wdiff draft-ietf-oauth-saml2-bearer-04.txt draft-ietf-oauth-saml2-bearer-05.txt

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.

Status of this Memo

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provisions of BCP 78 and BCP 79.

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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.

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

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].

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

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