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<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<table summary="layout" width="66%" border="0" cellpadding="0" cellspacing="0"><tr><td><table summary="layout" width="100%" border="0" cellpadding="2" cellspacing="1">
<tr><td class="header">Network Working Group</td><td class="header">Y. Goland</td></tr>
<tr><td class="header">Internet-Draft</td><td class="header">M. Jones</td></tr>
<tr><td class="header">Intended status: Experimental</td><td class="header">Microsoft</td></tr>
<tr><td class="header">Expires: March 20, 2011</td><td class="header">September 16, 2010</td></tr>
</table></td></tr></table>
<h1><br />JSON Web Token (JWT)<br />draft-goland-json-web-token-00</h1>
<h3>Abstract</h3>
<p>JSON Web Token (JWT) defines a token format that can move claims between
two parties. The claims in a JWT are encoded as a JSON
object that is then optionally HMAC'ed or digitally signed.
</p>
<h3>Requirements Language</h3>
<p>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 <a class='info' href='#RFC2119'>RFC 2119<span> (</span><span class='info'>Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels,” March 1997.</span><span>)</span></a> [RFC2119].
</p>
<h3>Status of this Memo</h3>
<p>
This Internet-Draft is submitted in full
conformance with the provisions of BCP 78 and BCP 79.</p>
<p>
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/.</p>
<p>
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.”</p>
<p>
This Internet-Draft will expire on March 20, 2011.</p>
<h3>Copyright Notice</h3>
<p>
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.</p>
<p>
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
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.</p>
<a name="toc"></a><br /><hr />
<h3>Table of Contents</h3>
<p class="toc">
<a href="#anchor1">1.</a>
Introduction<br />
<a href="#anchor2">2.</a>
Terminology<br />
<a href="#anchor3">3.</a>
JSON Web Token (JWT) Overview<br />
<a href="#anchor4">3.1.</a>
Example Unsigned JWT<br />
<a href="#anchor5">3.2.</a>
Example Signed JWT<br />
<a href="#anchor6">4.</a>
JWT Claims<br />
<a href="#ReservedClaimName">4.1.</a>
Reserved Claim Names<br />
<a href="#PublicClaimName">4.2.</a>
Public Claim Names<br />
<a href="#PrivateClaimName">4.3.</a>
Private Claim Names<br />
<a href="#anchor7">5.</a>
General rules for creating and validating a JWT<br />
<a href="#base64urllogic">6.</a>
Base64url encoding as used by JWTs<br />
<a href="#Signing">7.</a>
Signing JWTs with Cryptographic Algorithms<br />
<a href="#SigningWithHMACSHA256">7.1.</a>
HMAC'ing a JWT with HMAC SHA-256<br />
<a href="#DefiningRSA">7.2.</a>
Signing a JWT with RSA SHA-256<br />
<a href="#DefiningECDSA">7.3.</a>
Signing a JWT with ECDSA P-256 SHA-256<br />
<a href="#anchor8">7.4.</a>
Additional Algorithms<br />
<a href="#IANA">8.</a>
IANA Considerations<br />
<a href="#Security">9.</a>
Security Considerations<br />
<a href="#anchor9">9.1.</a>
Unicode Comparison Security Issues<br />
<a href="#OpenIssues">10.</a>
Open Issues<br />
<a href="#Acknowledgements">11.</a>
Acknowledgements<br />
<a href="#JWTExamples">12.</a>
Appendix - Non-Normative - JWT Examples<br />
<a href="#HMACSHA256Example">12.1.</a>
JWT using HMAC SHA-256<br />
<a href="#anchor10">12.1.1.</a>
Encoding<br />
<a href="#anchor11">12.1.2.</a>
Decoding<br />
<a href="#anchor12">12.1.3.</a>
Validating<br />
<a href="#anchor13">12.2.</a>
JWT using RSA SHA-256<br />
<a href="#anchor14">12.2.1.</a>
Encoding<br />
<a href="#anchor15">12.2.2.</a>
Decoding<br />
<a href="#anchor16">12.2.3.</a>
Validating<br />
<a href="#anchor17">12.3.</a>
JWT using ECDSA P-256 SHA-256<br />
<a href="#anchor18">12.3.1.</a>
Encoding<br />
<a href="#anchor19">12.3.2.</a>
Decoding<br />
<a href="#anchor20">12.3.3.</a>
Validating<br />
<a href="#anchor21">13.</a>
Appendix - Non-Normative - Relationship of JWTs to SAML Tokens<br />
<a href="#anchor22">14.</a>
Appendix - Non-Normative - Relationship of JWTs to Simple Web Tokens (SWTs)<br />
<a href="#rfc.references1">15.</a>
References<br />
<a href="#rfc.references1">15.1.</a>
Normative References<br />
<a href="#rfc.references2">15.2.</a>
Informative References<br />
<a href="#rfc.authors">§</a>
Authors' Addresses<br />
</p>
<br clear="all" />
<a name="anchor1"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.1"></a><h3>1.
Introduction</h3>
<p>JSON Web Token (JWT) is a simple token format intended for space
constrained environments such as HTTP Authorization headers and URI
query parameters. JWTs encode the claims to be transmitted as
a JSON object (as defined in <a class='info' href='#RFC4627'>RFC 4627<span> (</span><span class='info'>Crockford, D., “The application/json Media Type for JavaScript Object Notation (JSON),” July 2006.</span><span>)</span></a> [RFC4627])
that is then base64url encoded and optionally HMAC'ed or digitally signed.
</p>
<p>The suggested pronunciation of JWT is the same as the English word "jot".
</p>
<a name="anchor2"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.2"></a><h3>2.
Terminology</h3>
<p></p>
<blockquote class="text"><dl>
<dt>JSON Web Token (JWT)</dt>
<dd>A string consisting of
one or two JWT Token Segments. The JWT Claim Segment is
always present. If the token is HMAC'ed or digitally signed,
then a JWT Crypto Segment precedes the JWT Claim Segment,
with the segments being separated by a period character ('.').
</dd>
<dt>JWT Token Segment</dt>
<dd>One of the two parts that
make up a JSON Web Token (JWT). JWT Token Segments are
always base64url encoded values.
</dd>
<dt>JWT Claim Segment</dt>
<dd>A JWT Token Segment
containing a base64url encoded JSON object that encodes the
claims being made by the JWT.
</dd>
<dt>JWT Crypto Segment</dt>
<dd>A JWT Token Segment
containing base64url encoded cryptographic material such as
an HMAC or signature that secures the token's contents.
</dd>
<dt>Decoded JWT Claim Segment</dt>
<dd>A JWT Claim Segment that
has been base64url decoded back into a JSON object.
</dd>
<dt>Decoded JWT Crypto Segment</dt>
<dd>A JWT Crypto Segment that
has been base64url decoded back into cryptographic material.
</dd>
<dt>Signed JWT</dt>
<dd>A JWT that is HMAC'ed or digitally
signed, which consists of a JWT Crypto Segment followed by a
period character ('.') followed by a JWT Claim Segment.
</dd>
<dt>Unsigned JWT</dt>
<dd>A JWT that is not HMAC'ed or
digitally signed, which consists of solely a JWT Claim
Segment, and contains no period character or JWT Crypto
Segment.
</dd>
<dt>Base64url Encoding</dt>
<dd>For the purposes of this specification,
this term always refers to the he URL- and filename-safe Base64
encoding described in <a class='info' href='#RFC4648'>RFC 4648<span> (</span><span class='info'>Josefsson, S., “The Base16, Base32, and Base64 Data Encodings,” October 2006.</span><span>)</span></a> [RFC4648], Section 5,
with the '=' padding characters omitted, as permitted by Section 3.2;
see <a class='info' href='#base64urllogic'>Section 6<span> (</span><span class='info'>Base64url encoding as used by JWTs</span><span>)</span></a> for more details.
</dd>
</dl></blockquote>
<a name="anchor3"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.3"></a><h3>3.
JSON Web Token (JWT) Overview</h3>
<p>JWTs represent a set of claims as a JSON object that is then
base64url encoded and optionally HMAC'ed or digitally signed.
As per <a class='info' href='#RFC4627'>RFC 4627<span> (</span><span class='info'>Crockford, D., “The application/json Media Type for JavaScript Object Notation (JSON),” July 2006.</span><span>)</span></a> [RFC4627] Section 2.2, the
JSON object consists of zero or more name/value pairs (or
members), where the names are strings and the values are
arbitrary JSON values. These members are the claims represented
by the JWT.
</p>
<p>The names within the object MUST be unique. The names within
the JSON object are referred to as Claim Names. The
corresponding values are referred to as Claim Values.
</p>
<p>JWTs MAY contain a signature or HMAC that ensures the
integrity of the content of the JSON Claim Segment. If present,
this signature or HMAC value is carried in the JWT Crypto
Segment. If the JWT contains a JWT Crypto Segment, the JSON
object MUST contain an "alg" claim, the value of which
unambiguously identifies the algorithm used to sign or HMAC the
JWT Claim Segment to produce the JWT Crypto Segment. If a JWT
Crypto Segment is not present, the JSON object MUST NOT contain
an "alg" claim.
