profile.		o Removed device profile.
	o Added verification code support to user-agent flow.		o Added verification code support to user-agent flow.
	o Removed multiple formats support, leaving JSON as the only format.		o Removed multiple formats support, leaving JSON as the only format.
	o Changed assertion "assertion_format" parameter to		o Changed assertion "assertion_format" parameter to
	"assertion_type".		"assertion_type".
	o Removed "type" parameter from token endpoint.		o Removed "type" parameter from token endpoint.
	-06		-06
	o Editorial changes, corrections, clarifications, etc.		o Editorial changes, corrections, clarifications, etc.
	o Removed conformance section.		o Removed conformance section.
	o Moved authors section to contributors appendix.		o Moved authors section to contributors appendix.
	o Added section on native applications.		o Added section on native applications.
	o Changed error response to use the requested format. Added support		o Changed error response to use the requested format. Added support
	for HTTP "Accept" header.		for HTTP "Accept" header.
	o Flipped the order of the web server and user-agent flows.		o Flipped the order of the web server and user-agent flows.
	o Renamed assertion flow "format" parameter name to		o Renamed assertion flow "format" parameter name to
	"assertion_format" to resolve conflict.		"assertion_format" to resolve conflict.
	o Removed the term identifier from token definitions. Added a		o Removed the term identifier from token definitions. Added a
	cryptographic token definition.		cryptographic token definition.
	o Added figure titles.		o Added figure titles.
	o Added server response 401 when client tried to authenticate using		o Added server response 401 when client tried to authenticate using
	multiple credentials.		multiple credentials.
	o Clarified support for TLS alternatives, and added requirement for		o Clarified support for TLS alternatives, and added requirement for
	TLS 1.2 support for token endpoint.		TLS 1.2 support for token endpoint.
	o Removed all signature and cryptography.		o Removed all signature and cryptography.
	o Removed all discovery.		o Removed all discovery.
	o Updated HTML4 reference.		o Updated HTML4 reference.
	-05		-05
	o Corrected device example.		o Corrected device example.
	o Added client credentials parameters to the assertion flow as		o Added client credentials parameters to the assertion flow as
	OPTIONAL.		OPTIONAL.
	o Added the ability to send client credentials using an HTTP		o Added the ability to send client credentials using an HTTP
	authentication scheme.		authentication scheme.
	o Initial text for the "WWW-Authenticate" header (also added scope		o Initial text for the "WWW-Authenticate" header (also added scope
	support).		support).
			o Change authorization endpoint to resource owner endpoint.
	o Change authorization endpoint to end-user endpoint.
	o In the device flow, change the "user_uri" parameter to		o In the device flow, change the "user_uri" parameter to
	"verification_uri" to avoid confusion with the end-user endpoint.		"verification_uri" to avoid confusion with the resource owner
			endpoint.
	o Add "format" request parameter and support for XML and form-		o Add "format" request parameter and support for XML and form-
	encoded responses.		encoded responses.
	-04		-04
	o Changed all token endpoints to use "POST"		o Changed all token endpoints to use "POST"
	o Clarified the authorization server's ability to issue a new		o Clarified the authorization server's ability to issue a new
	refresh token when refreshing a token.		refresh token when refreshing a token.
	o Changed the flow categories to clarify the autonomous group.		o Changed the flow categories to clarify the autonomous group.
	o Changed client credentials language not to always be server-		o Changed client credentials language not to always be server-
	issued.		issued.
	o Added a "scope" response parameter.		o Added a "scope" response parameter.
	o Fixed typos.		o Fixed typos.
	o Fixed broken document structure.		o Fixed broken document structure.
	-03		-03
	o Fixed typo in JSON error examples.		o Fixed typo in JSON error examples.
	o Fixed general typos.		o Fixed general typos.
	o Moved all flows sections up one level.		o Moved all flows sections up one level.
	-02		-02
	o Removed restriction on "redirect_uri" including a query.		o Removed restriction on "redirect_uri" including a query.
	o Added "scope" parameter.		o Added "scope" parameter.
	o Initial proposal for a JSON-based token response format.		o Initial proposal for a JSON-based token response format.
	-01		-01
	o Editorial changes based on feedback from Brian Eaton, Bill Keenan,		o Editorial changes based on feedback from Brian Eaton, Bill Keenan,
	and Chuck Mortimore.		and Chuck Mortimore.
	o Changed device flow "type" parameter values and switch to use only		o Changed device flow "type" parameter values and switch to use only
	the token endpoint.		the token endpoint.
