One document matched: draft-ietf-oauth-web-delegation-01.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-ietf-oauth-web-delegation-01">
<?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">The OAuth Protocol: Web Delegation</title>
<author initials="E" surname="Hammer-Lahav" fullname="Eran Hammer-Lahav" role="editor">
<organization>
Yahoo!
</organization>
<address>
<email>eran@hueniverse.com</email>
<uri>http://hueniverse.com</uri>
</address>
</author>
<date year="2009"/>
<abstract>
<t>
This document specifies the OAuth protocol web delegation method. OAuth allows clients
to access server resources on behalf of another party (such a different client or an end
user). This document defines a redirection-based user-agent process for end users to authorize
access to clients by substituting their credentials (typically, a username and password
pair) with a different set of delegation-specific credentials.
</t>
</abstract>
</front>
<middle>
<section title="Introduction">
<t>
The OAuth protocol provides a method for servers to allow third-party access to protected
resources, without forcing their end users to share their credentials. This pattern is
common among services that allow third-party developers to extend the service functionality,
by building applications using an open API.
</t>
<t>
For example, a web user (resource owner) can grant a printing service (client) access to
its private photos stored at a photo sharing service (server), without sharing its
credentials with the printing service. Instead, the user authenticates directly with
the photo sharing service and issue the printing service delegation-specific credentials.
</t>
<t>
OAuth introduces a third role to the traditional client-server authentication model: the
resource owner. In the OAuth model, the client requests access to resources hosted by the
server but not controlled by the client, but by the resource owner. In addition, OAuth
allows the server to verify not only the resource owner's credentials, but also those of
the client making the request.
</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 substitute the need for the resource owner to
share its server credentials (usually a username and password pair) with the client. Unlike
server credentials, tokens can be issued with a restricted scope and limited lifetime.
</t>
<t>
This specification consists of two parts. <xref target="draft-ietf-oauth-authentication" />
defines a method for making authenticated HTTP 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>
This document 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.
</t>
<section title="Terminology">
<t>
<list style="hanging" hangIndent="6">
<t hangText="client">
<vspace />
An HTTP client (per <xref target="RFC2616" />) capable of making
OAuth-authenticated requests per <xref target="draft-ietf-oauth-authentication" />.
</t>
<t hangText="server">
<vspace />
An HTTP server (per <xref target="RFC2616" />) capable of accepting
OAuth-authenticated requests per <xref target="draft-ietf-oauth-authentication" />.
</t>
<t hangText="protected resource">
<vspace />
An access-restricted resource (per <xref target="RFC2616" />) which can be obtained
from the server using an OAuth-authenticated request per
<xref target="draft-ietf-oauth-authentication" />.
</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="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>
</section>
</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 title="Redirection-Based Authorization">
<t>
OAuth uses a set of token credentials 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 using
its server credentials (usually a username and password pair).
</t>
<t>
There are many ways in which a resource owner 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.
</t>
<t>
The resource owner authorizes the server to issue token credentials to the client
using 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.
The temporary credentials discarded.
</t>
</list>
</t>
<t>
The temporary credentials MUST be revoked 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
these three endpoints, as well as the HTTP method (GET, POST, etc.) used to make each requests.
To assist in communicating these endpoint, each is given a name:
<list style="hanging" hangIndent="6">
<t hangText="Temporary Credential Request">
<vspace />
The endpoint used by the client to obtain 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
temporary credentials as described in <xref target="auth_step3" />.
</t>
</list>
</t>
<t>
The three URIs 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.
</t>
<t>
The method in which the server advertises its three endpoint is beyond the scope of this
specification.
</t>
</section>
<section title="Temporary Credentials" anchor="auth_step1">
<t>
The client obtains a set of temporary credentials from the server by making an
authenticated request per <xref target="draft-ietf-oauth-authentication" />.
The client MUST use the HTTP method advertised by the server. The HTTP POST method is RECOMMENDED.
The client constructs a request URI by adding the following parameter to the
Temporary Credential Request endpoint URI:
<list style="hanging" hangIndent="6">
<t hangText="oauth_callback:">
An absolute URL 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 MUST omit the <spanx style="verb">oauth_token</spanx> protocol parameter from the
request and use an empty string as the token secret value.
</t>
<t>
The server MUST verify that the request is valid per <xref target="draft-ietf-oauth-authentication" />
and respond back to the client with a set of temporary credentials. 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" />.
</t>
<t>
The response contains the following 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 client
MAY use this to confirm that the server received the callback value.
</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>
oauth_token=ab3cd9j4ks73hf7g&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 parameters to the Resource Owner Authorization endpoint URI:
<list style="hanging" hangIndent="6">
<t hangText="oauth_token">
<vspace />
REQUIRED. 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 redirects 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 GET method.
</t>
<t>
The way in which the server handles the authorization request 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 parameter to the
callback URI query component:
<list style="hanging" hangIndent="6">
<t hangText="oauth_token">
<vspace />
The temporary credentials identifier the resource owner authorized or denied access
to.