</p>
<a name="anchor4"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.3.1"></a><h3>3.1.
Example Unsigned JWT</h3>
<p>The following is an example of a JSON object that can be
encoded to produce a unsigned JWT, which consists of only a JWT
Claim Segment:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>{"iss":"joe",
"exp":"1300752001",
"http://example.com/is_root":true}</pre></div>
<p>Base64url encoding the UTF-8 representation of the JSON
Object yields:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>eyJpc3MiOiJqb2UiLA0KICJleHAiOiIxMzAwNzUyMDAxIiwNCiAiaHR0cDovL2V4YW1wbGUuY29tL2lzX3Jvb3QiOnRydWV9</pre></div>
<p>which is the JWT Claim Segment value. In this case, it is also the
complete JWT value.
</p>
<a name="anchor5"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.3.2"></a><h3>3.2.
Example Signed JWT</h3>
<p>The following is an example of a JSON object that can be
encoded to produce a signed JWT, which consists of a JWT Crypto
Segment and a JWT Claim Segment separated by a period
character:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>{"iss":"joe",
"alg":"HS256",
"exp":"1300752001",
"http://example.com/is_root":true}</pre></div>
<p>Base64url encoding the UTF-8 representation of the JSON
Object yields:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>eyJpc3MiOiJqb2UiLA0KICJhbGciOiJIUzI1NiIsDQogImV4cCI6IjEzMDA3NTIwMDEiLA0KICJodHRwOi8vZXhhbXBsZS5jb20vaXNfcm9vdCI6dHJ1ZX0</pre></div>
<p>which is the JWT Claim Segment value. HMAC'ing the JWT Claim
Segment with the HMAC SHA-256 algorithm and base64url encoding
the result, as per <a class='info' href='#SigningWithHMACSHA256'>Section 7.1<span> (</span><span class='info'>HMAC'ing a JWT with HMAC SHA-256</span><span>)</span></a>,
yields:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>CsV_CMwjIZOr6DMxSbJ9_eOJgW75zfxvZd_Zrt8Gxzc</pre></div>
<p>This is the JWT Crypto Segment. Combining these segments
yields the complete JWT:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>CsV_CMwjIZOr6DMxSbJ9_eOJgW75zfxvZd_Zrt8Gxzc.eyJpc3MiOiJqb2UiLA0KICJhbGciOiJIUzI1NiIsDQogImV4cCI6IjEzMDA3NTIwMDEiLA0KICJodHRwOi8vZXhhbXBsZS5jb20vaXNfcm9vdCI6dHJ1ZX0</pre></div>
<p>This computation is illustrated in more detail in <a class='info' href='#HMACSHA256Example'>Section 12.1<span> (</span><span class='info'>JWT using HMAC SHA-256</span><span>)</span></a>.
</p>
<a name="anchor6"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.4"></a><h3>4.
JWT Claims</h3>
<p>The members of the JSON Object represented by the Decoded JWT
Claim Segment contain the claims. Note however, that the set of
claims a JWT must contain to be considered valid is
context-dependent and is outside the scope of this
specification.
</p>
<p>There are three classes of JWT Claim Names: Reserved Claim Names, Public Claim Names, and Private Claim Names.
</p>
<a name="ReservedClaimName"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.4.1"></a><h3>4.1.
Reserved Claim Names</h3>
<p>The following claim names are reserved. None of the claims
defined in the table below are intended to be mandatory, but
rather, provide a starting point for a set of useful,
interoperable claims. All the names are short because a core
goal of JWTs is for the tokens themselves to be short.
</p><br /><hr class="insert" />
<a name="ClaimTable"></a>
<table class="full" align="center" border="0" cellpadding="2" cellspacing="2">
<col align="left"><col align="left"><col align="left"><col align="left">
<tr><th align="left">Claim Name</th><th align="left">JSON Value Type</th><th align="left">Claim Syntax</th><th align="left">Claim Semantics</th></tr>
<tr>
<td align="left">alg</td>
<td align="left">string</td>
<td align="left">StringAndURI</td>
<td align="left">Identifies the cryptographic algorithm being used to secure the
JWT. A list of reserved alg values is in <a class='info' href='#AlgTable'>Table 4<span> (</span><span class='info'>JSON Web Token Reserved Algorithm Values</span><span>)</span></a>.</td>
</tr>
<tr>
<td align="left">exp</td>
<td align="left">integer</td>
<td align="left">IntDate</td>
<td align="left">Identifies the expiration time on or after which the token
MUST NOT be accepted for processing.</td>
</tr>
<tr>
<td align="left">iss</td>
<td align="left">string</td>
<td align="left">StringAndURI</td>
<td align="left">Identifies the principal who issued the JWT.</td>
</tr>
<tr>
<td align="left">aud</td>
<td align="left">string</td>
<td align="left">StringAndURI</td>
<td align="left">Identifies the JWT audience that the JWT is intended for.</td>
</tr>
</table>
<br clear="all" />
<table border="0" cellpadding="0" cellspacing="2" align="center"><tr><td align="center"><font face="monaco, MS Sans Serif" size="1"><b> Table 1: Reserved Claim Definitions </b></font><br /></td></tr></table><hr class="insert" />
<p>The following claim-specific processing rules apply:
</p>
<blockquote class="text"><dl>
<dt>alg</dt>
<dd>The processing of the "alg" claim, if
present, requires that the value of the "alg" claim MUST be
one that is both supported and for which there exists a key
for use with that algorithm associated with the issuer of
the JWT. Note however, that if the "iss" (issuer) claim is not
included, then the manner in which the issuer is determined
is application specific.
</dd>
<dt>exp</dt>
<dd>The processing of the "exp" claim, if
present, requires that the current date/time MUST be before
the expiration date/time listed in the "exp"
claim. Implementers MAY provide for some small leeway,
usually no more than a few minutes, to account for clock
skew.
</dd>
<dt>iss</dt>
<dd>The processing of the "iss" (issuer) claim is generally
application specific.
</dd>
<dt>aud</dt>
<dd>The processing of the "aud" claim requires
that if a JWT consumer receives a JWT with an "aud" value
that does not identify itself as the JWT audience, then the
JWT is to be rejected. The interpretation of the audience
value is generally application specific.
</dd>
</dl></blockquote><p>
Additional reserved claim names MAY be defined via the IANA JSON
Web Token Claims registry, as per <a class='info' href='#IANA'>Section 8<span> (</span><span class='info'>IANA Considerations</span><span>)</span></a>.
</p>
<p>The claim value syntaxes referred to above are:
</p><br /><hr class="insert" />
<a name="ClaimSyntaxDefinition"></a>
<table class="full" align="center" border="0" cellpadding="2" cellspacing="2">
<col align="left"><col align="left">
<tr><th align="left">Claim Syntax Name</th><th align="left">Claim Syntax Definition</th></tr>
<tr>
<td align="left">StringAndURI</td>
<td align="left">Any string value MAY be used but a value containing a ":" character
MUST be a URI as defined in <a class='info' href='#RFC3986'>RFC
3986<span> (</span><span class='info'>Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifier (URI): Generic Syntax,” January 2005.</span><span>)</span></a> [RFC3986].</td>
</tr>
<tr>
<td align="left">IntDate</td>
<td align="left">The number of seconds from 1970-01-01T0:0:0Z as measured in UTC
until the desired date/time. See <a class='info' href='#RFC3339'>RFC
3339<span> (</span><span class='info'>Klyne, G., Ed. and C. Newman, “Date and Time on the Internet: Timestamps,” July 2002.</span><span>)</span></a> [RFC3339] for details regarding date/times in general and UTC in
particular.</td>
</tr>
</table>
<br clear="all" />
<table border="0" cellpadding="0" cellspacing="2" align="center"><tr><td align="center"><font face="monaco, MS Sans Serif" size="1"><b> Table 2 </b></font><br /></td></tr></table><hr class="insert" />
<a name="PublicClaimName"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.4.2"></a><h3>4.2.
Public Claim Names</h3>
<p>Claim names can be defined at will by those using
JWTs. However, in order to prevent collisions, any new claim
name or algorithm value SHOULD either be defined in the IANA
JSON Web Token Claims registry or be defined as
a URI that contains a collision resistant namespace. Examples
of collision resistant namespaces include:
</p>
<ul class="text">
<li>Domain Names,
</li>
<li>Object Identifiers (OIDs) as defined in the ITU-T X 660 and X
670 Recommendation series or
</li>
<li>Universally Unique IDentifier (UUID) as defined in <a class='info' href='#RFC4122'>RFC 4122<span> (</span><span class='info'>Leach, P., Mealling, M., and R. Salz, “A Universally Unique IDentifier (UUID) URN Namespace,” July 2005.</span><span>)</span></a> [RFC4122].
</li>
</ul><p>
In each case, the definer of the name or value MUST take
reasonable precautions to make sure they are in control of the part of
the namespace they use to define the claim name.
</p>
<a name="PrivateClaimName"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.4.3"></a><h3>4.3.
