< draft-ietf-oauth-v2-00.txt		draft-ietf-oauth-v2-01.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: October 31, 2010 Facebook		Expires: October 31, 2010 Facebook
	D. Hardt		D. Hardt
	April 29, 2010		April 29, 2010
	The OAuth 2.0 Protocol		The OAuth 2.0 Protocol
	draft-ietf-oauth-v2-00		draft-ietf-oauth-v2-01
	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
	identifier used to denote an access grant with specific scope,		identifier used to denote an access grant with specific scope,
	duration, and other attributes. Tokens are issued to third-party		duration, and other attributes. Tokens are issued to third-party
	clients by an authorization server with the approval of the resource		clients by an authorization server with the approval of the resource
	owner. OAuth defines multiple flows for obtaining a token to support		owner. OAuth defines multiple flows for obtaining a token to support
	a wide range of client types and user experience.		a wide range of client types and user experience.
	skipping to change at page 3, line 21 ¶		skipping to change at page 3, line 21 ¶
	2.3. Example . . . . . . . . . . . . . . . . . . . . . . . . . 8		2.3. Example . . . . . . . . . . . . . . . . . . . . . . . . . 8
	2.4. Notational Conventions . . . . . . . . . . . . . . . . . . 8		2.4. Notational Conventions . . . . . . . . . . . . . . . . . . 8
	2.5. Conformance . . . . . . . . . . . . . . . . . . . . . . . 8		2.5. Conformance . . . . . . . . . . . . . . . . . . . . . . . 8
	3. Obtaining an Access Token . . . . . . . . . . . . . . . . . . 8		3. Obtaining an Access Token . . . . . . . . . . . . . . . . . . 8
	3.1. Authorization Endpoint . . . . . . . . . . . . . . . . . . 9		3.1. Authorization Endpoint . . . . . . . . . . . . . . . . . . 9
	3.2. Token Endpoint . . . . . . . . . . . . . . . . . . . . . . 9		3.2. Token Endpoint . . . . . . . . . . . . . . . . . . . . . . 9
	3.3. Flow Parameters . . . . . . . . . . . . . . . . . . . . . 10		3.3. Flow Parameters . . . . . . . . . . . . . . . . . . . . . 10
	3.4. Client Credentials . . . . . . . . . . . . . . . . . . . . 10		3.4. Client Credentials . . . . . . . . . . . . . . . . . . . . 10
	3.5. User Delegation Flows . . . . . . . . . . . . . . . . . . 11		3.5. User Delegation Flows . . . . . . . . . . . . . . . . . . 11
	3.5.1. User-Agent Flow . . . . . . . . . . . . . . . . . . . 11		3.5.1. User-Agent Flow . . . . . . . . . . . . . . . . . . . 11
	3.5.2. Web Server Flow . . . . . . . . . . . . . . . . . . . 15		3.5.2. Web Server Flow . . . . . . . . . . . . . . . . . . . 16
	3.5.3. Device Flow . . . . . . . . . . . . . . . . . . . . . 21		3.5.3. Device Flow . . . . . . . . . . . . . . . . . . . . . 22
	3.6. End User Credentials Flows . . . . . . . . . . . . . . . . 27		3.6. End-user Credentials Flows . . . . . . . . . . . . . . . . 27
	3.6.1. Username and Password Flow . . . . . . . . . . . . . . 27		3.6.1. Username and Password Flow . . . . . . . . . . . . . . 27
	3.7. Autonomous Client Flows . . . . . . . . . . . . . . . . . 30		3.7. Autonomous Client Flows . . . . . . . . . . . . . . . . . 30
	3.7.1. Client Credentials Flow . . . . . . . . . . . . . . . 30		3.7.1. Client Credentials Flow . . . . . . . . . . . . . . . 30
	3.7.2. Assertion Flow . . . . . . . . . . . . . . . . . . . . 33		3.7.2. Assertion Flow . . . . . . . . . . . . . . . . . . . . 33
	4. Refreshing an Access Token . . . . . . . . . . . . . . . . . . 35		4. Refreshing an Access Token . . . . . . . . . . . . . . . . . . 35
	5. Accessing a Protected Resource . . . . . . . . . . . . . . . . 38		5. Accessing a Protected Resource . . . . . . . . . . . . . . . . 38
	5.1. The Authorization Request Header . . . . . . . . . . . . . 38		5.1. The Authorization Request Header . . . . . . . . . . . . . 38
	5.2. Bearer Token Requests . . . . . . . . . . . . . . . . . . 40		5.2. Bearer Token Requests . . . . . . . . . . . . . . . . . . 40
	5.2.1. URI Query Parameter . . . . . . . . . . . . . . . . . 40		5.2.1. URI Query Parameter . . . . . . . . . . . . . . . . . 40
	5.2.2. Form-Encoded Body Parameter . . . . . . . . . . . . . 41		5.2.2. Form-Encoded Body Parameter . . . . . . . . . . . . . 41
	skipping to change at page 4, line 27 ¶		skipping to change at page 4, line 27 ¶
	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
	authenticate and gain access.		authenticate and gain access.
	Resource owners should not be required to share their credentials		Resource owners should not be required to share their credentials
	when granting third-party applications access to their protected		when granting third-party applications access to their protected
	resources. They should also have the ability to restrict access to a		resources. They should also have the ability to restrict access to a
	limited subset of the resources they control, to limit access		limited subset of the resources they control, to limit access
	duration, or to limit access to the methods supported by these		duration, or to limit access to the HTTP methods supported by these
	resources.		resources.
	OAuth provides a method for making authenticated HTTP requests using		OAuth provides a method for making authenticated HTTP requests using
	a token - an identifier used to denote an access grant with specific		a token - an identifier used to denote an access grant with specific
	scope, duration, and other attributes. Tokens are issued to third-		scope, duration, and other attributes. Tokens are issued to third-
	party clients by an authorization server with the approval of the		party clients by an authorization server with the approval of the
	resource owner. Instead of sharing their credentials with the		resource owner. Instead of sharing their credentials with the
	client, resource owners grant access by authenticating directly with		client, resource owners grant access by authenticating directly with
	the authorization server which in turn issues a token to the client.		the authorization server which in turn issues a token to the client.
	The client uses the token (and optional secret) to authenticate with		The client uses the token (and optional secret) to authenticate with
	the resource server and gain access.		the resource server and gain access.
	For example, a web user (resource owner) can grant a printing service		For example, a web user (resource owner) can grant a printing service
	(client) access to her protected photos stored at a photo sharing		(client) access to her protected photos stored at a photo sharing
	service (resource server), without sharing her username and password		service (resource server), without sharing her username and password
	with the printing service. Instead, she authenticates directly with		with the printing service. Instead, she authenticates directly with
	the photo sharing service (authorization server) which issues the		the photo sharing service (authorization server) which issues the
	printing service delegation-specific credentials (token).		printing service delegation-specific credentials (token).
	The use of OAuth with any other transport protocol than HTTP		This specification defines the use of OAuth over HTTP [RFC2616] (or
	[RFC2616] (or HTTP over TLS 1.0 as defined by [RFC2818] is undefined.		HTTP over TLS 1.0 as defined by [RFC2818]. Other specifications may
			extend it for use with other tranport protocols.
	2.1. Terminology		2.1. Terminology
	resource server		resource server
	An HTTP [RFC2616] server capable of accepting authenticated		An HTTP [RFC2616] server capable of accepting authenticated
	resource requests using the OAuth protocol.		resource requests using the OAuth protocol.
	protected resource		protected resource
	An access-restricted resource which can be obtained from a		An access-restricted resource which can be obtained from a
	resource server using an OAuth-authenticated request.		resource server using an OAuth-authenticated request.
	client		client
	An HTTP client capable of making authenticated requests for		An HTTP client capable of making authenticated requests for
	protected resources using the OAuth protocol.		protected resources using the OAuth protocol.
	resource owner		resource owner
	An entity capable of granting access to a protected resource.		An entity capable of granting access to a protected resource.
	end user		end-user
	A human resource owner.		A human resource owner.
	access token		access token
	A unique identifier used by the client to make authenticated		A unique identifier used by the client to make authenticated
	requests on behalf of the resource owner. Access tokens may		requests on behalf of the resource owner. Access tokens may
	have a matching secret.		have a matching secret.
			bearer token An access token without a matching secret, used to
			obtain access to a protected resource by simply presenting the
			access token as-is to the resource server.
	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.
	authorization endpoint		authorization endpoint
	The authorization server's HTTP endpoint capable of		The authorization server's HTTP endpoint capable of
	authenticating the resource owner and obtaining authorization.		authenticating the resource owner and obtaining authorization.
	skipping to change at page 7, line 21 ¶		skipping to change at page 7, line 21 ¶
	| | HTTP Request +---------------+		| | HTTP Request +---------------+
	| |--(C)--- with Access Token ------>| Resource |		| |--(C)--- with Access Token ------>| Resource |
	| | | Server |		| | | Server |
	| |<-(D)----- HTTP Response ---------| |		| |<-(D)----- HTTP Response ---------| |
	+--------+ +---------------+		+--------+ +---------------+
	Figure 2		Figure 2
	This specification defines a number of authorization flows to support		This specification defines a number of authorization flows to support
	different client types and scenarios. These authorization flows can		different client types and scenarios. These authorization flows can
	be separated into three groups: user delegation flows where the		be separated into three groups: user delegation flows, end-user
	client is acting on behalf of an end user, end user credentials flows		credentials flows, and autonomous flows.
	where the client uses the end user's credentials directly to obtain
	authorization, and autonomous flows where the client is acting for
	itself (the client is also the resource owner).
	Additional authorization flows may be defined by other specifications		Additional authorization flows may be defined by other specifications
	to cover different scenarios and client types.		to cover different scenarios and client types.
	The user delegation authorization flows defined by this		User delegation authorization enable clients to act on behalf of an
	specifications are:		end-user after obtaining authorization from the end-user. The user
			delegation flows defined by this specifications are:
	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), and therefore cannot		a user-agent (typically a web browser). This flow is described in
	receive incoming requests from the authorization server. This		Section 3.5.1.
	flow is described in Section 3.5.1.
	o Web Server Flow - This flow is optimized for cases where the		o Web Server Flow - This flow is optimized for clients that are part
	client is capable of receiving incoming HTTP requests (act as an		of a web server application, accessible via HTTP requests. This
	HTTP server). This flow is described in Section 3.5.2.		flow is described in Section 3.5.2.
	o Device Flow - This flow suitable for clients executing on limited		o Device Flow - This flow is suitable for clients executing on
	devices, but where the end user has separate access to a user-		limited devices, but where the end-user has separate access to a
	agent on another computer or device. This flow is described in		user-agent on another computer or device. This flow is described
	Section 3.5.3.		in Section 3.5.3.
