< draft-ietf-oauth-v2-06.txt		draft-ietf-oauth-v2-07.txt >
	Network Working Group E. Hammer-Lahav, Ed.		Network Working Group E. Hammer-Lahav, Ed.
	Internet-Draft Yahoo!		Internet-Draft Yahoo!
	Intended status: Standards Track D. Recordon		Intended status: Standards Track D. Recordon
	Expires: December 11, 2010 Facebook		Expires: December 13, 2010 Facebook
	D. Hardt		D. Hardt
	Microsoft		Microsoft
	June 9, 2010		June 11, 2010
	The OAuth 2.0 Protocol		The OAuth 2.0 Protocol
	draft-ietf-oauth-v2-06		draft-ietf-oauth-v2-07
	Abstract		Abstract
	This specification describes the OAuth 2.0 protocol. OAuth provides		This specification describes the OAuth 2.0 protocol. OAuth provides
	a method for making authenticated HTTP requests using a token - an		a method for making authenticated HTTP requests using a token - an
	string used to denote an access grant with specific scope, duration,		string used to denote an access grant with specific scope, duration,
	and other attributes. Tokens are issued to third-party clients by an		and other attributes. Tokens are issued to third-party clients by an
	authorization server with the approval of the resource owner. OAuth		authorization server with the approval of the resource owner. OAuth
	defines multiple flows for obtaining a token to support a wide range		defines multiple flows for obtaining a token to support a wide range
	of client types and user experience.		of client types and user experience.
	skipping to change at page 1, line 39 ¶		skipping to change at page 1, line 39 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.		Drafts is at http://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on December 11, 2010.		This Internet-Draft will expire on December 13, 2010.
	Copyright Notice		Copyright Notice
	Copyright (c) 2010 IETF Trust and the persons identified as the		Copyright (c) 2010 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 3, line 12 ¶		skipping to change at page 3, line 12 ¶
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
	1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4		1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
	1.2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . 6		1.2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . 6
	1.3. Example . . . . . . . . . . . . . . . . . . . . . . . . . 8		1.3. Example . . . . . . . . . . . . . . . . . . . . . . . . . 8
	1.4. Notational Conventions . . . . . . . . . . . . . . . . . . 8		1.4. Notational Conventions . . . . . . . . . . . . . . . . . . 8
	2. Obtaining an Access Token . . . . . . . . . . . . . . . . . . 8		2. Client Flows . . . . . . . . . . . . . . . . . . . . . . . . . 8
	2.1. Client Credentials . . . . . . . . . . . . . . . . . . . . 9		2.1. Web Server Flow . . . . . . . . . . . . . . . . . . . . . 8
	2.2. End-User Endpoint . . . . . . . . . . . . . . . . . . . . 9		2.2. User-Agent Flow . . . . . . . . . . . . . . . . . . . . . 10
	2.3. Token Endpoint . . . . . . . . . . . . . . . . . . . . . . 10		2.3. Username and Password Flow . . . . . . . . . . . . . . . . 11
	2.3.1. Client Authentication . . . . . . . . . . . . . . . . 10		2.4. Client Credentials Flow . . . . . . . . . . . . . . . . . 13
	2.3.2. Response Format . . . . . . . . . . . . . . . . . . . 11		2.5. Assertion Flow . . . . . . . . . . . . . . . . . . . . . . 13
	2.4. Flow Parameters . . . . . . . . . . . . . . . . . . . . . 14		2.6. Native Application Considerations . . . . . . . . . . . . 14
	2.5. Web Server Flow . . . . . . . . . . . . . . . . . . . . . 14		3. Client Credentials . . . . . . . . . . . . . . . . . . . . . . 15
	2.5.1. Client Requests Authorization . . . . . . . . . . . . 16		3.1. Client Authentication . . . . . . . . . . . . . . . . . . 15
	2.5.2. Client Requests Access Token . . . . . . . . . . . . . 18		4. Establishing Resource Owner Authorization . . . . . . . . . . 16
	2.6. User-Agent Flow . . . . . . . . . . . . . . . . . . . . . 20		4.1. Verification Code . . . . . . . . . . . . . . . . . . . . 17
	2.6.1. Client Requests Authorization . . . . . . . . . . . . 22		4.1.1. End-User Authorization Endpoint . . . . . . . . . . . 17
	2.6.2. Client Extracts Access Token . . . . . . . . . . . . . 25		4.2. Resource Owner Credentials . . . . . . . . . . . . . . . . 20
	2.7. Device Flow . . . . . . . . . . . . . . . . . . . . . . . 25		4.3. Assertion . . . . . . . . . . . . . . . . . . . . . . . . 21
	2.7.1. Client Requests Authorization . . . . . . . . . . . . 27		5. Obtaining an Access Token . . . . . . . . . . . . . . . . . . 21
	2.7.2. Client Requests Access Token . . . . . . . . . . . . . 29		5.1. Token Endpoint . . . . . . . . . . . . . . . . . . . . . . 21
	2.8. Username and Password Flow . . . . . . . . . . . . . . . . 31		5.1.1. Verification Code . . . . . . . . . . . . . . . . . . 22
	2.8.1. Client Requests Access Token . . . . . . . . . . . . . 32		5.1.2. Resource Owner Credentials . . . . . . . . . . . . . . 22
	2.9. Client Credentials Flow . . . . . . . . . . . . . . . . . 34		5.1.3. Assertion . . . . . . . . . . . . . . . . . . . . . . 23
	2.9.1. Client Requests Access Token . . . . . . . . . . . . . 35		5.1.4. Refresh Token . . . . . . . . . . . . . . . . . . . . 24
	2.10. Assertion Flow . . . . . . . . . . . . . . . . . . . . . . 36		5.1.5. Access Token Response . . . . . . . . . . . . . . . . 25
	2.10.1. Client Requests Access Token . . . . . . . . . . . . . 37		5.1.6. Error Response . . . . . . . . . . . . . . . . . . . . 26
	2.11. Native Application Considerations . . . . . . . . . . . . 39		6. Accessing a Protected Resource . . . . . . . . . . . . . . . . 27
	3. Refreshing an Access Token . . . . . . . . . . . . . . . . . . 40		6.1. The Authorization Request Header . . . . . . . . . . . . . 28
	4. Accessing a Protected Resource . . . . . . . . . . . . . . . . 42		6.2. URI Query Parameter . . . . . . . . . . . . . . . . . . . 28
	4.1. The Authorization Request Header . . . . . . . . . . . . . 43		6.3. Form-Encoded Body Parameter . . . . . . . . . . . . . . . 29
	4.2. URI Query Parameter . . . . . . . . . . . . . . . . . . . 44		7. Identifying a Protected Resource . . . . . . . . . . . . . . . 30
	4.3. Form-Encoded Body Parameter . . . . . . . . . . . . . . . 44		7.1. The WWW-Authenticate Response Header . . . . . . . . . . . 30
	5. Identifying a Protected Resource . . . . . . . . . . . . . . . 45		8. Security Considerations . . . . . . . . . . . . . . . . . . . 31
	5.1. The WWW-Authenticate Response Header . . . . . . . . . . . 45		9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 31
	6. Security Considerations . . . . . . . . . . . . . . . . . . . 46		Appendix A. Contributors . . . . . . . . . . . . . . . . . . . . 31
	7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 46		Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 31
	Appendix A. Contributors . . . . . . . . . . . . . . . . . . . . 46		Appendix C. Document History . . . . . . . . . . . . . . . . . . 32
	Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 47		10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 34
	Appendix C. Differences from OAuth 1.0a . . . . . . . . . . . . . 47		10.1. Normative References . . . . . . . . . . . . . . . . . . . 34
	Appendix D. Document History . . . . . . . . . . . . . . . . . . 47		10.2. Informative References . . . . . . . . . . . . . . . . . . 35
	8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 49		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 36
	8.1. Normative References . . . . . . . . . . . . . . . . . . . 49
	8.2. Informative References . . . . . . . . . . . . . . . . . . 50
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 51
	1. Introduction		1. Introduction
	With the increasing use of distributed web services and cloud		With the increasing use of distributed web services and cloud
	computing, third-party applications require access to server-hosted		computing, third-party applications require access to server-hosted
	resources. These resources are usually protected and require		resources. These resources are usually protected and require
	authentication using the resource owner's credentials (typically a		authentication using the resource owner's credentials (typically a
	username and password). In the traditional client-server		username and password). In the traditional client-server
	authentication model, a client accessing a protected resource on a		authentication model, a client accessing a protected resource on a
	server presents the resource owner's credentials in order to		server presents the resource owner's credentials in order to
	skipping to change at page 5, line 28 ¶		skipping to change at page 5, line 28 ¶
	token		token
	A string representing an access grant issued to the client.		A string representing an access grant issued to the client.
	The string is usually opaque to the client and can self-contain		The string is usually opaque to the client and can self-contain
	the authorization information in a verifiable manner (i.e.		the authorization information in a verifiable manner (i.e.
	signed), or denotes an identifier used to retrieve the		signed), or denotes an identifier used to retrieve the
	authorization information.		authorization information.
	access token		access token
	A token used by the client to make authenticated requests on		A token used by the client to make authenticated requests on
	behalf of the resource owner.		behalf of the resource owner. Access tokens represent a
			specific scope, duration, and other access attributes granted
			by the resource owner and enforced by the resource and
			authorization servers.
	refresh token		refresh token
	A token used by the client to replace an expired access token		A token used by the client to replace an expired access token
	with a new access token without having to involve the resource		with a new access token without having to involve the resource
	owner. A refresh token is used when the access token is valid		owner. A refresh token is used when the access token is valid
	for a shorter time period than the duration of the access grant		for a shorter time period than the duration of the access grant
	approved by the resource owner.		granted by the resource owner.
	authorization server		authorization server
	An HTTP server capable of issuing tokens after successfully		An HTTP server capable of issuing tokens 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		The authorization server may be the same server as the resource
	server, or a separate entity.		server, or a separate entity.
	end-user endpoint		end-user authorization endpoint
	The authorization server's HTTP endpoint capable of		The authorization server's HTTP endpoint capable of
	authenticating the end-user and obtaining authorization.		authenticating the end-user and obtaining authorization.
	token endpoint		token endpoint
	The authorization server's HTTP endpoint capable of issuing		The authorization server's HTTP endpoint capable of issuing
	tokens and refreshing expired tokens.		tokens and refreshing expired tokens.
	client identifier		client identifier
	An unique identifier issued to the client to identify itself to		An unique identifier issued to the client to identify itself to
	the authorization server. Client identifiers may have a		the authorization server. Client identifiers may have a
	skipping to change at page 7, line 36 ¶		skipping to change at page 7, line 37 ¶
	User delegation flows are used to grant client access to protected		User delegation flows are used to grant client access to protected
	resources by the end-user without sharing the end-user credentials		resources by the end-user without sharing the end-user credentials
	(e.g. a username and password) with the client. Instead, the end-		(e.g. a username and password) with the client. Instead, the end-
	user authenticates directly with the authorization server, and grants		user authenticates directly with the authorization server, and grants
	client access to its protected resources. The user delegation flows		client access to its protected resources. The user delegation flows
	defined by this specifications are:		defined by this specifications are:
	o Web Server Flow - This flow is optimized for clients that are part		o Web Server Flow - This flow is optimized for clients that are part
	of a web server application, accessible via HTTP requests. This		of a web server application, accessible via HTTP requests. This
	flow is described in Section 2.5.		flow is described in Section 2.1.
	o User-Agent Flow - This flow is designed for clients running inside		o User-Agent Flow - This flow is designed for clients running inside
	a user-agent (typically a web browser). This flow is described in		a user-agent (typically a web browser). This flow is described in
	Section 2.6.		Section 2.2.
	o Device Flow - This flow is suitable for clients executing on
	limited devices, but where the end-user has separate access to a
	user-agent on another computer or device. This flow is described
	in Section 2.7.
