One document matched: draft-hammer-oauth-v2-mac-token-00.xml
<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE rfc SYSTEM 'rfc2629.dtd'>
<?xml-stylesheet type='text/xsl' href='rfc2629.xslt' ?>
<rfc category='std' ipr='trust200902' docName='draft-hammer-oauth-v2-mac-token-00'>
<?rfc strict='yes' ?>
<?rfc toc='yes' ?>
<?rfc tocdepth='3' ?>
<?rfc symrefs='yes' ?>
<?rfc sortrefs='yes' ?>
<?rfc compact='yes' ?>
<?rfc subcompact='no' ?>
<front>
<title abbrev='OAuth 2.0 MAC Token'>OAuth 2.0 MAC Token and Authentication</title>
<author fullname='Eran Hammer-Lahav' surname='Hammer-Lahav' initials='E'>
<organization>Yahoo!</organization>
<address>
<email>eran@hueniverse.com</email>
<uri>http://hueniverse.com</uri>
</address>
</author>
<date year='2011'/>
<abstract>
<t>
This document specifies the OAuth 2.0 MAC token type and authentication scheme.
</t>
</abstract>
</front>
<middle>
<section title='Introduction'>
<t>
OAuth 2.0 (<xref target='I-D.ietf-oauth-v2' />) defines a token-based authentication
framework in which third-party applications (clients) access protected resources using
access tokens. Access tokens are obtained via the resource owners' authorization from an
authorization server.
</t>
<t>
This specification defines the MAC token type for use with the OAuth 2.0 framework. It
defines type-specific token attributes and provides a method for making authenticated HTTP
requests with partial cryptographic verification of the request - covering the HTTP
method, request URI, host, and in some cases the request body.
</t>
<t>
This specification does not define methods for the client to specifically request a
MAC-type token from the authorization server. Additionally, it does not include any
discovery facilities for identifying which token types are supported by a resource server
or how the client may go about obtaining access tokens. This specification assumes that the
authorization server has issued the client a MAC-type token and describes how the client
authenticates using that access token.
</t>
<t>
The MAC token type is not compatible with the <spanx style='verb'>HMAC-SHA1</spanx>
signature method defined in <xref target='RFC5849'>OAuth 1.0</xref>.
</t>
<t>
This specification is an extension of <xref target='I-D.ietf-oauth-v2' /> and uses its
terminology.
</t>
<t>
Please discuss this draft on the
<eref target='https://www.ietf.org/mailman/listinfo/oauth'>oauth@ietf.org</eref> mailing
list.
</t>
<section title='Example'>
<figure>
<preamble>
The client attempts to access a protected resource without authentication, making the
following HTTP request to the resource server:
</preamble>
<artwork>
<![CDATA[
GET /resource/1?b=1&a=2 HTTP/1.1
Host: example.com
]]>
</artwork>
</figure>
<figure>
<preamble>
The resource server returns the following authentication challenge:
</preamble>
<artwork>
<![CDATA[
HTTP/1.1 401 Unauthorized
WWW-Authenticate: OAuth2
Date: Thu, 02 Dec 2010 21:39:45 GMT
]]>
</artwork>
</figure>
<t>
The client has previously obtained a set of token credentials for accessing resources on
the <spanx style='verb'>http://example.com/</spanx> resource server. The credentials issued to the
client by the authorization server included the following attributes:
<list style='hanging' hangIndent='6'>
<t hangText='Access token:'>h480djs93hd8</t>
<t hangText='Token type:'>mac</t>
<t hangText='MAC algorithm:'>hmac-sha-1</t>
<t hangText='Token secret:'>489dks293j39</t>
</list>
</t>
<t>
The client attempts the HTTP request again, this time using the token credentials
issued by the authorization server earlier to authenticate. To construct the
authentication header, the client calculates the current timestamp and a nonce. The nonce
is unique to the timestamp used, typically a random string:
<list style='hanging' hangIndent='6'>
<t hangText='Timestamp:'>137131200</t>
<t hangText='Nonce:'>dj83hs9s</t>
</list>
</t>
<t>
The client normalizes the request and constructs the signature base string (the new line
separator character is represented by <spanx style='verb'>\n</spanx> for display purposes
only):
</t>
<figure>
<artwork>
<![CDATA[
h480djs93hd8\n
137131200\n
dj83hs9s\n
GET\n
example.com\n
80\n
/resource/1\n
a=2\n
b=1
]]>
</artwork>
</figure>
<t>
The signature base string is signed using the specified MAC token algorithm
<spanx style='verb'>hmac-sha-1</spanx> with the signature base string as text and the
token secret as key. The resulting digest is base64-encoded to produce the request
signature:
</t>
<figure>
<artwork>
<![CDATA[
IdSrHQHTwCPWGrqzGGIR791ZJXE=
]]>
</artwork>
</figure>
<t>
The client includes the access token, timestamp, nonce, and signature with the request
using the <spanx style='verb'>Authorization</spanx> request header field:
</t>
<figure>
<artwork>
<![CDATA[
GET /resource/1 HTTP/1.1
Host: example.com
Authorization: MAC token='h480djs93hd8',
timestamp='137131200',
nonce='dj83hs9s',
signature='IdSrHQHTwCPWGrqzGGIR791ZJXE='
]]>
</artwork>
</figure>
<t>
The resource server validates the request by calculating the signature again based on the
request received and verifies the validity and scope of the access token. If valid, the
resource server responds with the requested protected resource representation.