Private Claim Names</h3>
<p>A producer and consumer of a JWT may agree to any claim
name that is not a Reserved Name <a class='info' href='#ReservedClaimName'>Section 4.1<span> (</span><span class='info'>Reserved Claim Names</span><span>)</span></a>
or a Public Name <a class='info' href='#PublicClaimName'>Section 4.2<span> (</span><span class='info'>Public Claim Names</span><span>)</span></a>. Unlike
Public Names, these private names are subject to collision and
should be used with caution.
</p>
<a name="anchor7"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.5"></a><h3>5.
General rules for creating and validating a JWT</h3>
<p>To create a JWT one MUST follow these steps:
</p>
<ol class="text">
<li>Create a JSON object containing the desired claims. Note
that white space is explicitly allowed in the representation
and no canonicalization is performed before encoding.
</li>
<li>Translate the JSON object's Unicode code points into UTF-8, as
defined in <a class='info' href='#RFC3629'>RFC 3629<span> (</span><span class='info'>Yergeau, F., “UTF-8, a transformation format of ISO 10646,” November 2003.</span><span>)</span></a> [RFC3629].
</li>
<li>Base64url encode the UTF-8 representation of the JSON
object as defined in this specification (without
padding). This encoding becomes the JWT Claim Segment.
</li>
<li>If a Signed JWT is being created, construct the JWT
Crypto Segment as defined for the particular algorithm being
used.
</li>
<li>If a Signed JWT is being created, combine the JWT Crypto
Segment and then the JWT Claim Segment, separated by a
period character, to create the JWT. Otherwise, an Unsigned
JWT is being created and the JWT consists of simply the JWT
Claim Segment.
</li>
</ol>
<p>When validating a JWT the following steps MUST be taken. If
any of the listed steps fails then the token MUST be rejected for
processing.
</p>
<p></p>
<ol class="text">
<li>The JWT MUST contain either zero or one period character.
</li>
<li>If a period is present, the JWT MUST be split on the
period character resulting in two non-empty segments.
Otherwise, the JWT MUST consist of one non-empty
segment.
</li>
<li>The JWT Claim Segment (the second of the two if period
was present, otherwise the entire JWT) MUST be successfully
base64url decoded following the restriction given in this
spec that no padding characters may have been used.
</li>
<li>The Decoded JWT Claim Segment MUST be completely valid JSON
syntax.
</li>
<li>When used in a security-related context, the JWT Claim
Segment MUST be validated to only include claims whose
syntax and semantics are both understood and supported.
</li>
<li>If a period was present, the JWT Crypto Segment (the
first of the two non-empty segments) MUST be successfully
validated against the JWT Claim Segment in the manner
defined for the algorithm being used.
</li>
</ol>
<p>Processing a JWT inevitably requires comparing known strings
to values in the token. For example, in checking what the algorithm is
(assuming the "alg" claim is used), the Unicode string encoding
"alg" will be checked against the member names in the Decoded
JWT Claim Segment to see if there is a matching claim name. A similar
process occurs when determining if the value of the "alg" claim
represents a supported algorithm. Comparing Unicode strings, however, has
significant security implications, as per <a class='info' href='#Security'>Section 9<span> (</span><span class='info'>Security Considerations</span><span>)</span></a>.
</p>
<p>Comparisons between JSON strings and other Unicode strings MUST be
performed as specified below:
</p>
<p></p>
<ol class="text">
<li>Remove any JSON applied escaping to produce an array of Unicode
code points.
</li>
<li><a class='info' href='#USA15'>Unicode Normalization<span> (</span><span class='info'>Davis, M., Whistler, K., and M. Dürst, “Unicode Normalization Forms,” 09 2009.</span><span>)</span></a> [USA15] MUST NOT be
applied at any point to either the JSON string or to the string it
is to be compared against.
</li>
<li>Comparisons between the two strings MUST be performed as a
Unicode code point to code point equality comparison.
</li>
</ol>
<a name="base64urllogic"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.6"></a><h3>6.
Base64url encoding as used by JWTs</h3>
<p>JWTs make use of the base64url encoding as defined in <a class='info' href='#RFC4648'>RFC 4648<span> (</span><span class='info'>Josefsson, S., “The Base16, Base32, and Base64 Data Encodings,” October 2006.</span><span>)</span></a> [RFC4648]. However, as allowed by Section 3.2 of
RFC 4648, this specification mandates that base64url encoding when used
with JWTs MUST NOT use padding. The reason for this restriction
is that the padding character ('=') is not URL safe.
</p>
<p>To process a base64url value in a JWT, one must first calculate
the size of the base64url value and then divide that size by four using
modular arithmetic. Look up the remainder of the modular division in the
table below to determine the amount of padding needed.
</p><br /><hr class="insert" />
<a name="PaddingHandling"></a>
<table class="full" align="center" border="0" cellpadding="2" cellspacing="2">
<col align="left"><col align="left">
<tr><th align="left">Remainder</th><th align="left">Action to take</th></tr>
<tr>
<td align="left">0</td>
<td align="left">No padding is needed.</td>
</tr>
<tr>
<td align="left">1</td>
<td align="left">The base64url encoded value is malformed and MUST be rejected for
processing.</td>
</tr>
<tr>
<td align="left">2</td>
<td align="left">Two padding characters are needed.</td>
</tr>
<tr>
<td align="left">3</td>
<td align="left">One padding character is needed.</td>
</tr>
</table>
<br clear="all" />
<table border="0" cellpadding="0" cellspacing="2" align="center"><tr><td align="center"><font face="monaco, MS Sans Serif" size="1"><b> Table 3: Guidance on how to handle base64url encoded values without padding </b></font><br /></td></tr></table><hr class="insert" />
<a name="Signing"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.7"></a><h3>7.
Signing JWTs with Cryptographic Algorithms</h3>
<p>Signed JWTs use cryptographic algorithms to secure the contents
of the token by HMAC'ing or signing the contents of the JWT Claims
Segment. The use of the following algorithms for producing JWTs
is defined in this section. The table below is the list of "alg"
claim values reserved by this specification, each of which is
explained in more detail in the following sections:
</p><br /><hr class="insert" />
<a name="AlgTable"></a>
<table class="full" align="center" border="0" cellpadding="2" cellspacing="2">
<col align="left"><col align="left">
<tr><th align="left">Alg Claim Value</th><th align="left">Algorithm</th></tr>
<tr>
<td align="left">HS256</td>
<td align="left">HMAC SHA-256</td>
</tr>
<tr>
<td align="left">RS256</td>
<td align="left">RSA SHA-256</td>
</tr>
<tr>
<td align="left">E256S256</td>
<td align="left">ECDSA P-256 SHA-256</td>
</tr>
</table>
<br clear="all" />
<table border="0" cellpadding="0" cellspacing="2" align="center"><tr><td align="center"><font face="monaco, MS Sans Serif" size="1"><b> Table 4: JSON Web Token Reserved Algorithm Values </b></font><br /></td></tr></table><hr class="insert" />
<a name="SigningWithHMACSHA256"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.7.1"></a><h3>7.1.
HMAC'ing a JWT with HMAC SHA-256</h3>
<p>Hash based Message Authentication Codes (HMACs) enable one to
use a secret plus a cryptographic hash function to generate a
Message Authentication Code (MAC). This can be used to
demonstrate that the MAC matches the hashed content, in this
case the JWT Claim Segment, which therefore demonstrates that
whoever generated the MAC was in possession of the
secret. Unlike digital signatures, HMACs can provide validation
but not non-repudiation, since both the sender and receiver of
the HMAC must be in possession of the secret, and so either
could have generated the HMAC.
</p>
<p>The algorithm for implementing and validating HMACs is
provided in <a class='info' href='#RFC2104'>RFC 2104<span> (</span><span class='info'>Krawczyk, H., Bellare, M., and R. Canetti, “HMAC: Keyed-Hashing for Message Authentication,” February 1997.</span><span>)</span></a> [RFC2104]. Although any
HMAC can be used with JWTs, this section defines the use of the
SHA-256 cryptographic hash function as defined in <a class='info' href='#FIPS.180-3'>FIPS 180-3<span> (</span><span class='info'>National Institute of Standards and Technology, “Secure Hash Standard (SHS),” October 2008.</span><span>)</span></a> [FIPS.180‑3]. The reserved "alg" claim
value "HS256" is used in the JWT Claim Segment to indicate that
the JWT Crypto Segment contains a base64url encoded HMAC SHA-256
HMAC value.
</p>
<p>The HMAC SHA-256 MAC is generated as follows:
</p>
<ol class="text">
<li>Take the JWT Claim Segment and execute the HMAC SHA-256
algorithm on it using the desired key to produce an HMAC.
</li>
<li>Base64url encode the HMAC as defined in this document.
</li>
</ol><p>
The output then becomes the JWT Crypto Segment for that JWT.
</p>
<p>The HMAC SHA-256 MAC on a JWT is validated as follows:
</p>
<ol class="text">
<li>Take the JWT Claim Segment and calculate an HMAC SHA-256 MAC on
it using the key to be tested.
</li>
<li>Base64url encode the previously generated HMAC as defined in this
document.
