One document matched: draft-hammer-oauth-10.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE rfc SYSTEM "rfc2629.dtd">
<?xml-stylesheet type="text/xsl" href="rfc2629.xslt" ?>
<rfc category="info" ipr="trust200902" docName="draft-hammer-oauth-10">
<?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 1.0">The OAuth 1.0 Protocol</title>
<author initials="E" surname="Hammer-Lahav" fullname="Eran Hammer-Lahav" role="editor">
<organization />
<address>
<email>eran@hueniverse.com</email>
<uri>http://hueniverse.com</uri>
</address>
</author>
<date year="2010"/>
<abstract>
<t>
OAuth provides a method for clients to access server resources on behalf of a resource
owner (such as a different client or an end-user). It also provides a process for end-users
to authorize third-party access to their server resources without sharing their credentials
(typically, a username and password pair), using user-agent redirections.
</t>
</abstract>
</front>
<middle>
<section title="Introduction">
<t>
The OAuth protocol was originally created by a small community of web developers from a
variety of websites and other Internet services, who wanted to solve the common problem of
enabling delegated access to protected resources. The resulting OAuth protocol was
stabilized at version 1.0 in October 2007, revised in June 2009, and published as
<xref target="OAuth Core 1.0 Revision A" />.
</t>
<t>
This specification provides an informational documentation of the OAuth 1.0 protocol as
revised in <xref target="OAuth Core 1.0 Revision A" />, and includes several errata
reported since that time, as well as numerous editorial clarifications. The publication
of this specification represents the transfer of change control from the community to the
IETF by the authors of the original work.
</t>
<t>
In the traditional client-server authentication model, the client uses its credentials to
access its resources hosted by the server. With the increasing use of distributed web
services and cloud computing, third-party applications require access to these
server-hosted resources.
</t>
<t>
OAuth introduces a third role to the traditional client-server authentication model: the
resource owner. In the OAuth model, the client (which is not the resource owner, but
is acting on its behalf) requests access to resources controlled by the resource owner, but
hosted by the server. In addition, OAuth allows the server to verify not only the resource
owner authorization, but also the identity of the client making the request.
</t>
<t>
OAuth provides a method for clients to access server resources on behalf of a resource
owner (such as a different client or an end-user). It also provides a process for end-users
to authorize third-party access to their server resources without sharing their credentials
(typically, a username and password pair), using user-agent redirections.
</t>
<t>
For example, a web user (resource owner) can grant a printing service (client) access to
her private photos stored at a photo sharing service (server), without sharing her
username and password with the printing service. Instead, she authenticates directly with
the photo sharing service which issues the printing service delegation-specific credentials.
</t>
<t>
In order for the client to access resources, it first has to obtain permission from the
resource owner. This permission is expressed in the form of a token and matching
shared-secret. The purpose of the token is to make it unnecessary for the resource owner to
share its credentials with the client. Unlike the resource owner credentials, tokens can be
issued with a restricted scope and limited lifetime, and revoked independently.
</t>
<t>
This specification consists of two parts. The first part defines a redirection-based
user-agent process for end-users to authorize client access to their resources, by
authenticating directly with the server and provisioning tokens to the client for use with
the authentication method. The second part defines a method for making authenticated HTTP
<xref target="RFC2616" /> requests using two sets of credentials, one identifying the
client making the request, and a second identifying the resource owner on whose behalf the
request is being made.
</t>
<t>
The use of OAuth with any other transport protocol than <xref target="RFC2616" /> is
undefined.
</t>
<section title="Terminology">
<t>
<list style="hanging" hangIndent="6">
<t hangText="client">
<vspace />
An HTTP client (per <xref target="RFC2616" />) capable of making
<xref target="requests">OAuth-authenticated requests</xref>.
</t>
<t hangText="server">
<vspace />
An HTTP server (per <xref target="RFC2616" />) capable of accepting
<xref target="requests">OAuth-authenticated requests</xref>.
</t>
<t hangText="protected resource">
<vspace />
An access-restricted resource which can be obtained from the server using an
<xref target="requests">OAuth-authenticated request</xref>.
</t>
<t hangText="resource owner">
<vspace />
An entity capable of accessing and controlling protected resources by using credentials
to authenticate with the server.
</t>
<t hangText="credentials">
<vspace />
Credentials are a pair of a unique identifier and a matching shared secret. OAuth
defines three classes of credentials: client, temporary, and token, used to identify
and authenticate the client making the request, the authorization request, and the
access grant, respectively.
</t>
<t hangText="token">
<vspace />
An unique identifier issued by the server and used by the client to associate
authenticated requests with the resource owner whose authorization is requested or
has been obtained by the client. Tokens have a matching shared-secret that is used
by the client to establish its ownership of the token, and its authority to represent
the resource owner.
</t>
</list>
</t>
<t>
The original community specification used a somewhat different terminology which maps to
this specifications as follows (original community terms provided on left):
<list style="hanging">
<t hangText="Consumer:">client</t>
<t hangText="Service Provider:">server</t>
<t hangText="User:">resource owner</t>
<t hangText="Consumer Key and Secret:">client credentials</t>
<t hangText="Request Token and Secret:">temporary credentials</t>
<t hangText="Access Token and Secret:">token credentials</t>
</list>
</t>
</section>
<section title="Example">
<t>
Jane (resource owner) has recently uploaded some private vacation photos (protected
resources) to her photo sharing site 'photos.example.net' (server). She would like to use
the 'printer.example.com' website (client) to print one of these photos. Typically, Jane
signs-into 'photos.example.net' using her username and password.
</t>
<t>
However, Jane does not wish to share her username and password with the 'printer.example.com'
website, which needs to access the photo in order to print it. In order to provide its
users with better service, 'printer.example.com' has signed-up for a set of 'photos.example.net'
client credentials ahead of time:
<list style="hanging" hangIndent="6">
<t hangText="Client Identifier">
<vspace />
dpf43f3p2l4k3l03
</t>
<t hangText="Client Shared-Secret:">
<vspace />
kd94hf93k423kf44
</t>
</list>
The 'printer.example.com' website has also configured its application to use the protocol
endpoints listed in the 'photos.example.net' API documentation, which use the
<spanx style="verb">HMAC-SHA1</spanx> signature method:
<list style="hanging" hangIndent="6">
<t hangText="Temporary Credential Request">
<vspace />
https://photos.example.net/initiate
</t>
<t hangText="Resource Owner Authorization URI:">
<vspace />
https://photos.example.net/authorize
</t>
<t hangText="Token Request URI:">
<vspace />
https://photos.example.net/token
</t>
</list>
</t>
<t>
Before 'printer.example.com' can ask Jane to grant it access to the photos, it must
first establish a set of temporary credentials with 'photos.example.net' to identify
the delegation request. To do so, the client sends the following HTTPS
<xref target="RFC2818" /> request to the server:
</t>
<figure>
<artwork xml:space="preserve"><![CDATA[
POST /initiate HTTP/1.1
Host: photos.example.net
Authorization: OAuth realm="Photos",
oauth_consumer_key="dpf43f3p2l4k3l03",
oauth_signature_method="HMAC-SHA1",
oauth_timestamp="137131200",
oauth_nonce="wIjqoS",
oauth_callback="http%3A%2F%2Fprinter.example.com%2Fready",
oauth_signature="74KNZJeDHnMBp0EMJ9ZHt%2FXKycU%3D"
]]>
</artwork>
</figure>
<t>
The server validates the request and replies with a set of temporary credentials in the
body of the HTTP response (line breaks are for display purposes only):
</t>
<figure>
<artwork xml:space="preserve"><![CDATA[
HTTP/1.1 200 OK
Content-Type: application/x-www-form-urlencoded
oauth_token=hh5s93j4hdidpola&oauth_token_secret=hdhd0244k9j7ao03&
oauth_callback_confirmed=true
]]>
</artwork>
</figure>
<t>
The client redirects Jane's user-agent to the server's Resource Owner Authorization
endpoint to obtain Jane's approval for accessing her private photos:
</t>
<figure>
<artwork xml:space="preserve"><![CDATA[
https://photos.example.net/authorize?oauth_token=hh5s93j4hdidpola
]]>
</artwork>
</figure>
<t>
The server requests Jane to sign-in using her username and password and if successful,
asks her to approve granting 'printer.example.com' access to her private photos. Jane
approves the request and her user-agent is redirected to the callback URI provided by
the client in the previous request (line breaks are for display purposes only):
</t>
<figure>
<artwork xml:space="preserve"><![CDATA[
http://printer.example.com/ready?
oauth_token=hh5s93j4hdidpola&oauth_verifier=hfdp7dh39dks9884
]]>
</artwork>
</figure>
<t>
The callback request informs the client that Jane completed the authorization process.
