B. Campbell, Ed.
Internet-Draft                                       Ping Identity Corp.
Intended status: Standards Track                            C. Mortimore
Expires: November 24, 2011 February 2, 2012                                 Salesforce.com
                                                            May 23,
                                                                Aug 2011

            SAML 2.0 Bearer Assertion Grant Type Profile Profiles for OAuth 2.0
                    draft-ietf-oauth-saml2-bearer-04
                    draft-ietf-oauth-saml2-bearer-05

Abstract

   This specification defines the use of a SAML 2.0 Bearer Assertion as
   means for requesting an OAuth 2.0 access token. token as well as for use as
   a means of client authentication.

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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Notational Conventions . . . . . . . . . . . . . . . . . .  3  4
   2.  SAML Assertion Access Token Request  . . . . . . . .  HTTP Parameter Bindings for Transporting Assertions  . . . . .  4
     2.1.  Client Requests Access Token . . . .  Using SAML Assertions as Authorization Grants  . . . . . .  4
     2.2.  Using SAML Assertions for Client Authentication  . . . . .  4
     2.2.
   3.  Assertion Format and Processing Requirements . . . . . . .  5
     2.3.  Error Response . . .  5
     3.1.  Authorization Grant Processing . . . . . . . . . . . . . .  7
     3.2.  Client Authentication Processing . . . . .  7
     2.4.  Example (non-normative) . . . . . . . .  8
   4.  Authorization Grant Example (non-normative)  . . . . . . . . .  7
   3.  8
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . .  9
   4. 10
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  9
     4.1.  Parameter 10
     6.1.  Sub-Namspace Registration Request . . . . . . . of
           urn:ietf:params:oauth:grant-type:saml2-bearer  . . . . . . 10
     6.2.  Sub-Namspace Registration of
           urn:ietf:params:oauth:client-assertion-type:saml2-bearer .  9 10
   Appendix A.  Contributors  . . . . . . . . . . . . . . . . . . . .  9 11
   Appendix B.  Document History  . . . . . . . . . . . . . . . . . . 10
   5. 11
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
     5.1. 14
     7.1.  Normative References . . . . . . . . . . . . . . . . . . . 12
     5.2. 14
     7.2.  Informative References . . . . . . . . . . . . . . . . . . 12 15
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 15

1.  Introduction

   The Security Assertion Markup Language (SAML) 2.0
   [OASIS.saml-core-2.0-os] is an XML-based framework that allows
   identity and security information to be shared across security
   domains.  The SAML specification, while primarily targeted at
   providing cross domain Web browser single sign-on, was also designed
   to be modular and extensible to facilitate use in other contexts.

   The Assertion, an XML security token, is a fundamental construct of
   SAML that is often adopted for use in other protocols and
   specifications.  An Assertion is generally issued by an identity
   provider and consumed by a service provider who relies on its content
   to identify the Assertion's subject for security related purposes.

   The OAuth 2.0 Authorization Protocol [I-D.ietf.oauth-v2] provides a
   method for making authenticated HTTP requests to a resource using an
   access token.  Access tokens are issued to third-party clients by an
   authorization server (AS) with the (sometimes implicit) approval of
   the resource owner.  In OAuth, an authorization grant is an abstract
   term used to describe intermediate credentials that represent the
   resource owner authorization.  An authorization grant is used by the
   client to obtain an access token.  Several authorization grant types
   are defined to support a wide range of client types and user
   experiences.  OAuth also allows for the definition of new extension
   grant types to support additional clients or to provide a bridge
   between OAuth and other trust frameworks.  Finally, OAuth allows the
   definition of additional authentication mechanisms to be used by
   clients when interacting with the authorization server.