</t>
</section>
<section title='Notational Conventions'>
<t>
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
<xref target='RFC2119' />.
</t>
<t>
This document uses the Augmented Backus-Naur Form (ABNF) notation of
<xref target='I-D.ietf-httpbis-p1-messaging' />.
</t>
</section>
</section>
<section title='Issuing MAC-Type Access Tokens' anchor='issue'>
<t>
Authorization servers issuing MAC-type access tokens MUST include the following parameters
whenever a response includes the <spanx style='verb'>access_token</spanx> parameter:
<list style='hanging' hangIndent='6'>
<t hangText='secret'>
<vspace />
REQUIRED. The token shared secret used as the MAC algorithm key.
</t>
<t hangText='algorithm'>
<vspace />
REQUIRED. The MAC algorithm used to calculate the request signature. Value MUST be one
of <spanx style='verb'>hmac-sha-1</spanx>, <spanx style='verb'>hmac-sha-256</spanx>, or
a registered extension algorithm name as described in <xref target='extensions' />.
</t>
</list>
</t>
</section>
<section title='Making Requests' anchor='requests'>
<t>
To make authenticated requests, the client must be in possession of a valid MAC-type access
token, issued by an authorization server accepted by the resource server. The client
constructs the request by calculating of a set of attributes, and adding them to the HTTP
request using the <xref target='authz_header'>Authorization header field</xref>.
Authenticated request can be sent in response to an authentication challenge or directly.
</t>
<section title='The Authorization Request Header' anchor='authz_header'>
<t>
The <spanx style='verb'>Authorization</spanx> request header field uses the framework
defined by <xref target='RFC2617' /> as follows:
</t>
<figure>
<artwork>
<![CDATA[
credentials = 'MAC' [ RWS 1#param ]
param = access-token /
timestamp /
nonce /
signature
access-token = 'token' '=' quoted-string
timestamp = 'timestamp' '=' <"> 1*DIGIT <">
nonce = 'nonce' '=' quoted-string
signature = 'signature' '=' quoted-string
]]>
</artwork>
</figure>
<t>
The <spanx style='verb'>token</spanx> attribute value is set to the access token received
from the authorization server.
</t>
<t>
The <spanx style='verb'>timestamp</spanx> attribute value is set to the current time
expressed in the number of seconds since January 1, 1970 00:00:00 GMT, and MUST be a
positive integer.
</t>
<t>
The <spanx style='verb'>nonce</spanx> attribute value is set to a random string, uniquely
generated by the client to allow the resource server to verify that a request has never
been made before and helps prevent replay attacks when requests are made over an insecure
channel. The nonce value MUST be unique across all requests with the same timestamp and
access token combination.
</t>
<t>
To avoid the need to retain an infinite number of nonce values for future checks, servers
MAY choose to restrict the time period after which a request with an old timestamp is
rejected. Such a restriction implies a level of synchronization between the client's and
server's clocks. The client MAY use the <spanx style='verb'>Date</spanx> response header
field to synchronize its clock after a failed request.
</t>
<t>
The <spanx style='verb'>signature</spanx> attribute value is set as described in
<xref target='signature' />.
</t>
<t>
Each of the four attributes MUST appear once, and only once.