The client then requests a set of token credentials using its temporary credentials
(over a secure TLS channel):
</t>
<figure>
<artwork xml:space="preserve"><![CDATA[
POST /token HTTP/1.1
Host: photos.example.net
Authorization: OAuth realm="Photos",
oauth_consumer_key="dpf43f3p2l4k3l03",
oauth_token="hh5s93j4hdidpola",
oauth_signature_method="HMAC-SHA1",
oauth_timestamp="137131201",
oauth_nonce="walatlh",
oauth_verifier="hfdp7dh39dks9884",
oauth_signature="gKgrFCywp7rO0OXSjdot%2FIHF7IU%3D"
]]>
</artwork>
</figure>
<t>
The server validates the request and replies with a set of token credentials in the body
of the HTTP response:
</t>
<figure>
<artwork xml:space="preserve"><![CDATA[
HTTP/1.1 200 OK
Content-Type: application/x-www-form-urlencoded
oauth_token=nnch734d00sl2jdk&oauth_token_secret=pfkkdhi9sl3r4s00
]]>
</artwork>
</figure>
<t>
With a set of token credentials, the client is now ready to request the private photo:
</t>
<figure>
<artwork xml:space="preserve"><![CDATA[
GET /photos?file=vacation.jpg&size=original HTTP/1.1
Host: photos.example.net
Authorization: OAuth realm="Photos",
oauth_consumer_key="dpf43f3p2l4k3l03",
oauth_token="nnch734d00sl2jdk",
oauth_signature_method="HMAC-SHA1",
oauth_timestamp="137131202",
oauth_nonce="chapoH",
oauth_signature="MdpQcU8iPSUjWoN%2FUDMsK2sui9I%3D"
]]>
</artwork>
</figure>
<t>
The 'photos.example.net' server validates the request and responds with the requested
photo. 'printer.example.com' is able to continue accessing Jane's private photos using
the same set of token credentials for the duration of Jane's authorization, or until
Jane revokes access.
</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>
</section>
</section>
<section title="Redirection-Based Authorization" anchor="redirect_workflow">
<t>
OAuth uses tokens to represent the authorization granted to the client by the resource
owner. Typically, token credentials are issued by the server at the resource owner's
request, after authenticating the resource owner's identity (usually using a username and
password).
</t>
<t>
There are many ways in which a server can facilitate the provisioning of token credentials.
This section defines one such way, using HTTP redirections and the resource owner's
user-agent. This redirection-based authorization method includes three steps:
<list style="numbers">
<t>
The client obtains a set of temporary credentials from the server (in the form of an
identifier and shared-secret). The temporary credentials are used to identify the
access request throughout the authorization process.
</t>
<t>
The resource owner authorizes the server to grant the client's access request
(identified by the temporary credentials).
</t>
<t>
The client uses the temporary credentials to request a set of token credentials from
the server, which will enable it to access the resource owner's protected resources.
</t>
</list>
</t>
<t>
The server MUST revoke the temporary credentials after being used once to obtain the token
credentials. It is RECOMMENDED that the temporary credentials have a limited lifetime.
Servers SHOULD enable resource owners to revoke token credentials after they have been
issued to clients.
</t>
<t>
In order for the client to perform these steps, the server needs to advertise the URIs of
the following three endpoints:
<list style="hanging" hangIndent="6">
<t hangText="Temporary Credential Request">
<vspace />
The endpoint used by the client to obtain a set of temporary credentials as described
in <xref target="auth_step1" />.
</t>
<t hangText="Resource Owner Authorization">
<vspace />
The endpoint to which the resource owner is redirected to grant authorization as
described in <xref target="auth_step2" />.
</t>
<t hangText="Token Request">
<vspace />
The endpoint used by the client to request a set of token credentials using the
set of temporary credentials as described in <xref target="auth_step3" />.
</t>
</list>
</t>
<t>
The three URIs advertised by the server MAY include a query component as defined by
<xref target="RFC3986" /> section 3, but if present, the query MUST NOT contain any
parameters beginning with the <spanx style="verb">oauth_</spanx> prefix, to avoid conflicts
with the protocol parameters added to the URIs when used.
</t>
<t>
The methods in which the server advertises and documents its three endpoints are beyond the
scope of this specification. Clients should avoid making assumptions about the size of
tokens and other server-generated values, which are left undefined by this specification.
In addition, protocol parameters MAY include values which require encoding when
transmitted. Clients and servers should not make assumptions about the possible range of
their values.
</t>
<section title="Temporary Credentials" anchor="auth_step1">
<t>
The client obtains a set of temporary credentials from the server by making an
<xref target="requests">authenticated</xref> HTTP <spanx style="verb">POST</spanx>
request to the Temporary Credential Request endpoint (unless the server advertises
another HTTP request method for the client to use). The client constructs a request URI
by adding the following REQUIRED parameter to the request (in addition to the other
protocol parameters, using the same parameter transmission method):
<list style="hanging" hangIndent="6">
<t hangText="oauth_callback:">
An absolute URI to which the server will redirect the resource owner back when the
Resource Owner Authorization step (<xref target="auth_step2" />) is completed. If the
client is unable to receive callbacks or a callback URI has been established via other
means, the parameter value MUST be set to <spanx style="verb">oob</spanx> (case sensitive),
to indicate an out-of-band configuration.
</t>
<t hangText="Servers MAY specify additional parameters.">
</t>
</list>
</t>
<t>
When making the request, the client authenticates using only the client credentials. The
client MAY omit the empty <spanx style="verb">oauth_token</spanx> protocol parameter
from the request and MUST use the empty string as the token secret value.
</t>
<t>
Since the request results in the transmission of plain text credentials in the HTTP
response, the server MUST require the use of a transport-layer mechanisms such as TLS
or SSL (or a secure channel with equivalent protections).
</t>
<figure>
<preamble>
For example, the client makes the following HTTPS request:
</preamble>
<artwork xml:space="preserve"><![CDATA[
POST /request_temp_credentials HTTP/1.1
Host: server.example.com
Authorization: OAuth realm="Example",
oauth_consumer_key="jd83jd92dhsh93js",
oauth_signature_method="PLAINTEXT",
oauth_callback="http%3A%2F%2Fclient.example.net%2Fcb%3Fx%3D1",
oauth_signature="ja893SD9%26"
]]>
</artwork>
</figure>
<t>
The server MUST <xref target="verify_request">verify</xref> the request and if valid,
respond back to the client with a set of temporary credentials (in the form of an
identifier and shared-secret). The temporary credentials are included in the HTTP
response body using the <spanx style="verb">application/x-www-form-urlencoded</spanx>
content type as defined by <xref target="W3C.REC-html40-19980424" /> with a 200 status
code (OK).
</t>
<t>
The response contains the following REQUIRED parameters:
<list style="hanging" hangIndent="6">
<t hangText="oauth_token">
<vspace />
The temporary credentials identifier.
</t>
<t hangText="oauth_token_secret">
<vspace />
The temporary credentials shared-secret.
</t>
<t hangText="oauth_callback_confirmed:">
MUST be present and set to <spanx style="verb">true</spanx>. The parameter is used
to differentiate from previous versions of the protocol.
</t>
</list>
</t>
<t>
Note that even though the parameter names include the term 'token', these credentials are
not token credentials, but are used in the next two steps in a similar manner to token
credentials.
</t>
<figure>
<preamble>
For example (line breaks are for display purposes only):
</preamble>
<artwork xml:space="preserve"><![CDATA[
HTTP/1.1 200 OK
Content-Type: application/x-www-form-urlencoded
oauth_token=hdk48Djdsa&oauth_token_secret=xyz4992k83j47x0b&
oauth_callback_confirmed=true
]]>
</artwork>
</figure>
</section>
<section title="Resource Owner Authorization" anchor="auth_step2">
<t>
Before the client requests a set of token credentials from the server, it MUST send
the user to the server to authorize the request. The client constructs a request URI by
adding the following REQUIRED query parameter to the Resource Owner Authorization
endpoint URI:
<list style="hanging" hangIndent="6">
<t hangText="oauth_token">
<vspace />
The temporary credentials identifier obtained in <xref target="auth_step1" />
in the <spanx style="verb">oauth_token</spanx> parameter. Servers MAY declare this
parameter as OPTIONAL, in which case they MUST provide a way for the resource owner
to indicate the identifier through other means.
</t>
<t hangText="Servers MAY specify additional parameters.">
</t>
</list>
</t>
<t>
The client directs the resource owner to the constructed URI using an HTTP redirection
response, or by other means available to it via the resource owner's user-agent. The
request MUST use the HTTP <spanx style="verb">GET</spanx> method.