   The OAuth 2.0 Assertion Profile [I-D.ietf.oauth-assertions] is an
   abstract extension to OAuth 2.0 that provides a general framework for
   the use of assertions as client credentials and/or authorization
   grants with OAuth 2.0.  This specification defines profiles the OAuth 2.0
   Assertion Profile [I-D.ietf.oauth-assertions] to define an extension
   grant type that profiles the
   use of usues a SAML 2.0 Bearer Assertion in requesting to request an OAuth
   2.0 access
   token. token as well as for use as client credentials.  The
   format and processing rules for the SAML Assertion defined in this
   specification are intentionally similar, though not identical, to
   those in the Web Browser SSO Profile defined in SAML Profiles
   [OASIS.saml-profiles-2.0-os].  This specification is reusing, to the
   extent reasonable, concepts and patterns from that well-established
   Profile.

1.1.  Notational Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this

   This document are to be interpreted as described in RFC 2119 [RFC2119].

   Unless otherwise noted, all the protocol parameter names and values
   are case sensitive.

2.  SAML Assertion Access Token Request

   A defines how a SAML Assertion can be used to request an
   access token when a client wishes to utilize an existing trust
   relationship, expressed through the semantics of (and digital
   signature calculated over) the SAML Assertion, without a direct user
   approval step at the authorization server.  It also defines how a
   SAML Assertion can be used as a client authentication mechanism.  The
   use of an Assertion for client authentication is orthogonal and
   separable from using an Assertion as an authorization grant and can
   be used either in combination or in isolation.

   The process by which the client obtains the SAML Assertion, prior to
   exchanging it with the authorization server, server or using it for client
   authentication, is out of scope.

        +--------+                                  +---------------+
        |        |                                  |               |
        |        |>--(A)-- SAML 2.0 Assertion ----->| Authorization |
        | Client |                                  |     Server    |
        |        |<--(B)---- Access Token ---------<|               |
        |        |                                  |               |
        +--------+                                  +---------------+

                 Figure 1: Assertion Access Token Request

1.1.  Notational Conventions

   The request/response flow illustrated key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in Figure 1 includes this
   document are to be interpreted as described in RFC 2119 [RFC2119].

   Unless otherwise noted, all the
   following steps:

   (A) protocol parameter names and values
   are case sensitive.

2.  HTTP Parameter Bindings for Transporting Assertions

   The client sends an access OAuth 2.0 Assertion Profile [I-D.ietf.oauth-assertions] defines
   generic HTTP parameters for transporting assertions during
   interactions with a token request to endpoint.  This section defines the authorization
        server that includes a values
   of those parameters for use with SAML 2.0 Assertion and Bearer Assertions.

2.1.  Using SAML Assertions as Authorization Grants

   To use a grant_type of
        "http://oauth.net/grant_type/saml/2.0/bearer".

   (B)  The authorization server validates the SAML Bearer Assertion per as an authorization grant, use the
        processing rules defined in this specification
   following paramter values and issues an
        access token.

2.1.  Client Requests Access Token encodings.

   The client includes the Assertion in the access token request, the
   core details of which are defined in OAuth [I-D.ietf.oauth-v2], by
   specifying "http://oauth.net/grant_type/saml/2.0/bearer" as the
   absolute URI value of the "grant_type" parameter and by adding the
   following parameter:

   assertion
         REQUIRED. MUST be
   "urn:ietf:params:oauth:grant-type:saml2-bearer"

   The value of the assertion "assertion" parameter MUST contain a single SAML 2.0
   Assertion.  When used with the
         "http://oauth.net/grant_type/saml/2.0/bearer" grant type, the
         assertion MUST be a SAML 2.0 Assertion.  The SAML Assertion XML data MUST be encoded using
   base64url, where the encoding adheres to the definition in Section 5
   of RFC4648 [RFC4648] and where the padding bits are set to zero.  To to
   avoid the need for subsequent encoding steps (by "application/
   x-www-form-urlencoded" [W3C.REC-html401-19991224], for example), the
   base64url encoded data SHOULD NOT be line wrapped and pad characters
   ("=") SHOULD NOT be included.

   scope
         OPTIONAL.