	-00		-00
	o Initial draft based on a combination of WRAP and OAuth 1.0a.		o Initial draft based on a combination of WRAP and OAuth 1.0a.
	10. References		11. References
	10.1. Normative References		11.1. Normative References
	[I-D.ietf-httpbis-p1-messaging]		[I-D.ietf-httpbis-p1-messaging]
	Fielding, R., Gettys, J., Mogul, J., Nielsen, H.,		Fielding, R., Gettys, J., Mogul, J., Nielsen, H.,
	Masinter, L., Leach, P., Berners-Lee, T., and J. Reschke,		Masinter, L., Leach, P., Berners-Lee, T., and J. Reschke,
	"HTTP/1.1, part 1: URIs, Connections, and Message		"HTTP/1.1, part 1: URIs, Connections, and Message
	Parsing", draft-ietf-httpbis-p1-messaging-09 (work in		Parsing", draft-ietf-httpbis-p1-messaging-09 (work in
	progress), March 2010.		progress), March 2010.
	[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail		[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
	Extensions (MIME) Part One: Format of Internet Message		Extensions (MIME) Part One: Format of Internet Message
	skipping to change at page 45, line 41 ¶		skipping to change at page 44, line 50 ¶
	IANA Considerations Section in RFCs", BCP 26, RFC 5226,		IANA Considerations Section in RFCs", BCP 26, RFC 5226,
	May 2008.		May 2008.
	[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, August 2008.		(TLS) Protocol Version 1.2", RFC 5246, August 2008.
	[RFC5849] Hammer-Lahav, E., "The OAuth 1.0 Protocol", RFC 5849,		[RFC5849] Hammer-Lahav, E., "The OAuth 1.0 Protocol", RFC 5849,
	April 2010.		April 2010.
	[W3C.REC-html401-19991224]		[W3C.REC-html401-19991224]
	Raggett, D., Hors, A., and I. Jacobs, "HTML 4.01		Hors, A., Raggett, D., and I. Jacobs, "HTML 4.01
	Specification", World Wide Web Consortium		Specification", World Wide Web Consortium
	Recommendation REC-html401-19991224, December 1999,		Recommendation REC-html401-19991224, December 1999,
	<http://www.w3.org/TR/1999/REC-html401-19991224>.		<http://www.w3.org/TR/1999/REC-html401-19991224>.
	10.2. Informative References		11.2. Informative References
			[I-D.hammer-oauth-v2-mac-token]
			Hammer-Lahav, E., "HTTP Authentication: MAC
			Authentication", draft-hammer-oauth-v2-mac-token-01 (work
			in progress), January 2011.
			[I-D.ietf-oauth-saml2-bearer]
			Campbell, B. and C. Mortimore, "SAML 2.0 Bearer Assertion
			Grant Type Profile for OAuth 2.0",
			draft-ietf-oauth-saml2-bearer-00 (work in progress),
			December 2010.
			[I-D.ietf-oauth-v2-bearer]
			Jones, M., Hardt, D., and D. Recordon, "The OAuth 2.0
			Protocol: Bearer Tokens", draft-ietf-oauth-v2-bearer-01
			(work in progress), December 2010.
	[OASIS.saml-core-2.0-os]		[OASIS.saml-core-2.0-os]
	Cantor, S., Kemp, J., Philpott, R., and E. Maler,		Cantor, S., Kemp, J., Philpott, R., and E. Maler,
	"Assertions and Protocol for the OASIS Security Assertion		"Assertions and Protocol for the OASIS Security Assertion
	Markup Language (SAML) V2.0", OASIS Standard saml-core-		Markup Language (SAML) V2.0", OASIS Standard saml-core-
	2.0-os, March 2005.		2.0-os, March 2005.
	Authors' Addresses		Authors' Addresses
	Eran Hammer-Lahav (editor)		Eran Hammer-Lahav (editor)
	Yahoo!		Yahoo!
	Email: eran@hueniverse.com		Email: eran@hueniverse.com
	URI: http://hueniverse.com		URI: http://hueniverse.com
	David Recordon		David Recordon
	Facebook		Facebook
	Email: davidrecordon@facebook.com		Email: dr@fb.com
	URI: http://www.davidrecordon.com/		URI: http://www.davidrecordon.com/
	Dick Hardt		Dick Hardt
	Microsoft		Microsoft
	Email: dick.hardt@gmail.com		Email: dick.hardt@gmail.com
	URI: http://dickhardt.org/		URI: http://dickhardt.org/
End of changes. 354 change blocks.
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