</t>
<figure>
<preamble>
For example, the client redirects the resource owner's user-agent to make the following
HTTPS request:
</preamble>
<artwork xml:space="preserve"><![CDATA[
GET /authorize_access?oauth_token=hdk48Djdsa HTTP/1.1
Host: server.example.com
]]>
</artwork>
</figure>
<t>
The way in which the server handles the authorization request, including whether it uses
a secure channel such as TLS/SSL is beyond the scope of this specification. However, the
server MUST first verify the identity of the resource owner.
</t>
<t>
When asking the resource owner to authorize the requested access, the server SHOULD
present to the resource owner information about the client requesting access based on the
association of the temporary credentials with the client identity. When displaying any
such information, the server SHOULD indicate if the information has been verified.
</t>
<t>
After receiving an authorization decision from the resource owner, the server redirects
the resource owner to the callback URI if one was provided in the
<spanx style="verb">oauth_callback</spanx> parameter or by other means.
</t>
<t>
To make sure that the resource owner granting access is the same resource owner returning
back to the client to complete the process, the server MUST generate a verification code:
an unguessable value passed to the client via the resource owner and REQUIRED to complete
the process. The server constructs the request URI by adding the following REQUIRED
parameters to the callback URI query component:
<list style="hanging" hangIndent="6">
<t hangText="oauth_token">
<vspace />
The temporary credentials identifier received from the client.
</t>
<t hangText="oauth_verifier">
<vspace />
The verification code.
</t>
</list>
If the callback URI already includes a query component, the server MUST append the
OAuth parameters to the end of the existing query.
</t>
<figure>
<preamble>
For example, the server redirects the resource owner's user-agent to make the following
HTTP request:
</preamble>
<artwork xml:space="preserve"><![CDATA[
GET /cb?x=1&oauth_token=hdk48Djdsa&oauth_verifier=473f82d3 HTTP/1.1
Host: client.example.net
]]>
</artwork>
</figure>
<t>
If the client did not provide a callback URI, the server SHOULD display the value of the
verification code, and instruct the resource owner to manually inform the client that
authorization is completed. If the server knows a client to be running on a limited device
it SHOULD ensure that the verifier value is suitable for manual entry.
</t>
</section>
<section title="Token Credentials" anchor="auth_step3">
<t>
The client obtains a set of token credentials from the server by making an
<xref target="requests">authenticated</xref> HTTP <spanx style="verb">POST</spanx>
request to the Token Request endpoint (unless the server advertises another HTTP
request method for the client to use). The client constructs a request URI by adding the
following REQUIRED parameter to the request (in addition to the other protocol
parameters, using the same parameter transmission method):
<list style="hanging" hangIndent="6">
<t hangText="oauth_verifier">
<vspace />
The verification code received from the server in the previous step.
</t>
</list>
</t>
<t>
When making the request, the client authenticates using the client credentials as well as
the temporary credentials. The temporary credentials are used as a substitute for token
credentials in the authenticated request and transmitted using the
<spanx style="verb">oauth_token</spanx> parameter.
</t>
<t>
Since the request results in the transmission of plain text credentials in the HTTP
response, the server MUST require the use of a transport-layer mechanisms such as TLS
or SSL (or a secure channel with equivalent protections).
</t>
<figure>
<preamble>
For example, the client makes the following HTTPS request:
</preamble>
<artwork xml:space="preserve"><![CDATA[
POST /request_token HTTP/1.1
Host: server.example.com
Authorization: OAuth realm="Example",
oauth_consumer_key="jd83jd92dhsh93js",
oauth_token="hdk48Djdsa",
oauth_signature_method="PLAINTEXT",
oauth_verifier="473f82d3",
oauth_signature="ja893SD9%26xyz4992k83j47x0b"
]]>
</artwork>
</figure>
<t>
The server MUST <xref target="verify_request">verify</xref> the validity of the request,
ensure that the resource owner has authorized the provisioning of token credentials to
the client, and ensure that the temporary credentials have not expired or been used
before. The server MUST also verify the verification code received from the client. If
the request is valid and authorized, the token credentials are included in the HTTP
response body using the <spanx style="verb">application/x-www-form-urlencoded</spanx>
content type as defined by <xref target="W3C.REC-html40-19980424" /> with a 200 status
code (OK).
</t>
<t>
The response contains the following REQUIRED parameters:
<list style="hanging" hangIndent="6">
<t hangText="oauth_token">
<vspace />
The token identifier.
</t>
<t hangText="oauth_token_secret">
<vspace />
The token shared-secret.
</t>
</list>
</t>
<figure>
<preamble>
For example:
</preamble>
<artwork xml:space="preserve"><![CDATA[
HTTP/1.1 200 OK
Content-Type: application/x-www-form-urlencoded
oauth_token=j49ddk933skd9dks&oauth_token_secret=ll399dj47dskfjdk
]]>
</artwork>
</figure>
<t>
The server must retain the scope, duration, and other attributes approved by the resource
owner, and enforce these restrictions when receiving a client request made with the token
credentials issued.
</t>
<t>
Once the client receives and stores the token credentials, it can proceed to access
protected resources on behalf of the resource owner by making
<xref target="requests">authenticated requests</xref> using the client credentials
together with the token credentials received.
</t>
</section>
</section>
<section title="Authenticated Requests" anchor="requests">
<t>
The HTTP authentication methods defined by <xref target="RFC2617" />, enable clients
to make authenticated HTTP requests. Clients using these methods gain access to protected
resources by using their credentials (typically a username and password pair), which
allow the server to verify their authenticity. Using these methods for delegation requires
the client to assume the role of the resource owner.
</t>
<t>
OAuth provides a method designed to include two sets of credentials with each request, one
to identify the client, and another to identify the resource owner. Before a client can
make authenticated requests on behalf of the resource owner, it must obtain a token
authorized by the resource owner. <xref target="redirect_workflow" /> provides one such
method through which the client can obtain a token authorized by the resource owner.
</t>
<t>
The client credentials take the form of a unique identifier, and an associated shared-secret
or RSA key pair. Prior to making authenticated requests, the client establishes a set of
credentials with the server. The process and requirements for provisioning these are
outside the scope of this specification. Implementers are urged to consider the security
ramifications of using client credentials, some of which are described in
<xref target="client_cred_sec" />.
</t>
<t>
Making authenticated requests requires prior knowledge of the server's configuration.
OAuth includes multiple methods for transmitting protocol parameters with requests
(<xref target="param_include" />), as well as multiple methods for the client to
prove its rightful ownership of the credentials used (<xref target="signature" />).
The way in which clients discover the required configuration is outside the scope of
this specification.
</t>
<section title="Making Requests">
<t>
An authenticated request includes several protocol parameters. Each parameter name
begins with the <spanx style="verb">oauth_</spanx> prefix, and the parameter names and
values are case sensitive. Clients make authenticated requests by calculating the values
of a set of protocol parameters and adding them to the HTTP request as follows:
<list style="numbers">
<t>
The client assigns value to each of these REQUIRED (unless specified otherwise)
protocol parameters:
<list style="hanging" hangIndent="6">
<t hangText="oauth_consumer_key">
<vspace />
The identifier portion of the client credentials (equivalent to a username). The
parameter name reflects a deprecated term (Consumer Key) used in previous
revisions of the specification, and has been retained to maintain backward
compatibility.
</t>
<t hangText="oauth_token">
<vspace />
The token value used to associate the request with the resource owner. If the
request is not associated with a resource owner (no token available), clients
MAY omit the parameter.
</t>
<t hangText="oauth_signature_method">
<vspace />
The name of the signature method used by the client to sign the request,
as defined in <xref target="signature" />.
</t>
<t hangText="oauth_timestamp">
<vspace />
The timestamp value as defined in <xref target="nonce" />. The parameter MAY
be omitted when using the <spanx style="verb">PLAINTEXT</spanx> signature method.
</t>
<t hangText="oauth_nonce">
<vspace />
The nonce value as defined in <xref target="nonce" />. The parameter MAY be
omitted when using the <spanx style="verb">PLAINTEXT</spanx> signature method.
</t>
<t hangText="oauth_version">
<vspace />
OPTIONAL. If present, MUST be set to <spanx style="verb">1.0</spanx>. Provides
the version of the authentication process as defined in this specification.
</t>
</list>
</t>
<t>
The protocol parameters are added to the request using one of the transmission
methods listed in <xref target="param_include" />. Each parameter MUST NOT appear
more than once per request.
</t>
<t>
The client calculates and assigns the value of the <spanx style="verb">oauth_signature</spanx>
parameter as described in <xref target="signature" /> and adds the parameter to the
request using the same method used in the previous step.