</t>
<t hangText="oauth_verifier:">
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 (line breaks are for display purposes only):
</preamble>
<artwork>
http://client.example.net/cb?state=1&oauth_token=ab3cd9j4ks73hf7g&
oauth_verifier=473829k9302sa
</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
authenticated request per <xref target="draft-ietf-oauth-authentication" />. The client
MUST use the HTTP method advertised by the server. The HTTP POST method is RECOMMENDED.
The client constructs a request URI by adding the following parameter to the
Token Request endpoint URI:
<list style="hanging" hangIndent="6">
<t hangText="oauth_verifier:">
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 substitution for token
credentials in the authenticated request.
</t>
<t>
The server MUST verify the validity of the request per <xref target="draft-ietf-oauth-authentication" />,
ensure that the resource owner has authorized the provisioning of token credentials to
the client, and that the temporary credentials have not expired or 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" />.
</t>
<t>
The response contains the following 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>
oauth_token=j49ddk933skd9dks&oauth_token_secret=ll399dj47dskfjdk
</artwork>
</figure>
<t>
The token credentials issued by the server MUST reflect the exact scope, duration, and
other attributes approved by the resource owner.
</t>
<t>
Once the client receives the token credentials, it can proceed to access protected
resources on behalf of the resource owner by making an authenticated request per
<xref target="draft-ietf-oauth-authentication" /> using the client credentials and the
token credentials received.
</t>
</section>
<section title="IANA Considerations" anchor="IANA">
<t>
This memo includes no request to IANA.
</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="Credentials Transmission">
<t>
The OAuth specification does not describe any mechanism for protecting tokens and
shared-secrets from eavesdroppers when they are transmitted from the server to the
client during the authorization phase. Servers should ensure that these transmissions are
protected using transport-layer mechanisms such as TLS or SSL.
</t>
</section>
<section title="Phishing Attacks">
<t>
Wide deployment of OAuth 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.
</t>
</section>
<section title="Scoping of Access Requests">
<t>
By itself, OAuth 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 OAuth, 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 OAuth 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>
The OAuth protocol has a number of features which may make resource exhaustion attacks
against servers possible. For example, if a server includes a nontrivial amount of
entropy in token shared-secrets as recommended above, then an attacker may be able to
exhaust the server's entropy pool very quickly by repeatedly obtaining temporary credentials
from the server.
</t>
<t>
Similarly, OAuth 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, OAuth 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 OAuth. However, OAuth implementers
should be careful to consider the additional avenues of attack that OAuth 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 OAuth, servers should consider
which of these presents a more serious risk for their application and design accordingly.
</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 OAuth 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 OAuth endpoints.
</t>
<t>
CSRF attacks on OAuth callback URIs hosted by client 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.
</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>
<appendix title="Examples">
<t>
In this example, photos.example.net is a photo sharing website (server), and
printer.example.com is a photo printing service (client). Jane (resource owner) would like
printer.example.com to print a private photo stored at photos.example.net.
</t>
<t>
When Jane signs-into photos.example.net using her username and password, she can access the
photo by requesting the URI <spanx style="verb">http://photos.example.net/photo?file=vacation.jpg</spanx>
(which also supports the optional <spanx style="verb">size</spanx> parameter).
Jane does not want to share her username and password with printer.example.com, but would
like it to access the photo and print it.
</t>
<t>
The server documentation advertises support for the <spanx style="verb">HMAC-SHA1</spanx>
and <spanx style="verb">PLAINTEXT</spanx> methods, with <spanx style="verb">PLAINTEXT</spanx>
restricted to secure (HTTPS) requests. It also advertises the following endpoint URIs:
<list style="hanging" hangIndent="6">
<t hangText="Temporary Credential Request">
<vspace />
https://photos.example.net/initiate, using HTTP POST
</t>
<t hangText="Resource Owner Authorization URI:">
<vspace />
http://photos.example.net/authorize, using HTTP GET
</t>
<t hangText="Token Request URI:">
<vspace />
https://photos.example.net/token, using HTTP POST
</t>
</list>
</t>
<t>
The printer.example.com has already established client credentials with photos.example.net:
<list style="hanging" hangIndent="6">
<t hangText="Client Identifier">
<vspace />
<spanx style="verb">dpf43f3p2l4k3l03</spanx>
</t>
<t hangText="Client Shared-Secret:">
<vspace />
<spanx style="verb">kd94hf93k423kf44</spanx>
</t>
</list>
</t>
<t>
When printer.example.com attempts to print the request photo, it receives an HTTP response
with a 401 (Unauthorized) status code, and a challenge to use OAuth:
<figure>
<artwork>
WWW-Authenticate: OAuth realm="http://photos.example.net/"
</artwork>
</figure>
</t>
<appendix title="Obtaining Temporary Credentials">
<t>
The client sends the following HTTPS POST request to the server:
<figure>
<artwork>
POST /initiate HTTP/1.1
Host: photos.example.net
Authorization: OAuth realm="http://photos.example.com/",
oauth_consumer_key="dpf43f3p2l4k3l03",
oauth_signature_method="PLAINTEXT",
oauth_signature="kd94hf93k423kf44%26",
oauth_timestamp="1191242090",
oauth_nonce="hsu94j3884jdopsl",
oauth_version="1.0",
oauth_callback="http%3A%2F%2Fprinter.example.com%2Fready"
</artwork>
</figure>
</t>
<t>
The server validates the request and replies with a set of temporary credentials in the body
of the HTTP response:
<figure>
<artwork>
oauth_token=hh5s93j4hdidpola&oauth_token_secret=hdhd0244k9j7ao03&
oauth_callback_confirmed=true
</artwork>
</figure>
</t>
</appendix>
<appendix title="Requesting Resource Owner Authorization">
<t>
The client redirects Jane's browser to the server's Resource Owner Authorization endpoint
URI to obtain Jane's approval for accessing her private photos.
