Network Working Group M. Jones
Internet-Draft Microsoft
Intended status: Standards Track D. Hardt
Expires: April 21, 2012 independent
D. Recordon
Facebook
October 19, 2011
The OAuth 2.0 Authorization Protocol: Bearer Tokens
draft-ietf-oauth-v2-bearer-10
Abstract
This specification describes how to use bearer tokens in HTTP
requests to access OAuth 2.0 protected resources. Any party in
possession of a bearer token (a "bearer") can use it to get access to
granted resources (without demonstrating possession of a
cryptographic key). To prevent misuse, the bearer token MUST be
protected from disclosure in storage and in transport.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 21, 2012.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
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to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 3
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
1.3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Authenticated Requests . . . . . . . . . . . . . . . . . . . . 5
2.1. The Authorization Request Header Field . . . . . . . . . . 5
2.2. Form-Encoded Body Parameter . . . . . . . . . . . . . . . 5
2.3. URI Query Parameter . . . . . . . . . . . . . . . . . . . 6
3. The WWW-Authenticate Response Header Field . . . . . . . . . . 7
3.1. Error Codes . . . . . . . . . . . . . . . . . . . . . . . 8
4. Security Considerations . . . . . . . . . . . . . . . . . . . 9
4.1. Security Threats . . . . . . . . . . . . . . . . . . . . . 9
4.2. Threat Mitigation . . . . . . . . . . . . . . . . . . . . 9
4.3. Summary of Recommendations . . . . . . . . . . . . . . . . 10
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
5.1. OAuth Access Token Type Registration . . . . . . . . . . . 11
5.1.1. The "Bearer" OAuth Access Token Type . . . . . . . . . 11
5.2. Authentication Scheme Registration . . . . . . . . . . . . 12
5.2.1. The "Bearer" Authentication Scheme . . . . . . . . . . 12
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
6.1. Normative References . . . . . . . . . . . . . . . . . . . 12
6.2. Informative References . . . . . . . . . . . . . . . . . . 13
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 14
Appendix B. Document History . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18
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1. Introduction
OAuth enables clients to access protected resources by obtaining an
access token, which is defined in [I-D.ietf-oauth-v2] as "a string
representing an access authorization issued to the client", rather
than using the resource owner's credentials directly.
Tokens are issued to clients by an authorization server with the
approval of the resource owner. The client uses the access token to
access the protected resources hosted by the resource server. This
specification describes how to make protected resource requests when
the OAuth access token is a bearer token.
This specification defines the use of bearer tokens with OAuth over
HTTP [RFC2616] using TLS [RFC5246]. Other specifications may extend
it for use with other transport protocols.
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], which is based upon the Augmented
Backus-Naur Form (ABNF) notation of [RFC5234]. Additionally, the
following rules are included from [I-D.ietf-httpbis-p7-auth]:
b64token, auth-param, and realm; from
[I-D.ietf-httpbis-p1-messaging]: quoted-string; and from [RFC3986]:
URI-Reference.
Unless otherwise noted, all the protocol parameter names and values
are case sensitive.
1.2. Terminology
Bearer Token
A security token with the property that any party in possession of
the token (a "bearer") can use the token in any way that any other
party in possession of it can. Using a bearer token does not
require a bearer to prove possession of cryptographic key material
(proof-of-possession).
All other terms are as defined in [I-D.ietf-oauth-v2].
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1.3. Overview
OAuth provides a method for clients to access a protected resource on
behalf of a resource owner. In the general case, before a client can
access a protected resource, it must first obtain an authorization
grant from the resource owner and then exchange the authorization
grant for an access token. The access token represents the grant's
scope, duration, and other attributes granted by the authorization
grant. The client accesses the protected resource by presenting the
access token to the resource server. In some cases, a client can
directly present its own credentials to an authorization server to
obtain an access token without having to first obtain an
authorization grant from a resource owner.
The access token provides an abstraction layer, replacing different
authorization constructs (e.g. username and password, assertion) for
a single token understood by the resource server. This abstraction
enables issuing access tokens valid for a short time period, as well
as removing the resource server's need to understand a wide range of
authentication schemes.