</t>
</section>
<section title='Signature' anchor='signature'>
<t>
The client uses the MAC token algorithm and the access token secret - both provided by
the authorization server - to calculate the request signature. This specification defines
two algorithms: <spanx style='verb'>hmac-sha-1</spanx> and
<spanx style='verb'>hmac-sha-256</spanx>, and provides an extension registry for
additional algorithms.
</t>
<section title='Normalized Request String' anchor='base_string'>
<t>
The normalized request string is a consistent, reproducible concatenation of several of
the HTTP request elements into a single string. By normalizing the request into a
reproducible string, the client and resource server can both sign the same string. The
string is constructed by concatenating together, in order, the following HTTP request
elements:
<list style='numbers'>
<t>
The access token.
</t>
<t>
A new line character (ASCII code 10).
</t>
<t>
The timestamp value calculated for the request.
</t>
<t>
A new line character (ASCII code 10).
</t>
<t>
The nonce value generated for the request.
</t>
<t>
A new line character (ASCII code 10).
</t>
<t>
The HTTP request method in upper case. For example: <spanx style='verb'>HEAD</spanx>,
<spanx style='verb'>GET</spanx>, <spanx style='verb'>POST</spanx>, etc.
</t>
<t>
A new line character (ASCII code 10).
</t>
<t>
The hostname included in the HTTP request using the <spanx style='verb'>Host</spanx>
request header field in lower case.
</t>
<t>
A new line character (ASCII code 10).
</t>
<t>
The port as included in the HTTP request using the
<spanx style='verb'>Host</spanx> request header field. If the header field does not
include a port, the default value for the scheme MUST be used (e.g. 80 for HTTP and
443 for HTTPS).
</t>
<t>
A new line character (ASCII code 10).
</t>
<t>
The path component of the HTTP request URI as defined by <xref target='RFC3986' />
section 3.3.
</t>
<t>
A new line character (ASCII code 10).
</t>
<t>
The query component of the HTTP request URI as defined by <xref target='RFC3986' />
section 3.4, normalized as described in <xref target='parameters' />.
</t>
</list>
</t>
<figure>
<preamble>
For example, the HTTP request:
</preamble>
<artwork>
<![CDATA[
GET /request?b5=%3D%253D&a3=a&c%40=&a2=r%20b&c2&a3=2+q HTTP/1.1
Host: example.com
]]>
</artwork>
<postamble>
using access token <spanx style="verb">kkk9d7dh3k39sjv7</spanx>, timestamp
<spanx style="verb">137131201</spanx>, and nonce <spanx style="verb">7d8f3e4a</spanx>
is normalized into the following string (the new line Separator character is
represented by <spanx style='verb'>\n</spanx> for display purposes only):
</postamble>
</figure>
<figure>
<artwork>
<![CDATA[
kkk9d7dh3k39sjv7\n
137131201\n
7d8f3e4a\n
GET\n
example.com\n
80\n
/request\n
a2=r%20b\n
a3=2%20q\n
a3=a\n
b5=%3D%253D\n
c%40=\n
c2=
]]>
</artwork>
</figure>
<section title="Parameters Normalization" anchor="parameters">
<t>
The query component is parsed into a list of name/value parameter pairs by
treating it as an <spanx style="verb">application/x-www-form-urlencoded</spanx>
string, separating the names and values and decoding them as defined by
<xref target="W3C.REC-html401-19991224" /> section 17.13.4.
</t>
<t>
Once separated and decoded, the parameters are concatenated back together as
follows:
<list style="numbers">
<t>
First, the name and value of each parameter are escaped using the
<xref target="RFC3986" /> percent-encoding (%XX) mechanism. Characters in the
unreserved character set as defined by <xref target="RFC3986" /> section 2.3
(ALPHA, DIGIT, "-", ".", "_", "~") MUST NOT be encoded. All other characters MUST
be encoded. The two hexadecimal characters used to represent encoded characters
MUST be upper case.
</t>
<t>
The parameters are sorted by name, using ascending byte value ordering. If
two or more parameters share the same name, they are sorted by their value.
</t>
<t>
The name of each parameter is concatenated to its corresponding value using an
<spanx style="verb">=</spanx> character (ASCII code 61) as separator, even if the
value is empty.
</t>
<t>
The sorted name/value pairs are concatenated together into a single string by
using an new line character (ASCII code 10) as separator.