</li>
<li>If the JWT Crypto Segment and the previously calculated value
exactly match in a character by character, case sensitive
comparison, then one has confirmation that the key being tested was
used to generate the HMAC on the JWT and that the contents of
the JWT Claim Segment have not be tampered with.
</li>
</ol>
<p>JWT implementations MUST support the HMAC SHA-256 algorithm
as defined in this section.
</p>
<a name="DefiningRSA"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.7.2"></a><h3>7.2.
Signing a JWT with RSA SHA-256</h3>
<p>RSA digital signatures can be used both to sign messages and provide
non-repudiation, since they demonstrate that whoever generated the
signature was in possession of the signer's private key.
The means of key establishment between the communicating parties
is beyond the scope of this specification.
</p>
<p>This section defines the use of the RSASSA-PKCS1-v1_5
signature algorithm as defined in <a class='info' href='#RFC3447'>RFC
3447<span> (</span><span class='info'>Jonsson, J. and B. Kaliski, “Public-Key Cryptography Standards (PKCS) #1: RSA Cryptography Specifications Version 2.1,” February 2003.</span><span>)</span></a> [RFC3447], Section 8.2 (commonly known as PKCS#1), using
SHA-256 as the hash function. Note that the use of the
RSASSA-PKCS1-v1_5 algorithm is permitted in <a class='info' href='#FIPS.186-3'>FIPS 186-3<span> (</span><span class='info'>National Institute of Standards and Technology, “Digital Signature Standard (DSS),” June 2009.</span><span>)</span></a> [FIPS.186‑3], Section 5.5, as is the
SHA-256 cryptographic hash function, which is defined in <a class='info' href='#FIPS.180-3'>FIPS 180-3<span> (</span><span class='info'>National Institute of Standards and Technology, “Secure Hash Standard (SHS),” October 2008.</span><span>)</span></a> [FIPS.180‑3]. The reserved "alg"
claim value "RS256" is used in the JWT Claim Segment to
indicate that the JWT Crypto Segment contains an RSA SHA-256
signature.
</p>
<p>A 2048-bit or longer key length MUST be used.
</p>
<p>The RSA SHA-256 signature is generated as follows:
</p>
<ol class="text">
<li>Let K be the signer's RSA private key and let M be the JWT Claim Segment.
</li>
<li>Compute the octet string S = RSASSA-PKCS1-V1_5-SIGN (K, M).
</li>
<li>Base64url encode the octet string S, as defined in this document.
</li>
</ol><p>
The output then becomes the JWT Crypto Segment for that JWT.
</p>
<p>The RSA SHA-256 signature on a JWT is validated as follows:
</p>
<ol class="text">
<li>Take the JWT Crypto Segment and base64url decode it into
an octet string S. If decoding fails, then the test MUST fail.
</li>
<li>Let M be the JWT Claim Segment and let (n, e) be the
public key corresponding to the private key used by the signer.
</li>
<li> Validate the signature with RSASSA-PKCS1-V1_5-VERIFY ((n, e), M, S).
</li>
</ol><p>
If the signature does not validate, the token MUST be discarded.
</p>
<p>JWT implementations SHOULD support the RSA SHA-256 algorithm,
and if supported, MUST do so as defined in this section.
</p>
<a name="DefiningECDSA"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.7.3"></a><h3>7.3.
Signing a JWT with ECDSA P-256 SHA-256</h3>
<p>The Elliptic Curve Digital Signature Algorithm (ECDSA) is defined by
<a class='info' href='#FIPS.186-3'>FIPS 186-3<span> (</span><span class='info'>National Institute of Standards and Technology, “Digital Signature Standard (DSS),” June 2009.</span><span>)</span></a> [FIPS.186‑3]. ECDSA provides for the use
of Elliptic Curve cryptography which is able to provide equivalent
security to RSA cryptography but using shorter key lengths and with
greater processing speed. This means that ECDSA signatures will be
substantially smaller in terms of length than equivalently strong RSA
Digital Signatures.
</p>
<p>This specification defines the use of ECDSA with the P-256 curve and
the SHA-256 cryptographic hash function. The P-256 curve is also defined
in FIPS 186-3. The "alg" claim value "E256S256" is used to
identify a JWT signed with ECDSA P-256 SHA-256.
</p>
<p>A JWT is signed with an ECDSA P-256 SHA-256 signature as
follows:
</p>
<ol class="text">
<li>Take the JWT Claim Segment and generate a digital
signature for it using ECDSA P-256 SHA-256 with the desired
private key. The output will be the EC point (R, S), where R
and S are unsigned integers.
</li>
<li>Turn R and S into byte arrays in big endian order. Each array
will be 32 bytes long.
</li>
<li>Concatenate the two byte arrays in the order R and then S.
</li>
<li>Base64url encode the 64 byte array as defined in this specification.
</li>
</ol><p>
The output is then the JWT Crypto Segment for the JWT.
</p>
<p>The following procedure may be used to verify the ECDSA signature of a JWT:
</p>
<ol class="text">
<li>Take the JWT Crypto Segment and base64url decode it into
a byte array. If decoding fails, then the test MUST fail.
</li>
<li>The output of the base64url decoding MUST be a 64 byte array.
</li>
<li>Split the 64 byte array into two 32 byte arrays. The first array
will be R and the second S. Please remember that the byte arrays are
in big endian byte order; please check the ECDSA validator in
use to see what byte order it requires.
</li>
<li>Submit the JWT Claim Segment, R, S and the public key (x, y)
that is being tested to the ECDSA P-256 SHA-256 validator.
</li>
</ol><p>
The ECDSA validator will then determine if the digital signature
is valid, given the inputs. Please note that ECDSA digital signature
contains a value referred to as K, which is a random number generated for
each digital signature instance. This means that two ECDSA digital
signatures using exactly the same input parameters will output
different signatures because their K values will be different. The
consequence of this is that one must validate an ECDSA signature by submitting
the previously specified inputs to an ECDSA validator. One cannot, as
with HMACs, check the signature directly oneself.
</p>
<p>JWT implementations SHOULD support the ECDSA P-256 SHA-256 algorithm,
and if supported, MUST do so as defined in this section.
</p>
<a name="anchor8"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.7.4"></a><h3>7.4.
Additional Algorithms</h3>
<p>Additional algorithms MAY be used to protect JWTs with
corresponding "alg" claim values being defined to refer to
them. Like claim names, new "alg" claim values SHOULD either be
defined in the IANA JSON Web Token Algorithms registry or
be a URI that contains a collision resistant namespace. In
particular, the use of algorithm identifiers defined in <a class='info' href='#RFC3275'>XML DSIG<span> (</span><span class='info'>Eastlake, D., Reagle, J., and D. Solo, “(Extensible Markup Language) XML-Signature Syntax and Processing,” March 2002.</span><span>)</span></a> [RFC3275] and related specifications is
permitted.
</p>
<a name="IANA"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.8"></a><h3>8.
IANA Considerations</h3>
<p>This specification calls for:
</p>
<ul class="text">
<li>A new IANA registry entitled "JSON Web Token Claims" for
reserved claim names <a class='info' href='#ReservedClaimName'>Section 4.1<span> (</span><span class='info'>Reserved Claim Names</span><span>)</span></a> used in a Decoded JWT
Claim Segment. Inclusion in the registry is RFC Required in
the <a class='info' href='#RFC5226'>RFC 5226<span> (</span><span class='info'>Narten, T. and H. Alvestrand, “Guidelines for Writing an IANA Considerations Section in RFCs,” May 2008.</span><span>)</span></a> [RFC5226] sense for
reserved JWT claim names that are intended to be
interoperable between implementations. The registry will
just record the reserved claim name and a pointer to the RFC
that defines it. This specification defines inclusion of the
claim names defined in <a class='info' href='#ClaimTable'>Table 1<span> (</span><span class='info'>Reserved Claim Definitions</span><span>)</span></a>.
</li>
<li>A new IANA registry entitled "JSON Web Token Algorithms" for
values used with the "alg" claim used in a decoded
JWT Claim Segment. Inclusion in the registry is RFC Required in the <a class='info' href='#RFC5226'>RFC 5226<span> (</span><span class='info'>Narten, T. and H. Alvestrand, “Guidelines for Writing an IANA Considerations Section in RFCs,” May 2008.</span><span>)</span></a> [RFC5226] sense. The registry will just
record the "alg" value and a pointer to the RFC that defines it.
This specification defines inclusion of the algorithm values
"HS256", "RS256", and "E256S256".
</li>
</ul>
<a name="Security"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.9"></a><h3>9.
Security Considerations</h3>
<p>TBD: Lots of work to do here. We need to remember to look
into any issues relating to security and JSON parsing. One wonders just
how secure most JSON parsing libraries are. Were they ever hardened for
security scenarios? If not, what kind of holes does that open up? Also
need to walk through the JSON standard and see what kind of issues we
have especially around comparison of names, already found an issue with
escaping strings (needed to define that comparisons of strings must
occur after they are unescaped). Need to also put in text about:
Importance of keeping secrets secret. Rotating keys. Strengths and
weaknesses of the different algorithms. Case sensitivity and more
generally Unicode comparison issues that can cause security holes,
especially in claim names and explain why Unicode Normalization is such
a problem.