	Direct credentials flows enable clients to obtain an access token		Direct credentials flows enable clients to obtain an access token
	with a single request using the client credentials or end-user		with a single request using the client credentials or end-user
	credentials without seeking additional resource owner authorization.		credentials without seeking additional resource owner authorization.
	The direct credentials flows defined by this specification are:		The direct credentials flows defined by this specification are:
	o Username and Password Flow - This flow is used in cases where the		o Username and Password Flow - This flow is used in cases where the
	end-user trusts the client to handle its credentials but it is		end-user trusts the client to handle its credentials but it is
	still undesirable for the client to store the end-user's username		still undesirable for the client to store the end-user's username
	and password. This flow is only suitable when there is a high		and password. This flow is only suitable when there is a high
	degree of trust between the end-user and the client. This flow is		degree of trust between the end-user and the client. This flow is
	described in Section 2.8.		described in Section 2.3.
	o Client Credentials Flow - The client uses its credentials to		o Client Credentials Flow - The client uses its credentials to
	obtain an access token. This flow is described in Section 2.9.		obtain an access token. This flow is described in Section 2.4.
	Autonomous flows enable clients to use utilize existing trust		Autonomous flows enable clients to utilize existing trust
	relationships or different authorization constructs to obtain an		relationships or different authorization constructs to obtain an
	access token. They provide a bridge between OAuth and other trust		access token. They provide a bridge between OAuth and other trust
	frameworks. The autonomous authorization flow defined by this		frameworks. The autonomous authorization flow defined by this
	specifications is:		specifications is:
	o Assertion Flow - The client presents an assertion such as a SAML		o Assertion Flow - The client presents an assertion such as a SAML
	[OASIS.saml-core-2.0-os] assertion to the authorization server in		[OASIS.saml-core-2.0-os] assertion to the authorization server in
	exchange for an access token. This flow is described in		exchange for an access token. This flow is described in
	Section 2.10.		Section 2.5.
			The sizes of tokens and other values received from the authorization
			server, are left undefined by this specification. Clients should
			avoid making assumptions about value sizes. Servers should document
			the expected size of any value they issue.
	1.3. Example		1.3. Example
	[[ Todo ]]		[[ Todo ]]
	1.4. Notational Conventions		1.4. Notational Conventions
	The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT',		The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT',
	'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and 'OPTIONAL' in this		'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and 'OPTIONAL' in this
	document are to be interpreted as described in [RFC2119].		document are to be interpreted as described in [RFC2119].
	This document uses the Augmented Backus-Naur Form (ABNF) notation of		This document uses the Augmented Backus-Naur Form (ABNF) notation of
	[I-D.ietf-httpbis-p1-messaging]. Additionally, the realm and auth-		[I-D.ietf-httpbis-p1-messaging]. Additionally, the realm and auth-
	param rules are included from [RFC2617], and the URI-Reference rule		param rules are included from [RFC2617].
	from [RFC3986].
	2. Obtaining an Access Token
	The client obtains an access token by using one of the authorization
	flows supported by the authorization server. The authorization flows
	all use the same authorization and token endpoints, each with a
	different set of request parameters and values.
	Access tokens have a scope, duration, and other access attributes
	granted by the resource owner. These attributes MUST be enforced by
	the resource server when receiving a protected resource request, and
	by the authorization server when receiving a token refresh request.
	In many cases it is desirable to issue access tokens with a shorter
	lifetime than the duration of the authorization grant. However, it
	may be undesirable to require the resource owner to authorize the
	request again. Instead, the authorization server issues a refresh
	token in addition to the access token. When the access token
	expires, the client can request a new access token without involving
	the resource owner as long as the authorization grant is still valid.
	The token refresh method is described in Section 3.
	2.1. Client Credentials
	When requesting access from the authorization server, the client
	identifies itself using a set of client credentials. The client
	credentials include a client identifier and an OPTIONAL symmetric
	shared secret. The means through which the client obtains these
	credentials are beyond the scope of this specification, but usually
	involve registration with the authorization server.
	The client identifier is used by the authorization server to
	establish the identity of the client for the purpose of presenting
	information to the resource owner prior to granting access, as well
	as for providing different service levels to different clients. They
	can also be used to block unauthorized clients from requesting
	access.
	Due to the nature of some clients, authorization servers SHOULD NOT
	make assumptions about the confidentiality of client credentials
	without establishing trust with the client operator. Authorization
	servers SHOULD NOT issue client secrets to clients incapable of
	keeping their secrets confidential.
	2.2. End-User Endpoint
	In flows that involved an end-user, clients direct the end-user to
	the end-user endpoint to approve their access request. When
	accessing the end-user endpoint, the end-user first authenticates
	with the authorization server, and then approves or denies the access
	request.
	The way in which the authorization server authenticates the end-user
	(e.g. username and password login, OpenID, session cookies) and in
	which the authorization server obtains the end-user's authorization,
	including whether it uses a secure channel such as TLS, is beyond the
	scope of this specification. However, the authorization server MUST
	first verify the identity of the end-user.
	The URI of the end-user endpoint can be found in the service
	documentation, or can be obtained by using [[ OAuth Discovery ]].
	The end-user endpoint advertised by the resource server MAY include a
	query component as defined by [RFC3986] section 3, which must be
	retained when adding additional query parameters.
	Since requests to the end-user endpoint result in user authentication
	and the transmission of sensitive values, the authorization server
	SHOULD require the use of a transport-layer mechanism such as TLS
	when sending requests to the end-user endpoint.
	2.3. Token Endpoint
	After obtaining authorization from the resource owner, clients
	request an access token from the authorization server's token
	endpoint.
	The URI of the token endpoint can be found in the service
	documentation, or can be obtained by using [[ OAuth Discovery ]].
	The token endpoint advertised by the resource server MAY include a
	query component as defined by [RFC3986] section 3.
	Since requests to the token endpoint result in the transmission of
	plain text credentials in the HTTP request and response, the
	authorization server MUST require the use of a transport-layer
	mechanism when sending requests to the token endpoints. Servers MUST
	support TLS 1.2 as defined in [RFC5246] and MAY support addition
	mechanisms with equivalent protections.
	2.3.1. Client Authentication
	The token endpoint requires the client to authenticate itself to the
	authorization server. This is done by including the client
	identifier (and optional secret) in the request. The client
	identifier and secret are included in the request using two request
	parameters: "client_id" and "client_secret".
	For example (line breaks are for display purposes only):
	POST /token HTTP/1.1
	Host: server.example.com
	Content-Type: application/x-www-form-urlencoded
	type=web_server&client_id=s6BhdRkqt3&
	client_secret=gX1fBat3bV&code=i1WsRn1uB1&
	redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
	The client MAY include the client credentials using an HTTP
	authentication scheme which supports authenticating using a username
	and password, instead of using the "client_id" and "client_secret"
	request parameters. Including the client credentials using an HTTP
	authentication scheme fulfills the requirements of including the
	parameters as defined by the various flows.
	The client MUST NOT include the client credentials using more than
	one mechanism. If more than one mechanism is used, regardless if the
	credentials are identical, the server MUST reply with an HTTP 400
	status code (Bad Request) and include the "multiple-credentials"
	error message.
	The authorization server MUST accept the client credentials using
	both the request parameters, and the HTTP Basic authentication scheme
	as defined in [RFC2617]. The authorization server MAY support
	additional HTTP authentication schemes.
	For example (line breaks are for display purposes only):
	POST /token HTTP/1.1
	Host: server.example.com
	Authorization: Basic czZCaGRSa3F0MzpnWDFmQmF0M2JW
	Content-Type: application/x-www-form-urlencoded
	type=web_server&code=i1WsRn1uB1&
	redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
	2.3.2. Response Format
	Authorization servers respond to client requests by including a set
	of response parameters in the entity body of the HTTP response. The
	response uses one of three formats based on the format requested by
	the client (using the "format" request parameter or the HTTP "Accept"
	header field):
	o 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:
	{
	"access_token":"SlAV32hkKG",
	"expires_in":3600,
	"refresh_token":"8xLOxBtZp8"
	}
	o The "application/xml" media type as defined by [RFC3023]. The
	parameters are serialized into an XML structure by adding each
	parameter as a child element of the root "<OAuth>" element. [[ Add
	namespace ]]
	For example:
	<?xml version='1.0' encoding="utf-8"?>
	<OAuth>
	<access_token>SlAV32hkKG</access_token>
	<expires_in>3600</expires_in>
	<refresh_token>8xLOxBtZp8</refresh_token>
	</OAuth>
	o The "application/x-www-form-urlencoded" media type as defined by
	[W3C.REC-html401-19991224].
	For example (line breaks are for display purposes only):
	access_token=SlAV32hkKG&expires_in=3600&
	refresh_token=8xLOxBtZp8
	The authorization server MUST include the HTTP "Cache-Control"
	response header field with a value of "no-store" in any response
	containing tokens, secrets, or other sensitive information.
	2.3.2.1. Access Token Response
	After receiving and verifying a valid and authorized access token
	request from the client (as described in each of the flows below),
	the authorization server constructs the response using the format
	requested by the client, which includes the parameters listed below,
	as well as additional flow-specific parameters. The formatted
	parameters are sent to the client in the entity body of the HTTP
	response with a 200 status code (OK).
	The token response contains the following common parameters:
	access_token
	REQUIRED. The access token issued by the authorization server.
	expires_in
	OPTIONAL. The duration in seconds of the access token
	lifetime.
	refresh_token
	OPTIONAL. The refresh token used to obtain new access tokens
	using the same end-user access grant as described in Section 3.
	scope
	OPTIONAL. The scope of the access token as a list of space-
	delimited strings. The value of the "scope" parameter 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.
	For example:
	HTTP/1.1 200 OK
	Content-Type: application/json
	Cache-Control: no-store
	{
	"access_token":"SlAV32hkKG",
	"expires_in":3600,
	"refresh_token":"8xLOxBtZp8"
	}
	2.3.2.2. Error Response
	If the token request is invalid or unauthorized, the authorization
	server constructs the response using the format requested by the
	client which includes the parameters listed below, as well as
	additional flow-specific parameters. The formatted parameters are
	sent to the client in the entity body of the HTTP response with a 400
	status code (Bad Request).
	The response contains the following common parameter:
	error
	REQUIRED. The parameter value MUST be set to one of the values
	specified by each flow.
	For example:
	HTTP/1.1 400 Bad Request
	Content-Type: application/json
	Cache-Control: no-store
	{
	"error":"incorrect_client_credentials"
	}
	2.4. Flow Parameters
	The sizes of tokens and other values received from the authorization
	server, are left undefined by this specification. Clients should
	avoid making assumptions about value sizes. Servers should document
	the expected size of any value they issue.
	Unless otherwise noted, all the protocol parameter names and values		Unless otherwise noted, all the protocol parameter names and values
	are case sensitive.		are case sensitive.