	The end user credentials flow defined by this specification is:		End-user credentials flow enable clients with direct access to the
			end-user's credentials to exchange them for an access token without
			seeking additional authorization. These flows are only suitable when
			there is a high degree of trust between the end-user and the client.
			The end-user credentials flow defined by this specification is:
	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 described in Section 3.6.1.		and password. This flow is described in Section 3.6.1.
	The autonomous authorization flows defined by this specifications		Autonomous flows enable clients to act for their own behalf (the
	are:		client is also the resource owner). The autonomous authorization
			flows defined by this specifications are:
	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 3.7.1.		obtain an access token. This flow is described in Section 3.7.1.
	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 3.7.2.		Section 3.7.2.
	2.3. Example		2.3. Example
	skipping to change at page 8, line 49 ¶		skipping to change at page 9, line 5 ¶
	MUST level requirements but not all the SHOULD level requirements for		MUST level requirements but not all the SHOULD level requirements for
	its flows is said to be "conditionally compliant."		its flows is said to be "conditionally compliant."
	3. Obtaining an Access Token		3. Obtaining an Access Token
	The client obtains an access token by using one of the authorization		The client obtains an access token by using one of the authorization
	flows supported by the authorization server. The authorization flows		flows supported by the authorization server. The authorization flows
	all use the same authorization and token endpoints, each with a		all use the same authorization and token endpoints, each with a
	different set of request parameters and values.		different set of request parameters and values.
	When issuing an access token, the scope, duration, and other access		Access tokens have a scope, duration, and other access attributes
	attributes granted by the resource owner must be retained and		granted by the resource owner. These attributes MUST be enforced by
	enforced by the resource server when receiving a protected resource		the resource server when receiving a protected resource request, and
	request and by the authorization server when receiving a token		by the authorization server when receiving a token refresh request.
	refresh request made with the access token issued.
	In many cases it is desirable to issue access tokens with a shorter		In many cases it is desirable to issue access tokens with a shorter
	lifetime than the duration of the authorization grant. However, it		lifetime than the duration of the authorization grant. However, it
	may be undesirable to require the resource owner to authorize the		may be undesirable to require the resource owner to authorize the
	request again. Instead, the authorization server issues a refresh		request again. Instead, the authorization server issues a refresh
	token in addition to the access token. When the access token		token in addition to the access token. When the access token
	expires, the client can request a new access token without involving		expires, the client can request a new access token without involving
	the resource owner as long as the authorization grant is still valid.		the resource owner as long as the authorization grant is still valid.
	The token refresh method is described in Section 4.		The token refresh method is described in Section 4.
	3.1. Authorization Endpoint		3.1. Authorization Endpoint
	Clients direct the resource owner to the authorization endpoint to		Clients direct the resource owner to the authorization endpoint to
	approve their access request. Before granting access, the resource		approve their access request. Before granting access, the resource
	owner first authenticate with the authorization server. The way in		owner first authenticates with the authorization server. The way in
	which the authorization server authenticates the end user (e.g.		which the authorization server authenticates the end-user (e.g.
	username and password login, OpenID, session cookies) and in which		username and password login, OpenID, session cookies) and in which
	the authorization server obtains the end user's authorization,		the authorization server obtains the end-user's authorization,
	including whether it uses a secure channel such as TLS/SSL, is beyond		including whether it uses a secure channel such as TLS/SSL, is beyond
	the scope of this specification. However, the authorization server		the scope of this specification. However, the authorization server
	MUST first verify the identity of the end user.		MUST first verify the identity of the end-user.
	The URI of the authorization endpoint can be found in the service		The URI of the authorization endpoint can be found in the service
	documentation, or can be obtained by the client by making an		documentation, or can be obtained by the client by making an
	unauthorized protected resource request (from the "WWW-Authenticate"		unauthorized protected resource request (from the "WWW-Authenticate"
	response header auth-uri (Section 6.1.2) attribute).		response header auth-uri (Section 6.1.2) attribute).
	The authorization endpoint advertised by the resource server MAY		The authorization endpoint advertised by the resource server MAY
	include a query components as defined by [RFC3986] section 3.		include a query component as defined by [RFC3986] section 3.
	Since requests to the authorization endpoint result in user		Since requests to the authorization endpoint result in user
	authentication and the transmission of sensitive values, the		authentication and the transmission of sensitive values, the
	authorization server SHOULD require the use of a transport-layer		authorization server SHOULD require the use of a transport-layer
	mechanism such as TLS or SSL (or a secure channel with equivalent		mechanism such as TLS/SSL (or a secure channel with equivalent
	protections) when sending requests to the authorization endpoints.		protections) when sending requests to the authorization endpoints.
	3.2. Token Endpoint		3.2. Token Endpoint
	After obtaining authorization from the resource owner, clients		After obtaining authorization from the resource owner, clients
	request an access token from the authorization server's token		request an access token from the authorization server's token
	endpoint.		endpoint.
	The URI of the token endpoint can be found in the service		The URI of the token endpoint can be found in the service
	documentation, or can be obtained by the client by making an		documentation, or can be obtained by the client by making an
	unauthorized protected resource request (from the "WWW-Authenticate"		unauthorized protected resource request (from the "WWW-Authenticate"
	response header token-uri (Section 6.1.2) attribute).		response header token-uri (Section 6.1.2) attribute).
	The token endpoint advertised by the resource server MAY include a		The token endpoint advertised by the resource server MAY include a
	query components as defined by [RFC3986] section 3.		query component as defined by [RFC3986] section 3.
	Since requests to the token endpoint result in the transmission of		Since requests to the token endpoint result in the transmission of
	plain text credentials in the HTTP request and response, the		plain text credentials in the HTTP request and response, the
	authorization server MUST require the use of a transport-layer		authorization server MUST require the use of a transport-layer
	mechanism such as TLS or SSL (or a secure channel with equivalent		mechanism such as TLS/SSL (or a secure channel with equivalent
	protections) when sending requests to the token endpoints.		protections) when sending requests to the token endpoints.
	The authorization server MUST include the HTTP "Cache-Control"		The authorization server MUST include the HTTP "Cache-Control"
	response header field with a value of "no-store" in any response		response header field with a value of "no-store" in any response
	containing tokens, secrets, or other sensitive information.		containing tokens, secrets, or other sensitive information.
	3.3. Flow Parameters		3.3. Flow Parameters
	Clients should avoid making assumptions about the size of tokens and		The sizes of tokens and other values received from the authorization
	other values received from the authorization server, which are left		server, are left undefined by this specification. Clients should
	undefined by this specification. Servers should document the		avoid making assumptions about value sizes. Servers should document
	expected size of any value they issue.		the expected size of any value they issue.
			Unless otherwise noted, all the protocol parameter names and values
			are case sensitive.
	3.4. Client Credentials		3.4. Client Credentials
	When requesting access from the authorization server, the client		When requesting access from the authorization server, the client
	identifies itself using its authorization-server-issued client		identifies itself using its authorization-server-issued client
	credentials. The client credentials include a client identifier and		credentials. The client credentials include a client identifier and
	an OPTIONAL symmetric shared secret. The means through which the		an OPTIONAL symmetric shared secret. The means through which the
	client obtains these credentials are beyond the scope of this		client obtains these credentials are beyond the scope of this
	specification, but usually involve registration with the		specification, but usually involve registration with the
	authorization server.		authorization server.
	skipping to change at page 10, line 46 ¶		skipping to change at page 10, line 50 ¶
	The client identifier is used by the authorization server to		The client identifier is used by the authorization server to
	establish the identity of the client for the purpose of presenting		establish the identity of the client for the purpose of presenting
	information to the resource owner prior to granting access, as well		information to the resource owner prior to granting access, as well
	as for providing different service levels to different clients. They		as for providing different service levels to different clients. They
	can also be used to block unauthorized clients from requesting		can also be used to block unauthorized clients from requesting
	access.		access.
	Due to the nature of some clients, authorization servers SHOULD NOT		Due to the nature of some clients, authorization servers SHOULD NOT
	make assumptions about the confidentiality of client credentials		make assumptions about the confidentiality of client credentials
	without establishing trust with the client operator. Authorization		without establishing trust with the client operator. Authorization
	servers SHOULD NOT issue client secrets to the client incapable or		servers SHOULD NOT issue client secrets to clients incapable of
	keeping their secrets confidential.		keeping their secrets confidential.
	3.5. User Delegation Flows		3.5. User Delegation Flows
	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.		client access to its protected resources.
	3.5.1. User-Agent Flow		3.5.1. 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. The client is		browser using a scripting language such as JavaScript. These clients
	capable of interacting with the end user's user-agent but is		cannot keep client secrets confidential and the authentication of the
	incapable of receiving incoming requests from the authorization		client is based on the user-agent's same-origin policy.
	server (incapable of acting as an HTTP server).
	Instead of receiving incoming requests, the client requests the		Unlike other flows in which the client makes separate authorization
	authorization server to redirect the user-agent to another web server		and access token requests, the client received the access token as a
	or local resource accessible to the browser which is capable of		result of the authorization request in the form of an HTTP
	extracting the access token from the response and passing it to the		redirection. The client requests the authorization server to
	client.		redirect the user-agent to another web server or local resource
			accessible to the browser which is capable of extracting the access
			token from the response and passing it to the client.
	This user-agent flow does not utilize the client secret since the		This user-agent flow does not utilize the client secret since the
	client executables reside on the end user's computer or device which		client executables reside on the end-user's computer or device which
	makes the client secret accessible and exploitable. Because the		makes the client secret accessible and exploitable. Because the
	client is incapable of receiving incoming requests, the access token		access token is encoded into the redirection URI, it may be exposed
	is encoded into the redirection URI which exposes it to the end user		to the end-user and other applications residing on the computer or
	and other applications residing on the computer or device.		device.