+--------+ +---------------+
| |--(A)- Authorization Request ->| Resource |
| | | Owner |
| |<-(B)-- Authorization Grant ---| |
| | +---------------+
| |
| | Authorization Grant & +---------------+
| |--(C)--- Client Credentials -->| Authorization |
| Client | | Server |
| |<-(D)----- Access Token -------| |
| | +---------------+
| |
| | +---------------+
| |--(E)----- Access Token ------>| Resource |
| | | Server |
| |<-(F)--- Protected Resource ---| |
+--------+ +---------------+
Figure 1: Abstract Protocol Flow
The abstract flow illustrated in Figure 1 describes the overall OAuth
2.0 protocol architecture. The following steps are specified within
this document:
E) The client makes a protected resource request to the resource
server by presenting the access token.
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F) The resource server validates the access token, and if valid,
serves the request.
2. Authenticated Requests
Clients MAY use bearer tokens to make authenticated requests to
access protected resources. This section defines three methods of
sending bearer access tokens in resource requests to resource
servers. Clients MUST NOT use more than one method to transmit the
token in each request
2.1. The Authorization Request Header Field
When sending the access token in the "Authorization" request header
field defined by [I-D.ietf-httpbis-p7-auth], the client uses the
"Bearer" authentication scheme to transmit the access token.
For example:
GET /resource HTTP/1.1
Host: server.example.com
Authorization: Bearer vF9dft4qmT
The "Authorization" header field uses the framework defined by
[I-D.ietf-httpbis-p7-auth] follows:
credentials = "Bearer" 1*SP b64token
Clients SHOULD make authenticated requests with a bearer token using
the "Authorization" request header field with the "Bearer" HTTP
authorization scheme. Resource servers MUST support this method.
2.2. Form-Encoded Body Parameter
When sending the access token in the HTTP request entity-body, the
client adds the access token to the request body using the
"access_token" parameter. The client MUST NOT use this method unless
all of the following conditions are met:
o The HTTP request entity-body is single-part.
o The entity-body follows the encoding requirements of the
"application/x-www-form-urlencoded" content-type as defined by
[W3C.REC-html401-19991224].
o The HTTP request entity-header includes the "Content-Type" header
field set to "application/x-www-form-urlencoded".
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o The HTTP request method is one for which the request body has
defined semantics. In particular, this means that the "GET"
method MUST NOT be used.
The entity-body MAY include other request-specific parameters, in
which case, the "access_token" parameter MUST be properly separated
from the request-specific parameters using "&" character(s) (ASCII
code 38).
For example, the client makes the following HTTP request using
transport-layer security:
POST /resource HTTP/1.1
Host: server.example.com
Content-Type: application/x-www-form-urlencoded
access_token=vF9dft4qmT
The "application/x-www-form-urlencoded" method SHOULD NOT be used
except in application contexts where participating browsers do not
have access to the "Authorization" request header field. Resource
servers MAY support this method.
2.3. URI Query Parameter
When sending the access token in the HTTP request URI, the client
adds the access token to the request URI query component as defined
by [RFC3986] using the "access_token" parameter.
For example, the client makes the following HTTP request using
transport-layer security:
GET /resource?access_token=vF9dft4qmT HTTP/1.1
Host: server.example.com
The HTTP request URI query can include other request-specific
parameters, in which case, the "access_token" parameter MUST be
properly separated from the request-specific parameters using "&"
character(s) (ASCII code 38).
For example:
https://server.example.com/resource?x=y&access_token=vF9dft4qmT&p=q
Because of the Security Considerations (Section 4) associated with
the URI method, it SHOULD NOT be used unless it is the only feasible
method. Resource servers MAY support this method.