</t>
<t>
The client sends the authenticated HTTP request to the server.
</t>
</list>
</t>
<figure>
<preamble>
For example, to make the following HTTP request authenticated (the
<spanx style="verb">c2&a3=2+q</spanx> string in the following examples is used to
illustrate the impact of a form-encoded entity-body) :
</preamble>
<artwork xml:space="preserve"><![CDATA[
GET /request?b5=%3D%253D&a3=a&c%40=&a2=r%20b HTTP/1.1
Host: example.com
Content-Type: application/x-www-form-urlencoded
c2&a3=2+q
]]>
</artwork>
</figure>
<figure>
<preamble>
The client assigns values to the following protocol parameters using its client
credentials, token credentials, the current timestamp, a uniquely generated nonce, and
indicates it will use the <spanx style="verb">HMAC-SHA1</spanx> signature method:
</preamble>
<artwork xml:space="preserve"><![CDATA[
oauth_consumer_key: 9djdj82h48djs9d2
oauth_token: kkk9d7dh3k39sjv7
oauth_signature_method: HMAC-SHA1
oauth_timestamp: 137131201
oauth_nonce: 7d8f3e4a
]]>
</artwork>
</figure>
<figure>
<preamble>
The client adds the protocol parameters to the request using the OAuth HTTP
Authorization header field:
</preamble>
<artwork xml:space="preserve"><![CDATA[
Authorization: OAuth realm="Example",
oauth_consumer_key="9djdj82h48djs9d2",
oauth_token="kkk9d7dh3k39sjv7",
oauth_signature_method="HMAC-SHA1",
oauth_timestamp="137131201",
oauth_nonce="7d8f3e4a"
]]>
</artwork>
</figure>
<figure>
<preamble>
Then calculates the value of the <spanx style="verb">oauth_signature</spanx> parameter,
adds it to the request, and sends the HTTP request to the server:
</preamble>
<artwork xml:space="preserve"><![CDATA[
GET /request?b5=%3D%253D&a3=a&c%40=&a2=r%20b HTTP/1.1
Host: example.com
Content-Type: application/x-www-form-urlencoded
Authorization: OAuth realm="Example",
oauth_consumer_key="9djdj82h48djs9d2",
oauth_token="kkk9d7dh3k39sjv7",
oauth_signature_method="HMAC-SHA1",
oauth_timestamp="137131201",
oauth_nonce="7d8f3e4a",
oauth_signature="djosJKDKJSD8743243%2Fjdk33klY%3D"
c2&a3=2+q
]]>
</artwork>
</figure>
</section>
<section title="Verifying Requests" anchor="verify_request">
<t>
Servers receiving an authenticated request MUST validate it by:
<list style="symbols">
<t>
Recalculate the request signature independently as described in
<xref target="signature" /> and compare it to the value received from the client via
the <spanx style="verb">oauth_signature</spanx> parameter.
</t>
<t>
If using the <spanx style="verb">HMAC-SHA1</spanx> or
<spanx style="verb">RSA-SHA1</spanx> signature methods, ensure that the combination
of nonce/timestamp/token (if present) received from the client has not been used
before in a previous request (the server MAY reject requests with stale timestamps as
described in <xref target="nonce" />).
</t>
<t>
If a token is present, verify the scope and status of the client authorization as
represented by the token (the server MAY choose to restrict token usage to the client
to which it was issued).
</t>
<t>
If the <spanx style="verb">oauth_version</spanx> parameter is present, ensure its
value is <spanx style="verb">1.0</spanx>.
</t>
</list>
</t>
<t>
If the request fails verification, the server SHOULD respond with the appropriate HTTP
response status code. The server MAY include further details about why the request was
rejected in the response body.
</t>
<t>
The server SHOULD return a 400 (bad request) status code
when receiving a request with unsupported parameters, unsupported signature method,
missing parameters, or duplicated protocol parameters. The server SHOULD return a 401
(unauthorized) status code when receiving a request with invalid client credentials,
invalid or expired token, invalid signature, or invalid or used nonce.
</t>
</section>
<section title="Nonce and Timestamp" anchor="nonce">
<t>
The timestamp value MUST be a positive integer. Unless otherwise specified by the
server's documentation, the timestamp is expressed in the number of seconds since
January 1, 1970 00:00:00 GMT.
</t>
<t>
A nonce is a random string, uniquely generated by the client to allow the server to
verify that a request has never been made before and helps prevent replay attacks when
requests are made over a non-secure channel. The nonce value MUST be unique across all
requests with the same timestamp, client credentials, and token combinations.
</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. Note that this restriction implies a level of synchronization between the
client's and server's clocks. Servers applying such a restriction MAY provide a way for
the client to sync with the server's clock; alternatively both systems could synchronize
with a trusted time service. Details of clock synchronization strategies are beyond the
scope of this specification.
</t>
</section>
<section title="Signature" anchor="signature">
<t>
OAuth-authenticated requests can have two sets of credentials: those passed via the
<spanx style="verb">oauth_consumer_key</spanx> parameter and those in the
<spanx style="verb">oauth_token</spanx> parameter. In order for the server to
verify the authenticity of the request and prevent unauthorized access, the client needs
to prove that it is the rightful owner of the credentials. This is accomplished using the
shared-secret (or RSA key) part of each set of credentials.
</t>
<t>
OAuth provides three methods for the client to prove its rightful ownership of the
credentials: <spanx style="verb">HMAC-SHA1</spanx>, <spanx style="verb">RSA-SHA1</spanx>,
and <spanx style="verb">PLAINTEXT</spanx>. These methods are generally referred to as
signature methods, even though <spanx style="verb">PLAINTEXT</spanx> does not involve a
signature. In addition, <spanx style="verb">RSA-SHA1</spanx> utilizes an RSA key instead
of the shared-secrets associated with the client credentials.
</t>
<t>
OAuth does not mandate a particular signature method, as each implementation can have its
own unique requirements. Servers are free to implement and document their own custom
methods. Recommending any particular method is beyond the scope of this specification.
Implementers should review the <xref target="Security">Security Considerations section</xref>
before deciding on which method to support.
</t>
<t>
The client declares which signature method is used via the
<spanx style="verb">oauth_signature_method</spanx> parameter. It then generates a signature
(or a string of an equivalent value), and includes it in the
<spanx style="verb">oauth_signature</spanx> parameter. The server verifies the signature
as specified for each method.
</t>
<t>
The signature process does not change the request or its parameters, with the exception of
the <spanx style="verb">oauth_signature</spanx> parameter.
</t>
<section title="Signature Base String">
<t>
The signature base string is a consistent, reproducible concatenation of several
of the HTTP request elements into a single string. The string is used as an input to
the <spanx style="verb">HMAC-SHA1</spanx> and <spanx style="verb">RSA-SHA1</spanx>
signature methods.
</t>
<t>
The signature base string includes the following components of the HTTP request:
<list style="symbols">
<t>
The HTTP request method (e.g. <spanx style="verb">GET</spanx>,
<spanx style="verb">POST</spanx>, etc.).
</t>
<t>
The authority as declared by the HTTP <spanx style="verb">Host</spanx> request
header field.
</t>
<t>
The path and query components of the request resource URI.
</t>
<t>
The protocol parameters excluding the
<spanx style="verb">oauth_signature</spanx>.
</t>
<t>
Parameters included in the request entity-body if they comply with the strict
restrictions defined in <xref target="collect_param" />.
</t>
</list>
</t>
<t>
The signature base string does not cover the entire HTTP request. Most notably, it
does not include the entity-body in most requests, nor does it include most HTTP
entity-headers. It is important to note that the server cannot verify the authenticity
of the excluded request components without using additional protections such as SSL/TLS or
other methods.
</t>
<section title="String Construction" anchor="base_string">
<t>
The signature base string is constructed by concatenating together, in order, the
following HTTP request elements:
<list style="numbers">
<t>
The HTTP request method in uppercase. For example: <spanx style="verb">HEAD</spanx>,
<spanx style="verb">GET</spanx>, <spanx style="verb">POST</spanx>, etc. If the
request uses a custom HTTP method, it MUST be <xref target="encoding">encoded</xref>.
</t>
<t>
An <spanx style="verb">&</spanx> character (ASCII code 38).
</t>
<t>
The base string URI from <xref target="sig_uri" />, after being
<xref target="encoding">encoded</xref>.
</t>
<t>
An <spanx style="verb">&</spanx> character (ASCII code 38).
</t>
<t>
The request parameters as normalized in <xref target="sig_norm_param" />, after
being <xref target="encoding">encoded</xref>.