	+----------+ Client Identifier +----------------+		+----------+ Client Identifier +----------------+
	| |>---(A)-- & Redirection URI --->| |		| |>---(A)-- & Redirection URI --->| |
	| | | |		| | | |
	End <--+ - - - +----(B)-- User authenticates -->| Authorization |		End <--+ - - - +----(B)-- User authenticates -->| Authorization |
	User | | | Server |		User | | | Server |
	| |<---(C)-- Redirect URI --------<| |		| |<---(C)-- Redirect URI --------<| |
	| Client | with Access Token | |		| Client | with Access Token | |
	| in | (w/ Optional Refresh Token) +----------------+		| in | (w/ Optional Refresh Token) +----------------+
	| Browser | in Fragment		| Browser | in Fragment
	skipping to change at page 12, line 4 ¶		skipping to change at page 12, line 22 ¶
	| 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 3		Figure 3
	The user-agent flow illustrated in Figure 3 includes the following		The user-agent flow illustrated in Figure 3 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 authorization server and
	includes its client identifier and redirection URI in the		includes its client identifier and redirection URI in the
	request.		request.
	(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 in the
	URI fragment.		URI fragment.
	(D) The user-agent follows the redirection instructions by making a		(D) The user-agent follows the redirection instructions by making a
	request to the web server which does not include the fragment.		request to the web server which does not include the fragment.
	The user-agent retains the fragment information locally.		The user-agent retains the fragment information locally.
	(E) The web server returns a web page containing a script capable of		(E) The web server returns a web page containing a script capable of
	extracting the access token from the URI fragment retained by		extracting the access token from the URI fragment retained by
	the user-agent.		the user-agent.
	(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.
	3.5.1.1. Client Requests Authorization		3.5.1.1. Client Requests Authorization
	In order for the end user to grant the client access, the client		In order for the end-user to grant the client access, the client
	sends the end user to the authorization server. The client		sends the end-user to the authorization server. The client
	constructs the request URI by adding the following URI query		constructs the request URI by adding the following URI query
	parameters to the user authorization endpoint URI:		parameters to the user authorization endpoint URI:
	type		type
	REQUIRED. The parameter value MUST be set to "user_agent"		REQUIRED. The parameter value MUST be set to "user_agent".
	(case sensitive).
	client_id		client_id
	REQUIRED. The client identifier as described in Section 3.4.		REQUIRED. The client identifier as described in Section 3.4.
	redirect_uri		redirect_uri
	REQUIRED unless a redirection URI has been established between		REQUIRED unless a redirection URI has been established between
	the client and authorization server via other means. An		the client and authorization server via other means. An
	absolute URI to which the authorization server will redirect		absolute URI to which the authorization server will redirect
	the user-agent to when the end user authorization step is		the user-agent to when the end-user authorization step is
	completed. The authorization server SOULD require the client		completed. The authorization server SHOULD require the client
	to pre-register their redirection URI. The redirection URI		to pre-register their redirection URI. The redirection URI
	MUST NOT includes a query component as defined by [RFC3986]		MUST NOT include a query component as defined by [RFC3986]
	section 3 if the "state" parameter is present.		section 3 if the "state" parameter is present.
	state		state
	OPTIONAL. An opaque value used by the client to maintain state		OPTIONAL. An opaque value used by the client to maintain state
	between the request and callback. The authorization server		between the request and callback. The authorization server
	includes this value when redirecting the user-agent back to the		includes this value when redirecting the user-agent back to the
	client.		client.
	immediate		immediate
	OPTIONAL. The parameter value must be set to "true" or "false"		OPTIONAL. The parameter value must be set to "true" or
	(case sensitive). If set to "true", the authorization server		"false". If set to "true", the authorization server MUST NOT
	MUST NOT prompt the end user to authenticate or approve access.		prompt the end-user to authenticate or approve access.
	Instead, the authorization server attempts to establish the end		Instead, the authorization server attempts to establish the
	user's identity via other means (e.g. browser cookies) and		end-user's identity via other means (e.g. browser cookies) and
	checks if the end user has previously approved an identical		checks if the end-user has previously approved an identical
	access request by the same client and if that access grant is		access request by the same client and if that access grant is
	still active. If the authorization server does not support an		still active. If the authorization server does not support an
	immediate check or if it is unable to establish the end user's		immediate check or if it is unable to establish the end-user's
	identity or approval status, it MUST deny the request without		identity or approval status, it MUST deny the request without
	prompting the end user. Defaults to "false" if omitted.		prompting the end-user. Defaults to "false" if omitted.
	secret_type		secret_type
	OPTIONAL. The access token secret type as described by		OPTIONAL. The access token secret type as described by
	Section 5.3. If omitted, the authorization server will issue a		Section 5.3. If omitted, the authorization server will issue a
	bearer token (an access token without a matching secret) as		bearer token (an access token without a matching secret) as
	described by Section 5.2.		described by Section 5.2.
	The client directs the end user to the constructed URI using an HTTP		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		redirection response, or by other means available to it via the end-
	user's user-agent. The request MUST use the HTTP "GET" method.		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		For example, the client directs the end-user's user-agent to make the
	following HTTPS request (line breaks are for display purposes only):		following HTTPS request (line breaks are for display purposes only):
	GET /authorize?type=user_agent&client_id=s6BhdRkqt3&		GET /authorize?type=user_agent&client_id=s6BhdRkqt3&
	redirect_uri=https%3A%2F%2FEexample%2Ecom%2Frd HTTP/1.1		redirect_uri=https%3A%2F%2FEexample%2Ecom%2Frd HTTP/1.1
	Host: server.example.com		Host: server.example.com
	If the client has previously registered a redirection URI with the		If the client has previously registered a redirection URI with the
	authorization server, the authorization server MUST verify that the		authorization server, the authorization server MUST verify that the
	redirection URI received matches the registered URI associated with		redirection URI received matches the registered URI associated with
	the client identifier.		the client identifier.
	The authorization server authenticates the end user and obtains an		The authorization server authenticates the end-user and obtains an
	authorization decision (by asking the end user or establishing		authorization decision (by asking the end-user or establishing
	approval via other means). The authorization server sends the end		approval via other means). The authorization server sends the end-
	user's user-agent to the provided client redirection URI using an		user's user-agent to the provided client redirection URI using an
	HTTP redirection response.		HTTP redirection response.
	3.5.1.1.1. End User Grants Authorization		3.5.1.1.1. End-user Grants Authorization
	If the end user authorizes the access request, the authorization		If the end-user authorizes the access request, the authorization
	server issues an access token and delivers it to the client by adding		server issues an access token and delivers it to the client by adding
	the following parameters, using the		the following parameters, using the
	"application/x-www-form-urlencoded" format as defined by		"application/x-www-form-urlencoded" format as defined by
	[W3C.REC-html40-19980424], to the redirection URI fragment:		[W3C.REC-html40-19980424], to the redirection URI fragment:
	access_token		access_token
	REQUIRED. The access token.		REQUIRED. The access token.
	expires_in		expires_in
	OPTIONAL. The duration in seconds of the access token		OPTIONAL. The duration in seconds of the access token
	skipping to change at page 14, line 36 ¶		skipping to change at page 15, line 14 ¶
	state		state
	REQUIRED if the "state" parameter was present in the client		REQUIRED if the "state" parameter was present in the client
	authorization request. Set to the exact value received from		authorization request. Set to the exact value received from
	the client.		the client.
	access_token_secret		access_token_secret
	REQUIRED if requested by the client. The corresponding access		REQUIRED if requested by the client. The corresponding access
	token secret as requested by the client.		token secret as requested by the client.
	For example, the authorization server redirects the end user's user-		For example, the authorization server redirects the end-user's user-
	agent by sending the following HTTP response:		agent by sending the following HTTP response:
	HTTP/1.1 302 Found		HTTP/1.1 302 Found
	Location: http://example.com/rd#access_token=FJQbwq9&expires_in=3600		Location: http://example.com/rd#access_token=FJQbwq9&expires_in=3600
	3.5.1.1.2. End User Denies Authorization		3.5.1.1.2. End-user Denies Authorization
	If the end user denied the access request, the authorization server		If the end-user denied the access request, the authorization server
	responds to the client by adding the following parameters, using the		responds to the client by adding the following parameters, using the
	"application/x-www-form-urlencoded" format as defined by		"application/x-www-form-urlencoded" format as defined by
	[W3C.REC-html40-19980424], to the redirection URI fragment:		[W3C.REC-html40-19980424], to the redirection URI fragment:
	error		error
	REQUIRED. The parameter value MUST be set to "user_denied"		REQUIRED. The parameter value MUST be set to "user_denied".
	(case sensitive).
	state		state
	REQUIRED if the "state" parameter was present in the client		REQUIRED if the "state" parameter was present in the client
	authorization request. Set to the exact value received from		authorization request. Set to the exact value received from
	the client.		the client.
	For example, the authorization server responds with the following:		For example, the authorization server responds with the following:
	HTTP/1.1 302 Found		HTTP/1.1 302 Found
	Location: http://example.com/rd#error=user_denied		Location: http://example.com/rd#error=user_denied
	skipping to change at page 15, line 46 ¶		skipping to change at page 16, line 21 ¶
	The HTTP response to the redirection request returns a web page		The HTTP response to the redirection request returns a web page
	(typically an HTML page with an embedded script) capable of accessing		(typically an HTML page with an embedded script) capable of accessing
	the full redirection URI including the fragment retained by the user-		the full redirection URI including the fragment retained by the user-
	agent, and extracting the access token (and other parameters)		agent, and extracting the access token (and other parameters)
	contained in the fragment.		contained in the fragment.
	3.5.2. Web Server Flow		3.5.2. 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 |
	| Browser | | |		| Browser | | |
	| -+----(C)-- Verification Code ----<| |		| -+----(C)-- Verification Code ----<| |
	+-|----|---+ +---------------+		+-|----|---+ +---------------+
	| | ^ v		| | ^ v
	(A) (C) | |		(A) (C) | |
	| | | |		| | | |
	^ v | |		^ v | |
	+---------+ | |		+---------+ | |
	| |>---(D)-- Client Credentials, --------' |		| |>---(D)-- Client Credentials, --------' |
	skipping to change at page 16, line 29 ¶		skipping to change at page 17, line 5 ¶
	| Client | & Redirect URI |		| Client | & Redirect URI |
	| | |		| | |
	| |<---(E)------- Access Token -----------------'		| |<---(E)------- Access Token -----------------'
	+---------+ (w/ Optional Refresh Token)		+---------+ (w/ Optional Refresh Token)
	Figure 4		Figure 4
	The web server flow illustrated in Figure 4 includes the following		The web server flow illustrated in Figure 4 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 authorization endpoint with its client		user-agent to the authorization endpoint with its client
	identifier and a redirect URI to which the authorization server		identifier and a redirect URI to which the authorization server
	will send the end user back once authorization is received (or		will send the end-user back once authorization is received (or
	denied).		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 including its client credentials (identifier and
	secret), as well as the verification code received in the		secret), as well as the verification code received in the
	previous step.		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.