2.2.  Using SAML Assertions for Client Authentication

   To use a SAML Bearer Assertion for client authentication grant, use
   the following paramter values and encodings.

   The scope value of "client_assertion_type" parameter MUST be
   "urn:ietf:params:oauth:client-assertion-type:saml2-bearer"

   The value of the access request expressed as "client_assertion" parameter MUST contain a list
         of space-delimited, case sensitive strings. single
   SAML 2.0 Assertion.  The value is
         defined by SAML Assertion XML data MUST be encoded
   using base64url, where the authorization server.  If encoding adheres to the value contains
         multiple space-delimited strings, their order does not matter, definition in
   Section 5 of RFC4648 [RFC4648] and each string adds an additional access range where the padding bits are set to
   zero.  To avoid the
         requested scope.

   Authorization servers need for subsequent encoding steps (by
   "application/x-www-form-urlencoded" [W3C.REC-html401-19991224], for
   example), the base64url encoded data SHOULD issue access tokens with a limited
   lifetime NOT be line wrapped and require clients to refresh them by requesting a new
   access token using the same assertion, if it is still valid, or with
   a new assertion.  The authorization server
   pad characters ("=") SHOULD NOT issue a refresh
   token.

2.2. be included.

3.  Assertion Format and Processing Requirements

   Prior

   In order to issuing issue an access token response as described in
   [I-D.ietf.oauth-v2], The OAuth
   2.0 Authorization Protocol [I-D.ietf.oauth-v2] or to rely on an
   assertion for client authentication, the authorization server MUST
   validate the Assertion according to the criteria below.  If present, the
   authorization server MUST also validate the client credentials.  Application
   of additional restrictions and policy are at the discretion of the
   authorization server.

   o  The Assertion's <Issuer> element MUST contain a unique identifier
      for the entity that issued the Assertion.  The Format attribute
      MUST be omitted or have a value of
      "urn:oasis:names:tc:SAML:2.0:nameid-format:entity".

   o  The Assertion MUST contain an <AudienceRestriction> element with
      an <Audience> element containing a URI reference that identifies
      the authorization server, or the service provider SAML entity of
      its controlling domain, as an intended audience.  The token
      endpoint URL of the authorization server MAY be used as an
      acceptable value for an <Audience> element.  The authorization
      server MUST verify that it is an intended audience for the
      Assertion.

   o  The Assertion MUST contain a <Subject> element.  The subject MAY
      identify the resource owner for whom the access token is being
      requested.  For client authentication, the Subject MUST be the
      client_id of the OAuth client.  When using assertions as an
      authorization grant, the Subject SHOULD identify an authorized
      accessor for whom the access token is being requested (typically
      the resource owner, or an authorized delegate).  Additional
      information identifying the subject/principal of the transaction
      MAY be included in an <AttributeStatement>.

   o  The Assertion MUST have an expiry that limits the time window
      during which the it can be used.  The expiry can be expressed
      either as the NotOnOrAfter attribute of the <Conditions> element
      or as the NotOnOrAfter attribute of a suitable
      <SubjectConfirmationData> element.

      If the Assertion has a NotOnOrAfter attribute on the <Conditions>
      element, the authorization server MUST verify that the
      NotOnOrAfter instant has not passed, subject to allowable clock
      skew between systems.  The authorization server SHOULD reject
      assertions with an expiry instant that is unreasonably far in the
      future.

      If the Assertion does not have a NotOnOrAfter attribute on the
      <Conditions> element, then the Assertion's <Subject> element MUST
      contain at least one <SubjectConfirmation> element that allows the
      authorization server to confirm it as a Bearer Assertion.
      Conditions for bearer subject confirmation are described below.

      *  The <SubjectConfirmation> <SubjectConfirmation< MUST have a Method attribute with a
         value of "urn:oasis:names:tc:SAML:2.0:cm:bearer" and MUST
         contain a <SubjectConfirmationData> element.