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3. The WWW-Authenticate Response Header Field
If the protected resource request does not include authentication
credentials or does not contain an access token that enables access
to the protected resource, the resource server MUST include the HTTP
"WWW-Authenticate" response header field; it MAY include it in
response to other conditions as well. The "WWW-Authenticate" header
field uses the framework defined by [I-D.ietf-httpbis-p7-auth] as
follows:
challenge = "Bearer" [ 1*SP 1#param ]
param = realm / scope /
error / error-desc / error-uri /
auth-param
scope = "scope" "=" <"> scope-val *( SP scope-val ) <">
scope-val = 1*scope-val-char
scope-val-char = %x21 / %x23-5B / %x5D-7E
; HTTPbis P1 qdtext except whitespace, restricted to US-ASCII
error = "error" "=" quoted-string
error-desc = "error_description" "=" <"> *error-desc-char <">
error-desc-char = SP / VCHAR
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. The "scope" value is intended for programmatic use and is not
meant to be displayed to end users.
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 3.1. In addition, the resource server MAY include the
"error_description" attribute to provide developers a human-readable
explanation that is not meant to be displayed to end users. It also
MAY include 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
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WWW-Authenticate: Bearer realm="example"
And in response to a protected resource request with an
authentication attempt using an expired access token:
HTTP/1.1 401 Unauthorized
WWW-Authenticate: Bearer realm="example",
error="invalid_token",
error_description="The access token expired"
3.1. Error Codes
When a request fails, the resource server responds using the
appropriate HTTP status code (typically, 400, 401, or 403), and
includes one of the following error codes in the response:
invalid_request
The request is missing a required parameter, includes an
unsupported parameter or parameter value, repeats the same
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
The access token provided is expired, revoked, malformed, or
invalid for other reasons. The resource SHOULD respond with
the HTTP 401 (Unauthorized) status code. The client MAY
request a new access token and retry the protected resource
request.
insufficient_scope
The request requires higher privileges than provided by the
access token. The resource server SHOULD respond with the HTTP
403 (Forbidden) status code and MAY include the "scope"
attribute with the scope necessary to access the protected
resource.
If the request lacks any authentication information (i.e. the client
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:
HTTP/1.1 401 Unauthorized
WWW-Authenticate: Bearer realm="example"
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4. Security Considerations
This section describes the relevant security threats regarding token
handling when using bearer tokens and describes how to mitigate these
threats.
4.1. Security Threats
The following list presents several common threats against protocols
utilizing some form of tokens. This list of threats is based on NIST
Special Publication 800-63 [NIST800-63]. Since this document builds
on the OAuth 2.0 specification, we exclude a discussion of threats
that are described there or in related documents.
Token manufacture/modification: An attacker may generate a bogus
token or modify the token contents (such as the authentication or
attribute statements) of an existing token, causing the resource
server to grant inappropriate access to the client. For example,
an attacker may modify the token to extend the validity period; a
malicious client may modify the assertion to gain access to
information that they should not be able to view.
Token disclosure: Tokens may contain authentication and attribute
statements that include sensitive information.
Token redirect: An attacker uses a token generated for consumption
by one resource server to gain access to a different resource
server that mistakenly believes the token to be for it.
Token replay: An attacker attempts to use a token that has already
been used with that resource server in the past.
4.2. Threat Mitigation
A large range of threats can be mitigated by protecting the contents
of the token by using a digital signature or a Message Authentication
Code (MAC). Alternatively, a bearer token can contain a reference to
authorization information, rather than encoding the information
directly. Such references MUST be infeasible for an attacker to
guess; using a reference may require an extra interaction between a
server and the token issuer to resolve the reference to the
authorization information. The mechanics of such an interaction are
not defined by this specification.
This document does not specify the encoding or the contents of the
token; hence detailed recommendations for token integrity protection
are outside the scope of this document. We assume that the token
integrity protection is sufficient to prevent the token from being
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modified.
To deal with token redirect, it is important for the authorization
server to include the identity of the intended recipients (the
audience), typically a single resource server (or a list of resource
servers), in the token. Restricting the use of the token to a
specific scope is also recommended.