	3.5.2.1. Client Requests Authorization		3.5.2.1. Client Requests Authorization
	In order for the end user to grant the client access, the client		In order for the end-user to grant the client access, the client
	sends the end user to the authorization server. The client		sends the end-user to the authorization server. The client
	constructs the request URI by adding the following URI query		constructs the request URI by adding the following URI query
	parameters to the user authorization endpoint URI:		parameters to the user authorization endpoint URI:
	type		type
	REQUIRED. The parameter value MUST be set to "web_server"		REQUIRED. The parameter value MUST be set to "web_server".
	(case sensitive).
	client_id		client_id
	REQUIRED. The client identifier as described in Section 3.4.		REQUIRED. The client identifier as described in Section 3.4.
	redirect_uri		redirect_uri
	REQUIRED unless a redirection URI has been established between		REQUIRED unless a redirection URI has been established between
	the client and authorization server via other means. An		the client and authorization server via other means. An
	absolute URI to which the authorization server will redirect		absolute URI to which the authorization server will redirect
	the user-agent to when the end user authorization step is		the user-agent to when the end-user authorization step is
	completed. The authorization server MAY require the client to		completed. The authorization server MAY require the client to
	pre-register their redirection URI. The redirection URI MUST		pre-register their redirection URI. The redirection URI MUST
	NOT includes a query component as defined by [RFC3986] section		NOT include a query component as defined by [RFC3986] section 3
	3 if the "state" parameter is present.		if the "state" parameter is present.
	state		state
	OPTIONAL. An opaque value used by the client to maintain state		OPTIONAL. An opaque value used by the client to maintain state
	between the request and callback. The authorization server		between the request and callback. The authorization server
	includes this value when redirecting the user-agent back to the		includes this value when redirecting the user-agent back to the
	client.		client.
	immediate		immediate
	OPTIONAL. The parameter value must be set to "true" or "false"		OPTIONAL. The parameter value must be set to "true" or
	(case sensitive). If set to "true", the authorization server		"false". If set to "true", the authorization server MUST NOT
	MUST NOT prompt the end user to authenticate or approve access.		prompt the end-user to authenticate or approve access.
	Instead, the authorization server attempts to establish the end		Instead, the authorization server attempts to establish the
	user's identity via other means (e.g. browser cookies) and		end-user's identity via other means (e.g. browser cookies) and
	checks if the end user has previously approved an identical		checks if the end-user has previously approved an identical
	access request by the same client and if that access grant is		access request by the same client and if that access grant is
	still active. If the authorization server does not support an		still active. If the authorization server does not support an
	immediate check or if it is unable to establish the end user's		immediate check or if it is unable to establish the end-user's
	identity or approval status, it MUST deny the request without		identity or approval status, it MUST deny the request without
	prompting the end user. Defaults to "false" if omitted.		prompting the end-user. Defaults to "false" if omitted.
	The client directs the end user to the constructed URI using an HTTP		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		redirection response, or by other means available to it via the end-
	user's user-agent. The request MUST use the HTTP "GET" method.		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		For example, the client directs the end-user's user-agent to make the
	following HTTPS requests (line breaks are for display purposes only):		following HTTPS requests (line breaks are for display purposes only):
	GET /authorize?type=web_server&client_id=s6BhdRkqt3&redirect_uri=		GET /authorize?type=web_server&client_id=s6BhdRkqt3&redirect_uri=
	https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb HTTP/1.1		https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb HTTP/1.1
	Host: server.example.com		Host: server.example.com
	If the client has previously registered a redirection URI with the		If the client has previously registered a redirection URI with the
	authorization server, the authorization server MUST verify that the		authorization server, the authorization server MUST verify that the
	redirection URI received matches the registered URI associated with		redirection URI received matches the registered URI associated with
	the client identifier.		the client identifier.
	The authorization server authenticates the end user and obtains an		The authorization server authenticates the end-user and obtains an
	authorization decision (by asking the end user or establishing		authorization decision (by asking the end-user or establishing
	approval via other means). The authorization server sends the end		approval via other means). The authorization server sends the end-
	user's user-agent to the provided client redirection URI using an		user's user-agent to the provided client redirection URI using an
	HTTP redirection response, or by other means available to it via the		HTTP redirection response, or by other means available to it via the
	end user's user-agent.		end-user's user-agent.
	3.5.2.1.1. End User Grants Authorization		3.5.2.1.1. End-user Grants Authorization
	If the end user authorizes the access request, the authorization		If the end-user authorizes the access request, the authorization
	server generates a verification code and associates it with the		server generates a verification code and associates it with the
	client identifier and redirection URI. The authorization server		client identifier and redirection URI. The authorization server
	constructs the request URI by adding the following parameters to the		constructs the request URI by adding the following parameters to the
	query component of redirection URI provided by the client:		query component of redirection URI provided by the client:
	code		code
	REQUIRED. The verification code generated by the authorization		REQUIRED. The verification code generated by the authorization
	server.		server.
	state		state
	REQUIRED if the "state" parameter was present in the client		REQUIRED if the "state" parameter was present in the client
	authorization request. Set to the exact value received from		authorization request. Set to the exact value received from
	the client.		the client.
	The verification code SHOULD expire shortly after it is issued and		The verification code should expire shortly after it is issued and
	allowed for a single use.		allowed for a single use.
	For example, the authorization server redirects the end user's user-		For example, the authorization server redirects the end-user's user-
	agent by sending the following HTTP response:		agent by sending the following HTTP response:
	HTTP/1.1 302 Found		HTTP/1.1 302 Found
	Location: https://client.example.com/cb?code=i1WsRn1uB1		Location: https://client.example.com/cb?code=i1WsRn1uB1
	In turn, the end user's user-agent makes the following HTTPS "GET"		In turn, the end-user's user-agent makes the following HTTPS "GET"
	request:		request:
	GET /cb?code=i1WsRn1uB1 HTTP/1.1		GET /cb?code=i1WsRn1uB1 HTTP/1.1
	Host: client.example.com		Host: client.example.com
	3.5.2.1.2. End User Denies Authorization		3.5.2.1.2. End-user Denies Authorization
	If the end user denied the access request, the authorization server		If the end-user denied the access request, the authorization server
	constructs the request URI by adding the following parameters to the		constructs the request URI by adding the following parameters to the
	query component of the redirection URI provided by the client:		query component of the redirection URI provided by the client:
	error		error
	REQUIRED. The parameter value MUST be set to "user_denied"		REQUIRED. The parameter value MUST be set to "user_denied".
	(case sensitive).
	state		state
	REQUIRED if the "state" parameter was present in the client		REQUIRED if the "state" parameter was present in the client
	authorization request. Set to the exact value received from		authorization request. Set to the exact value received from
	the client.		the client.
	For example, the authorization server directs the client to make the		For example, the authorization server directs the client to make the
	following HTTP request:		following HTTP request:
	GET /cb?error=user_denied HTTP/1.1		GET /cb?error=user_denied HTTP/1.1
	skipping to change at page 19, line 42 ¶		skipping to change at page 20, line 15 ¶
	The authorization flow concludes unsuccessfully.		The authorization flow concludes unsuccessfully.
	3.5.2.2. Client Requests Access Token		3.5.2.2. Client Requests Access Token
	The client obtains an access token from the authorization server by		The client obtains an access token from the authorization server by
	making an HTTP "POST" request to the token endpoint. The client		making an HTTP "POST" request to the token endpoint. The client
	constructs a request URI by adding the following parameters to the		constructs a request URI by adding the following parameters to the
	request:		request:
	type		type
	REQUIRED. The parameter value MUST be set to "web_server"		REQUIRED. The parameter value MUST be set to "web_server".
	(case sensitive).
	client_id		client_id
	REQUIRED. The client identifier as described in Section 3.4.		REQUIRED. The client identifier as described in Section 3.4.
	client_secret		client_secret
	REQUIRED if the client identifier has a matching secret. The		REQUIRED if the client identifier has a matching secret. The
	client secret as described in Section 3.4.		client secret as described in Section 3.4.
	code		code
	REQUIRED. The verification code received from the		REQUIRED. The verification code received from the
	skipping to change at page 21, line 7 ¶		skipping to change at page 21, line 19 ¶
	access_token		access_token
	REQUIRED. The access token issued by the authorization server.		REQUIRED. The access token issued by the authorization server.
	expires_in		expires_in
	OPTIONAL. The duration in seconds of the access token		OPTIONAL. The duration in seconds of the access token
	lifetime.		lifetime.
	refresh_token		refresh_token
	OPTIONAL. The refresh token used to obtain new access tokens		OPTIONAL. The refresh token used to obtain new access tokens
	using the same end user access grant as described in Section 4.		using the same end-user access grant as described in Section 4.
	access_token_secret		access_token_secret
	REQUIRED if requested by the client. The corresponding access		REQUIRED if requested by the client. The corresponding access
	token secret as requested by the client.		token secret as requested by the client.
	For example:		For example:
	HTTP/1.1 200 OK		HTTP/1.1 200 OK
	Content-Type: application/x-www-form-urlencoded		Content-Type: application/x-www-form-urlencoded
	skipping to change at page 21, line 29 ¶		skipping to change at page 21, line 41 ¶
	If the request is invalid, the authorization server returns an error		If the request is invalid, the authorization server returns an error
	message in the HTTP response body using the		message in the HTTP response body using the
	"application/x-www-form-urlencoded" content type as defined by		"application/x-www-form-urlencoded" content type as defined by
	[W3C.REC-html40-19980424] with a 400 status code (Bad Request).		[W3C.REC-html40-19980424] with a 400 status code (Bad Request).
	The response contains the following parameter:		The response contains the following parameter:
	error		error
	OPTIONAL. The parameter value MUST be set to either		OPTIONAL. The parameter value MUST be set to either
	"redirect_uri_mismatch" or "expired_verification_code" (case		"redirect_uri_mismatch", "bad_verification_code",
	sensitive).		"incorrect_client_credentials".