	2.5. Web Server Flow		2. Client Flows
			2.1. Web Server Flow
	The web server flow is a user delegation flow suitable for clients		The web server flow is a user delegation flow suitable for clients
	capable of interacting with the end-user's user-agent (typically a		capable of interacting with the end-user's user-agent (typically a
	web browser) and capable of receiving incoming requests from the		web browser) and capable of receiving incoming requests from the
	authorization server (capable of acting as an HTTP server).		authorization server (capable of acting as an HTTP server).
	+----------+ Client Identifier +---------------+		+----------+ Client Identifier +---------------+
	| -+----(A)-- & Redirect URI ------->| |		| -+----(A)-- & Redirect URI ------->| |
	| End-user | | Authorization |		| End-user | | Authorization |
	| at |<---(B)-- User authenticates --->| Server |		| at |<---(B)-- User authenticates --->| Server |
	skipping to change at page 15, line 30 ¶		skipping to change at page 9, line 32 ¶
	| | |		| | |
	| |<---(E)------- Access Token -----------------'		| |<---(E)------- Access Token -----------------'
	+---------+ (w/ Optional Refresh Token)		+---------+ (w/ Optional Refresh Token)
	Figure 3: Web Server Flow		Figure 3: Web Server Flow
	The web server flow illustrated in Figure 3 includes the following		The web server flow illustrated in Figure 3 includes the following
	steps:		steps:
	(A) The web client initiates the flow by redirecting the end-user's		(A) The web client initiates the flow by redirecting the end-user's
	user-agent to the end-user endpoint with its client identifier		user-agent to the end-user authorization endpoint as described
			in Section 4.1.1 using client type "web_server". The client
			includes its client identifier, requested scope, local state,
	and a redirect URI to which the authorization server will send		and a redirect URI to which the authorization server will send
	the end-user back once authorization is received (or denied).		the end-user back once authorization is granted (or denied).
	(B) The authorization server authenticates the end-user (via the		(B) The authorization server authenticates the end-user (via the
	user-agent) and establishes whether the end-user grants or		user-agent) and establishes whether the end-user grants or
	denies the client's access request.		denies the client's access request.
	(C) Assuming the end-user granted access, the authorization server		(C) Assuming the end-user granted access, the authorization server
	redirects the user-agent back to the client to the redirection		redirects the user-agent back to the client to the redirection
	URI provided earlier. The authorization includes a verification		URI provided earlier. The authorization includes a verification
	code for the client to use to obtain an access token.		code for the client to use to obtain an access token.
	(D) The client requests an access token from the authorization		(D) The client requests an access token from the authorization
	server by including its client credentials (identifier and		server by authenticating and including the verification code
	secret), as well as the verification code received in the		received in the previous step as described in Section 5.1.
	previous step.
	(E) The authorization server validates the client credentials and		(E) The authorization server validates the client credentials and
	the verification code and responds back with the access token.		the verification code and responds back with the access token.
	2.5.1. Client Requests Authorization		2.2. User-Agent Flow
	In order for the end-user to grant the client access, the client
	sends the end-user to the authorization server. The client
	constructs the request URI by adding the following URI query
	parameters to the end-user endpoint URI:
	type
	REQUIRED. The parameter value MUST be set to "web_server".
	client_id
	REQUIRED. The client identifier as described in Section 2.1.
	redirect_uri
	REQUIRED unless a redirection URI has been established between
	the client and authorization server via other means. An
	absolute URI to which the authorization server will redirect
	the user-agent to when the end-user authorization step is
	completed. The authorization server MAY require the client to
	pre-register their redirection URI. Authorization servers MAY
	restrict the redirection URI to not include a query component
	as defined by [RFC3986] section 3.
	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.
	scope
	OPTIONAL. The scope of the access request expressed as a list
	of space-delimited strings. The value of the "scope" parameter
	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.
	immediate
	OPTIONAL. The parameter value must be set to "true" or
	"false". If set to "true", the authorization server MUST NOT
	prompt the end-user to authenticate or approve access.
	Instead, the authorization server attempts to establish the
	end-user's identity via other means (e.g. browser cookies) and
	checks if the end-user has previously approved an identical
	access request by the same client and if that access grant is
	still active. If the authorization server does not support an
	immediate check or if it is unable to establish the end-user's
	identity or approval status, it MUST deny the request without
	prompting the end-user. Defaults to "false" if omitted.
	The client directs the end-user to the constructed URI using an HTTP
	redirection response, or by other means available to it via the end-
	user's user-agent. The request MUST use the HTTP "GET" method.
	For example, the client directs the end-user's user-agent to make the
	following HTTPS requests (line breaks are for display purposes only):
	GET /authorize?type=web_server&client_id=s6BhdRkqt3&redirect_uri=
	https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb HTTP/1.1
	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 authenticates the end-user and obtains an
	authorization decision (by asking the end-user or establishing
	approval via other means). The authorization server sends 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.
	2.5.1.1. End-user Grants Authorization
	If the end-user authorizes the access request, the authorization
	server generates a verification code and associates it with the
	client identifier and redirection URI. The authorization server
	constructs the request URI by adding the following parameters to the
	query component of redirection URI provided by the client:
	code
	REQUIRED. The verification code generated by the authorization
	server.
	state
	REQUIRED if the "state" parameter was present in the client
	authorization request. Set to the exact value received from
	the client.
	The verification code should expire shortly after it is issued and
	allowed for a single use.
	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
	In turn, the end-user's user-agent makes the following HTTPS "GET"
	request:
	GET /cb?code=i1WsRn1uB1 HTTP/1.1
	Host: client.example.com
	2.5.1.2. End-user Denies Authorization
	If the end-user denied the access request, the authorization server
	constructs the request URI by adding the following parameters to the
	query component of the redirection URI provided by the client:
	error
	REQUIRED. The parameter value MUST be set to "user_denied".
	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 directs the client to make the
	following HTTP request:
	GET /cb?error=user_denied HTTP/1.1
	Host: client.example.com
	The authorization flow concludes unsuccessfully.
	2.5.2. Client Requests Access Token
	The client obtains an access token from the authorization server by
	making an HTTP "POST" request to the token endpoint. The client
	constructs a request URI by adding the following parameters to the
	request:
	type
	REQUIRED. The parameter value MUST be set to "web_server".
	client_id
	REQUIRED. The client identifier as described in Section 2.1.
	client_secret
	REQUIRED if the client identifier has a matching secret. The
	client secret as described in Section 2.1.
	code
	REQUIRED. The verification code received from the
	authorization server.
	redirect_uri
	REQUIRED. The redirection URI used in the initial request.
	format
	OPTIONAL. The response format requested by the client. Value
	MUST be one of "json", "xml", or "form". Alternatively, the
	client MAY use the HTTP "Accept" header field with the desired
	media type. Defaults to "json" if omitted and no "Accept"
	header field is present.
	For example, the client makes the following HTTPS request (line
	breaks are for display purposes only):
	POST /token HTTP/1.1
	Host: server.example.com
	Content-Type: application/x-www-form-urlencoded
	type=web_server&client_id=s6BhdRkqt3&
	client_secret=gX1fBat3bV&code=i1WsRn1uB1&
	redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
	The authorization server MUST verify that the verification code,
	client identity, client secret, 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 2.3.2.1.
	For example:
	HTTP/1.1 200 OK
	Content-Type: application/json
	Cache-Control: no-store
	{
	"access_token":"SlAV32hkKG",
	"expires_in":3600,
	"refresh_token":"8xLOxBtZp8"
	}
	If the request is invalid, the authorization server returns an error
	response as described in Section 2.3.2.2 with one of the following
	error codes:
	o "redirect_uri_mismatch"
	o "bad_verification_code"
	o "incorrect_client_credentials"
	For example:
	HTTP/1.1 400 Bad Request
	Content-Type: application/json
	Cache-Control: no-store
	{
	"error":"incorrect_client_credentials"
	}
	2.6. User-Agent Flow
	The user-agent flow is a user delegation flow suitable for client		The user-agent flow is a user delegation flow suitable for client
	applications residing in a user-agent, typically implemented in a		applications residing in a user-agent, typically implemented in a
	browser using a scripting language such as JavaScript. These clients		browser using a scripting language such as JavaScript. These clients
	cannot keep client secrets confidential and the authentication of the		cannot keep client secrets confidential and the authentication of the
	client is based on the user-agent's same-origin policy.		client is based on the user-agent's same-origin policy.
	Unlike other flows in which the client makes separate authorization		Unlike other flows in which the client makes separate authorization
	and access token requests, the client received the access token as a		and access token requests, the client received the access token as a
	result of the authorization request in the form of an HTTP		result of the authorization request in the form of an HTTP
	skipping to change at page 21, line 32 ¶		skipping to change at page 11, line 4 ¶
	| in | (w/ Optional Refresh Token) +----------------+		| in | (w/ Optional Refresh Token) +----------------+
	| Browser | in Fragment		| Browser | in Fragment
	| | +----------------+		| | +----------------+
	| |>---(D)-- Redirect URI -------->| |		| |>---(D)-- Redirect URI -------->| |
	| | without Fragment | Web Server |		| | without Fragment | Web Server |
	| | | with Client |		| | | with Client |
	| (F) |<---(E)-- Web Page with -------<| Resource |		| (F) |<---(E)-- Web Page with -------<| Resource |
	| Access | Script | |		| Access | Script | |
	| Token | +----------------+		| Token | +----------------+
	+----------+		+----------+
	Figure 4: User-Agent Flow		Figure 4: User-Agent Flow
	The user-agent flow illustrated in Figure 4 includes the following		The user-agent flow illustrated in Figure 4 includes the following
	steps:		steps:
	(A) The client sends the user-agent to the authorization server and		(A) The client sends the user-agent to the end-user authorization
	includes its client identifier and redirection URI in the		endpoint as described in Section 4.1.1 using client type
	request.		"user-agent". 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
			authorization is granted (or denied).
	(B) The authorization server authenticates the end-user (via the		(B) The authorization server authenticates the end-user (via the
	user-agent) and establishes whether the end-user grants or		user-agent) and establishes whether the end-user grants or
	denies the client's access request.		denies the client's access request.
	(C) Assuming the end-user granted access, the authorization server		(C) Assuming the end-user granted access, the authorization server
	redirects the user-agent to the redirection URI provided		redirects the user-agent to the redirection URI provided
	earlier. The redirection URI includes the access token in the		earlier. The redirection URI includes the access token (and an
	URI fragment.		optional verification code) in the URI fragment.
	(D) The user-agent follows the redirection instructions by making a		(D) The user-agent follows the redirection instructions by making an
	request to the web server which does not include the fragment.		HTTP "GET" request to the web server which does not include the
	The user-agent retains the fragment information locally.		fragment. The user-agent retains the fragment information
			locally. The user-agent MUST NOT include the fragment component
			with the request.
	(E) The web server returns a web page containing a script capable of		(E) The web server returns a web page (typically an HTML page with
	extracting the access token from the URI fragment retained by		an embedded script) capable of accessing the full redirection
	the user-agent.		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		(F) The user-agent executes the script provided by the web server
	which extracts the access token and passes it to the client.		which extracts the access token and passes it to the client. If
			a verification code was issued, the client can pass it to a web
	2.6.1. Client Requests Authorization		server component to obtain another access token for additional
			server-based protected resources interaction.