      *  The <SubjectConfirmationData> element MUST have a Recipient
         attribute with a value indicating the token endpoint URL of the
         authorization server.  The authorization server MUST verify
         that the value of the Recipient attribute matches the token
         endpoint URL (or an acceptable alias) to which the Assertion
         was delivered.

      *  The <SubjectConfirmationData> element MUST have a NotOnOrAfter
         attribute that limits the window during which the Assertion can
         be confirmed.  The authorization server MUST verify that the
         NotOnOrAfter instant has not passed, subject to allowable clock
         skew between systems.  The authorization server MAY ensure that
         Bearer Assertions are not replayed, by maintaining the set of
         used ID values for the length of time for which the Assertion
         would be considered valid based on the NotOnOrAfter attribute
         in the <SubjectConfirmationData>.  The authorization server MAY
         reject assertions with a NotOnOrAfter instant that is
         unreasonably far in the future.

      *  The <SubjectConfirmationData> element MAY also contain an
         Address attribute limiting the client address from which the
         Assertion can be delivered.  Verification of the Address is at
         the discretion of the authorization server.

   o  If the Assertion issuer authenticated the subject, the Assertion
      SHOULD contain a single <AuthnStatement> representing that
      authentication event.

   o  If the Assertion was issued with the intention that the client presenter
      act autonomously on behalf of the subject, an <AuthnStatement>
      SHOULD NOT be included.  The client presenter SHOULD be identified in the <NameID>
      <NamseID> or similar element, the <SubjectConfirmation> element,
      or by other available means like [OASIS.saml-deleg-cs].

   o  Other statements, in particular <AttributeStatement> elements, MAY
      be included in the Assertion.

   o  The Assertion MUST contain an <AudienceRestriction> element with
      an <Audience> element containing a URI reference that identifies
      the authorization server, or the service provider SAML entity of
      its controlling domain, as an intended audience.  The
      authorization server MUST verify that it is an intended audience
      for the Assertion.

   o  The Assertion MUST be digitally signed by the issuer and the
      authorization server MUST verify the signature.

   o  Encrypted elements MAY appear in place of their plain text
      counterparts as defined in [OASIS.saml-core-2.0-os].

   o  The authorization server MUST verify that the Assertion is valid
      in all other respects per [OASIS.saml-core-2.0-os], such as (but
      not limited to) evaluating all content within the Conditions
      element including the NotOnOrAfter and NotBefore attributes,
      rejecting unknown condition types, etc.

2.3.  Error Response

3.1.  Authorization Grant Processing

   If present, the authorization server MUST also validate the client
   credentials.

   Authorization servers SHOULD issue access tokens with a limited
   lifetime and require clients to refresh them by requesting a new
   access token using the same assertion, if it is still valid, or with
   a new assertion.  The authorization server SHOULD NOT issue a refresh
   token.

   If the Assertion is not valid, or its subject confirmation
   requirements cannot be met, the authorization server MUST construct
   an error response as defined in [I-D.ietf.oauth-v2].  The value of
   the error parameter MUST be the "invalid_grant" error code.  The
   authorization server MAY include additional information regarding the
   reasons the Assertion was considered invalid using the
   error_description or error_uri parameters.

   For example:

   HTTP/1.1 400 Bad Request
   Content-Type: application/json
   Cache-Control: no-store

   {
     "error":"invalid_grant",
     "error_description":"Audience validation failed"
   }

2.4.

3.2.  Client Authentication Processing

   If the client Assertion is not valid, or its subject confirmation
   requirements cannot be met, the authorization server MUST construct
   an error response as defined in [I-D.ietf.oauth-v2].  The value of
   the error parameter MUST be the "invalid_client" error code.  The
   authorization server MAY include additional information regarding the
   reasons the Assertion was considered invalid using the
   error_description or error_uri parameters.

4.  Authorization Grant Example (non-normative)

   Though non-normative, the following examples illustrate what a
   conforming Assertion and access token request would look like.