</p>
<p>TBD: Need to put in text about why strict JSON validation is necessary.
Basically that if malformed JSON is received then the intent of the
sender is impossible to reliably discern. While in non-security
contexts it's o.k. to be generous in what one accepts in security
contexts this can lead to serious security holes. For example, malformed
JSON might indicate that someone has managed to find a security hole in
the issuer's code and is leveraging it to get the issuer to issue "bad"
tokens whose content the attack can control.
</p>
<a name="anchor9"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.9.1"></a><h3>9.1.
Unicode Comparison Security Issues</h3>
<p>Claim names in JWTs are Unicode strings. For security
reasons, the representations these names must be compared verbatim after performing
any escape processing (as per <a class='info' href='#RFC4627'>RFC
4627<span> (</span><span class='info'>Crockford, D., “The application/json Media Type for JavaScript Object Notation (JSON),” July 2006.</span><span>)</span></a> [RFC4627], Section 2.5). In particular, <a class='info' href='#USA15'>Unicode Normalization<span> (</span><span class='info'>Davis, M., Whistler, K., and M. Dürst, “Unicode Normalization Forms,” 09 2009.</span><span>)</span></a> [USA15] or case folding
MUST NOT be applied at any point to either the JSON string or
to the string it is to be compared against.
</p>
<p>This means, for instance, that these JSON strings must
compare as being equal ("JWT", "\u004aWT"), whereas these must
all compare as being not equal to the first set or to each other
("jwt", "Jwt", "JW\u0074").
</p>
<p>JSON strings MAY contain characters outside the Unicode
Basic Multilingual Plane. For instance, the G clef character
(U+1D11E) may be represented in a JSON string as
"\uD834\uDD1E". Ideally, JWT implementations SHOULD ensure
that characters outside the Basic Multilingual Plane are
preserved and compared correctly; alternatively, if this is
not possible due to these characters exercising limitations
present in the underlying JSON implementation, then input
containing them MUST be rejected.
</p>
<a name="OpenIssues"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.10"></a><h3>10.
Open Issues</h3>
<p>The following open issues have been identified during review
of previous drafts. Additional input on them is solicited.
</p>
<ul class="text">
<li>There is presently no means specified for a sender to
include his public key or identity information in the token.
One possibility would be to define a key identifier claim so
that can be done in an interoperable manner. The counter
argument against adding this is that how the issuer and his
key are identified is context dependent.
</li>
</ul>
<a name="Acknowledgements"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.11"></a><h3>11.
Acknowledgements</h3>
<p>The authors acknowledge that the design of JWTs was
intentionally influenced by the design and simplicity of Simple
Web Tokens <a class='info' href='#SWT'>SWT<span> (</span><span class='info'>Hardt, D. and Y. Goland, “Simple Web Token (SWT),” November 2009.</span><span>)</span></a> [SWT].
</p>
<p>Additional acknowledgements TBD.
</p>
<a name="JWTExamples"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.12"></a><h3>12.
Appendix - Non-Normative - JWT Examples</h3>
<a name="HMACSHA256Example"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.12.1"></a><h3>12.1.
JWT using HMAC SHA-256</h3>
<a name="anchor10"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.12.1.1"></a><h3>12.1.1.
Encoding</h3>
<p>The Decoded JWT Claim Segment used in this example is:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>{"iss":"joe",
"alg":"HS256",
"exp":"1300752001",
"http://example.com/is_root":true}</pre></div>
<p>Note that white space is explicitly allowed in Decoded JWT Claim Segments
and no canonicalization is performed before encoding. The
following byte array contains the UTF-8 characters for the
Decoded JWT Claim Segment:
</p>
<p>
[123, 34, 105, 115, 115, 34, 58, 34, 106, 111, 101, 34,
44, 13, 10, 32, 34, 97, 108, 103, 34, 58, 34, 72, 83,
50, 53, 54, 34, 44, 13, 10, 32, 34, 101, 120, 112,
34, 58, 34, 49, 51, 48, 48, 55, 53, 50, 48, 48, 49,
34, 44, 13, 10, 32, 34, 104, 116, 116, 112, 58, 47,
47, 101,
120, 97, 109, 112, 108, 101, 46, 99, 111, 109, 47, 105,
115, 95, 114, 111, 111, 116, 34, 58, 116, 114, 117,
101, 125]
</p>
<p>Base64url encoding the above yields the JWT Claim Segment value:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>eyJpc3MiOiJqb2UiLA0KICJhbGciOiJIUzI1NiIsDQogImV4cCI6IjEzMDA3NTIwMDEiLA0KICJodHRwOi8vZXhhbXBsZS5jb20vaXNfcm9vdCI6dHJ1ZX0</pre></div>
<p>HMACs are generated using keys. In this case used the
key represented by the following byte array:
</p>
<p>
[105, 152, 181, 115, 44, 90, 189, 185, 83, 198, 55, 218,
221, 234, 63, 142, 206, 90, 148, 149, 172, 37, 77, 147,
161, 15, 124, 42, 114, 117, 217, 196, 125, 48, 157,
225, 41, 123, 5, 213, 133, 180, 150, 27, 107, 141, 129,
128, 220, 21, 74, 43, 213, 88, 165, 163, 169, 200, 2,
130, 153, 141, 117, 13]
</p>
<p>Running the HMAC SHA-256 algorithm on the JWT Claim Segment
with this key yields the following byte array:
</p>
<p>
[10, 197, 127, 8, 204, 35, 33, 147, 171, 232, 51, 49,
73, 178, 125, 253, 227, 137, 129, 110, 249, 205, 252,
111, 101, 223, 217, 174, 223, 6, 199, 55]
</p>
<p>Base64url encoding the above HMAC output yields the JWT Crypto Segment value:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>CsV_CMwjIZOr6DMxSbJ9_eOJgW75zfxvZd_Zrt8Gxzc</pre></div>
<p>Therefore the entire JWT is represented as the following string:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>CsV_CMwjIZOr6DMxSbJ9_eOJgW75zfxvZd_Zrt8Gxzc.eyJpc3MiOiJqb2UiLA0KICJhbGciOiJIUzI1NiIsDQogImV4cCI6IjEzMDA3NTIwMDEiLA0KICJodHRwOi8vZXhhbXBsZS5jb20vaXNfcm9vdCI6dHJ1ZX0</pre></div>
<a name="anchor11"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.12.1.2"></a><h3>12.1.2.
Decoding</h3>
<p>Decoding the JWT Claim Segment first requires removing the
base64url encoding. Per <a class='info' href='#base64urllogic'>Section 6<span> (</span><span class='info'>Base64url encoding as used by JWTs</span><span>)</span></a>,
we calculate the length of the JWT Claim Segment string, which
is 142 characters, and divide that number by 4 and get the
remainder which is 2. Per <a class='info' href='#PaddingHandling'>Table 3<span> (</span><span class='info'>Guidance on how to handle base64url encoded values without padding</span><span>)</span></a> we now know we need to add
two padding bytes. We then base64url decode the JWT Claim
Segment string and turn it into the previously provided UTF-8
byte array which we then translate into the Decoded JWT Claim
Segment string.
</p>
<a name="anchor12"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.12.1.3"></a><h3>12.1.3.
Validating</h3>
<p>Next we validate the decoded results. If any of the
validation steps fail, the token MUST be rejected.
</p>
<p>First, we validate that the resulting string is legal
JSON.
</p>
<p>To validate the signature, we repeat the previous process of
using the correct key and the JWT Claim Segment as input to a
SHA-256 HMAC function and then taking the output, base64url
encoding it, and determining if it matches the JWT Crypto
Segment in the JWT character for character. If it matches
exactly, the token has been validated.
</p>
<a name="anchor13"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.12.2"></a><h3>12.2.
JWT using RSA SHA-256</h3>
<a name="anchor14"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.12.2.1"></a><h3>12.2.1.