</t>
</list>
</t>
<t>
Note that the percent-encoding method described is different from the encoding scheme
used by the <spanx style="verb">application/x-www-form-urlencoded</spanx>
content-type (for example, it encodes space characters as
<spanx style="verb">%20</spanx> instead of the <spanx style="verb">+</spanx>
character). It MAY be different from the percent-encoding functions provided by web
development frameworks (e.g. encode different characters, use lower case hexadecimal
characters).
</t>
<figure>
<preamble>
For example, the HTTP request URI:
</preamble>
<artwork>
<![CDATA[
/request?b5=%3D%253D&a3=a&c%40=&a2=r%20b&c2&a3=2+q
]]>
</artwork>
<postamble>
Contains the following (fully decoded) parameters used in the signature base
sting:
</postamble>
</figure>
<texttable>
<ttcol align='center'>Name</ttcol>
<ttcol align='center'>Value</ttcol>
<c>b5</c>
<c>=%3D</c>
<c>a3</c>
<c>a</c>
<c>c@</c>
<c></c>
<c>a2</c>
<c>r b</c>
<c>c2</c>
<c></c>
<c>a3</c>
<c>2 q</c>
</texttable>
<t>
Note that the value of <spanx style="verb">b5</spanx> is <spanx style="verb">=%3D</spanx>
and not <spanx style="verb">==</spanx>. Both <spanx style="verb">c@</spanx> and
<spanx style="verb">c2</spanx> have empty values. While the encoding rules
specified in this specification for the purpose of constructing the signature base
string exclude the use of a <spanx style="verb">+</spanx> character (ASCII code 43)
to represent an encoded space character (ASCII code 32), this practice is widely
used in <spanx style="verb">application/x-www-form-urlencoded</spanx> encoded
values, and MUST be properly decoded, as demonstrated by one of the
<spanx style="verb">a3</spanx> parameter instances (the <spanx style="verb">a3</spanx>
parameter is used twice in this request).
</t>
<t>
The parsed parameters are normalized as follows:
</t>
<texttable>
<preamble>
Encoded:
</preamble>
<ttcol align='center'>Name</ttcol>
<ttcol align='center'>Value</ttcol>
<c>b5</c>
<c>%3D%253D</c>
<c>a3</c>
<c>a</c>
<c>c%40</c>
<c></c>
<c>a2</c>
<c>r%20b</c>
<c>c2</c>
<c></c>
<c>a3</c>
<c>2%20q</c>
</texttable>
<texttable>
<preamble>
Sorted:
</preamble>
<ttcol align='center'>Name</ttcol>
<ttcol align='center'>Value</ttcol>
<c>a2</c>
<c>r%20b</c>
<c>a3</c>
<c>2%20q</c>
<c>a3</c>
<c>a</c>
<c>b5</c>
<c>%3D%253D</c>
<c>c%40</c>
<c></c>
<c>c2</c>
<c></c>
</texttable>
<texttable>
<preamble>
Concatenated Pairs:
</preamble>
<ttcol align='center'>Name=Value</ttcol>
<c>a2=r%20b</c>
<c>a3=2%20q</c>
<c>a3=a</c>
<c>b5=%3D%253D</c>
<c>c%40=</c>
<c>c2=</c>
</texttable>
<figure>
<preamble>
And concatenated together into a single string (the new line separator character is
represented by <spanx style='verb'>\n</spanx> for display purposes only):
</preamble>
<artwork>
<![CDATA[
a2=r%20b\n
a3=2%20q\n
a3=a\n
b5=%3D%253D\n
c%40=\n
c2=
]]>
</artwork>
</figure>
</section>
</section>
<section title='hmac-sha-1'>
<t>
<spanx style='verb'>hmac-sha-1</spanx> uses the HMAC-SHA1 algorithm as defined in
<xref target='RFC2104' />:
<figure>
<artwork>
<![CDATA[
digest = HMAC-SHA1 (key, text)
]]>
</artwork>
</figure>
</t>
<t>
Where:
<list style='hanging' hangIndent='6'>
<t hangText='text'>
<vspace />
is set to the value of the normalize request string as described in
<xref target='base_string' />.
</t>
<t hangText='key'>
<vspace />
is set to the access token shared-secret provided by the authorization server.
</t>
<t hangText='digest'>
<vspace />
is used to set the value of the <spanx style='verb'>signature</spanx> attribute,
after the result octet string is base64-encoded per <xref target='RFC2045' />
section 6.8.