	In order for the end-user to grant the client access, the client
	sends the end-user to the authorization server. The client
	constructs the request URI by adding the following URI query
	parameters to the end-user endpoint URI:
	type		2.3. Username and Password Flow
	REQUIRED. The parameter value MUST be set to "user_agent".
	client_id		The username and password flow is suitable for clients capable of
	REQUIRED. The client identifier as described in Section 2.1.		asking end-users for their usernames and passwords. It is also used
			to migrate existing clients using direct authentication schemes such
			as HTTP Basic or Digest authentication to OAuth by converting the
			end-user credentials stored with tokens.
	redirect_uri		However, unlike the HTTP Basic authentication scheme defined in
	REQUIRED unless a redirection URI has been established between
	the client and authorization server via other means. An
	absolute URI to which the authorization server will redirect
	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. Authorization servers
	MAY restrict the redirection URI to not include a query
	component as defined by [RFC3986] section 3.
	state		[RFC2617], the end-user's credentials are used in a single request
	OPTIONAL. An opaque value used by the client to maintain state		and are exchanged for an access token and refresh token which
	between the request and callback. The authorization server		eliminates the client need to store them for future use.
	includes this value when redirecting the user-agent back to the
	client.
	scope		The methods through which the client prompts end users for their
	OPTIONAL. The scope of the access request expressed as a list		usernames and passwords is beyond the scope of this specification.
	of space-delimited strings. The value of the "scope" parameter		The client MUST discard the usernames and passwords once an access
	is defined by the authorization server. If the value contains		token has been obtained.
	multiple space-delimited strings, their order does not matter,
	and each string adds an additional access range to the
	requested scope.
	immediate		This flow is suitable in cases where the end-user already has a trust
	OPTIONAL. The parameter value must be set to "true" or		relationship with the client, such as its computer operating system
	"false". If set to "true", the authorization server MUST NOT		or highly privileged applications. Authorization servers should take
	prompt the end-user to authenticate or approve access.		special care when enabling the username and password flow, and only
	Instead, the authorization server attempts to establish the		when other delegation flows are not viable.
	end-user's identity via other means (e.g. browser cookies) and
	checks if the end-user has previously approved an identical
	access request by the same client and if that access grant is
	still active. If the authorization server does not support an
	immediate check or if it is unable to establish the end-user's
	identity or approval status, it MUST deny the request without
	prompting the end-user. Defaults to "false" if omitted.
	The client directs the end-user to the constructed URI using an HTTP		End-user
	redirection response, or by other means available to it via the end-		v
	user's user-agent. The request MUST use the HTTP "GET" method.		:
			(A)
			:
			v
			+--------+ +---------------+
			| | Client Credentials | |
			| |>--(B)--- & User Credentials ---->| Authorization |
			| Client | | Server |
			| |<--(C)---- Access Token ---------<| |
			| | (w/ Optional Refresh Token) | |
			+--------+ +---------------+
	For example, the client directs the end-user's user-agent to make the		Figure 5: Username and Password Flow
	following HTTPS request (line breaks are for display purposes only):
	GET /authorize?type=user_agent&client_id=s6BhdRkqt3&		The username and password flow illustrated in Figure 5 includes the
	redirect_uri=https%3A%2F%2FEexample%2Ecom%2Frd HTTP/1.1		following steps:
	Host: server.example.com
	If the client has previously registered a redirection URI with the		(A) The end-user provides the client with its username and password.
	authorization server, the authorization server MUST verify that the
	redirection URI received matches the registered URI associated with
	the client identifier.
	The authorization server authenticates the end-user and obtains an		(B) The client requests an access token from the authorization
	authorization decision (by asking the end-user or establishing		server by authenticating and including the end-user's username
	approval via other means). The authorization server sends the end-		and password, and desired scope as described in Section 5.1.
	user's user-agent to the provided client redirection URI using an
	HTTP redirection response.
	2.6.1.1. End-user Grants Authorization		(C) The authorization server validates the end-user credentials and
			the client credentials and issues an access token.
	If the end-user authorizes the access request, the authorization		2.4. Client Credentials Flow
	server issues an access token and delivers it to the client by adding
	the following parameters, using the
	"application/x-www-form-urlencoded" format as defined by
	[W3C.REC-html401-19991224], to the redirection URI fragment:
	access_token		The client credentials flow is used when the client acts on behalf of
	REQUIRED. The access token.		itself (the client is the resource owner), or when the client
			credentials are used to obtain an access token representing a
			previously established access authorization. The client secret is
			assumed to be high-entropy since it is not designed to be memorized
			by an end-user.
	expires_in		+--------+ +---------------+
	OPTIONAL. The duration in seconds of the access token		| | | |
	lifetime.		| |>--(A)--- Client Credentials ---->| Authorization |
			| Client | | Server |
			| |<--(B)---- Access Token ---------<| |
			| | (w/ Optional Refresh Token) | |
			+--------+ +---------------+
	refresh_token		Figure 6: Client Credentials Flow
	OPTIONAL. The refresh token.
	state		The client credential flow illustrated in Figure 6 includes the
	REQUIRED if the "state" parameter was present in the client		following steps:
	authorization request. Set to the exact value received from
	the client.
	For example, the authorization server redirects the end-user's user-		(A) The client requests an access token from the authorization
	agent by sending the following HTTP response:		server by authenticating and including the desired scope as
			described in Section 5.1. No additional authorization grant
			information is needed.
	HTTP/1.1 302 Found		(B) The authorization server validates the client credentials and
	Location: http://example.com/rd#access_token=FJQbwq9&expires_in=3600		issues an access token.
	2.6.1.2. End-user Denies Authorization		2.5. Assertion Flow
	If the end-user denied the access request, the authorization server		The assertion flow is used when a client wishes to exchange an
	responds to the client by adding the following parameters, using the		existing security token or assertion for an access token. This flow
	"application/x-www-form-urlencoded" format as defined by		is suitable when the client is the resource owner or is acting on
	[W3C.REC-html401-19991224], to the redirection URI fragment:		behalf of the resource owner (based on the content of the assertion
			used).
	error		The assertion flow requires the client to obtain a assertion (such as
	REQUIRED. The parameter value MUST be set to "user_denied".		a SAML [OASIS.saml-core-2.0-os] assertion) from an assertion issuer
			or to self-issue an assertion prior to initiating the flow. 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.
	state		+--------+ +---------------+
	REQUIRED if the "state" parameter was present in the client		| | | |
	authorization request. Set to the exact value received from		| |>--(A)------ Assertion ---------->| Authorization |
	the client.		| Client | | Server |
			| |<--(B)---- Access Token ---------<| |
			| | | |
			+--------+ +---------------+
	For example, the authorization server responds with the following:		Figure 7: Assertion Flow
	HTTP/1.1 302 Found		The assertion flow illustrated in Figure 7 includes the following
	Location: http://example.com/rd#error=user_denied		steps:
	The authorization flow concludes unsuccessfully. To extract the		(A) The client requests an access token from the authorization
	error message, the client follows the steps described in		server by authenticating and including the assertion, assertion
	Section 2.6.2.		type, and desired scope as described in Section 5.1.
	2.6.2. Client Extracts Access Token		(B) The authorization server validates the assertion and issues an
			access token.
	The user-agent follows the authorization server redirection response		2.6. Native Application Considerations
	by making an HTTP "GET" request to the URI received in the "Location"
	HTTP response header. The user-agent SHALL NOT include the fragment
	component with the request.
	For example, the user-agent makes the following HTTP "GET" request in		Native application are clients running as native code on the end-
	response to the redirection directive received from the authorization		user's computer or device (i.e. executing outside a browser or as a
	server:		desktop program). These clients are often capable of interacting
			with (or embedding) the end-user's user-agent but are incapable of
			receiving callback requests from the server (incapable of acting as
			an HTTP server).
	GET /rd HTTP/1.1		Native application clients can utilize many of the flows defined in
	Host: example.com		this specification with little or no changes. For example:
	The HTTP response to the redirection request returns a web page		o Launch an external user-agent and have it redirect back to the
	(typically an HTML page with an embedded script) capable of accessing		client using a custom URI scheme. This works with the web server
	the full redirection URI including the fragment retained by the user-		flow and user-agent flow.
	agent, and extracting the access token (and other parameters)
	contained in the fragment.
	2.7. Device Flow		o Launch an external user-agent and poll for changes to the window
			title. This works with the web server flow with a server-hosted
			custom redirect result page that puts the verification code in the
			title.
	The device flow is a user delegation flow suitable for clients		o Use an embedded user-agent and obtain the redirection URI. This
	executing on devices which do not have an easy data-entry method		works with the web server flow and user-agent flow.
	(e.g. game consoles or media hub), but where the end-user has
	separate access to a user-agent on another computer or device (e.g.
	home computer, a laptop, or a smart phone). The client is incapable
	of receiving incoming requests from the authorization server
	(incapable of acting as an HTTP server).
	Instead of interacting with the end-user's user-agent, the client		o Use the username and password flow and prompt the end-users for
	instructs the end-user to use another computer or device and connect		their credentials. This is generally discouraged as it hands the
	to the authorization server to approve the access request. Since the		end-user's password directly to the 3rd party and may not work
	client cannot receive incoming requests, it polls the authorization		with some authentication schemes.
	server repeatedly until the end-user completes the approval process.
	This device flow does not utilize the client secret since the client		When choosing between launching an external browser and an embedded
	executables reside on a local device which makes the client secret		user-agent, developers should consider the following:
	accessible and exploitable.
	+----------+ +----------------+		o External user-agents may improve completion rate as the end-user
	| |>---(A)-- Client Identifier --->| |		may already be logged-in and not have to re-authenticate.
	| | | |
	| |<---(B)-- Verification Code, --<| |
	| | User Code, | |
	| | & Verification URI | |
	| Device | | |
	| Client | Client Identifier & | |
	| |>---(E)-- Verification Code --->| |
	| | ... | |
	| |>---(E)---> | |
	| | | Authorization |
	| |<---(F)-- Access Token --------<| Server |
	+----------+ (w/ Optional Refresh Token) | |
	v | |
	: | |
	(C) User Code & Verification URI | |
	: | |
	v | |
	+----------+ | |
	| End-user | | |
	| at |<---(D)-- User authenticates -->| |
	| Browser | | |
	+----------+ +----------------+
	Figure 5: Device Flow		o Embedded user-agents often offer a better end-user flow, as they
			remove the need to switch context and open new windows.
	The device flow illustrated in Figure 5 includes the following steps:		o Embedded user-agents are less secure because users are
			authenticating in unidentified window without access to the
			protections offered by many user-agents.
	(A) The client requests access from the authorization server and		3. Client Credentials
	includes its client identifier in the request.
	(B) The authorization server issues a verification code, an end-user		When requesting access from the authorization server, the client
	code, and provides the end-user verification URI.		identifies itself using a set of client credentials. The client
			credentials include a client identifier and an OPTIONAL symmetric
			shared secret. The means through which the client obtains these
			credentials are beyond the scope of this specification, but usually
			involve registration with the authorization server.
	(C) The client instructs the end-user to use its user-agent		The client identifier is used by the authorization server to
	(elsewhere) and visit the provided end-user verification URI.		establish the identity of the client for the purpose of presenting
	The client provides the end-user with the end-user code to enter		information to the resource owner prior to granting access, as well
	in order to grant access.		as for providing different service levels to different clients. They
			can also be used to block unauthorized clients from requesting
			access.