To provide protection against token disclosure, confidentiality
protection is applied via TLS [RFC5246] with a ciphersuite that
offers confidentiality protection. This requires that the
communication interaction between the client and the authorization
server, as well as the interaction between the client and the
resource server, utilize confidentiality protection. Since TLS is
mandatory to implement and to use with this specification, it is the
preferred approach for preventing token disclosure via the
communication channel. For those cases where the client is prevented
from observing the contents of the token, token encryption MUST be
applied in addition to the usage of TLS protection.
To deal with token capture and replay, the following recommendations
are made: First, the lifetime of the token MUST be limited by putting
a validity time field inside the protected part of the token. Note
that using short-lived (one hour or less) tokens reduces the impact
of them being leaked. Second, confidentiality protection of the
exchanges between the client and the authorization server and between
the client and the resource server MUST be applied, for instance,
through the use of TLS [RFC5246]. As a consequence, no eavesdropper
along the communication path is able to observe the token exchange.
Consequently, such an on-path adversary cannot replay the token.
Furthermore, when presenting the token to a resource server, the
client MUST verify the identity of that resource server, as per
[RFC2818]. Note that the client MUST validate the TLS certificate
chain when making these requests to protected resources. Presenting
the token to an unauthenticated and unauthorized resource server or
failing to validate the certificate chain will allow adversaries to
steal the token and gain unauthorized access to protected resources.
4.3. Summary of Recommendations
Safeguard bearer tokens Client implementations MUST ensure that
bearer tokens are not leaked to unintended parties, as they will
be able to use them to gain access to protected resources. This
is the primary security consideration when using bearer tokens and
underlies all the more specific recommendations that follow.
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Validate SSL certificate chains The client MUST validate the TLS
certificate chain when making requests to protected resources.
Failing to do so may enable DNS hijacking attacks to steal the
token and gain unintended access.
Always use TLS (https) Clients MUST always use TLS [RFC5246] (https)
or equivalent transport security when making requests with bearer
tokens. Failing to do so exposes the token to numerous attacks
that could give attackers unintended access.
Don't store bearer tokens in cookies Implementations MUST NOT store
bearer tokens within cookies that can be sent in the clear (which
is the default transmission mode for cookies). Implementations
that do store bearer tokens in cookies MUST take precautions
against cross site request forgery.
Issue short-lived bearer tokens Token servers SHOULD issue short-
lived (one hour or less) bearer tokens, particularly when issuing
tokens to clients that run within a web browser or other
environments where information leakage may occur. Using short-
lived bearer tokens can reduce the impact of them being leaked.
Issue scoped bearer tokens Token servers SHOULD issue bearer tokens
that contain an audience restriction, scoping their use to the
intended relying party or set of relying parties.
Don't pass bearer tokens in page URLs Bearer tokens SHOULD NOT be
passed in page URLs (for example as query string parameters).
Instead, bearer tokens SHOULD be passed in HTTP message headers or
message bodies for which confidentiality measures are taken.
Browsers, web servers, and other software may not adequately
secure URLs in the browser history, web server logs, and other
data structures. If bearer tokens are passed in page URLs,
attackers might be able to steal them from the history data, logs,
or other unsecured locations.
5. IANA Considerations
5.1. OAuth Access Token Type Registration
This specification registers the following access token type in the
OAuth Access Token Type Registry.
5.1.1. The "Bearer" OAuth Access Token Type
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Type name:
Bearer
Additional Token Endpoint Response Parameters:
(none)
HTTP Authentication Scheme(s):
Bearer
Change controller:
IETF
Specification document(s):
[[ this document ]]
5.2. Authentication Scheme Registration
This specification registers the following authentication scheme in
the Authentication Scheme Registry defined in
[I-D.ietf-httpbis-p7-auth].
5.2.1. The "Bearer" Authentication Scheme
Authentication Scheme Name:
Bearer
Pointer to specification text:
[[ this document ]]
Notes (optional):
(none)
6. References
6.1. Normative References
[I-D.ietf-httpbis-p1-messaging]
Fielding, R., Gettys, J., Mogul, J., Nielsen, H.,
Masinter, L., Leach, P., Berners-Lee, T., Reschke, J., and
Y. Lafon, "HTTP/1.1, part 1: URIs, Connections, and
Message Parsing", draft-ietf-httpbis-p1-messaging-16 (work
in progress), August 2011.