</t>
</list>
</t>
</section>
<section title='hmac-sha-256'>
<t>
<spanx style='verb'>hmac-sha-1</spanx> uses the HMAC algorithm as defined in
<xref target='RFC2104' /> together with the SHA-256 hash function defined in
<xref target='NIST FIPS-180-3' />:
<figure>
<artwork>
<![CDATA[
digest = HMAC-SHA256 (key, text)
]]>
</artwork>
</figure>
</t>
<t>
Where:
<list style='hanging' hangIndent='6'>
<t hangText='text'>
<vspace />
is set to the value of the normalize request string as described in
<xref target='base_string' />.
</t>
<t hangText='key'>
<vspace />
is set to the access token shared-secret provided by the authorization server.
</t>
<t hangText='digest'>
<vspace />
is used to set the value of the <spanx style='verb'>signature</spanx> attribute,
after the result octet string is base64-encoded per <xref target='RFC2045' />
section 6.8.
</t>
</list>
</t>
</section>
</section>
</section>
<section title='Verifying Requests' anchor='verify_request'>
<t>
A servers receiving an authenticated request validates it by performing the following
REQUIRED steps:
<list style='numbers'>
<t>
Recalculate the request signature as described in <xref target='signature' /> and
compare it to the value received from the client via the
<spanx style='verb'>signature</spanx> attribute.
</t>
<t>
Ensure that the combination of nonce, timestamp, and access token received from the
client has not been used before in a previous request (the server MAY reject requests
with stale timestamps; the determination of staleness is left up to the server to
define).
</t>
<t>
Verify the scope and status of the access token.
</t>
</list>
</t>
<t>
If the request fails verification, the server SHOULD respond with an HTTP 401 (unauthorized)
status code, and SHOULD include a token scheme authentication challenge using the
WWW-Authenticate header field. The server MAY include
further details about why the request was rejected using the
error attribute.
</t>
</section>
<section title='Scheme Extensions' anchor='extensions'>
<t>
[[ TBD ]]
</t>
</section>
<section title='Security Considerations' anchor='Security'>
<t>
As stated in <xref target='RFC2617' />, the greatest sources of risks are usually found not
in the core protocol itself but in policies and procedures surrounding its use. Implementers
are strongly encouraged to assess how this protocol addresses their security requirements.
</t>
<section title='Secrets Transmission'>
<t>
This specification does not describe any mechanism for obtaining or transmitting access
token secrets. Methods used to obtain tokens should ensure that these transmissions are
protected using transport-layer mechanisms such as TLS or SSL.
</t>
</section>
<section title='Confidentiality of Requests'>
<t>
While this protocol provides a mechanism for verifying the integrity of requests, it
provides no guarantee of request confidentiality. Unless further precautions are taken,
eavesdroppers will have full access to request content. Servers should carefully consider
the kinds of data likely to be sent as part of such requests, and should employ
transport-layer security mechanisms to protect sensitive resources.
</t>
</section>
<section title='Spoofing by Counterfeit Servers'>
<t>
This protocol makes no attempt to verify the authenticity of the resource server. A
hostile party could take advantage of this by intercepting the client's requests and
returning misleading or otherwise incorrect responses. Service providers should consider
such attacks when developing services using this protocol, and should require
transport-layer security for any requests where the authenticity of the resource server
or of request responses is an issue.
</t>
</section>
<section title='Plaintext Storage of Credentials'>
<t>
The access token shared-secret functions the same way passwords do in traditional
authentication systems. In order to compute the signature, the server must have access to
the secret in plaintext form. This is in contrast, for example, to modern operating
systems, which store only a one-way hash of user credentials.
</t>
<t>
If an attacker were to gain access to these secrets - or worse, to the server's database
of all such secrets - he or she would be able to perform any action on behalf of any
resource owner. Accordingly, it is critical that servers protect these secrets from
unauthorized access.
</t>
</section>
<section title='Entropy of Secrets'>
<t>
Unless a transport-layer security protocol is used, eavesdroppers will have full access
to authenticated requests and signatures, and will thus be able to mount offline brute-force
attacks to recover the secret used. Authorization servers should be careful to assign
shared-secrets which are long enough, and random enough, to resist such attacks for at
least the length of time that the shared-secrets are valid.