	For example:		For example:
	HTTP/1.1 400 Bad Request		HTTP/1.1 400 Bad Request
	Content-Type: application/x-www-form-urlencoded		Content-Type: application/x-www-form-urlencoded
	error=expired_verification_code		error=bad_verification_code
	3.5.3. Device Flow		3.5.3. Device Flow
	The device flow is a user delegation flow suitable for clients		The device flow is a user delegation flow suitable for clients
	executing on devices which do not have an easy data-entry method		executing on devices which do not have an easy data-entry method
	(e.g. game consoles or media hub), but where the end user has		(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.		separate access to a user-agent on another computer or device (e.g.
	home computer, a laptop, or a smartphone). The client is incapable		home computer, a laptop, or a smartphone). The client is incapable
	of receiving incoming requests from the authorization server		of receiving incoming requests from the authorization server
	(incapable of acting as an HTTP server).		(incapable of acting as an HTTP server).
	Instead of interacting with the end user's user-agent, the client		Instead of interacting with the end-user's user-agent, the client
	instructs the end user to use another computer or device and connect		instructs the end-user to use another computer or device and connect
	to the authorization server to approve the access request. Since the		to the authorization server to approve the access request. Since the
	client cannot receive incoming requests, it polls the authorization		client cannot receive incoming requests, it polls the authorization
	server repeatedly until the end user completes the approval process.		server repeatedly until the end-user completes the approval process.
	This device flow does not utilize the client secret since the client		This device flow does not utilize the client secret since the client
	executables reside on a local device which makes the client secret		executables reside on a local device which makes the client secret
	accessible and exploitable.		accessible and exploitable.
	+----------+ +----------------+		+----------+ +----------------+
	| |>---(A)-- Client Identifier --->| |		| |>---(A)-- Client Identifier --->| |
	| | | |		| | | |
	| |<---(B)-- Verification Code, --<| |		| |<---(B)-- Verification Code, --<| |
	| | User Code, | |		| | User Code, | |
	skipping to change at page 22, line 32 ¶		skipping to change at page 22, line 45 ¶
	| |>---(E)---> | |		| |>---(E)---> | |
	| | | Authorization |		| | | Authorization |
	| |<---(F)-- Access Token --------<| Server |		| |<---(F)-- Access Token --------<| Server |
	+----------+ (w/ Optional Refresh Token) | |		+----------+ (w/ Optional Refresh Token) | |
	v | |		v | |
	: | |		: | |
	(C) User Code & Verification URI | |		(C) User Code & Verification URI | |
	: | |		: | |
	v | |		v | |
	+----------+ | |		+----------+ | |
	| End User | | |		| End-user | | |
	| at |<---(D)-- User authenticates -->| |		| at |<---(D)-- User authenticates -->| |
	| Browser | | |		| Browser | | |
	+----------+ +----------------+		+----------+ +----------------+
	Figure 5		Figure 5
	The device flow illustrated in Figure 5 includes the following steps:		The device flow illustrated in Figure 5 includes the following steps:
	(A) The client requests access from the authorization server and		(A) The client requests access from the authorization server and
	includes its client identifier in the request.		includes its client identifier in the request.
	(B) The authorization server issues a verification code, a user		(B) The authorization server issues a verification code, a user
	code, and provides the end user authorization URI.		code, and provides the end-user authorization URI.
	(C) The client instructs the end user to use its user-agent		(C) The client instructs the end-user to use its user-agent
	(elsewhere) and visit the provided authorization URI. The		(elsewhere) and visit the provided authorization URI. The
	client provides the user with the user code to enter in order to		client provides the user with the user code to enter in order to
	grant access.		grant access.
	(D) The authorization server authenticates the end user (via the		(D) The authorization server authenticates the end-user (via the
	user-agent) and prompts the end user to grant the client's		user-agent) and prompts the end-user to grant the client's
	access request by entering the user code provided by the client.		access request by entering the user code provided by the client.
	(E) While the end user authorizes (or denies) the client's request		(E) While the end-user authorizes (or denies) the client's request
	(D), the client repeatedly polls the authorization server to		(D), the client repeatedly polls the authorization server to
	find out if the end user completed the user authorization step.		find out if the end-user completed the user authorization step.
	The client includes the verification code and its client		The client includes the verification code and its client
	identifier.		identifier.
	(F) Assuming the end user granted access, the authorization server		(F) Assuming the end-user granted access, the authorization server
	validates the verification code provided by the client and		validates the verification code provided by the client and
	responds back with the access token.		responds back with the access token.
	3.5.3.1. Client Requests Authorization		3.5.3.1. Client Requests Authorization
	The client initiates the flow by requesting a set of verification		The client initiates the flow by requesting a set of verification
	codes from the authorization server by making an HTTP "GET" request		codes from the authorization server by making an HTTP "GET" request
	to the authorization endpoint. The client constructs a request URI		to the token endpoint. The client constructs a request URI by adding
	by adding the following parameters to the request:		the following parameters to the request:
	type		type
	REQUIRED. The parameter value MUST be set to 'device' (case		REQUIRED. The parameter value MUST be set to "device_code".
	sensitive).
	client_id		client_id
	REQUIRED. The client identifier as described in Section 3.4.		REQUIRED. The client identifier as described in Section 3.4.
	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):
	GET /authorize?type=device&client_id=s6BhdRkqt3		GET /token?type=device_code&client_id=s6BhdRkqt3
	HTTP/1.1		HTTP/1.1
	Host: server.example.com		Host: server.example.com
	In response, the authorization server generates a verification code		In response, the authorization server generates a verification code
	and a user code and includes them in the HTTP response body using the		and a user code and includes them in the HTTP response body using the
	"application/x-www-form-urlencoded" format as defined by		"application/x-www-form-urlencoded" format as defined by
	[W3C.REC-html40-19980424] with a 200 status code (OK). The response		[W3C.REC-html40-19980424] with a 200 status code (OK). The response
	contains the following parameters:		contains the following parameters:
	code		code
	skipping to change at page 24, line 26 ¶		skipping to change at page 24, line 35 ¶
	interval		interval
	OPTIONAL. The minimum amount of time in seconds that the		OPTIONAL. The minimum amount of time in seconds that the
	client SHOULD wait between polling requests to the token		client SHOULD wait between polling requests to the token
	endpoint.		endpoint.
	For example (line breaks are for display purposes only):		For example (line breaks are for display purposes only):
	HTTP/1.1 200 OK		HTTP/1.1 200 OK
	Content-Type: application/x-www-form-urlencoded		Content-Type: application/x-www-form-urlencoded
	device_code=74tq5miHKB&user_code=94248&user_uri=http%3A%2F%2		code=74tq5miHKB&user_code=94248&user_uri=http%3A%2F%2
	Fwww%2Eexample%2Ecom%2Fdevice&interval=5		Fwww%2Eexample%2Ecom%2Fdevice&interval=5
	The client displays the user code and the user authorization URI to		The client displays the user code and the user authorization URI to
	the end-user, and instructs the end user to visit the URI using a		the end-user, and instructs the end-user to visit the URI using a
	user-agent and enter the user code.		user-agent and enter the user code.
	The end user manually types the provided URI and authenticates with		The end-user manually types the provided URI and authenticates with
	the authorization server. The authorization server prompts the end		the authorization server. The authorization server prompts the end-
	user to authorize the client's request by entering the user code		user to authorize the client's request by entering the user code
	provided by the client. Once the end user approves or denies the		provided by the client. Once the end-user approves or denies the
	request, the authorization server informs the end user to return to		request, the authorization server informs the end-user to return to
	the device for further instructions.		the device for further instructions.
	3.5.3.2. Client Requests Access Token		3.5.3.2. Client Requests Access Token
	Since the client is unable to receive incoming requests from the		Since the client is unable to receive incoming requests from the
	authorization server, it polls the authorization server repeatedly		authorization server, it polls the authorization server repeatedly
	until the end user grants or denies the request, or the verification		until the end-user grants or denies the request, or the verification
	code expires.		code expires.
	The client makes the following request at an arbitrary but reasonable		The client makes the following request at an arbitrary but reasonable
	interval which MUST NOT exceed the minimum interval rate provided by		interval which MUST NOT exceed the minimum interval rate provided by
	the authorization server (if present via the "interval" parameter).		the authorization server (if present via the "interval" parameter).
	Alternatively, the client MAY provide a user interface for the end		Alternatively, the client MAY provide a user interface for the end-
	user to manually inform it when authorization was granted.		user to manually inform it when authorization was granted.
	The client requests an access token by making an HTTP "GET" request		The client requests an access token by making an HTTP "GET" request
	to the token endpoint. The client constructs a request URI by adding		to the token endpoint. The client constructs a request URI by adding
	the following parameters to the request:		the following parameters to the request:
	type		type
	REQUIRED. The parameter value MUST be set to 'device' (case		REQUIRED. The parameter value MUST be set to "device_token".
	sensitive).
	client_id		client_id
	REQUIRED. The client identifier as described in Section 3.4.		REQUIRED. The client identifier as described in Section 3.4.
	code		code
	The verification code received from the authorization server.		The verification code received from the authorization server.
	secret_type		secret_type
	OPTIONAL. The access token secret type as described by		OPTIONAL. The access token secret type as described by
	Section 5.3. If omitted, the authorization server will issue a		Section 5.3. If omitted, the authorization server will issue a
	bearer token (an access token without a matching secret) as		bearer token (an access token without a matching secret) as
	described by Section 5.2.		described by Section 5.2.
	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):
	GET /token?type=device&client_id=s6BhdRkqt3		GET /token?type=device_token&client_id=s6BhdRkqt3
	&code=J2vC42OifV HTTP/1.1		&code=J2vC42OifV HTTP/1.1
	Host: server.example.com		Host: server.example.com
	3.5.3.2.1. End User Grants Authorization		3.5.3.2.1. End-user Grants Authorization
	If the end user authorized the request, the authorization server		If the end-user authorized the request, the authorization server
	issues an access token and delivers it to the client by including it		issues an access token and delivers it to the client by including it
	in the HTTP response body using the		in the HTTP response body using the
	"application/x-www-form-urlencoded" content type as defined by		"application/x-www-form-urlencoded" content type as defined by
	[W3C.REC-html40-19980424] with a 200 status code (OK). The response		[W3C.REC-html40-19980424] with a 200 status code (OK). The response
	contains the following parameters:		contains the following parameters:
	access_token		access_token
	REQUIRED. The access token.		REQUIRED. The access token.
	expires_in		expires_in
	skipping to change at page 26, line 16 ¶		skipping to change at page 26, line 26 ¶
	REQUIRED if requested by the client. The corresponding access		REQUIRED if requested by the client. The corresponding access
	token secret as requested by the client.		token secret as requested by the client.