Encoding</h3>
<p>The Decoded JWT Claim Segment used in this example is:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>{"iss":"joe",
"alg":"RS256",
"exp":"1300752001",
"http://example.com/is_root":true}</pre></div>
<p>The only difference from the previous Decoded JWT Claim
Segment is the algorithm. However the rest of the process of
generating the value of the JWT Claim Segment is the same. The
base64url encoded output from encoding the Decoded JWT Claim
Segment is:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>eyJpc3MiOiJqb2UiLA0KICJhbGciOiJSUzI1NiIsDQogImV4cCI6IjEzMDA3NTIwMDEiLA0KICJodHRwOi8vZXhhbXBsZS5jb20vaXNfcm9vdCI6dHJ1ZX0</pre></div>
<p>The RSA key consists of a public part (n, e), and a
private exponent d. The values of the RSA key used in this
example, presented as the byte arrays representing
big endian integers are:
</p><table class="full" align="center" border="0" cellpadding="2" cellspacing="2">
<col align="left"><col align="left">
<tr><th align="left">Parameter Name</th><th align="left">Value</th></tr>
<tr>
<td align="left">n</td>
<td align="left">
[192, 93, 179, 201, 35, 204, 26, 150, 237, 155, 52, 219,
205, 109, 142, 39, 200, 91, 119, 197, 207, 224, 77, 2,
60, 109, 226, 80, 50, 133, 211, 180, 111, 212, 65, 148,
73, 239, 10, 236, 236, 179, 83, 134, 23, 253, 117, 45,
188, 75, 10, 82, 153, 76, 36, 111, 111, 108, 85, 116,
137, 148, 158, 189,
185, 213, 55, 25, 170, 218, 85, 67, 187, 148, 128, 20,
193, 21, 54, 128, 144, 92, 214, 124, 89, 19, 120, 46,
219, 193, 101, 243, 180, 248, 179, 76, 12, 192, 117,
111, 184, 228, 56, 120, 115, 108, 241, 183, 53, 119,
38, 230, 136, 20, 142, 6, 20, 232, 129, 149, 43, 111,
216, 244, 163, 174, 208, 28,
223, 120, 48, 115, 63, 165, 171, 255, 223, 248, 250,
253, 240, 140, 153, 226, 102, 190, 79, 245, 27, 101,
86, 190, 205, 194, 83, 208, 188, 86, 244, 208, 77, 64,
223, 189, 82, 156, 103, 99, 230, 214, 188, 44, 80, 63,
228, 73, 109, 251, 200, 3, 118, 107, 5, 140, 79, 159,
81, 182, 27, 159, 224, 65,
16, 187, 29, 112, 196, 44, 97, 85, 84, 89, 111, 39,
123, 174, 144, 187, 153, 166, 249, 234, 214, 152, 58,
39, 240, 205, 127, 135, 80, 249, 225, 204, 191, 110,
129, 109, 99, 67, 14, 147, 5, 184, 6, 188, 10, 49, 7,
159, 44, 118, 154, 11, 194, 208, 63, 251, 169, 97, 202,
234, 169, 91, 199, 123]
</td>
</tr>
<tr>
<td align="left">e</td>
<td align="left">
[1, 0, 1]
</td>
</tr>
<tr>
<td align="left">d</td>
<td align="left">
[185, 110, 218, 43, 47, 149, 197, 159, 238, 5, 234, 107,
99, 216, 146, 235, 40, 137, 123, 168, 180, 221, 108,
126, 150, 79, 250, 148, 2, 79, 221, 39, 23, 145, 205,
113, 171, 223, 129, 113, 168, 46, 169, 122, 30, 208,
21, 207, 243, 173, 134, 146, 222, 241, 118, 65, 241,
111, 197, 228, 163, 231, 31, 42,
150, 227, 192, 204, 190, 84, 223, 82, 126, 149, 4, 238,
124, 189, 253, 30, 235, 138, 130, 187, 181, 134, 62,
25, 53, 127, 117, 206, 250, 137, 175, 20, 197, 74, 21,
42, 144, 89, 119, 82, 45, 58, 60, 187, 182, 15, 88,
241, 107, 6, 29, 110, 33, 99, 139, 222, 134, 211, 183,
153, 3, 220, 53, 1,
160, 1, 243, 59, 221, 174, 85, 183, 207, 22, 139, 231,
144, 45, 3, 31, 198, 73, 169, 14, 81, 78, 185, 192,
169, 224, 186, 244, 76, 216, 250, 119, 165, 28, 68, 23,
215, 229, 175, 50, 165, 92, 41, 167, 193, 74, 171, 91,
72, 246, 172, 240, 234, 142, 93, 31, 101, 87, 148, 252,
173, 178, 204, 204,
51, 224, 196, 54, 98, 211, 28, 144, 15, 35, 215, 190,
128, 157, 176, 62, 87, 164, 85, 58, 128, 113, 110, 66,
163, 171, 178, 21, 178, 127, 214, 105, 207, 173, 146,
210, 21, 212, 240, 95, 129, 198, 7, 142, 159, 129, 254,
154, 249, 242, 56, 252, 101, 62, 139, 235, 144, 154,
156, 50, 76, 66, 255, 145]
</td>
</tr>
</table>
<br clear="all" />
<p>The RSA private key (n, d) is then passed to the
RSA signing function, which also takes the hash type,
SHA-256, and the JWT Claim Segment as inputs. The
result of the signature is a byte array S, which
represents a big endian integer. In this example, S
is:
</p><table class="full" align="center" border="0" cellpadding="2" cellspacing="2">
<col align="left"><col align="left">
<tr><th align="left">Result Name</th><th align="left">Value</th></tr>
<tr>
<td align="left">S</td>
<td align="left">
[35, 74, 52, 119, 211, 12, 58, 45, 255, 51, 26, 224,
119, 117, 145, 78, 145, 146, 166, 14, 235, 153, 1, 42,
234, 206, 127, 244, 8, 111, 48, 233, 126, 67, 142, 128,
125, 198, 164, 157, 140, 202, 202, 207, 51, 175, 62,
137, 186, 153, 124, 49, 20, 2, 190, 34, 63, 45, 227,
208, 28, 34, 92, 233,
167, 149, 22, 230, 163, 88, 54, 179, 84, 242, 22, 97,
132, 130, 178, 250, 56, 24, 182, 77, 15, 239, 61, 231,
227, 60, 106, 87, 195, 226, 158, 80, 197, 128, 179,
212, 181, 2, 16, 108, 81, 94, 33, 211, 228, 148, 152,
160, 196, 128, 197, 114, 104, 207, 159, 151, 237, 75,
139, 87, 79, 60, 12, 249,
119, 134, 124, 129, 109, 23, 161, 169, 210, 238, 116,
172, 203, 158, 37, 1, 232, 201, 253, 9, 128, 105, 55,
26, 141, 40, 131, 138, 179, 49, 20, 103, 196, 141, 191,
185, 134, 202, 165, 185, 231, 55, 193, 132, 187, 3,
144, 178, 82, 47, 111, 140, 241, 116, 97, 53, 102, 156,
49, 95, 229, 97, 31, 62,
246, 69, 168, 105, 2, 27, 26, 170, 116, 142, 192, 78,
123, 196, 189, 91, 110, 171, 154, 197, 34, 188, 61,
192, 161, 190, 41, 156, 209, 15, 253, 127, 41, 211, 9,
213, 26, 236, 179, 165, 9, 85, 249, 35, 130, 147, 60,
47, 179, 140, 20, 59, 156, 100, 61, 15, 193, 72, 207,
96, 241, 215, 118, 193]
</td>
</tr>
</table>
<br clear="all" />
<p>Base64url encoding the signature produces this value for the JWT
Crypto Segment:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>I0o0d9MMOi3_Mxrgd3WRTpGSpg7rmQEq6s5_9AhvMOl-Q46AfcaknYzKys8zrz6Jupl8MRQCviI_LePQHCJc6aeVFuajWDazVPIWYYSCsvo4GLZND-895-M8alfD4p5QxYCz1LUCEGxRXiHT5JSYoMSAxXJoz5-X7UuLV088DPl3hnyBbRehqdLudKzLniUB6Mn9CYBpNxqNKIOKszEUZ8SNv7mGyqW55zfBhLsDkLJSL2-M8XRhNWacMV_lYR8-9kWoaQIbGqp0jsBOe8S9W26rmsUivD3Aob4pnNEP_X8p0wnVGuyzpQlV-SOCkzwvs4wUO5xkPQ_BSM9g8dd2wQ</pre></div>
<p>The complete JWT is therefore:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>I0o0d9MMOi3_Mxrgd3WRTpGSpg7rmQEq6s5_9AhvMOl-Q46AfcaknYzKys8zrz6Jupl8MRQCviI_LePQHCJc6aeVFuajWDazVPIWYYSCsvo4GLZND-895-M8alfD4p5QxYCz1LUCEGxRXiHT5JSYoMSAxXJoz5-X7UuLV088DPl3hnyBbRehqdLudKzLniUB6Mn9CYBpNxqNKIOKszEUZ8SNv7mGyqW55zfBhLsDkLJSL2-M8XRhNWacMV_lYR8-9kWoaQIbGqp0jsBOe8S9W26rmsUivD3Aob4pnNEP_X8p0wnVGuyzpQlV-SOCkzwvs4wUO5xkPQ_BSM9g8dd2wQ.eyJpc3MiOiJqb2UiLA0KICJhbGciOiJSUzI1NiIsDQogImV4cCI6IjEzMDA3NTIwMDEiLA0KICJodHRwOi8vZXhhbXBsZS5jb20vaXNfcm9vdCI6dHJ1ZX0</pre></div>
<a name="anchor15"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.12.2.2"></a><h3>12.2.2.
Decoding</h3>
<p>Decoding the JWT from this example requires processing the
JWT Claim Segment exactly as done in the previous
examples.
</p>
<a name="anchor16"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.12.2.3"></a><h3>12.2.3.
Validating</h3>
<p>Validating the JWT Crypto Segment is a little
different. First we base64url decode the JWT Crypto Segment
to produce a signature S to check. We then pass (n, e), S
and the JWT Claim Segment to an RSA signature verifier that
has been configured to use the SHA-256 hash function.
</p>
<a name="anchor17"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.12.3"></a><h3>12.3.