</t>
<t>
For example, if shared-secrets are valid for two weeks, authorization servers should
ensure that it is not possible to mount a brute force attack that recovers the
shared-secret in less than two weeks. Of course, authorization servers are urged to err
on the side of caution, and use the longest secrets reasonable.
</t>
<t>
It is equally important that the pseudo-random number generator (PRNG) used to generate
these secrets be of sufficiently high quality. Many PRNG implementations generate number
sequences that may appear to be random, but which nevertheless exhibit patterns or other
weaknesses which make cryptanalysis or brute force attacks easier. Implementers should be
careful to use cryptographically secure PRNGs to avoid these problems.
</t>
</section>
<section title='Denial of Service / Resource Exhaustion Attacks'>
<t>
This specification includes a number of features which may make resource exhaustion
attacks against servers possible. For example, this protocol requires servers to track
used nonces. If an attacker is able to use many nonces quickly, the resources required to
track them may exhaust available capacity. And again, this protocol can require servers
to perform potentially expensive computations in order to verify the signature on
incoming requests. An attacker may exploit this to perform a denial of service attack by
sending a large number of invalid requests to the server.
</t>
<t>
Resource Exhaustion attacks are by no means specific to this specification. However,
implementers should be careful to consider the additional avenues of attack that this
protocol exposes, and design their implementations accordingly. For example, entropy
starvation typically results in either a complete denial of service while the system
waits for new entropy or else in weak (easily guessable) secrets. When implementing this
protocol, servers should consider which of these presents a more serious risk for their
application and design accordingly.
</t>
</section>
<section title='Coverage Limitations'>
<t>
The normalized request string has been designed to support the authentication methods
defined in this specification. Those designing additional methods, should evaluated the
compatibility of the normalized request string with their security requirements.
Since the normalized request string does not cover the entire HTTP request, servers
should employ additional mechanisms to protect such elements.
</t>
</section>
</section>
<section title='IANA Considerations' anchor='IANA'>
<section title='The "secret" OAuth Parameter'>
<t>
<list style='hanging'>
<t hangText='Parameter name:'>
secret
</t>
<t hangText='Parameter usage location:'>
The end-user authorization endpoint response and the token endpoint response.
</t>
<t hangText='Change controller:'>
IETF
</t>
<t hangText='Specification document(s):'>
[[ this document ]]
</t>
<t hangText='Related information:'>
None
</t>
</list>
</t>
</section>
<section title='The "secret" OAuth Parameter'>
<t>
<list style='hanging'>
<t hangText='Parameter name:'>
secret
</t>
<t hangText='Parameter usage location:'>
The end-user authorization endpoint response and the token endpoint response.
</t>
<t hangText='Change controller:'>
IETF
</t>
<t hangText='Specification document(s):'>
[[ this document ]]
</t>
<t hangText='Related information:'>
None
</t>
</list>
</t>
</section>
</section>
<section title='Acknowledgments'>
<t>
The author would like to thank [[ some people ]] for their suggestions, feedback, and
continued support.
</t>
</section>
<appendix title='Document History' anchor='history'>
<t>
[[ To be removed by the RFC editor before publication as an RFC. ]]
</t>
<t>
-00
<list style='symbols'>
<t>
Initial draft.
</t>
</list>
</t>
</appendix>
</middle>
<back>
<references title='Normative References'>
<?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.2045.xml' ?>
<?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.2104.xml' ?>
<?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml' ?>
<?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.2617.xml' ?>
<?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.3986.xml' ?>
<?rfc include='http://xml.resource.org/public/rfc/bibxml3/reference.I-D.draft-ietf-httpbis-p1-messaging-08.xml' ?>
<?rfc include='http://xml.resource.org/public/rfc/bibxml3/reference.I-D.draft-ietf-oauth-v2-11.xml' ?>
<?rfc include='http://xml.resource.org/public/rfc/bibxml4/reference.W3C.REC-html401-19991224.xml' ?>
<reference anchor='NIST FIPS-180-3'>
<front>
<title>Secure Hash Standard (SHS). FIPS PUB 180-3, October 2008</title>
<author>
<organization>National Institute of Standards and Technology</organization>
</author>
</front>
<format type='pdf' target='http://csrc.nist.gov/publications/fips/fips180-3/fips180-3_final.pdf' />
</reference>
</references>
<references title='Informative References'>
<?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.5849.xml' ?>
</references>
</back>
</rfc>| PAFTECH AB 2003-2026 | 2026-04-24 13:39:17 |