</t>
</list>
</t>
<figure>
<preamble>
For example, the HTTP request:
</preamble>
<artwork xml:space="preserve"><![CDATA[
GET /request?b5=%3D%253D&a3=a&c%40=&a2=r%20b HTTP/1.1
Host: example.com
Content-Type: application/x-www-form-urlencoded
Authorization: OAuth realm="Example",
oauth_consumer_key="9djdj82h48djs9d2",
oauth_token="kkk9d7dh3k39sjv7",
oauth_signature_method="HMAC-SHA1",
oauth_timestamp="137131201",
oauth_nonce="7d8f3e4a",
oauth_signature="djosJKDKJSD8743243%2Fjdk33klY%3D"
c2&a3=2+q
]]>
</artwork>
</figure>
<figure>
<preamble>
Is represented by the following signature base string (line breaks are for display
purposes only):
</preamble>
<artwork xml:space="preserve"><![CDATA[
GET&http%3A%2F%2Fexample.com%2Frequest&a2%3Dr%2520b%26a3%3D2%2520q%
26a3%3Da%26b5%3D%253D%25253D%26c%2540%3D%26c2%3D%26oauth_consumer_k
ey%3D9djdj82h48djs9d2%26oauth_nonce%3D7d8f3e4a%26oauth_signature_me
thod%3DHMAC-SHA1%26oauth_timestamp%3D137131201%26oauth_token%3Dkkk9
d7dh3k39sjv7
]]>
</artwork>
</figure>
</section>
<section title="Base String URI" anchor="sig_uri">
<t>
The scheme, authority, and path of the request resource URI <xref target="RFC3986" />
are included by constructing an <spanx style="verb">http</spanx> or
<spanx style="verb">https</spanx> URI representing the request resource (without the
query or fragment) as follows:
<list style="numbers">
<t>
The scheme and host MUST be in lowercase.
</t>
<t>
The host and port values MUST match the content of the HTTP request
<spanx style="verb">Host</spanx> header field.
</t>
<t>
The port MUST be included if it is not the default port for the scheme, and MUST
be excluded if it is the default. Specifically, the port MUST be excluded when
making an HTTP request <xref target="RFC2616" /> to port 80 or when making an
HTTPS request <xref target="RFC2818" /> to port 443. All other non-default port
numbers MUST be included.
</t>
</list>
</t>
<figure>
<preamble>
For example, the HTTP request:
</preamble>
<artwork xml:space="preserve"><![CDATA[
GET /r%20v/X?id=123 HTTP/1.1
Host: EXAMPLE.COM:80
]]>
</artwork>
<postamble>
is represented by the base string URI:
<spanx style="verb">http://example.com/r%20v/X</spanx>.
</postamble>
</figure>
<figure>
<preamble>
In another example, the HTTPS request:
</preamble>
<artwork xml:space="preserve"><![CDATA[
GET /?q=1 HTTP/1.1
Host: www.example.net:8080
]]>
</artwork>
<postamble>
is represented by the base string URI:
<spanx style="verb">https://www.example.net:8080/</spanx>.
</postamble>
</figure>
</section>
<section title="Request Parameters" anchor="collect_param">
<t>
In order to guarantee a consistent and reproducible representation of the request
parameters, the parameters are collected and decoded to their original decoded form.
They are then sorted and encoded in a particular manner which is often different from
their original encoding scheme, and concatenated into a single string.
</t>
<section title="Parameter Sources">
<t>
The parameters from the following sources are collected into a single list of
name/value pairs:
<list style="symbols">
<t>
The query component of the HTTP request URI as defined by <xref target="RFC3986" />
section 3.4. The query component is parsed into a list of name/value 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-html40-19980424" /> section 17.13.4.
</t>
<t>
The OAuth HTTP Authorization header field (<xref target="auth_header" />) if
present. The header's content is parsed into a list of name/value pairs
excluding the <spanx style="verb">realm</spanx> parameter if present. The
parameter values are decoded as defined by <xref target="auth_header" />.
</t>
<t>
The HTTP request entity-body, but only if all of the following conditions are met:
<list style="symbols">
<t>
The entity-body is single-part.
</t>
<t>
The entity-body follows the encoding requirements of the
<spanx style="verb">application/x-www-form-urlencoded</spanx> content-type as
defined by <xref target="W3C.REC-html40-19980424" />.
</t>
<t>
The HTTP request entity-header includes the <spanx style="verb">Content-Type</spanx>
header field set to <spanx style="verb">application/x-www-form-urlencoded</spanx>.
</t>
</list>
The entity-body is parsed into a list of decoded name/value pairs as described in
<xref target="W3C.REC-html40-19980424" /> section 17.13.4.
</t>
</list>
</t>
<t>
The <spanx style="verb">oauth_signature</spanx> parameter MUST be excluded from the
signature base string if present. Parameters not explicitly included in the request
MUST be excluded from the signature base string (e.g. the
<spanx style="verb">oauth_version</spanx> parameter when omitted).
</t>
<figure>
<preamble>
For example, the HTTP request:
</preamble>
<artwork xml:space="preserve"><![CDATA[
GET /request?b5=%3D%253D&a3=a&c%40=&a2=r%20b HTTP/1.1
Host: example.com
Content-Type: application/x-www-form-urlencoded
Authorization: OAuth realm="Example",
oauth_consumer_key="9djdj82h48djs9d2",
oauth_token="kkk9d7dh3k39sjv7",
oauth_signature_method="HMAC-SHA1",
oauth_timestamp="137131201",
oauth_nonce="7d8f3e4a",
oauth_signature="djosJKDKJSD8743243%2Fjdk33klY%3D"
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>oauth_consumer_key</c><c>9djdj82h48djs9d2</c>
<c>oauth_token</c><c>kkk9d7dh3k39sjv7</c>
<c>oauth_signature_method</c><c>HMAC-SHA1</c>
<c>oauth_timestamp</c><c>137131201</c>
<c>oauth_nonce</c><c>7d8f3e4a</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>
</section>
<section title="Parameters Normalization" anchor="sig_norm_param">
<t>
The parameters collected in <xref target="collect_param" /> are normalized into a
single string as follows:
<list style="numbers">
<t>
First, the name and value of each parameter are <xref target="encoding">encoded</xref>.
</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 <spanx style="verb">&</spanx> character (ASCII code 38) as separator.
</t>
</list>
</t>
<t>
For example, the list of parameters from the previous section would be 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>oauth_consumer_key</c><c>9djdj82h48djs9d2</c>
<c>oauth_token</c><c>kkk9d7dh3k39sjv7</c>
<c>oauth_signature_method</c><c>HMAC-SHA1</c>
<c>oauth_timestamp</c><c>137131201</c>
<c>oauth_nonce</c><c>7d8f3e4a</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>
<c>oauth_consumer_key</c><c>9djdj82h48djs9d2</c>
<c>oauth_nonce</c><c>7d8f3e4a</c>
<c>oauth_signature_method</c><c>HMAC-SHA1</c>
<c>oauth_timestamp</c><c>137131201</c>
<c>oauth_token</c><c>kkk9d7dh3k39sjv7</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>
<c>oauth_consumer_key=9djdj82h48djs9d2</c>
<c>oauth_nonce=7d8f3e4a</c>
<c>oauth_signature_method=HMAC-SHA1</c>
<c>oauth_timestamp=137131201</c>
<c>oauth_token=kkk9d7dh3k39sjv7</c>
</texttable>
<figure>
<preamble>
And concatenated together into a single string (line breaks are for display
purposes only):
</preamble>
<artwork xml:space="preserve"><![CDATA[
a2=r%20b&a3=2%20q&a3=a&b5=%3D%253D&c%40=&c2=&oauth_consumer_key=9dj
dj82h48djs9d2&oauth_nonce=7d8f3e4a&oauth_signature_method=HMAC-SHA1
&oauth_timestamp=137131201&oauth_token=kkk9d7dh3k39sjv7
]]>
</artwork>
</figure>
</section>
</section>
</section>
<section title="HMAC-SHA1">
<t>
The <spanx style="verb">HMAC-SHA1</spanx> signature method uses the HMAC-SHA1 signature
algorithm as defined in <xref target="RFC2104" />:
<figure>
<artwork xml:space="preserve"><![CDATA[
digest = HMAC-SHA1 (key, text)
]]>
</artwork>
</figure>
</t>
<t>
The HMAC-SHA1 function variables are used in following way:
<list style="hanging" hangIndent="6">
<t hangText="text">
<vspace />
is set to the value of the signature base string from <xref target="base_string" />.
</t>
<t hangText="key">
<vspace />
is set to the concatenated values of:
<list style="numbers">
<t>
The client shared-secret, after being <xref target="encoding">encoded</xref>.
</t>
<t>
An <spanx style="verb">&</spanx> character (ASCII code 38), which MUST be
included even when either secret is empty.