	For example:		For example:
	HTTP/1.1 200 OK		HTTP/1.1 200 OK
	Content-Type: application/x-www-form-urlencoded		Content-Type: application/x-www-form-urlencoded
	access_token=FJQbwq9OD8&expires_in=3600		access_token=FJQbwq9OD8&expires_in=3600
	3.5.3.2.2. End User Denies Authorization		3.5.3.2.2. End-user Denies Authorization
	If the end user denied the request, the authorization server provides		If the end-user denied the request, the authorization server provides
	the client with the error message in the HTTP response body using the		the client with the error message in the HTTP response body using the
	"application/x-www-form-urlencoded" content type as defined by		"application/x-www-form-urlencoded" content type as defined by
	[W3C.REC-html40-19980424] with a 400 status code (Bad Request). The		[W3C.REC-html40-19980424] with a 400 status code (Bad Request). The
	response contains the following parameters:		response contains the following parameters:
	error		error
	REQUIRED. Value must be set to "authorization_declined".		REQUIRED. Value must be set to "authorization_declined".
	For example:		For example:
	HTTP/1.1 400 Bad Request		HTTP/1.1 400 Bad Request
	Content-Type: application/x-www-form-urlencoded		Content-Type: application/x-www-form-urlencoded
	error=authorization_declined		error=authorization_declined
	3.5.3.2.3. End User Authorization Pending or Expired		3.5.3.2.3. End-user Authorization Pending or Expired
	If the end user authorization is pending or expired without receiving		If the end-user authorization is pending or expired without receiving
	any response from the end user, or the client is exceeding the		any response from the end-user, or the client is exceeding the
	allowed polling interval, the authorization server provides the		allowed polling interval, the authorization server provides the
	client with the error message in the HTTP response body using the		client with the error message in the HTTP response body using the
	"application/x-www-form-urlencoded" content type as defined by		"application/x-www-form-urlencoded" content type as defined by
	[W3C.REC-html40-19980424] with a 400 status code (Bad Request). The		[W3C.REC-html40-19980424] with a 400 status code (Bad Request). The
	response contains the following parameters:		response contains the following parameters:
	error		error
	REQUIRED. Value MUST be set to "authorization_pending",		REQUIRED. Value MUST be set to "authorization_pending",
	"slow_down", or "code_expired" (case sensitive).		"slow_down", or "code_expired".
	For example:		For example:
	HTTP/1.1 400 Bad Request		HTTP/1.1 400 Bad Request
	Content-Type: application/x-www-form-urlencoded		Content-Type: application/x-www-form-urlencoded
	error=authorization_pending		error=authorization_pending
	3.6. End User Credentials Flows		3.6. End-user Credentials Flows
	End user credential flows are used to grant client access to		End-user credential flows are used to grant client access to
	protected resources by the end user directly sharing the end user		protected resources by the end-user directly sharing the end-user's
	credentials (typically a username and password) with the client.		username and password with the client. Unlike user delegation flows,
	Unlike user delegation flows, end user credentials flows require a		end-user credentials flows require a much higher degree of trust
	much higher degree of trust between the client and end user.		between the client and end-user.
	These flows are suitable in cases where the end user already has a		These flows are suitable in cases where the end-user already has a
	trust relationship with the client, such as its computer operating		trust relationship with the client, such as its computer operating
	system or highly privileged applications. Authorization servers		system or highly privileged applications. Authorization servers
	SHOULD take special care when enabling user credentials flows, and		SHOULD take special care when enabling user credentials flows, and
	SHOULD only do so when other delegation flows are not viable.		SHOULD only do so when other delegation flows are not viable.
	However, unlike the HTTP Basic authentication scheme defined in		However, unlike the HTTP Basic authentication scheme defined in
	[RFC2617], the end user's credentials are used in a single request		[RFC2617], the end-user's credentials are used in a single request
	and are exchanged for an access token and refresh token which		and are exchanged for an access token and refresh token which
	eliminates the client need to store them for future use.		eliminates the client need to store them for future use.
	3.6.1. Username and Password Flow		3.6.1. Username and Password Flow
	The username and password flow is an end user credentials flow		The username and password flow is an end-user credentials flow
	suitable for clients capable of asking end users for their usernames		suitable for clients capable of asking end users for their usernames
	and passwords. It is also used to migrate existing clients using		and passwords. It is also used to migrate existing clients using
	direct authentication schemes such as HTTP Basic or Digest		direct authentication schemes such as HTTP Basic or Digest
	authentication to OAuth by converting the end user credentials stored		authentication to OAuth by converting the end-user credentials stored
	with tokens.		with tokens.
	The methods through which the client prompts end users for their		The methods through which the client prompts end users for their
	usernames and passwords is beyond the scope of this specification.		usernames and passwords is beyond the scope of this specification.
	The client MUST discard the usernames and passwords once an access		The client MUST discard the usernames and passwords once an access
	token has been obtained.		token has been obtained.
	End User		End-user
	v		v
	:		:
	(A)		(A)
	:		:
	v		v
	+--------+ +---------------+		+--------+ +---------------+
	| | Client Credentials | |		| | Client Credentials | |
	| |>--(B)--- & User Credentials ---->| Authorization |		| |>--(B)--- & User Credentials ---->| Authorization |
	| Client | | Server |		| Client | | Server |
	| |<--(C)---- Access Token ---------<| |		| |<--(C)---- Access Token ---------<| |
	| | (w/ Optional Refresh Token) | |		| | (w/ Optional Refresh Token) | |
	+--------+ +---------------+		+--------+ +---------------+
	Figure 6		Figure 6
	The username and password flow illustrated in Figure 6 includes the		The username and password flow illustrated in Figure 6 includes the
	following steps:		following steps:
	(A) The end user provides the client with its username and password.		(A) The end-user provides the client with its username and password.
	(B) The client sends an access token request to the authorization		(B) The client sends an access token request to the authorization
	server and includes its client identifier and client secret, and		server and includes its client identifier and client secret, and
	the end user's username and password.		the end-user's username and password.
	(C) The authorization server validates the end user credentials and		(C) The authorization server validates the end-user credentials and
	the client credentials and issues an access token.		the client credentials and issues an access token.
	3.6.1.1. Client Requests Access Token		3.6.1.1. Client Requests Access Token
	The client requests an access token by making an HTTP "POST" request		The client requests an access token by making an HTTP "POST" request
	to the token endpoint. The client constructs a request URI by adding		to the token endpoint. The client constructs a request URI by adding
	the following parameters to the request:		the following parameters to the request:
	type		type
	REQUIRED. The parameter value MUST be set to 'username' (case		REQUIRED. The parameter value MUST be set to "username".
	sensitive).
	client_id		client_id
	REQUIRED. The client identifier as described in Section 3.4.		REQUIRED. The client identifier as described in Section 3.4.
	client_secret		client_secret
	REQUIRED. The client secret as described in Section 3.4.		REQUIRED. The client secret as described in Section 3.4.
	OPTIONAL if no client secret was issued.		OPTIONAL if no client secret was issued.
	username		username
	REQUIRED. The end user's username.		REQUIRED. The end-user's username.
	password		password
	REQUIRED. The end user's password.		REQUIRED. The end-user's password.
	secret_type		secret_type
	OPTIONAL. The access token secret type as described by		OPTIONAL. The access token secret type as described by
	Section 5.3. If omitted, the authorization server will issue a		Section 5.3. If omitted, the authorization server will issue a
	bearer token (an access token without a matching secret) as		bearer token (an access token without a matching secret) as
	described by Section 5.2.		described by Section 5.2.
	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
	type=username&client_id=s6BhdRkqt3&client_secret=		type=username&client_id=s6BhdRkqt3&client_secret=
	47HDu8s&username=johndoe&password=A3ddj3w		47HDu8s&username=johndoe&password=A3ddj3w
	The authorization server MUST validate the client credentials and end		The authorization server MUST validate the client credentials and
	user credentials and if valid issue an access token and deliver to		end-user credentials and if valid issue an access token and deliver
	the client in the HTTP response body using the		to the client in the HTTP response body using the
	"application/x-www-form-urlencoded" content type as defined by		"application/x-www-form-urlencoded" content type as defined by
	[W3C.REC-html40-19980424] with a 200 status code (OK).		[W3C.REC-html40-19980424] with a 200 status code (OK).
	The response contains the following parameters:		The response contains the following parameters:
	access_token		access_token
	REQUIRED. The access token.		REQUIRED. The access token.
	expires_in		expires_in
	OPTIONAL. The duration in seconds of the access token		OPTIONAL. The duration in seconds of the access token
	skipping to change at page 30, line 21 ¶		skipping to change at page 30, line 21 ¶
	If the request is invalid, the authorization server returns an error		If the request is invalid, the authorization server returns an error
	message in the HTTP response body using the		message in the HTTP response body using the
	"application/x-www-form-urlencoded" content type as defined by		"application/x-www-form-urlencoded" content type as defined by
	[W3C.REC-html40-19980424] with a 400 status code (Bad Request).		[W3C.REC-html40-19980424] with a 400 status code (Bad Request).
	The response contains the following parameter:		The response contains the following parameter:
	error		error
	OPTIONAL. The parameter value MUST be set to either		OPTIONAL. The parameter value MUST be set to either
	"incorrect_credentials" or "unauthorized_client" (case		"incorrect_client_credentials" or "unauthorized_client" (the
	sensitive).		client is not permitted to use this flow).
	For example:		For example:
	HTTP/1.1 400 Bad Request		HTTP/1.1 400 Bad Request
	Content-Type: application/x-www-form-urlencoded		Content-Type: application/x-www-form-urlencoded
	error=incorrect_credentials		error=incorrect_client_credentials
	3.7. Autonomous Client Flows		3.7. Autonomous Client Flows
	Autonomous client flows are used to grant client access to protected		Autonomous client flows are used to grant client access to protected
	resources controlled by the client (i.e. the client is the resource		resources controlled by the client (i.e. the client is the resource
	owner). For example, these flows are useful when a service provides		owner). For example, these flows are useful when a service provides
	both client-specific resources in addition to end user resources.		both client-specific resources in addition to end-user resources.