   Below is an example SAML 2.0 Assertion (whitespace formatting is for
   display purposes only):

   <Assertion IssueInstant="2010-10-01T20:07:34.619Z"
     ID="ef1xsbZxPV2oqjd7HTLRLIBlBb7"
     Version="2.0"
     xmlns="urn:oasis:names:tc:SAML:2.0:assertion">
    <Issuer>https://saml-idp.example.com</Issuer>
    <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
     [...omitted for brevity...]
    </ds:Signature>
    <Subject>
     <NameID
       Format="urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress">
      brian@example.com
     </NameID>
     <SubjectConfirmation
       Method="urn:oasis:names:tc:SAML:2.0:cm:bearer">
      <SubjectConfirmationData
        NotOnOrAfter="2010-10-01T20:12:34.619Z"
        Recipient="https://authz.example.net/token.oauth2"/>
      </SubjectConfirmation>
     </Subject>
     <Conditions>
       <AudienceRestriction>
         <Audience>https://saml-sp.example.net</Audience>
       </AudienceRestriction>
     </Conditions>
     <AuthnStatement AuthnInstant="2010-10-01T20:07:34.371Z">
       <AuthnContext>
         <AuthnContextClassRef>
           urn:oasis:names:tc:SAML:2.0:ac:classes:X509
         </AuthnContextClassRef>
       </AuthnContext>
     </AuthnStatement>
   </Assertion>

                   Figure 2: 1: Example SAML 2.0 Assertion

   To present the Assertion shown in the previous example as part of an
   access token request, for example, the client might make the
   following HTTPS request (line breaks are for display purposes only):

   POST /token.oauth2 HTTP/1.1
   Host: authz.example.net
   Content-Type: application/x-www-form-urlencoded

   grant_type=http%3A%2F%2Foauth.net%2Fgrant_type%2Fsaml%2F2.0%2F
   bearer&assertion=PEFzc2VydGlvbiBJc3N1ZUluc3RhbnQ9IjIwMTEtMDUtM

   grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Asaml2-
   bearer&assertion=PEFzc2VydGlvbiBJc3N1ZUluc3RhbnQ9IjIwMTEtMDU
   [...omitted for brevity...]V0aG5TdGF0ZW1lbnQ-PC9Bc3NlcnRpb24- brevity...]aG5TdGF0ZW1lbnQ-PC9Bc3NlcnRpb24-

                         Figure 3: 2: Example Request

3.

5.  Security Considerations

   No additional considerations beyond those described within the OAuth
   2.0 Protocol Framework [I-D.ietf.oauth-v2] and in the Security and
   Privacy Considerations for the OASIS Security Assertion Markup
   Language (SAML) V2.0 [OASIS.saml-sec-consider-2.0-os].

4.

6.  IANA Considerations

4.1.  Parameter

6.1.  Sub-Namspace Registration Request

   The following of
      urn:ietf:params:oauth:grant-type:saml2-bearer

   This is a request to IANA to please register the parameter registration request, as defined value grant-
   type:saml2-bearer in
   The OAuth Parameters Registry of The OAuth the registry urn:ietf:params:oauth established
   in [I-D.ietf.oauth-urn-sub-ns]

   o  URN: urn:ietf:params:oauth:grant-type:saml2-bearer

   o  Common Name: SAML 2.0 Authorization Protocol
   [I-D.ietf.oauth-v2], Bearer Assertion Grant Type Profile for the "assertion" parameter:
      OAuth 2.0

   o  Parameter name: assertion  Change controller: IETF

   o  Parameter usage location: token  Description: [[this document]]

6.2.  Sub-Namspace Registration of
      urn:ietf:params:oauth:client-assertion-type:saml2-bearer

   This is a request to IANA to please register the value client-
   assertion-type:saml2-bearer in the registry urn:ietf:params:oauth
   established in [I-D.ietf.oauth-urn-sub-ns]
   o  URN: urn:ietf:params:oauth:client-assertion-type:saml2-bearer

   o  Common Name: SAML 2.0 Bearer Assertion Profile for OAuth 2.0
      Client Authentication

   o  Change controller: IETF

   o  Specification document(s): draft-ietf-oauth-saml2-bearer  Description: [[this document]]