</t>
<t>
The token shared-secret, after being <xref target="encoding">encoded</xref>.
</t>
</list>
</t>
<t hangText="digest">
<vspace />
is used to set the value of the <spanx style="verb">oauth_signature</spanx>
protocol parameter, after the result octet string is base64-encoded per
<xref target="RFC2045" /> section 6.8.
</t>
</list>
</t>
</section>
<section title="RSA-SHA1">
<t>
The <spanx style="verb">RSA-SHA1</spanx> signature method uses the RSASSA-PKCS1-v1_5
signature algorithm as defined in <xref target="RFC3447" /> section 8.2 (also known as
PKCS#1), using SHA-1 as the hash function for EMSA-PKCS1-v1_5. To use this method, the
client MUST have established client credentials with the server which included its RSA
public key (in a manner which is beyond the scope of this specification).
</t>
<t>
The signature base string is signed using the client's RSA private key per
<xref target="RFC3447" /> section 8.2.1:
<figure>
<artwork xml:space="preserve"><![CDATA[
S = RSASSA-PKCS1-V1_5-SIGN (K, M)
]]>
</artwork>
</figure>
Where:
<list style="hanging" hangIndent="6">
<t hangText="K">
<vspace />
is set to the client's RSA private key,
</t>
<t hangText="M">
<vspace />
is set to the value of the signature base string from <xref target="base_string" />, and
</t>
<t hangText="S">
<vspace />
is the result signature used to set the value of the <spanx style="verb">oauth_signature</spanx>
protocol parameter, after the result octet string is base64-encoded per <xref target="RFC2045" />
section 6.8.
</t>
</list>
</t>
<t>
The server verifies the signature per <xref target="RFC3447" /> section 8.2.2:
<figure>
<artwork xml:space="preserve"><![CDATA[
RSASSA-PKCS1-V1_5-VERIFY ((n, e), M, S)
]]>
</artwork>
</figure>
Where:
<list style="hanging" hangIndent="6">
<t hangText="(n, e)">
<vspace />
is set to the client's RSA public key,
</t>
<t hangText="M">
<vspace />
is set to the value of the signature base string from <xref target="base_string" />, and
</t>
<t hangText="S">
<vspace />
is set to the octet string value of the <spanx style="verb">oauth_signature</spanx>
protocol parameter received from the client.
</t>
</list>
</t>
</section>
<section title="PLAINTEXT">
<t>
The <spanx style="verb">PLAINTEXT</spanx> method does not employ a signature algorithm.
It MUST be used with a transport-layer mechanism such as TLS or SSL (or sent over a secure
channel with equivalent protections). It does not utilize the signature base string nor
the <spanx style="verb">oauth_timestamp</spanx> and <spanx style="verb">oauth_nonce</spanx>
parameters.
</t>
<t>
The <spanx style="verb">oauth_signature</spanx> protocol parameter is set to the
concatenated value of:
<list style="numbers">
<t>
The client shared-secret, after being <xref target="encoding">encoded</xref>.
</t>
<t>
An <spanx style="verb">&</spanx> character (ASCII code 38), which MUST be
included even when either secret is empty.
</t>
<t>
The token shared-secret, after being <xref target="encoding">encoded</xref>.
</t>
</list>
</t>
</section>
</section>
<section title="Parameter Transmission" anchor="param_include">
<t>
When making an OAuth-authenticated request, protocol parameters as well as any other
parameter using the <spanx style="verb">oauth_</spanx> prefix SHALL be included in the
request using one and only one of the following locations, listed in order of decreasing
preference:
<list style="numbers">
<t>
The HTTP <spanx style="verb">Authorization</spanx> header field as described in
<xref target="auth_header" />.
</t>
<t>
The HTTP request entity-body as described in <xref target="auth_body" />.
</t>
<t>
The HTTP request URI query as described in <xref target="auth_query" />.
</t>
</list>
</t>
<t>
In addition to these three methods, future extensions MAY define other methods for
including protocol parameters in the request.
</t>
<section title="Authorization Header" anchor="auth_header">
<t>
Protocol parameters can be transmitted using the HTTP
<spanx style="verb">Authorization</spanx> header field as defined by <xref target="RFC2617" />
with the auth-scheme name set to <spanx style="verb">OAuth</spanx> (case-insensitive).
</t>
<figure>
<preamble>
For example:
</preamble>
<artwork xml:space="preserve"><![CDATA[
Authorization: OAuth realm="Example",
oauth_consumer_key="0685bd9184jfhq22",
oauth_token="ad180jjd733klru7",
oauth_signature_method="HMAC-SHA1",
oauth_signature="wOJIO9A2W5mFwDgiDvZbTSMK%2FPY%3D",
oauth_timestamp="137131200",
oauth_nonce="4572616e48616d6d65724c61686176",
oauth_version="1.0"
]]>
</artwork>
</figure>
<t>
Protocol parameters SHALL be included in the <spanx style="verb">Authorization</spanx>
header field as follows:
<list style="numbers">
<t>
Parameter names and values are encoded per
<xref target="encoding">Parameter Encoding</xref>.
</t>
<t>
Each parameter's name is immediately followed by an <spanx style="verb">=</spanx>
character (ASCII code 61), a <spanx style="verb">"</spanx> character (ASCII code 34),
the parameter value (MAY be empty), and another <spanx style="verb">"</spanx> character
(ASCII code 34).
</t>
<t>
Parameters are separated by a <spanx style="verb">,</spanx> character (ASCII code 44)
and OPTIONAL linear whitespace per <xref target="RFC2617" />.
</t>
<t>
The OPTIONAL <spanx style="verb">realm</spanx> parameter MAY be added and
interpreted per <xref target="RFC2617" /> section 1.2.
</t>
</list>
</t>
<t>
Servers MAY indicate their support for the <spanx style="verb">OAuth</spanx>
auth-scheme by returning the HTTP <spanx style="verb">WWW-Authenticate</spanx>
response header field upon client requests for protected resources. As per
<xref target="RFC2617" /> such a response MAY include additional HTTP
<spanx style="verb">WWW-Authenticate</spanx> header fields:
</t>
<figure>
<preamble>
For example:
</preamble>
<artwork xml:space="preserve"><![CDATA[
WWW-Authenticate: OAuth realm="http://server.example.com/"
]]>
</artwork>
</figure>
<t>
The realm parameter defines a protection realm per <xref target="RFC2617" />
section 1.2.
</t>
</section>
<section title="Form-Encoded Body" anchor="auth_body">
<t>
Protocol parameters can be transmitted in the HTTP request entity-body, but only if the
following REQUIRED conditions are met:
<list style="symbols">
<t>
The entity-body is single-part.
</t>
<t>
The entity-body follows the encoding requirements of the
<spanx style="verb">application/x-www-form-urlencoded</spanx> content-type as
defined by <xref target="W3C.REC-html40-19980424" />.
</t>
<t>
The HTTP request entity-header includes the <spanx style="verb">Content-Type</spanx>
header field set to <spanx style="verb">application/x-www-form-urlencoded</spanx>.
</t>
</list>
<figure>
<preamble>
For example (line breaks are for display purposes only):
</preamble>
<artwork xml:space="preserve"><![CDATA[
oauth_consumer_key=0685bd9184jfhq22&oauth_token=ad180jjd733klr
u7&oauth_signature_method=HMAC-SHA1&oauth_signature=wOJIO9A2W5
mFwDgiDvZbTSMK%2FPY%3D&oauth_timestamp=137131200&oauth_nonce=4
572616e48616d6d65724c61686176&oauth_version=1.0
]]>
</artwork>
</figure>
The entity-body MAY include other request-specific parameters, in which case, the
protocol parameters SHOULD be appended following the request-specific parameters,
properly separated by an <spanx style="verb">&</spanx> character (ASCII code 38).
</t>
</section>
<section title="Request URI Query" anchor="auth_query">
<t>
Protocol parameters can be transmitted by being added to the HTTP request URI as a
query parameter as defined by <xref target="RFC3986" /> section 3.
<figure>
<preamble>
For example (line breaks are for display purposes only):
</preamble>
<artwork xml:space="preserve"><![CDATA[
GET /example/path?oauth_consumer_key=0685bd9184jfhq22&
oauth_token=ad180jjd733klru7&oauth_signature_method=HM
AC-SHA1&oauth_signature=wOJIO9A2W5mFwDgiDvZbTSMK%2FPY%
3D&oauth_timestamp=137131200&oauth_nonce=4572616e48616
d6d65724c61686176&oauth_version=1.0 HTTP/1.1
]]>
</artwork>
</figure>
The request URI MAY include other request-specific query parameters, in which case,
the protocol parameters SHOULD be appended following the request-specific parameters,
properly separated by an <spanx style="verb">&</spanx> character (ASCII code 38).