	3.7.1. Client Credentials Flow		3.7.1. Client Credentials Flow
	The client credentials flow is used when the client acts autonomously		The client credentials flow is used when the client acts autonomously
	without acting on behalf of a separate resource owner. The client		without acting on behalf of a separate resource owner. The client
	secret is assumed to be high-entropy since it is not designed to be		secret is assumed to be high-entropy since it is not designed to be
	memorize by an end user.		memorized by an end-user.
	+--------+ +---------------+		+--------+ +---------------+
	| | | |		| | | |
	| |>--(A)--- Client Credentials ---->| Authorization |		| |>--(A)--- Client Credentials ---->| Authorization |
	| Client | | Server |		| Client | | Server |
	| |<--(B)---- Access Token ---------<| |		| |<--(B)---- Access Token ---------<| |
	| | (w/ Optional Refresh Token) | |		| | (w/ Optional Refresh Token) | |
	+--------+ +---------------+		+--------+ +---------------+
	Figure 7		Figure 7
	skipping to change at page 31, line 31 ¶		skipping to change at page 31, line 31 ¶
	(B) The authorization server validates the client credentials and		(B) The authorization server validates the client credentials and
	issues an access token.		issues an access token.
	3.7.1.1. Client Requests Access Token		3.7.1.1. Client Requests Access Token
	The client requests an access token by making an HTTP "POST" request		The client requests an access token by making an HTTP "POST" request
	to the token endpoint. The client constructs a request URI by adding		to the token endpoint. The client constructs a request URI by adding
	the following parameters to the request:		the following parameters to the request:
	type		type
	REQUIRED. The parameter value MUST be set to 'client_cred'		REQUIRED. The parameter value MUST be set to
	(case sensitive).		"client_credentials".
	client_id		client_id
	REQUIRED. The client identifier as described in Section 3.4.		REQUIRED. The client identifier as described in Section 3.4.
	client_secret		client_secret
	REQUIRED. The client secret as described in Section 3.4.		REQUIRED. The client secret as described in Section 3.4.
	secret_type		secret_type
	OPTIONAL. The access token secret type as described by		OPTIONAL. The access token secret type as described by
	Section 5.3. If omitted, the authorization server will issue a		Section 5.3. If omitted, the authorization server will issue a
	bearer token (an access token without a matching secret) as		bearer token (an access token without a matching secret) as
	described by Section 5.2.		described by Section 5.2.
	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
	type=client_cred&client_id=s6BhdRkqt3&client_secret=47HDu8s		type=client_credentials&client_id=s6BhdRkqt3&client_secret=47HDu8s
	The authorization server MUST validate the client credentials and if		The authorization server MUST validate the client credentials and if
	valid issue an access token and deliver to the client in the HTTP		valid issue an access token and deliver to the client in the HTTP
	response body using the "application/x-www-form-urlencoded" content		response body using the "application/x-www-form-urlencoded" content
	type as defined by [W3C.REC-html40-19980424] with a 200 status code		type as defined by [W3C.REC-html40-19980424] with a 200 status code
	(OK).		(OK).
	The response contains the following parameters:		The response contains the following parameters:
	access_token		access_token
	skipping to change at page 33, line 6 ¶		skipping to change at page 33, line 6 ¶
	access_token=FJQbwq9OD8		access_token=FJQbwq9OD8
	If the request is invalid, the authorization server returns an error		If the request is invalid, the authorization server returns an error
	message in the HTTP response body using the		message in the HTTP response body using the
	"application/x-www-form-urlencoded" content type as defined by		"application/x-www-form-urlencoded" content type as defined by
	[W3C.REC-html40-19980424] with a 400 status code (Bad Request).		[W3C.REC-html40-19980424] with a 400 status code (Bad Request).
	The response contains the following parameter:		The response contains the following parameter:
	error		error
	OPTIONAL. The parameter value MUST be set to either		OPTIONAL. The parameter value MUST be set to
	"incorrect_credentials" or "unauthorized_client" (case		"incorrect_client_credentials".
	sensitive).
	For example:		For example:
	HTTP/1.1 400 Bad Request		HTTP/1.1 400 Bad Request
	Content-Type: application/x-www-form-urlencoded		Content-Type: application/x-www-form-urlencoded
	error=incorrect_credentials		error=incorrect_client_credentials
	3.7.2. Assertion Flow		3.7.2. Assertion Flow
	The assertion flow requires the client to obtain a assertion such as		The assertion flow is used when a client wishes to exchange an
	a SAML [OASIS.saml-core-2.0-os] assertion from an assertion issuer		existing security token or assertion for an access token. This flow
	prior to initiating the flow. The process in which the assertion is		is suitable when the client is acting autonomously or on behalf of
	obtained is defined by the assertion issuer and the authorization		the end-user (based on the content of the assertion used).
	server, and is beyond the scope of this specification.
			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.
	The client credentials flow is used when the client acts autonomously		The client credentials flow is used when the client acts autonomously
	without acting on behalf of a separate resource owner.		without acting on behalf of a separate resource owner.
	+--------+ +---------------+		+--------+ +---------------+
	| | | |		| | | |
	| |>--(A)------ Assertion ---------->| Authorization |		| |>--(A)------ Assertion ---------->| Authorization |
	| Client | | Server |		| Client | | Server |
	| |<--(B)---- Access Token ---------<| |		| |<--(B)---- Access Token ---------<| |
	| | (w/ Optional Refresh Token) | |		| | | |
	+--------+ +---------------+		+--------+ +---------------+
	Figure 8		Figure 8
	The client credential flow illustrated in Figure 8 includes the		The client credential flow illustrated in Figure 8 includes the
	following steps:		following steps:
	(A) The client sends an access token request to the authorization		(A) The client sends an access token request to the authorization
	server and includes an assertion.		server and includes an assertion.
	(B) The authorization server validates the assertion and issues an		(B) The authorization server validates the assertion and issues an
	access token.		access token.
	3.7.2.1. Client Requests Access Token		3.7.2.1. Client Requests Access Token
	The client requests an access token by making an HTTP "POST" request		The client requests an access token by making an HTTP "POST" request
	to the token endpoint. The client constructs a request URI by adding		to the token endpoint. The client constructs a request URI by adding
	the following parameters to the request:		the following parameters to the request:
	type		type
	REQUIRED. The parameter value MUST be set to 'assertion' (case		REQUIRED. The parameter value MUST be set to "assertion".
	sensitive).
	format		format
	REQUIRED. The format of the assertion as defined by the		REQUIRED. The format of the assertion as defined by the
	authorization server.		authorization server. The value MUST be an absolute URI.
	assertion		assertion
	REQUIRED. The assertion.		REQUIRED. The assertion.
	secret_type		secret_type
	OPTIONAL. The access token secret type as described by		OPTIONAL. The access token secret type as described by
	Section 5.3. If omitted, the authorization server will issue a		Section 5.3. If omitted, the authorization server will issue a
	bearer token (an access token without a matching secret) as		bearer token (an access token without a matching secret) as
	described by Section 5.2.		described by Section 5.2.
	skipping to change at page 35, line 5 ¶		skipping to change at page 35, line 9 ¶
	The response contains the following parameters:		The response contains the following parameters:
	access_token		access_token
	REQUIRED. The access token.		REQUIRED. The access token.
	expires_in		expires_in
	OPTIONAL. The duration in seconds of the access token		OPTIONAL. The duration in seconds of the access token
	lifetime.		lifetime.
	refresh_token
	OPTIONAL. The refresh token.
	access_token_secret		access_token_secret
	REQUIRED if requested by the client. The corresponding access		REQUIRED if requested by the client. The corresponding access
	token secret as requested by the client.		token secret as requested by the client.
	For example:		For example:
	HTTP/1.1 200 OK		HTTP/1.1 200 OK
	Content-Type: application/x-www-form-urlencoded		Content-Type: application/x-www-form-urlencoded
	access_token=FJQbwq9OD8		access_token=FJQbwq9OD8
	If the assertion is invalid, the authorization server returns an		If the assertion is invalid, the authorization server returns an
	error message in the HTTP response body using the		error message in the HTTP response body using the
	"application/x-www-form-urlencoded" content type as defined by		"application/x-www-form-urlencoded" content type as defined by
	[W3C.REC-html40-19980424] with a 400 status code (Bad Request).		[W3C.REC-html40-19980424] with a 400 status code (Bad Request).
	The response contains the following parameter:		The response contains the following parameter:
	error		error
	OPTIONAL. The parameter value MUST be set to either		OPTIONAL. The parameter value MUST be set to either
	"invalid_assertion" or "unknown_format" (case sensitive).		"invalid_assertion" or "unknown_format".
	For example:		For example:
	HTTP/1.1 400 Bad Request		HTTP/1.1 400 Bad Request
	Content-Type: application/x-www-form-urlencoded		Content-Type: application/x-www-form-urlencoded
	error=incorrect_credentials		error=incorrect_credentials
	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
	skipping to change at page 35, line 49 ¶		skipping to change at page 36, line 4 ¶
	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.
	4. Refreshing an Access Token		4. 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 allows clients to
	obtain a new access token without having to go through the		obtain a new access token without having to go through the
	authorization flow again or involve the resource owner. It is also		authorization flow again or involve the resource owner. It is also
	used to obtain a new token with different security properties (e.g.		used to obtain a new token with different security properties (e.g.
	bearer token, token with shared symmetric secret).		bearer token, token with shared symmetric secret).