	(D) The authorization server authenticates the end-user (via the		Due to the nature of some clients, authorization servers SHOULD NOT
	user-agent) and prompts the end-user to grant the client's		make assumptions about the confidentiality of client credentials
	access request. If the end-user agrees to the client's access		without establishing trust with the client operator. Authorization
	request, the end-user enters the end-user code provided by the		servers SHOULD NOT issue client secrets to clients incapable of
	client. The authorization server validates the end-user code		keeping their secrets confidential.
	provided by the end-user.
	(E) While the end-user authorizes (or denies) the client's request		3.1. Client Authentication
	(D), the client repeatedly polls the authorization server to
	find out if the end-user completed the end-user authorization
	step. The client includes the verification code and its client
	identifier.
	(F) Assuming the end-user granted access, the authorization server		The token endpoint requires the client to authenticate itself to the
	validates the verification code provided by the client and		authorization server. This is done by including the client
	responds back with the access token.		identifier (and optional secret) in the request. The client
			identifier and secret are included in the request using two request
			parameters: "client_id" and "client_secret".
	2.7.1. Client Requests Authorization		For example (line breaks are for display purposes only):
	The client initiates the flow by requesting a set of verification		POST /token HTTP/1.1
	codes from the authorization server by making an HTTP "POST" request		Host: server.example.com
	to the token endpoint. The client constructs a request URI by adding		Content-Type: application/x-www-form-urlencoded
	the following parameters to the request:
	type		type=web_server&client_id=s6BhdRkqt3&
	REQUIRED. The parameter value MUST be set to "device_code".		client_secret=gX1fBat3bV&code=i1WsRn1uB1&
			redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
	client_id		The client MAY include the client credentials using an HTTP
	REQUIRED. The client identifier as described in Section 2.1.		authentication scheme which supports authenticating using a username
			and password, instead of using the "client_id" and "client_secret"
			request parameters. Including the client credentials using an HTTP
			authentication scheme fulfills the requirements of including the
			parameters as defined by the various flows.
	scope		The client MUST NOT include the client credentials using more than
	OPTIONAL. The scope of the access request expressed as a list		one mechanism. If more than one mechanism is used, regardless if the
	of space-delimited strings. The value of the "scope" parameter		credentials are identical, the server MUST reply with an HTTP 400
	is defined by the authorization server. If the value contains		status code (Bad Request) and include the "multiple-credentials"
	multiple space-delimited strings, their order does not matter,		error message.
	and each string adds an additional access range to the
	requested scope.
	format		The authorization server MUST accept the client credentials using
	OPTIONAL. The response format requested by the client. Value		both the request parameters, and the HTTP Basic authentication scheme
	MUST be one of "json", "xml", or "form". Alternatively, the		as defined in [RFC2617]. The authorization server MAY support
	client MAY use the HTTP "Accept" header field with the desired		additional HTTP authentication schemes.
	media type. Defaults to "json" if omitted and no "Accept"
	header field is present.
	For example, the client makes the following HTTPS request (line		For example (line breaks are for display purposes only):
	breaks are for display purposes only):
	POST /token HTTP/1.1		POST /token HTTP/1.1
	Host: server.example.com		Host: server.example.com
			Authorization: Basic czZCaGRSa3F0MzpnWDFmQmF0M2JW
	Content-Type: application/x-www-form-urlencoded		Content-Type: application/x-www-form-urlencoded
	type=device_code&client_id=s6BhdRkqt3		type=web_server&code=i1WsRn1uB1&
			redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
	In response, the authorization server generates a verification code
	and an end-user code and includes them in the HTTP response body
	using the "application/json" format as described by Section 2.3.2
	with a 200 status code (OK). The response contains the following
	parameters:
	code
	REQUIRED. The verification code.
	user_code
	REQUIRED. The end-user code.
	verification_uri
	REQUIRED. The end-user verification URI on the authorization
	server. The URI should be short and easy to remember as end-
	users will be asked to manually type it into their user-agent.
	expires_in
	OPTIONAL. The duration in seconds of the verification code
	lifetime.
	interval		4. Establishing Resource Owner Authorization
	OPTIONAL. The minimum amount of time in seconds that the
	client SHOULD wait between polling requests to the token
	endpoint.
	For example:		Before the client can obtain an access token, it must first attain
			authorization from the resource owner. The methods through which the
			client attains authorization are codified in the various
			authorization flows defined in Section 5, and depends on the client
			type and its trust relationship with the resource owner.
	HTTP/1.1 200 OK		Resource owner authorization can be expressed in multiple ways: a
	Content-Type: application/json		verification code obtained through direct interaction with an end-
	Cache-Control: no-store		user, the resource owner credentials (or the client credentials when
			the client is also the resource owner) obtained through a trust
			relationship with the resource owner, or an assertion obtained
			through means beyond the scope of this specification.
	{		4.1. Verification Code
	"code":"74tq5miHKB",
	"user_code":"94248",
	"verification_uri":"http://www.example.com/device",
	"interval"=5
	}
	The client displays the end-user code and the end-user verification		When an end-user is involved, the client attains authorization in the
	URI to the end-user, and instructs the end-user to visit the URI		form of a verification code by sending the end-user to the
	using a user-agent and enter the end-user code.		authorization server to review and grant the request. The client
			sends the end-user by directing the end-user's user-agent to the
			authorization server's end-user authorization endpoint.
	The end-user manually types the provided verification URI and		4.1.1. End-User Authorization Endpoint
	authenticates with the authorization server. The authorization
	server prompts the end-user to authorize the client's request by
	entering the end-user code provided by the client. Once the end-user
	approves or denies the request, the authorization server informs the
	end-user to return to the device for further instructions.
	2.7.2. Client Requests Access Token		When directed to the end-user authorization endpoint, the end-user
			first authenticates with the authorization server, and then grants or
			denies the access request. The way in which the authorization server
			authenticates the end-user (e.g. username and password login, OpenID,
			session cookies) and in which the authorization server obtains the
			end-user's authorization, including whether it uses a secure channel
			such as TLS, is beyond the scope of this specification. However, the
			authorization server MUST first verify the identity of the end-user.
	Since the client is unable to receive incoming requests from the		The location of the end-user authorization endpoint can be found in
	authorization server, it polls the authorization server repeatedly		the service documentation, or can be obtained by using [[ OAuth
	until the end-user grants or denies the request, or the verification		Discovery ]]. The end-user authorization endpoint URI MAY include a
	code expires.		query component as defined by [RFC3986] section 3, which must be
			retained when adding additional query parameters.
	The client makes the following request at an arbitrary but reasonable		Since requests to the end-user authorization endpoint result in user
	interval which MUST NOT exceed the minimum interval rate provided by		authentication and the transmission of sensitive information, the
	the authorization server (if present via the "interval" parameter).		authorization server SHOULD require the use of a transport-layer
	Alternatively, the client MAY provide a user interface for the end-		mechanism such as TLS when sending requests to the end-user
	user to manually inform it when authorization was granted.		authorization endpoint.
	The client requests an access token by making an HTTP "POST" request		In order to direct the end-user's user-agent to the authorization
	to the token endpoint. The client constructs a request URI by adding		server, the client constructs the request URI by adding the following
	the following parameters to the request:		parameters to the end-user authorization endpoint URI query component
			using the "application/x-www-form-urlencoded" format as defined by
			[W3C.REC-html401-19991224]:
	type		type
	REQUIRED. The parameter value MUST be set to "device_token".		REQUIRED. The client type (user-agent or web server).
			Determines how the authorization server delivers the
			authorization response back to the client. The parameter value
			MUST be set to "web_server" or "user_agent".
	client_id		client_id
	REQUIRED. The client identifier as described in Section 2.1.		REQUIRED. The client identifier as described in Section 3.
	code		redirect_uri
	REQUIRED. The verification code received from the		REQUIRED, unless a redirection URI has been established between
	authorization server.		the client and authorization server via other means. An
			absolute URI to which the authorization server will redirect
			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. Authorization servers
			MAY restrict the redirection URI to not include a query
			component as defined by [RFC3986] section 3.
	format		state
	OPTIONAL. The response format requested by the client. Value		OPTIONAL. An opaque value used by the client to maintain state
	MUST be one of "json", "xml", or "form". Alternatively, the		between the request and callback. The authorization server
	client MAY use the HTTP "Accept" header field with the desired		includes this value when redirecting the user-agent back to the
	media type. Defaults to "json" if omitted and no "Accept"		client.
	header field is present.
	For example, the client makes the following HTTPS request (line		scope
	breaks are for display purposes only):		OPTIONAL. The scope of the access request expressed as a list
			of space-delimited strings. The value of the "scope" parameter
			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.
	POST /token HTTP/1.1		The client directs the end-user to the constructed URI using an HTTP
			redirection response, or by other means available to it via the end-
			user's user-agent. The request MUST use the HTTP "GET" method.
			For example, the client directs the end-user's user-agent to make the
			following HTTPS request (line breaks are for display purposes only):
			GET /authorize?type=web_server&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
	type=device_token&client_id=s6BhdRkqt3		If the client has previously registered a redirection URI with the
	&code=74tq5miHKB		authorization server, the authorization server MUST verify that the
			redirection URI received matches the registered URI associated with
			the client identifier. [[ provide guidance on how to perform matching
			]]
	If the end-user authorized the request, the authorization server		The authorization server authenticates the end-user and obtains an
	issues an access token response as described in Section 2.3.2.1.		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.
	For example:		4.1.1.1. Authorization Server Response
	HTTP/1.1 200 OK		If the end-user grants the access request, the authorization server
	Content-Type: application/json		issues an access token, a verification code, or both, and delivers
	Cache-Control: no-store		them to the client by adding the following parameters to the
			redirection URI:
	{		code
	"access_token":"SlAV32hkKG",		REQUIRED if the client type is "web_server", otherwise
	"expires_in":3600,		OPTIONAL. The verification code generated by the authorization
	"refresh_token":"8xLOxBtZp8"		server. The verification code SHOULD expire shortly after it
	}		is issued and allowed for a single use. The verification code
			is bound to the client identifier and redirection URI.
	If the request is invalid, the authorization server returns an error		access_token
	response as described in Section 2.3.2.2 with one of the following		REQUIRED if the client type is "user_agent", otherwise MUST NOT
	error codes:		be included. The access token.
	o "authorization_declined"		expires_in
			OPTIONAL. The duration in seconds of the access token lifetime
			if an access token is included.
	o "bad_verification_code"		state
			REQUIRED if the "state" parameter was present in the client
			authorization request. Set to the exact value received from
			the client.
	For example:		If the end-user denies the access request, the authorization server
			informs the client by adding the following parameters to the
			redirection URI:
	HTTP/1.1 400 Bad Request		error
	Content-Type: application/json		REQUIRED. The parameter value MUST be set to "user_denied".
	Cache-Control: no-store
	{		state
	"error":"authorization_declined"		REQUIRED if the "state" parameter was present in the client
	}		authorization request. Set to the exact value received from
			the client.