[I-D.ietf-httpbis-p7-auth]
Fielding, R., Gettys, J., Mogul, J., Nielsen, H.,
Masinter, L., Leach, P., Berners-Lee, T., Reschke, J., and
Y. Lafon, "HTTP/1.1, part 7: Authentication",
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draft-ietf-httpbis-p7-auth-16 (work in progress),
August 2011.
[I-D.ietf-oauth-v2]
Hammer-Lahav, E., Recordon, D., and D. Hardt, "The OAuth
2.0 Authorization Protocol", draft-ietf-oauth-v2-22 (work
in progress), September 2011.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005.
[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, January 2008.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008.
[W3C.REC-html401-19991224]
Raggett, D., Hors, A., and I. Jacobs, "HTML 4.01
Specification", World Wide Web Consortium
Recommendation REC-html401-19991224, December 1999,
<http://www.w3.org/TR/1999/REC-html401-19991224>.
6.2. Informative References
[NIST800-63]
Burr, W., Dodson, D., Perlner, R., Polk, T., Gupta, S.,
and E. Nabbus, "NIST Special Publication 800-63-1,
INFORMATION SECURITY", December 2008.
[RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S.,
Leach, P., Luotonen, A., and L. Stewart, "HTTP
Authentication: Basic and Digest Access Authentication",
RFC 2617, June 1999.
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Appendix A. Acknowledgements
The following people contributed to preliminary versions of this
document: Blaine Cook (BT), Brian Eaton (Google), Yaron Y. Goland
(Microsoft), Brent Goldman (Facebook), Raffi Krikorian (Twitter),
Luke Shepard (Facebook), and Allen Tom (Yahoo!). The content and
concepts within are a product of the OAuth community, the WRAP
community, and the OAuth Working Group.
The OAuth Working Group has dozens of very active contributors who
proposed ideas and wording for this document, including: Michael
Adams, Amanda Anganes, Andrew Arnott, Dirk Balfanz, Brian Campbell,
Leah Culver, Bill de hOra, Brian Ellin, Igor Faynberg, George
Fletcher, Tim Freeman, Evan Gilbert, Justin Hart, John Kemp, Eran
Hammer-Lahav, Chasen Le Hara, Michael B. Jones, Torsten Lodderstedt,
Eve Maler, James Manger, Laurence Miao, Chuck Mortimore, Anthony
Nadalin, Justin Richer, Peter Saint-Andre, Nat Sakimura, Rob Sayre,
Marius Scurtescu, Naitik Shah, Justin Smith, Jeremy Suriel, Christian
Stuebner, Paul Tarjan, and Franklin Tse.
Appendix B. Document History
[[ to be removed by the RFC editor before publication as an RFC ]]
-10
o Removed the #auth-param option from Authorization header syntax
(leaving only the b64token syntax).
o Restricted the "scope" value character set to %x21 / %x23-5B /
%x5D-7E (printable ASCII characters excluding double-quote and
backslash). Indicated that scope is intended for programmatic use
and is not meant to be displayed to end users.
o Restricted the character set for "error_description" strings to SP
/ VCHAR and indicated that they are not meant to be displayed to
end users.
o Included more description in the Abstract, since Hannes Tschofenig
indicated that the RFC editor would require this.
o Changed "Access Grant" to "Authorization Grant", as was done in
the core spec.
o Simplified the introduction to the Authenticated Requests section.
-09
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o Incorporated working group last call comments. Specific changes
were:
o Use definitions from [I-D.ietf-httpbis-p7-auth] rather than
[RFC2617].
o Update credentials definition to conform to
[I-D.ietf-httpbis-p7-auth].
o Further clarified that query parameters may occur in any order.
o Specify that error_description is UTF-8 encoded (matching the core
specification).
o Registered "Bearer" Authentication Scheme in Authentication Scheme
Registry defined by [I-D.ietf-httpbis-p7-auth].
o Updated references to oauth-v2, httpbis-p1-messaging, and httpbis-
p7-auth drafts.
o Other wording improvements not introducing normative changes.