</t>
</section>
</section>
<section title="Percent Encoding" anchor="encoding">
<t>
Existing percent-encoding methods do not guarantee a consistent construction of the
signature base string. The following percent-encoding method is not defined to replace
the existing encoding methods defined by <xref target="RFC3986" /> and
<xref target="W3C.REC-html40-19980424" />. It is used only in the construction of the
signature base string and the <xref target="auth_header">authorization header field</xref>.
</t>
<t>
This specification defines the following method for percent-encoding strings:
<list style="numbers">
<t>
Text values are first encoded as UTF-8 octets per <xref target="RFC3629" /> if they are
not already. This does not include binary values which are not intended for human
consumption.
</t>
<t>
The values are then escaped using the <xref target="RFC3986" /> percent-encoding
(%XX) mechanism as follows:
<list style="symbols">
<t>
Characters in the unreserved character set as defined by <xref target="RFC3986" />
section 2.3 (ALPHA, DIGIT, "-", ".", "_", "~") MUST NOT be encoded.
</t>
<t>
All other characters MUST be encoded.
</t>
<t>
The two hexadecimal characters used to represent encoded characters MUST be
upper case.
</t>
</list>
</t>
</list>
</t>
<t>
This method 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> and not using 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>
</section>
</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="RSA-SHA1 Signature Method">
<t>
Authenticated requests made with <spanx style="verb">RSA-SHA1</spanx> signatures do not
use the token shared-secret, or any provisioned client shared-secret. This means the request
relies completely on the secrecy of the private key used by the client to sign requests.
</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 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 server or of request responses is
an issue.
</t>
</section>
<section title="Proxying and Caching of Authenticated Content">
<t>
The <xref target="auth_header">HTTP Authorization scheme</xref> is optional. However,
<xref target="RFC2616" /> relies on the <spanx style="verb">Authorization</spanx> and
<spanx style="verb">WWW-Authenticate</spanx> header fields to distinguish authenticated content
so that it can be protected. Proxies and caches, in particular, may fail to adequately
protect requests not using these header fields.
</t>
<t>
For example, private authenticated content may be stored in (and thus retrievable from)
publicly-accessible caches. Servers not using the
<xref target="auth_header">HTTP Authorization header field</xref> should take care to use other
mechanisms, such as the <spanx style="verb">Cache-Control</spanx> header field, to ensure that
authenticated content is protected.
</t>
</section>
<section title="Plaintext Storage of Credentials">
<t>
The client shared-secret and token shared-secret function the same way passwords do in
traditional authentication systems. In order to compute the signatures used in methods
other than <spanx style="verb">RSA-SHA1</spanx>, the server must have access to these
secrets 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="Secrecy of the Client Credentials" anchor="client_cred_sec">
<t>
In many cases, the client application will be under the control of potentially untrusted
parties. For example, if the client is a desktop application with freely available
source code or an executable binary, an attacker may be able to download a copy for
analysis. In such cases, attackers will be able to recover the client credentials.
</t>
<t>
Accordingly, servers should not use the client credentials alone to verify the identity
of the client. Where possible, other factors such as IP address should be used as well.
</t>
</section>
<section title="Phishing Attacks">
<t>
Wide deployment of this and similar protocols may cause resource owners to become inured
to the practice of being redirected to websites where they are asked to enter their
passwords. If resource owners are not careful to verify the authenticity of these
websites before entering their credentials, it will be possible for attackers to exploit
this practice to steal resource owners' passwords.
</t>
<t>
Servers should attempt to educate resource owners about the risks phishing attacks pose,
and should provide mechanisms that make it easy for resource owners to confirm the
authenticity of their sites. Client developers should consider the security implications
of how they interact with a user-agent (e.g. separate window, embedded), and the ability
of the end-user to verify the authenticity of the server website.
</t>
</section>
<section title="Scoping of Access Requests">
<t>
By itself, this protocol does not provide any method for scoping the access rights
granted to a client. However, most applications do require greater granularity of access
rights. For example, servers may wish to make it possible to grant access to some
protected resources but not others, or to grant only limited access (such as read-only
access) to those protected resources.
</t>
<t>
When implementing this protocol, servers should consider the types of access resource
owners may wish to grant clients, and should provide mechanisms to do so. Servers should
also take care to ensure that resource owners understand the access they are granting, as
well as any risks that may be involved.
</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 credentials used. 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, 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, 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="SHA-1 Cryptographic Attacks">
<t>
SHA-1, the hash algorithm used in <spanx style="verb">HMAC-SHA1</spanx> and
<spanx style="verb">RSA-SHA1</spanx> signature methods, has been shown to have a number
of cryptographic weaknesses that significantly reduce its resistance to collision
attacks. While these weaknesses do not seem to affect the use of SHA-1 with the
Hash-based Message Authentication Code (HMAC) and should not affect the
<spanx style="verb">HMAC-SHA1</spanx> signature method, it may affect the use of the
<spanx style="verb">RSA-SHA1</spanx> signature method. NIST has announced that it will
phase out use of SHA-1 in digital signtures by 2010 <xref target="NIST SHA-1 Comments" />.
</t>
<t>
Practically speaking, these weaknesses are difficult to exploit, and by themselves do not
pose a significant risk to users of this protocol. They may, however, make more efficient
attacks possible, and Servers should take this into account when considering whether
SHA-1 provides an adequate level of security for their applications.
</t>
</section>
<section title="Signature Base String Limitations">
<t>
The signature base string has been designed to support the signature methods defined in
this specification. Those designing additional signature methods, should evaluated the
compatibility of the signature base string with their security requirements.
</t>
<t>
Since the signature base string does not cover the entire HTTP request, such as most
request entity-body, most entity-headers, and the order in which parameters are sent,
servers should employ additional mechanisms to protect such elements.
</t>
</section>
<section title="Cross-Site Request Forgery (CSRF)">
<t>
Cross-Site Request Forgery (CSRF) is a web-based attack whereby HTTP requests are
transmitted from a user that the website trusts or has authenticated. CSRF attacks on
authorization approvals can allow an attacker to obtain authorization to protected
resources without the consent of the User. Servers SHOULD strongly consider best
practices in CSRF prevention at all the protocol authorization endpoints.
</t>
<t>
CSRF attacks on OAuth callback URIs hosted by clients are also possible. Clients should
prevent CSRF attacks on OAuth callback URIs by verifying that the resource owner at the
client site intended to complete the OAuth negotiation with the server. The methods for
preventing such CSRF attacks are beyond the scope of this specification.
</t>
</section>
<section title="User Interface Redress">
<t>
Servers should protect the authorization process against UI Redress attacks (also known
as "clickjacking"). As of the time of this writing, no complete defenses against UI
redress are available. Servers can mitigate the risk of UI redress attacks through the
following techniques:
<list style="symbols">
<t>
Javascript frame busting.
</t>
<t>
Javascript frame busting, and requiring that browsers have javascript enabled on the
authorization page.
</t>
<t>
Browser-specific anti-framing techniques.
</t>
<t>
Requiring password reentry before issuing OAuth tokens.
</t>
</list>
</t>
</section>
<section title="Automatic Processing of Repeat Authorizations">
<t>
Servers may wish to automatically process authorization requests
(<xref target="auth_step2" />) from clients which have been previously
authorized by the resource owner. When the resource owner is redirected to the server
to grant access, the server detects that the resource owner has already granted
access to that particular client. Instead of prompting the resource owner for approval,
the server automatically redirects the resource owner back to the client.
</t>
<t>
If the client credentials are compromised, automatic processing creates additional
security risks. An attacker can use the stolen client credentials to redirect
the resource owner to the server with an authorization request. The server
will then grant access to the resource owner's data without the resource owner's
explicit approval, or even awareness of an attack. If no automatic approval is
implemented, an attacker must use social engineering to convince the resource owner to
approve access.
</t>
<t>
Servers can mitigate the risks associated with automatic processing by
limiting the scope of token credentials obtained through automated approvals. Tokens
credentials obtained through explicit resource owner consent can remain unaffected. Clients
can mitigate the risks associated with automatic processing by protecting their client
credentials.
</t>
</section>
</section>
<section title="IANA Considerations" anchor="IANA">
<t>
This memo includes no request to IANA.
</t>
</section>
<section title="Acknowledgments">
<t>
This specification is directly based on the OAuth Core 1.0 Revision A community
specification which in turn was modeled after existing proprietary protocols and best
practices that have been independently implemented by various companies.