	+--------+ Client Credentials, +---------------+		+--------+ Client Credentials, +---------------+
	| | Refresh Token, | |		| | Refresh Token, | |
	| |>--(A)----- & Secret Type ------->| Authorization |		| |>--(A)----- & Secret Type ------->| Authorization |
	| Client | | Server |		| Client | | Server |
	| |<--(B)----- Access Token --------<| |		| |<--(B)----- Access Token --------<| |
	| | & Optional Secret | |		| | & Optional Secret | |
	+--------+ +---------------+		+--------+ +---------------+
	Figure 9		Figure 9
	To refresh a token, the client constructs an HTTP "POST" request to		To refresh a token, the client constructs an HTTP "POST" request to
	the token endpoint and includes the following parameters in the HTTP		the token endpoint and includes the following parameters in the HTTP
	request body using the "application/x-www-form-urlencoded" content		request body using the "application/x-www-form-urlencoded" content
	type as defined by [W3C.REC-html40-19980424]:		type as defined by [W3C.REC-html40-19980424]:
	type		type
	REQUIRED. The parameter value MUST be set to 'refresh' (case		REQUIRED. The parameter value MUST be set to "refresh".
	sensitive).
	client_id		client_id
	REQUIRED. The client identifier as described in Section 3.4.		REQUIRED. The client identifier as described in Section 3.4.
	client_secret		client_secret
	REQUIRED if the client was issued a secret. The 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.
	secret_type		secret_type
	OPTIONAL. The access token secret type as described by		OPTIONAL. The access token secret type as described by
	Section 5.3. If omitted, the authorization server will issue a		Section 5.3. If omitted, the authorization server will issue a
	bearer token (an access token without a matching secret) as		bearer token (an access token without a matching secret) as
	described by Section 5.2.		described by Section 5.2.
	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 /authorize 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		type=refresh_token&client_id=s6BhdRkqt3&client_secret=8eSEIpnqmM
	&refresh_token=n4E9O119d&secret_type=hmac-sha256		&refresh_token=n4E9O119d&secret_type=hmac-sha256
	The authorization server MUST verify the client credential, the		The authorization server MUST verify the client credential, the
	validity of the refresh token, and that the resource owner's		validity of the refresh token, and that the resource owner's
	authorization is still valid. If the request is valid, the		authorization is still valid. If the request is valid, the
	authorization server issues a new access token and includes the		authorization server issues a new access token and includes the
	skipping to change at page 37, line 41 ¶		skipping to change at page 37, line 41 ¶
	If the request fails verification, the authorization server returns		If the request fails verification, the authorization server returns
	an error message in the HTTP response body using the		an error message in the HTTP response body using the
	"application/x-www-form-urlencoded" content type as defined by		"application/x-www-form-urlencoded" content type as defined by
	[W3C.REC-html40-19980424] with a 400 status code (Bad Request).		[W3C.REC-html40-19980424] with a 400 status code (Bad Request).
	The response contains the following parameter:		The response contains the following parameter:
	error		error
	OPTIONAL. The parameter value MUST be set to either		OPTIONAL. The parameter value MUST be set to either
	"incorrect_credentials", "authorization_expired", or		"incorrect_credentials", "authorization_expired", or
	"unsupported_secret_type" (case sensitive).		"unsupported_secret_type".
	For example:		For example:
	HTTP/1.1 400 Bad Request		HTTP/1.1 400 Bad Request
	Content-Type: application/x-www-form-urlencoded		Content-Type: application/x-www-form-urlencoded
	error=incorrect_credentials		error=incorrect_credentials
	5. Accessing a Protected Resource		5. 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 methods used by the resource server to		the resource server. The methods used by the resource server to
	validate the access token are beyond the scope of this specification,		validate the access token are beyond the scope of this specification,
	but generally involve an interaction or coordination between the		but generally involve an interaction or coordination between the
	resource server and authorization server.		resource server and authorization server.
	The method in which a client uses an access token depends on the		The method in which a client uses an access token depends on the
	security properties of the access tokens. By default, access tokens		security properties of the access tokens. By default, access tokens
	are issued without a matching secret. Clients MAY request an access		are issued without a matching secret. Clients MAY request an access
	token with a matchin secret by specifying the desired secret type		token with a matching secret by specifying the desired secret type
	using the "secret_type" token request parameter.		using the "secret_type" token request parameter.
	When an access token does not include a matching secret, the access		When an access token does not include a matching secret, the access
	token acts as a bearer token, where the token string is a shared		token acts as a bearer token, where the token string is a shared
	symmetric secret. This requires treating the access token with the		symmetric secret. This requires treating the access token with the
	same care as other secrets (e.g. user passwords). Access tokens		same care as other secrets (e.g. user passwords). Access tokens
	SHOULD NOT be sent in the clear over an insecure channel.		SHOULD NOT be sent in the clear over an insecure channel.
	However, when it is necessary to transmit bearer tokens in the clear		However, when it is necessary to transmit bearer tokens in the clear
	without a secure channel, authorization servers must issue access		without a secure channel, authorization servers SHOULD issue access
	tokens with limited scope and lifetime to reduce the potential risk		tokens with limited scope and lifetime to reduce the potential risk
	from a compromised access token. Clients SHOULD request and utilize		from a compromised access token. Clients SHOULD request and utilize
	an access token with a matching secret when making protected resource		an access token with a matching secret when making protected resource
	requests over an insecure channel (e.g. an HTTP request without using		requests over an insecure channel (e.g. an HTTP request without using
	SSL/TLS).		TLS/SSL).
	When an access token includes a matching secret, the secret is not		When an access token includes a matching secret, the secret is not
	included directly in the request but is used instead to generate a		included directly in the request but is used instead to generate a
	cryptographic signature of the request. The signature can only be		cryptographic signature of the request. The signature can only be
	generated and verified by entities with access to the secret.		generated and verified by entities with access to the secret.
	Clients SHOULD NOT make authenticated requests with an access token		Clients SHOULD NOT make authenticated requests with an access token
	to unfamiliar resource servers, especially when using bearer tokens,		to unfamiliar resource servers, especially when using bearer tokens,
	regardless of the presence of a secure channel.		regardless of the presence of a secure channel.
	skipping to change at page 41, line 8 ¶		skipping to change at page 41, line 8 ¶
	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 includes the requested resource. If the resource		not expired and its scope includes the requested resource. If the
	expired or is not valid, the resource server MUST reply with an HTTP		resource expired or is not valid, the resource server MUST reply with
	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 6.1.		"WWW-Authenticate" response header as described in Section 6.1.
	5.2.2. Form-Encoded Body Parameter		5.2.2. 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.
	skipping to change at page 41, line 45 ¶		skipping to change at page 41, line 45 ¶
	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 includes the requested resource. If the resource		not expired and its scope includes the requested resource. If the
	expired or is not valid, the resource server MUST reply with an HTTP		resource expired or is not valid, the resource server MUST reply with
	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 6.1.		"WWW-Authenticate" response header as described in Section 6.1.
	5.3. Cryptographic Tokens Requests		5.3. Cryptographic Tokens Requests
	Clients make authenticated protected resource requests using an		Clients make authenticated protected resource requests using an
	access token with a matching secret by calculating a set of values		access token with a matching secret by calculating a set of values
	and including them in the request using the "Authorization" header		and including them in the request using the "Authorization" header
	field. The way clients calculate these values depends on the access		field. The way clients calculate these values depends on the access
	token secret type as issued by the authorization server.		token secret type as issued by the authorization server.
	This specification defines the "hmac-sha256" algorithm, and		This specification defines the "hmac-sha256" algorithm, and
	establishes a registry for providing additional algorithms. Clients		establishes a registry for providing additional algorithms. Clients
	obtain an access token with a matchin "hmac-sha256" secret by using		obtain an access token with a matching "hmac-sha256" secret by using
	the "token_type" parameter when requesting an access token.		the "token_type" parameter when requesting an access token.
	5.3.1. The 'hmac-sha256' Algorithm		5.3.1. The 'hmac-sha256' Algorithm
	The "hmac-sha256" algorithm uses the HMAC method as defined in		The "hmac-sha256" algorithm uses the HMAC method as defined in
	[RFC2104] together with the SHA-256 hash function defined in [NIST		[RFC2104] together with the SHA-256 hash function defined in [NIST
	FIPS-180-3] to apply the access token secret to the request and		FIPS-180-3] to apply the access token secret to the request and
	generate a signature value that is included in the request instead of		generate a signature value that is included in the request instead of
	transmitting the secret in the clear.		transmitting the secret in the clear.
	skipping to change at page 44, line 9 ¶		skipping to change at page 44, line 9 ¶
	concatenation of several of the HTTP request elements into a single		concatenation of several of the HTTP request elements into a single
	string. The string is used as an input to the selected cryptographic		string. The string is used as an input to the selected cryptographic
	method and includes the HTTP request method (e.g. "GET", "POST",		method and includes the HTTP request method (e.g. "GET", "POST",
	etc.), the authority as declared by the HTTP "Host" request header,		etc.), the authority as declared by the HTTP "Host" request header,
	and the request resource URI.		and the request resource URI.
	The normalized request string does not cover the entire HTTP request.		The normalized request string does not cover the entire HTTP request.
	Most notably, it does not include the entity-body or most HTTP		Most notably, it does not include the entity-body or most HTTP
	entity-headers. It is important to note that the resource server		entity-headers. It is important to note that the resource server
	cannot verify the authenticity of the excluded request elements		cannot verify the authenticity of the excluded request elements
	without using additional protections such as SSL/TLS.		without using additional protections such as TLS/SSL.
	The normalized request string is constructed by concatenating		The normalized request string is constructed by concatenating
	together, in order, the following HTTP request elements, separated by		together, in order, the following HTTP request elements, separated by
	the "," character (ASCII code 44):		the "," character (ASCII code 44):
	1. The request timestamp as described in Section 5.3.1.1.		1. The request timestamp as described in Section 5.3.1.1.
	2. The request nonce as described in Section 5.3.1.1.		2. The request nonce as described in Section 5.3.1.1.
	3. The cryptographic algorithm used.		3. The cryptographic algorithm used.
	skipping to change at page 47, line 9 ¶		skipping to change at page 47, line 9 ¶
	[[ Add OAuth 1.0a authors + WG contributors ]]		[[ Add OAuth 1.0a authors + WG contributors ]]
	Appendix A. Differences from OAuth 1.0a		Appendix A. Differences from OAuth 1.0a
	[[ Todo ]]		[[ Todo ]]
	Appendix B. Document History		Appendix B. Document History
	[[ to be removed by RFC editor before publication as an RFC ]]		[[ to be removed by RFC editor before publication as an RFC ]]
			-01
			o Editorial changes based on feedback from Brian Eaton, Bill Keenan,
			and Chuck Mortimore.
			o Changed devide flow "type" parameter values and switch to use only
			the token endpoint.
	-00		-00
	o Initial draft based on a combination of WRAP and OAuth 1.0a.		o Initial draft based on a combination of WRAP and OAuth 1.0a.
	10. References		10. References
	10.1. 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.,
End of changes. 146 change blocks.
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