-08
o Updated references to oauth-v2 and httpbis drafts.
-07
o Added missing comma in error response example.
-06
o Changed parameter name "bearer_token" to "access_token", per
working group consensus.
o Changed HTTP status code for "invalid_request" error code from
HTTP 401 (Unauthorized) back to HTTP 400 (Bad Request), per input
from HTTP working group experts.
-05
o Removed OAuth Errors Registry, per design team input.
o Changed HTTP status code for "invalid_request" error code from
HTTP 400 (Bad Request) to HTTP 401 (Unauthorized) to match HTTP
usage [[ change pending working group consensus ]].
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o Added missing quotation marks in error-uri definition.
o Added note to add language and encoding information to
error_description if the core specification does.
o Explicitly reference the Augmented Backus-Naur Form (ABNF) defined
in [RFC5234].
o Use auth-param instead of repeating its definition, which is (
token "=" ( token / quoted-string ) ).
o Clarify security considerations about including an audience
restriction in the token and include a recommendation to issue
scoped bearer tokens in the summary of recommendations.
-04
o Edits responding to working group last call feedback on -03.
Specific edits enumerated below.
o Added Bearer Token definition in Terminology section.
o Changed parameter name "oauth_token" to "bearer_token".
o Added realm parameter to "WWW-Authenticate" response to comply
with [RFC2617].
o Removed "[ RWS 1#auth-param ]" from "credentials" definition since
it did not comply with the ABNF in [I-D.ietf-httpbis-p7-auth].
o Removed restriction that the "bearer_token" (formerly
"oauth_token") parameter be the last parameter in the entity-body
and the HTTP request URI query.
o Do not require WWW-Authenticate Response in a reply to a malformed
request, as an HTTP 400 Bad Request response without a WWW-
Authenticate header is likely the right response in some cases of
malformed requests.
o Removed OAuth Parameters registry extension.
o Numerous editorial improvements suggested by working group
members.
-03
o Restored the WWW-Authenticate response header functionality
deleted from the framework specification in draft 12 based upon
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Internet-Draft OAuth 2.0 Bearer Tokens October 2011
the specification text from draft 11.
o Augmented the OAuth Parameters registry by adding two additional
parameter usage locations: "resource request" and "resource
response".
o Registered the "oauth_token" OAuth parameter with usage location
"resource request".
o Registered the "error" OAuth parameter.
o Created the OAuth Error registry and registered errors.
o Changed the "OAuth2" OAuth access token type name to "Bearer".
-02
o Incorporated feedback received on draft 01. Most changes were to
the security considerations section. No normative changes were
made. Specific changes included:
o Changed terminology from "token reuse" to "token capture and
replay".
o Removed sentence "Encrypting the token contents is another
alternative" from the security considerations since it was
redundant and potentially confusing.
o Corrected some references to "resource server" to be
"authorization server" in the security considerations.
o Generalized security considerations language about obtaining
consent of the resource owner.
o Broadened scope of security considerations description for
recommendation "Don't pass bearer tokens in page URLs".
o Removed unused reference to OAuth 1.0.
o Updated reference to framework specification and updated David
Recordon's e-mail address.
o Removed security considerations text on authenticating clients.
o Registered the "OAuth2" OAuth access token type and "oauth_token"
parameter.
-01
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o First public draft, which incorporates feedback received on -00
including enhanced Security Considerations content. This version
is intended to accompany OAuth 2.0 draft 11.
-00
o Initial draft based on preliminary version of OAuth 2.0 draft 11.
Authors' Addresses
Michael B. Jones
Microsoft
Email: mbj@microsoft.com
URI: http://self-issued.info/
Dick Hardt
independent
Email: dick.hardt@gmail.com
URI: http://dickhardt.org/
David Recordon
Facebook
Email: dr@fb.com
URI: http://www.davidrecordon.com/
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