</t>
<t>
The community specification was edited by Eran Hammer-Lahav and authored by: Mark Atwood,
Dirk Balfanz, Darren Bounds, Richard M. Conlan, Blaine Cook, Leah Culver,
Breno de Medeiros, Brian Eaton, Kellan Elliott-McCrea, Larry Halff, Eran Hammer-Lahav,
Ben Laurie, Chris Messina, John Panzer, Sam Quigley, David Recordon, Eran Sandler,
Jonathan Sergent, Todd Sieling, Brian Slesinsky, and Andy Smith.
</t>
<t>
The editor would like to thank the following individuals for their invaluable contribution
to the publication of this edition of the protocol: Lisa Dusseault, Justin Hart,
Avshalom Houri, Chris Messina, Mark Nottingham, Tim Polk, Peter Saint-Andre, Joseph Smarr,
and Paul Walker.
</t>
</section>
<appendix title="Differences from the Community Edition">
<t>
This specification includes the following changes made to the original community document
<xref target="OAuth Core 1.0 Revision A" /> in order to correct mistakes and omissions
identified since the document has been published:
<list style="symbols">
<t>
Changed using TLS/SSL when sending or requesting plain text credentials from SHOULD
to MUST. This change affects any use of the <spanx style="verb">PLAINTEXT</spanx>
signature method, as well as <xref target="auth_step1">requesting temporary credentials</xref>
and <xref target="auth_step3">obtaining token credentials</xref>.
</t>
<t>
Adjusted nonce language to indicate it is unique per token/timestamp/client combination.
</t>
<t>
Removed the requirement for timestamps to be equal to or greater than the timestamp
used in the previous request.
</t>
<t>
Changed the nonce and timestamp parameters to OPTIONAL when using the
<spanx style="verb">PLAINTEXT</spanx> signature method.
</t>
<t>
Extended signature base string coverage which includes <spanx style="verb">application/x-www-form-urlencoded</spanx>
entity-body parameters when the HTTP method used is other than <spanx style="verb">POST</spanx> and URI query
parameters when the HTTP method used is other than <spanx style="verb">GET</spanx>.
</t>
<t>
Incorporated corrections to the instructions in each signature method to encode the signature
value before inserting it into the <spanx style="verb">oauth_signature</spanx> parameter,
removing errors which would have caused double-encoded values.
</t>
<t>
Allowed omitting the <spanx style="verb">oauth_token</spanx> parameter when empty.
</t>
<t>
Permitted sending requests for temporary credentials with an empty
<spanx style="verb">oauth_token</spanx> parameter.
</t>
<t>
Removed the restrictions from defining additional <spanx style="verb">oauth_</spanx>
parameters.
</t>
</list>
</t>
</appendix>
<appendix title="Document History" anchor="history">
<t>
[[ To be removed by the RFC editor before publication as an RFC. ]]
</t>
<t>
-10
<list style="symbols">
<t>
Added missing 'oauth_token' in exmaple.
</t>
<t>
Changed realm values from URI to string to make them more generic (since
the protocol does not define any internal structure for them).
</t>
</list>
</t>
<t>
-09
<list style="symbols">
<t>
Added 'with a 200 status code (OK)' in two places.
</t>
<t>
Missing comma in example.
</t>
<t>
Corrected typos.
</t>
<t>
Changed the use of TLS/SSL when sending or receiving plain text credentials to a MUST.
</t>
<t>
Clarified text about change control moving from the community to the IETF.
</t>
</list>
</t>
<t>
-08
<list style="symbols">
<t>
Adjusted timestamp language to allow use of time servers for clock sync.
</t>
<t>
Revised security language for SHA-1 weakness and applicability.
</t>
<t>
Added link to the community specification.
</t>
<t>
Minor editorial changes.
</t>
</list>
</t>
<t>
-07
<list style="symbols">
<t>
Corrected typos.
</t>
<t>
Changed examples to use HTTPS in authorization step.
</t>
<t>
Clarified the use of 'oauth_' tokens in the three static endpoint URIs.
</t>
<t>
Edited abstract and introduction.
</t>
</list>
</t>
<t>
-06
<list style="symbols">
<t>
Moved parameter section into client instructions.
</t>
<t>
Added more examples in the delegation section, including more complete HTTP responses.
</t>
<t>
Removed language about restricting the use of the 'oauth_' prefix.
</t>
<t>
Changed the nonce and timestamp parameters to optional when using PLAINTEXT.
</t>
<t>
Allowed empty token in temporary credentials requests.
</t>
</list>
</t>
<t>
-05
<list style="symbols">
<t>
Replaced the word 'lexicographical' with 'ascending' in sorting instructions.
</t>
<t>
Added note that the 'a3' parameter appears twice in the example.
</t>
<t>
Made the note about the encoding scheme being different from most common implementations
more explicit.
</t>
<t>
Moved and cleaned up the example from appendix to introduction. Removed crypto details
from the example.
</t>
</list>
</t>
<t>
-04
<list style="symbols">
<t>
Corrected typo and other minor editorial changes.
</t>
<t>
Added warning about token sizes.
</t>
<t>
Clarified that all 'oauth_' parameters must be transmitted using the same method.
</t>
<t>
Added explicit requirement to exclude parameters not transmitted in a request in the
signature base string (for example oauth_version when omitted).
</t>
<t>
Explicitly set OAuth to use HTTP 1.1.
</t>
<t>
Rearranged the signature base string section to provide a better narrative of how the
HTTP request is normalized. Added the protocol parameters to the examples to better
demonstrate how they are incorporated in practice.
</t>
<t>
Flipped the document order between authentication and authorization.
</t>
<t>
Removed the requirement for timestamps to be equal or greater than previous timestamps.
</t>
</list>
</t>
<t>
-03
<list style="symbols">
<t>
Updated draft with changes from OAuth Core 1.0 Revision A to fix a session fixation exploit.
</t>
<t>
Small editorial corrections.
</t>
<t>
Removed confusing language from 'Denial of Service / Resource Exhaustion Attacks'.
</t>
<t>
Added new 'Differences from the Community Edition' appendix.
</t>
<t>
Updated acknowledgements section.
</t>
</list>
</t>
<t>
-02
<list style="symbols">
<t>
Corrected mistake in parameter sorting order (c%40 comes before c2).
</t>
<t>
Added requirement to normalize empty paths as '/'.
</t>
</list>
</t>
<t>
-01
<list style="symbols">
<t>
Complete rewrite of the entire specification from scratch. Separated the spec structure
into two parts and flipped their order.
</t>
<t>
Corrected errors in instructions to encode the signature base string by some methods. The
signature value is encoded using the transport rules, not the spec method for encoding.
</t>
<t>
Replaced the entire terminology.
</t>
</list>
</t>
<t>
-00
<list style="symbols">
<t>
Initial draft based on the OAuth Core 1.0 community specification
with the following changes.
</t>
<t>
Various changes required to accommodate the strict format requirements of the IETF,
such as moving sections around (Security, Contributors, Introduction, etc.), cleaning
references, adding IETF specific text, etc.
</t>
<t>
Moved the Parameter Encoding sub-section from section 5 (Parameters) to section 9.1
(Signature Base String) to make it clear it only applies to the signature base string.
</t>
<t>
Nonce language adjusted to indicate it is unique per token/timestamp/consumer
combination.
</t>
<t>
Added security language regarding lack of token secrets in RSA-SHA1.
</t>
<t>
Fixed the bug in the Normalize Request Parameters section. Removed the
<spanx style="verb">GET</spanx> limitation from the third bullet (query parameters).
</t>
<t>
Removed restriction of only signing application/x-www-form-urlencoded in
<spanx style="verb">POST</spanx> requests, allowing the entity-body to be used with all
HTTP request methods.
</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.2616.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.2818.xml"?>
<?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.3447.xml"?>
<?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.3629.xml"?>
<?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.3986.xml"?>
<?rfc include="http://xml.resource.org/public/rfc/bibxml4/reference.W3C.REC-html40-19980424.xml"?>
</references>
<references title="Informative References">
<reference anchor="OAuth Core 1.0 Revision A">
<front>
<title>OAuth Core 1.0 Revision A</title>
<author initials="OAuth Community" surname="OAuth" fullname="OAuth Community">
<organization />
</author>
</front>
<format type="HTML" target="http://oauth.net/core/1.0a" />
</reference>
<reference anchor="NIST SHA-1 Comments">
<front>
<title>NIST Comments on Cryptanalytic Attacks on SHA-1</title>
<author initials="W.E.B" surname="Burr" fullname="William E. Burr">
<organization>NIST</organization>
</author>
</front>
<format type="html" target="http://csrc.nist.gov/groups/ST/hash/statement.html" />
</reference>
</references>
</back>
</rfc>| PAFTECH AB 2003-2026 | 2026-04-23 08:42:04 |