	If the end-user authorization is pending or expired without receiving		The method in which the authorization server adds the parameter to
	any response from the end-user, or the client is exceeding the		the redirection URI is determined by the client type provided by the
	allowed polling interval, the authorization server returns an error		client in the authorization request using the "type" parameter.
	response as described in Section 2.3.2.2 with one of the following
	error codes:
	o "'authorization_pending"		If the client type is "web_server", 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].
	o "slow_down"		For example, the authorization server redirects the end-user's user-
	o "code_expired"		agent by sending the following HTTP response:
	For example:		HTTP/1.1 302 Found
			Location: https://client.example.com/cb?code=i1WsRn1uB1
	HTTP/1.1 400 Bad Request		If the client type is "user_agent", the authorization server adds the
	Content-Type: application/json		parameters to the redirection URI fragment component using the
	Cache-Control: no-store		"application/x-www-form-urlencoded" format as defined by
			[W3C.REC-html401-19991224]. [[ replace form-encoded with JSON? ]]
	{		For example, the authorization server redirects the end-user's user-
	"error":"authorization_pending"		agent by sending the following HTTP response:
	}
	2.8. Username and Password Flow		HTTP/1.1 302 Found
			Location: http://example.com/rd#access_token=FJQbwq9&expires_in=3600
	The username and password flow is suitable for clients capable of		4.2. Resource Owner Credentials
	asking end-users for their usernames and passwords. It is also used
	to migrate existing clients using direct authentication schemes such
	as HTTP Basic or Digest authentication to OAuth by converting the
	end-user credentials stored with tokens.
	However, unlike the HTTP Basic authentication scheme defined in		While OAuth seeks to eliminate the need for resource owners to share
	[RFC2617], the end-user's credentials are used in a single request		their credentials with the client, possesion of the resource owner
	and are exchanged for an access token and refresh token which		credentials constitute an authorization grant (if supported by the
	eliminates the client need to store them for future use.		authorization server). Resource owner credentials should only be
			used when there is a high degree of trust between the resource owner
			the client.
	The methods through which the client prompts end users for their		In cases where the client is also the resource owner, the client
	usernames and passwords is beyond the scope of this specification.		credentials can be used to obtain an access token provisioned for
	The client MUST discard the usernames and passwords once an access		accessing the client's protected resources.
	token has been obtained.
	This flow is suitable in cases where the end-user already has a trust		4.3. Assertion
	relationship with the client, such as its computer operating system
	or highly privileged applications. Authorization servers should take
	special care when enabling the username and password flow, and only
	when other delegation flows are not viable.
	End-user		Assertions enable the client to utilize existing trust relationships
	v		or different authorization constructs to obtain an access token.
	:		They provide a bridge between OAuth and other trust frameworks. The
	(A)		authorization grant represented by an assertion depends on the
	:		assertion type, its content, and how it was issued, which are beyond
	v		the scope of this specification.
	+--------+ +---------------+
	| | Client Credentials | |
	| |>--(B)--- & User Credentials ---->| Authorization |
	| Client | | Server |
	| |<--(C)---- Access Token ---------<| |
	| | (w/ Optional Refresh Token) | |
	+--------+ +---------------+
	Figure 6: Username and Password Flow		5. Obtaining an Access Token
	The username and password flow illustrated in Figure 6 includes the		The client obtains an access token by authenticating with the
	following steps:		authorization server and presenting its authorization grant.
	(A) The end-user provides the client with its username and password.		In many cases it is desirable to issue access tokens with a shorter
			lifetime than the duration of the authorization grant. However, it
			may be undesirable to require the resource owner to authorize the
			request again. Instead, the authorization server issues a refresh
			token in addition to the access token. When the access token
			expires, the client can request a new access token without involving
			the resource owner as long as the authorization grant is still valid.
			The token refresh method is described in Section 5.1.4.
	(B) The client sends an access token request to the authorization		5.1. Token Endpoint
	server and includes its client identifier and client secret, and
	the end-user's username and password.
	(C) The authorization server validates the end-user credentials and		After obtaining authorization from the resource owner, clients
	the client credentials and issues an access token.		request an access token from the authorization server's token
			endpoint. When requesting an access token, the client authenticates
			with the authorization server and includes the authorization grant
			(in the form of a verification code, resource owner credentials, an
			assertion, or a refresh token).
	2.8.1. Client Requests Access Token		The location of the token endpoint can be found in the service
			documentation, or can be obtained by using [[ OAuth Discovery ]].
			The token endpoint URI MAY include a query component, which must be
			retained when adding additional query parameters.
	The client requests an access token by making an HTTP "POST" request		Since requests to the token endpoint result in the transmission of
	to the token endpoint. The client constructs a request URI by adding		plain text credentials in the HTTP request and response, the
	the following parameters to the request:		authorization server MUST require the use of a transport-layer
			mechanism when sending requests to the token endpoints. Servers MUST
			support TLS 1.2 as defined in [RFC5246] and MAY support addition
			mechanisms with equivalent protections.
	type		The client obtains an access token by constructing a token request.
	REQUIRED. The parameter value MUST be set to "username".		The client constructs the request URI by:
	client_id		o Adding its client credentials to the request as described in
	REQUIRED. The client identifier as described in Section 2.1.		Section 3.1. For example, if the client uses a set of basic
			client credentials, it adds the "client_id" and "client_secret"
			parameters to the request (or uses the HTTP Basic authentication
			scheme).
	client_secret		o Adding the authorization grand in the form of a verification code,
	REQUIRED. The client secret as described in Section 2.1.		resource owner credentials, an assertion, or refresh token. If
	OPTIONAL if no client secret was issued.		the client is acting on behalf of itself (the client is also the
			resource owner), no additional information is needed. The
			authorization grant is added to the request URI query component
			using the "application/x-www-form-urlencoded" format as described
			below.
	username		5.1.1. Verification Code
	REQUIRED. The end-user's username.
	password		The client includes the verification code using following parameters:
	REQUIRED. The end-user's password.
	scope		code
	OPTIONAL. The scope of the access request expressed as a list		REQUIRED. The verification code received from the
	of space-delimited strings. The value of the "scope" parameter		authorization server.
	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.
	format		redirect_uri
	OPTIONAL. The response format requested by the client. Value		REQUIRED. The redirection URI used in the initial request.
	MUST be one of "json", "xml", or "form". Alternatively, the
	client MAY use the HTTP "Accept" header field with the desired
	media type. Defaults to "json" if omitted and no "Accept"
	header field is present.
	For example, the client makes the following HTTPS request (line		For example, the client makes the following HTTPS request (line
	breaks are for display purposes only):		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
	type=username&client_id=s6BhdRkqt3&client_secret=		client_id=s6BhdRkqt3&
	47HDu8s&username=johndoe&password=A3ddj3w		client_secret=gX1fBat3bV&code=i1WsRn1uB1&
			redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
	The authorization server MUST validate the client credentials and
	end-user credentials and if valid issues an access token response as
	described in Section 2.3.2.1.
	For example:
	HTTP/1.1 200 OK
	Content-Type: application/json
	Cache-Control: no-store
	{
	"access_token":"SlAV32hkKG",
	"expires_in":3600,
	"refresh_token":"8xLOxBtZp8"
	}
	If the request is invalid, the authorization server returns an error
	response as described in Section 2.3.2.2 with one of the following
	error codes:
	o "incorrect_client_credentials"
	o "unauthorized_client'" - The client is not permitted to use this
	flow.
	For example:
	HTTP/1.1 400 Bad Request
	Content-Type: application/json
	Cache-Control: no-store
	{
	"error":"incorrect_client_credentials"
	}
	2.9. Client Credentials Flow
	The client credentials flow is used when the client acts on behalf of
	itself (the client is the resource owner), or when the client
	credentials are used to obtain an access token representing a
	previously established access authorization. The client secret is
	assumed to be high-entropy since it is not designed to be memorized
	by an end-user.
	+--------+ +---------------+
	| | | |
	| |>--(A)--- Client Credentials ---->| Authorization |
	| Client | | Server |
	| |<--(B)---- Access Token ---------<| |
	| | (w/ Optional Refresh Token) | |
	+--------+ +---------------+
	Figure 7: Client Credentials Flow
	The client credential flow illustrated in Figure 7 includes the
	following steps:
	(A) The client sends an access token request to the authorization
	server and includes its client identifier and client secret.
	(B) The authorization server validates the client credentials and
	issues an access token.
	2.9.1. Client Requests Access Token		The authorization server MUST verify that the verification code,
			client identity, client secret, 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 5.1.5.
	The client requests an access token by making an HTTP "POST" request		5.1.2. Resource Owner Credentials
	to the token endpoint. The client constructs a request URI by adding
	the following parameters to the request:
	type		The client includes the resource owner credentials using the
	REQUIRED. The parameter value MUST be set to		following parameters: [[ add internationalization consideration for
	"client_credentials".		username and password ]]
	client_id		username
	REQUIRED. The client identifier as described in Section 2.1.		REQUIRED. The end-user's username.
	client_secret		password
	REQUIRED. The client secret as described in Section 2.1.		REQUIRED. The end-user's 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 of the "scope" parameter
	is defined by the authorization server. If the value contains		is defined by the authorization server. If the value contains
	multiple space-delimited strings, their order does not matter,		multiple space-delimited strings, their order does not matter,
	and each string adds an additional access range to the		and each string adds an additional access range to the
	requested scope.		requested scope.
	format		For example, the client makes the following HTTPS request (line
	OPTIONAL. The response format requested by the client. Value		breaks are for display purposes only):
	MUST be one of "json", "xml", or "form". Alternatively, the
	client MAY use the HTTP "Accept" header field with the desired
	media type. Defaults to "json" if omitted and no "Accept"
	header field is present.
	For example, the client makes the following HTTPS request:
	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
	type=client_credentials&client_id=s6BhdRkqt3&client_secret=47HDu8s		client_id=s6BhdRkqt3&client_secret=
			47HDu8s&username=johndoe&password=A3ddj3w
	The authorization server MUST validate the client credentials and if
	valid issues an access token response as described in
	Section 2.3.2.1.
	For example:
	HTTP/1.1 200 OK
	Content-Type: application/json
	Cache-Control: no-store
	{
	"access_token":"SlAV32hkKG",
	"expires_in":3600,
	"refresh_token":"8xLOxBtZp8"
	}
	If the request is invalid, the authorization server returns an error
	response as described in Section 2.3.2.2 with one of the following
	error codes:
	o "incorrect_client_credentials"
	For example:
	HTTP/1.1 400 Bad Request
	Content-Type: application/json
	Cache-Control: no-store
	{
	"error":"incorrect_client_credentials"
	}
	2.10. Assertion Flow
	The assertion flow is used when a client wishes to exchange an
	existing security token or assertion for an access token. This flow
	is suitable when the client is the resource owner or is acting on
	behalf of the resource owner (based on the content of the assertion
	used).
	The assertion flow requires the client to obtain a assertion (such as
	a SAML [OASIS.saml-core-2.0-os] assertion) from an assertion issuer
	or to self-issue an assertion prior to initiating the flow. 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.
	+--------+ +---------------+
	| | | |
	| |>--(A)------ Assertion ---------->| Authorization |
	| Client | | Server |
	| |<--(B)---- Access Token ---------<| |
	| | | |
	+--------+ +---------------+
	Figure 8: Assertion Flow
	The assertion flow illustrated in Figure 8 includes the following
	steps:
	(A) The client sends an access token request to the authorization
	server and includes an assertion.