Appendix A.  Contributors

   The following people contributed wording and concepts to this
   document: Paul Madsen, Patrick Harding, Peter Motykowski, Eran
   Hammer-Lahav, Peter Saint-Andre, Ian Barnett, Eric Fazendin, Torsten
   Lodderstedt, Susan Harper, Scott Tomilson, Scott Cantor, Michael
   Jones, Hannes Tschofenig and David Waite Waite.

Appendix B.  Document History

   [[ to be removed by RFC editor before publication as an RFC ]]

   draft-ietf-oauth-saml2-bearer-05

   o  Allow for subject confirmation data to be optional when Conditions
      contain audience and NotOnOrAfter

   o  Rework most of the spec to profile draft-ietf-oauth-assertions for
      both authn and authz including (but not limited to):

      *  remove requirement for issuer to be
         urn:oasis:names:tc:SAML:2.0:nameid-format:entity

      *  change wording on Subject requirements

   o  using a MAY, explicitly say that the Audience can be token
      endpoint URL of the authorization server

   o  Change title to be more generic (allowing for client authn too)

   o  added client authentication to the abstract

   o  register and use urn:ietf:params:oauth:grant-type:saml2-bearer for
      grant type rather than http://oauth.net/grant_type/saml/2.0/bearer

   o  register urn:ietf:params:oauth:client-assertion-type:saml2-bearer
   o  remove scope paramter as it is defined in
      http://tools.ietf.org/html/draft-ietf-oauth-assertions

   o  remove assertion param registration because it [should] be in
      http://tools.ietf.org/html/draft-ietf-oauth-assertions

   o  fix typo(s) and update/add references

   draft-ietf-oauth-saml2-bearer-04

   o  Changed the grant_type URI from
      "http://oauth.net/grant_type/assertion/saml/2.0/bearer" to
      "http://oauth.net/grant_type/saml/2.0/bearer" - dropping the word
      assertion from the path.  Recent versions of draft-ietf-oauth-v2
      no longer refer to extension grants using the word assertion so
      this URI is more reflective of that.  It also more closely aligns
      with the grant type URI in draft-jones-oauth-jwt-bearer-00 which
      is "http://oauth.net/grant_type/jwt/1.0/bearer".

   o  Added "case sensitive" to scope definition to align with
      draft-ietf-oauth-v2-15/16.

   o  Updated to reference draft-ietf-oauth-v2-16

   draft-ietf-oauth-saml2-bearer-03

   o  Cleanup of some editorial issues.

   draft-ietf-oauth-saml2-bearer-02

   o  Added scope parameter with text copied from draft-ietf-oauth-v2-12
      (the reorg of draft-ietf-oauth-v2-12 made it so scope wasn't
      really inherited by this spec anymore)

   o  Change definition of the assertion parameter to be more generally
      applicable per the suggestion near the end of
      http://www.ietf.org/mail-archive/web/oauth/current/msg05253.html

   o  Editorial changes based on feedback

   draft-ietf-oauth-saml2-bearer-01

   o  Update spec name when referencing draft-ietf-oauth-v2 (The OAuth
      2.0 Protocol Framework -> The OAuth 2.0 Authorization Protocol)

   o  Update wording in Introduction to talk about extension grant types
      rather than the assertion grant type which is a term no longer
      used in OAuth 2.0

   o  Updated to reference draft-ietf-oauth-v2-12 and denote as work in
      progress

   o  Update Parameter Registration Request to use similar terms as
      draft-ietf-oauth-v2-12 and remove Related information part

   o  Add some text giving discretion to AS on rejecting assertions with
      unreasonably long validity window.

   draft-ietf-oauth-saml2-bearer-00

   o  Added Parameter Registration Request for "assertion" to IANA
      Considerations.