JWT using ECDSA P-256 SHA-256</h3>
<a name="anchor18"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.12.3.1"></a><h3>12.3.1.
Encoding</h3>
<p>The Decoded JWT Claim Segment used in this example is:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>{"iss":"joe",
"alg":"E256S256",
"exp":"1300752001",
"http://example.com/is_root":true}</pre></div>
<p>The only difference from the previous Decoded JWT Claim
Segment is the algorithm. However the rest of the process of
generating the value of the JWT Claim Segment is the same. The
base64url encoded output from encoding the Decoded JWT Claim
Segment is:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>eyJpc3MiOiJqb2UiLA0KICJhbGciOiJFMjU2UzI1NiIsDQogImV4cCI6IjEzMDA3NTIwMDEiLA0KICJodHRwOi8vZXhhbXBsZS5jb20vaXNfcm9vdCI6dHJ1ZX0</pre></div>
<p>The ECDSA key consists of a public part, the EC point (x, y), and a
private part d. The values of the ECDSA key used in this
example, presented as the byte arrays representing
big endian integers are:
</p><table class="full" align="center" border="0" cellpadding="2" cellspacing="2">
<col align="left"><col align="left">
<tr><th align="left">Parameter Name</th><th align="left">Value</th></tr>
<tr>
<td align="left">x</td>
<td align="left">
[62, 153, 32, 76, 74, 133, 183, 28, 170, 213, 174, 17,
94, 172, 136, 221, 31, 92, 196, 11, 55, 1, 15, 185,
219, 237, 77, 48, 31, 156, 161, 121]
</td>
</tr>
<tr>
<td align="left">y</td>
<td align="left">
[63, 77, 14, 30, 95, 122, 150, 194, 139, 138, 16, 163,
165, 227, 137, 108, 222, 19, 112, 203, 101, 4, 48, 207,
38, 255, 69, 24, 73, 51, 3, 54]
</td>
</tr>
<tr>
<td align="left">d</td>
<td align="left">
[64, 134, 114, 32, 130, 253, 193, 56, 193, 53, 192, 223,
139, 141, 233, 1, 183, 198, 96, 10, 195, 211, 8, 120,
98, 101, 37, 169, 204, 144, 194, 87]
</td>
</tr>
</table>
<br clear="all" />
<p>The ECDSA private part d is then passed to an ECDSA
signing function, which also takes the curve type,
P-256, the hash type, SHA-256, and the JWT Claim
Segment as inputs. The result of the signature is the
EC point (R, S), where R and S are unsigned integers.
In this example, the R and S values, given as
byte arrays representing big endian integers are:
</p><table class="full" align="center" border="0" cellpadding="2" cellspacing="2">
<col align="left"><col align="left">
<tr><th align="left">Result Name</th><th align="left">Value</th></tr>
<tr>
<td align="left">R</td>
<td align="left">
[85, 237, 99, 139, 218, 232, 85, 26, 234, 227, 46, 243,
184, 173, 180, 108, 71, 75, 119, 187, 151, 51, 233,
103, 167, 87, 92, 138, 50, 32, 12, 97]
</td>
</tr>
<tr>
<td align="left">S</td>
<td align="left">
[213, 217, 11, 153, 95, 157, 245, 189, 103, 221, 211,
66, 96, 230, 228, 26, 73, 215, 75, 249, 29, 115, 49,
79, 255, 245, 42, 15, 174, 249, 108, 188]
</td>
</tr>
</table>
<br clear="all" />
<p>Concatenating the S array to the end of the R array and
base64url encoding the result produces this value for the JWT
Crypto Segment:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>Ve1ji9roVRrq4y7zuK20bEdLd7uXM-lnp1dcijIgDGHV2QuZX531vWfd00Jg5uQaSddL-R1zMU__9SoPrvlsvA</pre></div>
<p>The complete JWT is therefore:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>Ve1ji9roVRrq4y7zuK20bEdLd7uXM-lnp1dcijIgDGHV2QuZX531vWfd00Jg5uQaSddL-R1zMU__9SoPrvlsvA.eyJpc3MiOiJqb2UiLA0KICJhbGciOiJFMjU2UzI1NiIsDQogImV4cCI6IjEzMDA3NTIwMDEiLA0KICJodHRwOi8vZXhhbXBsZS5jb20vaXNfcm9vdCI6dHJ1ZX0</pre></div>
<a name="anchor19"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.12.3.2"></a><h3>12.3.2.
Decoding</h3>
<p>Decoding the JWT from this example requires processing the
JWT Claim Segment exactly as done in the previous
examples.
</p>
<a name="anchor20"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.12.3.3"></a><h3>12.3.3.
Validating</h3>
<p>Validating the JWT Crypto Segment is a little
different. We must base64url decode the JWT Crypto Segment as
in the previous examples but we then need to split the 64
member byte array that must result into two 32 byte arrays,
the first R and the second S. We then have to pass (x, y), (R, S)
and the JWT Claim Segment to an ECDSA signature verifier that
has been configured to use the P-256 curve with the SHA-256
hash function.
</p>
<p>As explained in <a class='info' href='#DefiningECDSA'>Section 7.3<span> (</span><span class='info'>Signing a JWT with ECDSA P-256 SHA-256</span><span>)</span></a>, the
use of the k value in ECDSA means that we cannot validate the
correctness of the signature in the same way we validated the
correctness of the HMAC. Instead, implementations MUST use an
ECDSA validator to validate the signature.
</p>
<a name="anchor21"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.13"></a><h3>13.
Appendix - Non-Normative - Relationship of JWTs to SAML Tokens</h3>
<p><a class='info' href='#OASIS.saml-core-2.0-os'>SAML 2.0<span> (</span><span class='info'>Cantor, S., Kemp, J., Philpott, R., and E. Maler, “Assertions and Protocol for the OASIS Security Assertion Markup Language (SAML) V2.0,” March 2005.</span><span>)</span></a> [OASIS.saml‑core‑2.0‑os]
provides a standard for creating tokens with much greater
expressivity and more security options than supported by
JWTs. However, the cost of this flexibility and expressiveness
is both size and complexity. In addition, SAML's use of <a class='info' href='#W3C.CR-xml11-20021015'>XML<span> (</span><span class='info'>Cowan, J., “Extensible Markup Language (XML) 1.1,” October 2002.</span><span>)</span></a> [W3C.CR‑xml11‑20021015] and <a class='info' href='#RFC3275'>XML DSIG<span> (</span><span class='info'>Eastlake, D., Reagle, J., and D. Solo, “(Extensible Markup Language) XML-Signature Syntax and Processing,” March 2002.</span><span>)</span></a> [RFC3275] only contributes to the size of
SAML tokens.
</p>
<p>JWTs are intended to provide a simple token format
that is small enough to fit into HTTP headers and query arguments in
URIs. It does this by supporting a much simpler token model than
SAML and using the <a class='info' href='#RFC4627'>JSON<span> (</span><span class='info'>Crockford, D., “The application/json Media Type for JavaScript Object Notation (JSON),” July 2006.</span><span>)</span></a> [RFC4627] object encoding
syntax. It also supports securing tokens using Hash-based Message
Authentication Codes (HMACs) and digital signatures using a smaller (and
less flexible) format than XML DSIG.
</p>
<p>Therefore, while JWTs can do some of the things SAML tokens
do, JWTs are not intended as a full replacement for SAML tokens, but
rather as a compromise token format to be used when space is at a
premium.
</p>
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<a name="rfc.section.14"></a><h3>14.
Appendix - Non-Normative - Relationship of JWTs to Simple Web Tokens (SWTs)</h3>
<p>Both JWTs and Simple Web Tokens <a class='info' href='#SWT'>SWT<span> (</span><span class='info'>Hardt, D. and Y. Goland, “Simple Web Token (SWT),” November 2009.</span><span>)</span></a> [SWT], at their core, enable sets of claims to
be communicated between applications. For SWTs, both the claim
names and claim values are strings. For JWTs, while
claim names are strings, claim values can be any JSON type.
Both token types require cryptographic protection of their
content: SWTs with HMAC SHA-256 and JWTs with a choice of
algorithms, including HMAC SHA-256, RSA SHA-256, and ECDSA P-256
SHA-256.
</p>
<a name="rfc.references"></a><br /><hr />
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<a name="rfc.section.15"></a><h3>15.