	(B) The authorization server validates the assertion and issues an		The authorization server MUST validate the client credentials and
	access token.		end-user credentials and if valid issues an access token response as
			described in Section 5.1.5.
	2.10.1. Client Requests Access Token		If the client is acting on behalf of itself (the client is also the
			resource owner), the client authentication alone suffice and the
			"username" and "password" parameters MUST NOT be used.
	The client requests an access token by making an HTTP "POST" request		5.1.3. Assertion
	to the token endpoint. The client constructs a request URI by adding
	the following parameters to the request:
	type		The client includes the assertion using the following parameters:
	REQUIRED. The parameter value MUST be set to "assertion".
	assertion_format		assertion_type
	REQUIRED. The format of the assertion as defined by the		REQUIRED. The format of the assertion as defined by the
	authorization server. The value MUST be an absolute URI.		authorization server. The value MUST be an absolute URI.
	assertion		assertion
	REQUIRED. The assertion.		REQUIRED. The assertion.
	client_id
	OPTIONAL. The client identifier as described in Section 2.1.
	The authorization server MAY require including the client
	credentials with the request based on the assertion properties.
	client_secret
	OPTIONAL. The client secret as described in Section 2.1. MUST
	NOT be included if the "client_id" parameter is omitted.
	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 of the "scope" parameter
	is defined by the authorization server. If the value contains		is defined by the authorization server. If the value contains
	multiple space-delimited strings, their order does not matter,		multiple space-delimited strings, their order does not matter,
	and each string adds an additional access range to the		and each string adds an additional access range to the
	requested scope.		requested scope.
	format
	OPTIONAL. The response format requested by the client. Value
	MUST be one of "json", "xml", or "form". Alternatively, the
	client MAY use the HTTP "Accept" header field with the desired
	media type. Defaults to "json" if omitted and no "Accept"
	header field is present.
	For example, the client makes the following HTTPS request (line		For example, the client makes the following HTTPS request (line
	breaks are for display purposes only):		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
	type=assertion&assertion_format=_______&assertion=_______		client_id=s6BhdRkqt3&client_secret=diejdsks&
			assertion_type=urn%3Aoasis%3Anames%sAtc%3ASAML%3A2.0%3Aassertion&
			assertion=PHNhbWxwOl...[ommited for brevity]...ZT4%3D
	The authorization server MUST validate the assertion and if valid		The authorization server MUST validate the assertion and if valid
	issues an access token response as described in Section 2.3.2.1. The		issues an access token response as described in Section 5.1.5. The
	authorization server SHOULD NOT issue a refresh token.		authorization server SHOULD NOT issue a refresh token.
	For example:
	HTTP/1.1 200 OK
	Content-Type: application/json
	Cache-Control: no-store
	{
	"access_token":"SlAV32hkKG",
	"expires_in":3600
	}
	If the request is invalid, the authorization server returns an error
	response as described in Section 2.3.2.2 with one of the following
	error codes:
	o "invalid_assertion"
	o "unknown_format"
	For example:
	HTTP/1.1 400 Bad Request
	Content-Type: application/json
	Cache-Control: no-store
	{
	"error":"invalid_assertion"
	}
	Authorization servers SHOULD issue access tokens with a limited		Authorization servers SHOULD issue access tokens with a limited
	lifetime and require clients to refresh them by requesting a new		lifetime and require clients to refresh them by requesting a new
	access token using the same assertion if it is still valid.		access token using the same assertion if it is still valid.
	Otherwise the client MUST obtain a new valid assertion.		Otherwise the client MUST obtain a new valid assertion.
	2.11. Native Application Considerations		5.1.4. Refresh Token
	Native application are clients running as native code on the end-
	user's computer or device (i.e. executing outside a browser or as a
	desktop program). These clients are often capable of interacting
	with (or embedding) the end-user's user-agent but are incapable of
	receiving callback requests from the server (incapable of acting as
	an HTTP server).
	Native application clients can utilize many of the flows defined in
	this specification with little or no changes. For example:
	o Launch an external user-agent and have it redirect back to the
	client using a custom URI scheme. This works with the web server
	flow and user-agent flow.
	o Launch an external user-agent and poll for changes to the window
	title. This works with the web server flow with a server-hosted
	custom redirect result page that puts the verification code in the
	title.
	o Use an embedded user-agent and obtain the redirection URI. This
	works with the web server flow and user-agent flow.
	o Use the device profile with an external or embedded user-agent.
	The application will open a user-agent and then poll the
	authorization server for results.
	o Use the username and password flow and prompt the end-users for
	their credentials. This is generally discouraged as it hands the
	end-user's password directly to the 3rd party and may not work
	with some authentication schemes.
	When choosing between launching an external browser and an embedded
	user-agent, developers should consider the following:
	o External user-agents may improve completion rate as the end-user
	may already be logged-in and not have to re-authenticate.
	o Embedded user-agents often offer a better end-user flow, as they
	remove the need to switch context and open new windows.
	o Embedded user-agents are less secure because users are
	authenticating in unidentified window without access to the
	protections offered by many user-agents.
	3. Refreshing an Access Token
	Token refresh is used when the lifetime of an access token is shorter		Token refresh is used when the lifetime of an access token is shorter
	than the lifetime of the authorization grant. It allows clients to		than the lifetime of the authorization grant. It enables the client
	obtain a new access token without having to go through the		to obtain a new access token without having to go through the
	authorization flow again or involve the resource owner.		authorization flow again or involve the resource owner.
	+--------+ +---------------+		The client includes the refresh token using the following parameters:
	| | Client Credentials, | |
	| |>--(A)----- Refresh Token ------->| Authorization |
	| Client | | Server |
	| |<--(B)----- Access Token --------<| |
	| | | |
	+--------+ +---------------+
	Figure 9: Refreshing an Access Token
	To refresh a token, the client constructs an HTTP "POST" request to
	the token endpoint and includes the following parameters in the HTTP
	request body using the "application/x-www-form-urlencoded" content
	type as defined by [W3C.REC-html401-19991224]:
	type
	REQUIRED. The parameter value MUST be set to "refresh".
	client_id
	REQUIRED. The client identifier as described in Section 2.1.
	client_secret
	REQUIRED if the client was issued a secret. The client secret.
	refresh_token		refresh_token
	REQUIRED. The refresh token associated with the access token		REQUIRED. The refresh token associated with the access token
	to be refreshed.		to be refreshed.
	format
	OPTIONAL. The response format requested by the client. Value
	MUST be one of "json", "xml", or "form". Alternatively, the
	client MAY use the HTTP "Accept" header field with the desired
	media type. Defaults to "json" if omitted and no "Accept"
	header field is present.
	For example, the client makes the following HTTPS request (line break		For example, the client makes the following HTTPS request (line break
	are for display purposes only):		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
	type=refresh_token&client_id=s6BhdRkqt3&client_secret=8eSEIpnqmM		client_id=s6BhdRkqt3&client_secret=8eSEIpnqmM
	&refresh_token=n4E9O119d		&refresh_token=n4E9O119d
	verify the client credential, the validity of the refresh token, and		The authorization server MUST verify the client credentials, the
	that the resource owner's authorization is still valid. If the		validity of the refresh token, and that the resource owner's
	request is valid, the authorization server issues an access token		authorization is still valid. If the request is valid, the
	response as described in Section 2.3.2.1. The authorization server		authorization server issues an access token response as described in
	MAY issue a new refresh token in which case the client MUST NOT use		Section 5.1.5. The authorization server MAY issue a new refresh
	the previous refresh token and replace it with the newly issued		token in which case the client MUST NOT use the previous refresh
	refresh token.		token and replace it with the newly issued refresh token.
			5.1.5. Access Token Response
			After receiving and verifying a valid and authorized access token
			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 status code (OK):
			The token response contains the following parameters:
			access_token
			REQUIRED. The access token issued by the authorization server.
			expires_in
			OPTIONAL. The duration in seconds of the access token
			lifetime.
			refresh_token
			OPTIONAL. The refresh token used to obtain new access tokens
			using the same end-user access grant as described in
			Section 5.1.4.
			scope
			OPTIONAL. The scope of the access token as a list of space-
			delimited strings. The value of the "scope" parameter 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 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.
			The authorization server MUST include the HTTP "Cache-Control"
			response header field with a value of "no-store" in any response
			containing tokens, secrets, or other sensitive information.
	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",
	"expires_in":3600		"expires_in":3600,
			"refresh_token":"8xLOxBtZp8"
	}		}
	If the request is invalid, the authorization server returns an error		5.1.6. Error Response
	response as described in Section 2.3.2.2 with one of the following
	error codes:
	o "incorrect_client_credentials"		If the token request is invalid or unauthorized, the authorization
			server constructs the response by adding the following parameter to
			the entity body of the HTTP response with a a 400 status code (Bad
			Request) using the "application/json" media type:
	o "authorization_expired"		error
			REQUIRED. The error code as described in Section 5.1.6.1.
	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":"incorrect_client_credentials"		"error":"incorrect_client_credentials"
	}		}
	4. Accessing a Protected Resource		5.1.6.1. Error Codes
			[[ expalain each error code: ]]
			o "redirect_uri_mismatch"
			o "bad_verification_code"
			o "incorrect_client_credentials"
			o "unauthorized_client'" - The client is not permitted to use this
			authorization grant type.
			o "invalid_assertion"
			o "unknown_format"
			o "authorization_expired"
			6. Accessing a Protected Resource
	Clients access protected resources by presenting an access token to		Clients access protected resources by presenting an access token to
	the resource server.		the resource server.
	For example:		For example:
	GET /resource HTTP/1.1		GET /resource HTTP/1.1
	Host: server.example.com		Host: server.example.com
	Authorization: Token token="vF9dft4qmT"		Authorization: Token token="vF9dft4qmT"
	skipping to change at page 43, line 27 ¶		skipping to change at page 28, line 14 ¶
	The methods used by the resource server to validate the access token		The methods used by the resource server to validate the access token
	are beyond the scope of this specification, but generally involve an		are beyond the scope of this specification, but generally involve an
	interaction or coordination between the resource server and		interaction or coordination between the resource server and
	authorization server.		authorization server.
	The resource server MUST validate the access token and ensure it has		The resource server MUST validate the access token and ensure it has
	not expired and that its scope covers the requested resource. If the		not expired and that its scope covers the requested resource. If the
	token expired or is invalid, the resource server MUST reply with an		token expired or is invalid, the resource server MUST reply with an
	HTTP 401 status code (Unauthorized) and include the HTTP		HTTP 401 status code (Unauthorized) and include the HTTP
	"WWW-Authenticate" response header as described in Section 5.1.		"WWW-Authenticate" response header as described in Section 7.1.
	For example:		For example:
	HTTP/1.1 401 Unauthorized		HTTP/1.1 401 Unauthorized
	WWW-Authenticate: Token realm='Service', error='token_expired'		WWW-Authenticate: Token realm='Service', error='token_expired'
	Clients make authenticated token requests using the "Authorization"		Clients make authenticated token requests using the "Authorization"
	request header field as described in Section 4.1. Alternatively,		request header field as described in Section 6.1. Alternatively,
	clients MAY include the access token using the HTTP request URI in		clients MAY include the access token using the HTTP request URI in
	the query component as described in Section 4.2, or in the HTTP body		the query component as described in Section 6.2, or in the HTTP body
	when using the "application/x-www-form-urlencoded" content type as		when using the "application/x-www-form-urlencoded" content type as
	described in Section 4.3.		described in Section 6.3.
