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