References</h3>
<a name="rfc.references1"></a><br /><hr />
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<h3>15.1. Normative References</h3>
<table width="99%" border="0">
<tr><td class="author-text" valign="top"><a name="FIPS.180-3">[FIPS.180-3]</a></td>
<td class="author-text">National Institute of Standards and
Technology, “<a href="http://csrc.nist.gov/publications/fips/fips180-3/fips180-3_final.pdf">Secure Hash Standard (SHS)</a>,” FIPS PUB 180-3, October 2008.</td></tr>
<tr><td class="author-text" valign="top"><a name="FIPS.186-3">[FIPS.186-3]</a></td>
<td class="author-text">National Institute of Standards and
Technology, “<a href="http://csrc.nist.gov/publications/fips/fips186-3/fips_186-3.pdf">Digital Signature Standard (DSS)</a>,” FIPS PUB 186-3, June 2009.</td></tr>
<tr><td class="author-text" valign="top"><a name="RFC2104">[RFC2104]</a></td>
<td class="author-text"><a href="mailto:hugo@watson.ibm.com">Krawczyk, H.</a>, <a href="mailto:mihir@cs.ucsd.edu">Bellare, M.</a>, and <a href="mailto:canetti@watson.ibm.com">R. Canetti</a>, “<a href="http://tools.ietf.org/html/rfc2104">HMAC: Keyed-Hashing for Message Authentication</a>,” RFC 2104, February 1997 (<a href="http://www.rfc-editor.org/rfc/rfc2104.txt">TXT</a>).</td></tr>
<tr><td class="author-text" valign="top"><a name="RFC2119">[RFC2119]</a></td>
<td class="author-text"><a href="mailto:sob@harvard.edu">Bradner, S.</a>, “<a href="http://tools.ietf.org/html/rfc2119">Key words for use in RFCs to Indicate Requirement Levels</a>,” BCP 14, RFC 2119, March 1997 (<a href="http://www.rfc-editor.org/rfc/rfc2119.txt">TXT</a>, <a href="http://xml.resource.org/public/rfc/html/rfc2119.html">HTML</a>, <a href="http://xml.resource.org/public/rfc/xml/rfc2119.xml">XML</a>).</td></tr>
<tr><td class="author-text" valign="top"><a name="RFC3339">[RFC3339]</a></td>
<td class="author-text"><a href="mailto:GK@ACM.ORG">Klyne, G., Ed.</a> and <a href="mailto:chris.newman@sun.com">C. Newman</a>, “<a href="http://tools.ietf.org/html/rfc3339">Date and Time on the Internet: Timestamps</a>,” RFC 3339, July 2002 (<a href="http://www.rfc-editor.org/rfc/rfc3339.txt">TXT</a>, <a href="http://xml.resource.org/public/rfc/html/rfc3339.html">HTML</a>, <a href="http://xml.resource.org/public/rfc/xml/rfc3339.xml">XML</a>).</td></tr>
<tr><td class="author-text" valign="top"><a name="RFC3447">[RFC3447]</a></td>
<td class="author-text">Jonsson, J. and B. Kaliski, “<a href="http://tools.ietf.org/html/rfc3447">Public-Key Cryptography Standards (PKCS) #1: RSA Cryptography Specifications Version 2.1</a>,” RFC 3447, February 2003 (<a href="http://www.rfc-editor.org/rfc/rfc3447.txt">TXT</a>).</td></tr>
<tr><td class="author-text" valign="top"><a name="RFC3629">[RFC3629]</a></td>
<td class="author-text">Yergeau, F., “<a href="http://tools.ietf.org/html/rfc3629">UTF-8, a transformation format of ISO 10646</a>,” STD 63, RFC 3629, November 2003 (<a href="http://www.rfc-editor.org/rfc/rfc3629.txt">TXT</a>).</td></tr>
<tr><td class="author-text" valign="top"><a name="RFC3986">[RFC3986]</a></td>
<td class="author-text"><a href="mailto:timbl@w3.org">Berners-Lee, T.</a>, <a href="mailto:fielding@gbiv.com">Fielding, R.</a>, and <a href="mailto:LMM@acm.org">L. Masinter</a>, “<a href="http://tools.ietf.org/html/rfc3986">Uniform Resource Identifier (URI): Generic Syntax</a>,” STD 66, RFC 3986, January 2005 (<a href="http://www.rfc-editor.org/rfc/rfc3986.txt">TXT</a>, <a href="http://xml.resource.org/public/rfc/html/rfc3986.html">HTML</a>, <a href="http://xml.resource.org/public/rfc/xml/rfc3986.xml">XML</a>).</td></tr>
<tr><td class="author-text" valign="top"><a name="RFC4627">[RFC4627]</a></td>
<td class="author-text">Crockford, D., “<a href="http://tools.ietf.org/html/rfc4627">The application/json Media Type for JavaScript Object Notation (JSON)</a>,” RFC 4627, July 2006 (<a href="http://www.rfc-editor.org/rfc/rfc4627.txt">TXT</a>).</td></tr>
<tr><td class="author-text" valign="top"><a name="RFC4648">[RFC4648]</a></td>
<td class="author-text">Josefsson, S., “<a href="http://tools.ietf.org/html/rfc4648">The Base16, Base32, and Base64 Data Encodings</a>,” RFC 4648, October 2006 (<a href="http://www.rfc-editor.org/rfc/rfc4648.txt">TXT</a>).</td></tr>
<tr><td class="author-text" valign="top"><a name="RFC5226">[RFC5226]</a></td>
<td class="author-text">Narten, T. and H. Alvestrand, “<a href="http://tools.ietf.org/html/rfc5226">Guidelines for Writing an IANA Considerations Section in RFCs</a>,” BCP 26, RFC 5226, May 2008 (<a href="http://www.rfc-editor.org/rfc/rfc5226.txt">TXT</a>).</td></tr>
<tr><td class="author-text" valign="top"><a name="USA15">[USA15]</a></td>
<td class="author-text"><a href="mailto:markdavis@google.com">Davis, M.</a>, <a href="mailto:ken@unicode.org">Whistler, K.</a>, and M. Dürst, “Unicode Normalization Forms,” Unicode Standard Annex 15, 09 2009.</td></tr>
</table>
<a name="rfc.references2"></a><br /><hr />
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<h3>15.2. Informative References</h3>
<table width="99%" border="0">
<tr><td class="author-text" valign="top"><a name="OASIS.saml-core-2.0-os">[OASIS.saml-core-2.0-os]</a></td>
<td class="author-text"><a href="mailto:cantor.2@osu.edu">Cantor, S.</a>, <a href="mailto:John.Kemp@nokia.com">Kemp, J.</a>, <a href="mailto:rphilpott@rsasecurity.com">Philpott, R.</a>, and <a href="mailto:eve.maler@sun.com">E. Maler</a>, “<a href="http://docs.oasis-open.org/security/saml/v2.0/saml-core-2.0-os.pdf">Assertions and Protocol for the OASIS Security Assertion Markup Language
(SAML) V2.0</a>,” OASIS Standard saml-core-2.0-os, March 2005.</td></tr>
<tr><td class="author-text" valign="top"><a name="RFC3275">[RFC3275]</a></td>
<td class="author-text">Eastlake, D., Reagle, J., and D. Solo, “<a href="http://tools.ietf.org/html/rfc3275">(Extensible Markup Language) XML-Signature Syntax and Processing</a>,” RFC 3275, March 2002 (<a href="http://www.rfc-editor.org/rfc/rfc3275.txt">TXT</a>).</td></tr>
<tr><td class="author-text" valign="top"><a name="RFC4122">[RFC4122]</a></td>
<td class="author-text"><a href="mailto:paulle@microsoft.com">Leach, P.</a>, <a href="mailto:michael@refactored-networks.com">Mealling, M.</a>, and <a href="mailto:rsalz@datapower.com">R. Salz</a>, “<a href="http://tools.ietf.org/html/rfc4122">A Universally Unique IDentifier (UUID) URN Namespace</a>,” RFC 4122, July 2005 (<a href="http://www.rfc-editor.org/rfc/rfc4122.txt">TXT</a>, <a href="http://xml.resource.org/public/rfc/html/rfc4122.html">HTML</a>, <a href="http://xml.resource.org/public/rfc/xml/rfc4122.xml">XML</a>).</td></tr>
<tr><td class="author-text" valign="top"><a name="SWT">[SWT]</a></td>
<td class="author-text">Hardt, D. and Y. Goland, “<a href="http://oauth-wrap-wg.googlegroups.com/web/SWT-v0.9.5.1.pdf?gda=Sn4MsEMAAABFB7PFAFiVedPtjcqT8uuIImHXUksNUKMXLyrSumAs_dF2tzlQ33RhT1wW8BFYO1QytiJ-HdGYYcPi_09pl8N7FWLveOaWjzbYnpnkpmxcWg">Simple Web Token (SWT)</a>,” Version 0.9.5.1, November 2009.</td></tr>
<tr><td class="author-text" valign="top"><a name="W3C.CR-xml11-20021015">[W3C.CR-xml11-20021015]</a></td>
<td class="author-text">Cowan, J., “<a href="http://www.w3.org/TR/2002/CR-xml11-20021015">Extensible Markup Language (XML) 1.1</a>,” W3C CR CR-xml11-20021015, October 2002.</td></tr>
</table>
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<h3>Authors' Addresses</h3>
<table width="99%" border="0" cellpadding="0" cellspacing="0">
<tr><td class="author-text"> </td>
<td class="author-text">Yaron Goland</td></tr>
<tr><td class="author-text"> </td>
<td class="author-text">Microsoft</td></tr>
<tr cellpadding="3"><td> </td><td> </td></tr>
<tr><td class="author-text"> </td>
<td class="author-text">Michael B. Jones</td></tr>
<tr><td class="author-text"> </td>
<td class="author-text">Microsoft</td></tr>
</table>
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