	Clients SHOULD only use the request URI or body when the		Clients SHOULD only use the request URI or body when the
	"Authorization" request header field is not available, and MUST NOT		"Authorization" request header field is not available, and MUST NOT
	use more than one method in each request. [[ specify error ]]		use more than one method in each request. [[ specify error ]]
	4.1. The Authorization Request Header		6.1. The Authorization Request Header
	The "Authorization" request header field is used by clients to make		The "Authorization" request header field is used by clients to make
	authenticated token requests. The client uses the "token" attribute		authenticated token requests. The client uses the "token" attribute
	to include the access token in the request.		to include the access token in the request.
	The "Authorization" header field uses the framework defined by		The "Authorization" header field uses the framework defined by
	[RFC2617] as follows:		[RFC2617] as follows:
	credentials = "Token" RWS access-token [ CS 1#auth-param ]		credentials = "Token" RWS access-token [ CS 1#auth-param ]
	access-token = "token" "=" <"> token <">		access-token = "token" "=" <"> token <">
	CS = OWS "," OWS		CS = OWS "," OWS
	4.2. URI Query Parameter		6.2. URI Query Parameter
	When including the access token in the HTTP request URI, the client		When including the access token in the HTTP request URI, the client
	adds the access token to the request URI query component as defined		adds the access token to the request URI query component as defined
	by [RFC3986] using the "oauth_token" parameter.		by [RFC3986] using the "oauth_token" parameter.
	For example, the client makes the following HTTPS request:		For example, the client makes the following HTTPS request:
	GET /resource?oauth_token=vF9dft4qmT HTTP/1.1		GET /resource?oauth_token=vF9dft4qmT HTTP/1.1
	Host: server.example.com		Host: server.example.com
	The HTTP request URI query can include other request-specific		The HTTP request URI query can include other request-specific
	parameters, in which case, the "oauth_token" parameters SHOULD be		parameters, in which case, the "oauth_token" parameters SHOULD be
	appended following the request-specific parameters, properly		appended following the request-specific parameters, properly
	separated by an "&" character (ASCII code 38).		separated by an "&" character (ASCII code 38).
	The resource server MUST validate the access token and ensure it has		The resource server MUST validate the access token and ensure it has
	not expired and its scope includes the requested resource. If the		not expired and its scope includes the requested resource. If the
	resource expired or is not valid, the resource server MUST reply with		resource expired or is not valid, the resource server MUST reply with
	an HTTP 401 status code (Unauthorized) and include the HTTP		an HTTP 401 status code (Unauthorized) and include the HTTP
	"WWW-Authenticate" response header as described in Section 5.1.		"WWW-Authenticate" response header as described in Section 7.1.
	4.3. Form-Encoded Body Parameter		6.3. Form-Encoded Body Parameter
	When including the access token in the HTTP request entity-body, the		When including the access token in the HTTP request entity-body, the
	client adds the access token to the request body using the		client adds the access token to the request body using the
	"oauth_token" parameter. The client can use this method only if the		"oauth_token" parameter. The client can use this method only if the
	following REQUIRED conditions are met:		following REQUIRED conditions are met:
	o The entity-body is single-part.		o The entity-body is single-part.
	o The entity-body follows the encoding requirements of the		o The entity-body follows the encoding requirements of the
	"application/x-www-form-urlencoded" content-type as defined by		"application/x-www-form-urlencoded" content-type as defined by
	skipping to change at page 45, line 17 ¶		skipping to change at page 30, line 4 ¶
	The entity-body can include other request-specific parameters, in		The entity-body can include other request-specific parameters, in
	which case, the "oauth_token" parameters SHOULD be appended following		which case, the "oauth_token" parameters SHOULD be appended following
	the request-specific parameters, properly separated by an "&"		the request-specific parameters, properly separated by an "&"
	character (ASCII code 38).		character (ASCII code 38).
	For example, the client makes the following HTTPS request:		For example, the client makes the following HTTPS request:
	POST /resource HTTP/1.1		POST /resource 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
	oauth_token=vF9dft4qmT		oauth_token=vF9dft4qmT
	The resource server MUST validate the access token and ensure it has		The resource server MUST validate the access token and ensure it has
	not expired and its scope includes the requested resource. If the		not expired and its scope includes the requested resource. If the
	resource expired or is not valid, the resource server MUST reply with		resource expired or is not valid, the resource server MUST reply with
	an HTTP 401 status code (Unauthorized) and include the HTTP		an HTTP 401 status code (Unauthorized) and include the HTTP
	"WWW-Authenticate" response header as described in Section 5.1.		"WWW-Authenticate" response header as described in Section 7.1.
	5. Identifying a Protected Resource		7. Identifying a Protected Resource
	Clients access protected resources after locating the appropriate		Clients access protected resources after locating the appropriate
	end-user and token endpoints and obtaining an access token. In many		end-user authorization endpoint and token endpoint and obtaining an
	cases, interacting with a protected resource requires prior knowledge		access token. In many cases, interacting with a protected resource
	of the protected resource properties and methods, as well as its		requires prior knowledge of the protected resource properties and
	authentication requirements (i.e. establishing client identity,		methods, as well as its authentication requirements (i.e.
	locating the end-user and token endpoints).		establishing client identity, locating the end-user authorization and
			token endpoints).
	However, there are cases in which clients are unfamiliar with the		However, there are cases in which clients are unfamiliar with the
	protected resource, including whether the resource requires		protected resource, including whether the resource requires
	authentication. When clients attempt to access an unfamiliar		authentication. When clients attempt to access an unfamiliar
	protected resource without an access token, the resource server		protected resource without an access token, the resource server
	denies the request and informs the client of the required credentials		denies the request and informs the client of the required credentials
	using an HTTP authentication challenge.		using an HTTP authentication challenge.
	In addition, when receiving an invalid authenticated request, the		In addition, when receiving an invalid authenticated request, the
	resource server issues an authentication challenge including the		resource server issues an authentication challenge including the
	error type and message.		error type and message.
	5.1. The WWW-Authenticate Response Header		7.1. The WWW-Authenticate Response Header
	A resource server receiving a request for a protected resource		A resource server receiving a request for a protected resource
	without a valid access token MUST respond with a 401 (Unauthorized)		without a valid access token MUST respond with a 401 (Unauthorized)
	or 403 (Forbidden) HTTP status code, and include at least one "Token"		or 403 (Forbidden) HTTP status code, and include at least one "Token"
	"WWW-Authenticate" response header field challenge.		"WWW-Authenticate" response header field challenge.
	The "WWW-Authenticate" header field uses the framework defined by		The "WWW-Authenticate" header field uses the framework defined by
	[RFC2617] as follows:		[RFC2617] as follows:
	challenge = "Token" RWS token-challenge		challenge = "Token" RWS token-challenge
	skipping to change at page 46, line 24 ¶		skipping to change at page 31, line 13 ¶
	[ CS 1#auth-param ]		[ CS 1#auth-param ]
	error = "error" "=" <"> token <">		error = "error" "=" <"> token <">
	The "realm" attribute is used to provide the protected resources		The "realm" attribute is used to provide the protected resources
	partition as defined by [RFC2617].		partition as defined by [RFC2617].
	The "error" attribute is used to inform the client the reason why an		The "error" attribute is used to inform the client the reason why an
	access request was declined. [[ Add list of error codes ]]		access request was declined. [[ Add list of error codes ]]
	6. Security Considerations		8. Security Considerations
	[[ Todo ]]		[[ Todo ]]
	7. IANA Considerations		9. IANA Considerations
	[[ Not Yet ]]		[[ Not Yet ]]
	Appendix A. Contributors		Appendix A. 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,
	skipping to change at page 47, line 13 ¶		skipping to change at page 32, line 5 ¶
	Michael Adams, Andrew Arnott, Dirk Balfanz, Brian Campbell, Leah		Michael Adams, Andrew Arnott, Dirk Balfanz, Brian Campbell, Leah
	Culver, Igor Faynberg, George Fletcher, Evan Gilbert, Justin Hart,		Culver, Igor Faynberg, George Fletcher, Evan Gilbert, Justin Hart,
	John Kemp, Torsten Lodderstedt, Eve Maler, James Manger, Chuck		John Kemp, Torsten Lodderstedt, Eve Maler, James Manger, Chuck
	Mortimore, Justin Richer, Peter Saint-Andre, Nat Sakimura, Rob Sayre,		Mortimore, Justin Richer, Peter Saint-Andre, Nat Sakimura, Rob Sayre,
	Marius Scurtescu, Justin Smith, and Franklin Tse.		Marius Scurtescu, Justin Smith, and Franklin Tse.
	Appendix B. Acknowledgements		Appendix B. Acknowledgements
	[[ Add OAuth 1.0a authors + WG contributors ]]		[[ Add OAuth 1.0a authors + WG contributors ]]
	Appendix C. Differences from OAuth 1.0a		Appendix C. Document History
	[[ Todo ]]		[[ to be removed by RFC editor before publication as an RFC ]]
	Appendix D. Document History		-07
	[[ to be removed by RFC editor before publication as an RFC ]]		o Major rewrite of entire document structure.
			o Removed device profile.
			o Added verification code support to user-agent flow.
			o Removed multiple formats support, leaving JSON as the only format.
			o Changed assertion "assertion_format" parameter to
			"assertion_type".
			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.
	skipping to change at page 49, line 30 ¶		skipping to change at page 34, line 30 ¶
	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.
	8. References		10. References
	8.1. Normative References		10.1. 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.
	[NIST FIPS-180-3]		[NIST FIPS-180-3]
	National Institute of Standards and Technology, "Secure		National Institute of Standards and Technology, "Secure
	skipping to change at page 50, line 41 ¶		skipping to change at page 35, line 41 ¶
	Resource Identifier (URI): Generic Syntax", STD 66,		Resource Identifier (URI): Generic Syntax", STD 66,
	RFC 3986, January 2005.		RFC 3986, January 2005.
	[RFC4627] Crockford, D., "The application/json Media Type for		[RFC4627] Crockford, D., "The application/json Media Type for
	JavaScript Object Notation (JSON)", RFC 4627, July 2006.		JavaScript Object Notation (JSON)", RFC 4627, July 2006.
	[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.
	[W3C.REC-html401-19991224]		[W3C.REC-html401-19991224]
	Hors, A., Jacobs, I., and D. Raggett, "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>.
	8.2. Informative References		10.2. Informative References
	[I-D.hammer-oauth]		[I-D.hammer-oauth]
	Hammer-Lahav, E., "The OAuth 1.0 Protocol",		Hammer-Lahav, E., "The OAuth 1.0 Protocol",
	draft-hammer-oauth-10 (work in progress), February 2010.		draft-hammer-oauth-10 (work in progress), February 2010.
	[I-D.hardt-oauth]		[I-D.hardt-oauth]
	Hardt, D., Tom, A., Eaton, B., and Y. Goland, "OAuth Web		Hardt, D., Tom, A., Eaton, B., and Y. Goland, "OAuth Web
	Resource Authorization Profiles", draft-hardt-oauth-01		Resource Authorization Profiles", draft-hardt-oauth-01
	(work in progress), January 2010.		(work in progress), January 2010.
End of changes. 185 change blocks.
	1256 lines changed or deleted		620 lines changed or added
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