   o  Changed document name to draft-ietf-oauth-saml2-bearer in
      anticipation of becoming a OAUTH WG item.

   o  Attempt to move the entire definition of the 'assertion' parameter
      into this draft (it will no longer be defined in OAuth 2 Protocol
      Framework).

   draft-campbell-oauth-saml-01

   o  Updated to reference draft-ietf-oauth-v2-11 and reflect changes
      from -10 to -11.

   o  Updated examples.

   o  Relaxed processing rules to allow for more than one
      SubjectConfirmation element.

   o  Removed the 'MUST NOT contain a NotBefore attribute' on
      SubjectConfirmationData.

   o  Relaxed wording that ties the subject of the Assertion to the
      resource owner.

   o  Added some wording about identifying the client when the subject
      hasn't directly authenticated including an informative reference
      to SAML V2.0 Condition for Delegation Restriction.

   o  Added a few examples to the language about verifying that the
      Assertion is valid in all other respects.

   o  Added some wording to the introduction about the similarities to
      Web SSO in the format and processing rules

   o  Changed the grant_type (was assertion_type) URI from
      http://oauth.net/assertion_type/saml/2.0/bearer to
      http://oauth.net/grant_type/assertion/saml/2.0/bearer

   o  Changed title to include "Grant Type" in it.

   o  Editorial updates based on feedback from the WG and others
      (including capitalization of Assertion when referring to SAML).

   draft-campbell-oauth-saml-00

   o  Initial I-D

5.

7.  References

5.1.

7.1.  Normative References

   [I-D.ietf.oauth-assertions]
              Mortimore, C., Ed., Campbell, B., Jones, M., and Y.
              Goland, "OAuth 2.0 Assertion Profile",
              ID draft-ietf-oauth-assertions-00 (work in progress),
              July 2011.

   [I-D.ietf.oauth-urn-sub-ns]
              Campbell, B., Ed. and H. Tschofenig, "An IETF URN Sub-
              Namespace for OAuth",
              ID draft-campbell-oauth-urn-sub-ns-01 (work in progress),
              Aug 2011.

   [I-D.ietf.oauth-v2]
              Hammer-Lahav, E., Ed., Recordon, D., and D. Hardt, "The
              OAuth 2.0 Authorization Protocol",
              ID draft-ietf-oauth-v2-16 (work in progress), May 2011.

   [OASIS.saml-core-2.0-os]
              Cantor, S., Kemp, J., Philpott, R., and E. Maler,
              "Assertions and Protocol for the OASIS Security Assertion
              Markup Language (SAML) V2.0", OASIS Standard saml-core-
              2.0-os, March 2005.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4648]  Josefsson, S., "The Base16, Base32, and Base64 Data
              Encodings", RFC 4648, October 2006.

5.2.

7.2.  Informative References

   [OASIS.saml-deleg-cs]
              Cantor, S., Ed., "SAML V2.0 Condition for Delegation
              Restriction", Nov 2009.

   [OASIS.saml-profiles-2.0-os]
              Hughes, J., Cantor, S., Hodges, J., Hirsch, F., Mishra,
              P., Philpott, R., and E. Maler, "Profiles for the OASIS
              Security Assertion Markup Language (SAML) V2.0", OASIS
              Standard OASIS.saml-profiles-2.0-os, March 2005.

   [OASIS.saml-sec-consider-2.0-os]
              Hirsch, F., Philpott, R., and E. Maler, "Security and
              Privacy Considerations for the OASIS Security Markup
              Language (SAML) V2.0", OASIS Standard saml-sec-consider-
              2.0-os, March 2005.

   [W3C.REC-html401-19991224]
              Hors, A., Jacobs, I., and D. Raggett, D., 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>.

Authors' Addresses

   Brian Campbell (editor)
   Ping Identity Corp.

   Email: brian.d.campbell@gmail.com

   Chuck Mortimore
   Salesforce.com

   Email: cmortimore@salesforce.com