<figure>
<artwork>
http://photos.example.net/authorize?oauth_token=hh5s93j4hdidpola
</artwork>
</figure>
</t>
<t>
The server asks Jane to sign-in using her username and password and if successful, asks
her if she approves granting printer.example.com access to her private photos. Jane approves
the request and is redirects her back to the client's callback URI:
<figure>
<artwork>
http://printer.example.com/ready?
oauth_token=hh5s93j4hdidpola&oauth_verifier=hfdp7dh39dks9884
</artwork>
</figure>
</t>
</appendix>
<appendix title="Obtaining Token Credentials">
<t>
After being informed by the callback request that Jane approved authorized access,
printer.example.com requests a set of token credentials using its temporary credentials:
<figure>
<artwork>
POST /token HTTP/1.1
Host: photos.example.net
Authorization: OAuth realm="http://photos.example.com/",
oauth_consumer_key="dpf43f3p2l4k3l03",
oauth_token="hh5s93j4hdidpola",
oauth_signature_method="PLAINTEXT",
oauth_signature="kd94hf93k423kf44%26hdhd0244k9j7ao03",
oauth_timestamp="1191242092",
oauth_nonce="dji430splmx33448",
oauth_version="1.0"
oauth_verifier="hfdp7dh39dks9884"
</artwork>
</figure>
</t>
<t>
The server validates the request and replies with a set of token credentials in the body
of the HTTP response:
<figure>
<artwork>
oauth_token=nnch734d00sl2jdk&oauth_token_secret=pfkkdhi9sl3r4s00
</artwork>
</figure>
</t>
</appendix>
<appendix title="Accessing protected resources">
<t>
The printer is now ready to request the private photo. Since the photo URI does not use
HTTPS, the <spanx style="verb">HMAC-SHA1</spanx> method is required.
</t>
<appendix title="Generating Signature Base String" anchor="sig_base_example">
<t>
To generate the signature, it first needs to generate the signature base string. The
request contains the following parameters (<spanx style="verb">oauth_signature</spanx>
excluded) which need to be ordered and concatenated into a normalized string:
<list style="hanging" hangIndent="6">
<t hangText="oauth_consumer_key">
<vspace />
<spanx style="verb">dpf43f3p2l4k3l03</spanx>
</t>
<t hangText="oauth_token">
<vspace />
<spanx style="verb">nnch734d00sl2jdk</spanx>
</t>
<t hangText="oauth_signature_method">
<vspace />
<spanx style="verb">HMAC-SHA1</spanx>
</t>
<t hangText="oauth_timestamp">
<vspace />
<spanx style="verb">1191242096</spanx>
</t>
<t hangText="oauth_nonce">
<vspace />
<spanx style="verb">kllo9940pd9333jh</spanx>
</t>
<t hangText="oauth_version">
<vspace />
<spanx style="verb">1.0</spanx>
</t>
<t hangText="file">
<vspace />
<spanx style="verb">vacation.jpg</spanx>
</t>
<t hangText="size">
<vspace />
<spanx style="verb">original</spanx>
</t>
</list>
</t>
<t>
The following inputs are used to generate the signature base string:
<list style="numbers">
<t>
The HTTP request method: <spanx style="verb">GET</spanx>
</t>
<t>
The request URI: <spanx style="verb">http://photos.example.net/photos</spanx>
</t>
<t>
The encoded normalized request parameters string:
<spanx style="verb">file=vacation.jpg&oauth_consumer_key=dpf43f3p2l4k3l03&oauth_nonce=kllo9940pd9333jh&oauth_signature_method=HMAC-SHA1&oauth_timestamp=1191242096&oauth_token=nnch734d00sl2jdk&oauth_version=1.0&size=original</spanx>
</t>
</list>
</t>
<t>
The signature base string is (line breaks are for display purposes only):
<figure>
<artwork>
GET&http%3A%2F%2Fphotos.example.net%2Fphotos&file%3Dvacation.jpg%26
oauth_consumer_key%3Ddpf43f3p2l4k3l03%26oauth_nonce%3Dkllo9940pd933
3jh%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D119124
2096%26oauth_token%3Dnnch734d00sl2jdk%26oauth_version%3D1.0%26size%
3Doriginal
</artwork>
</figure>
</t>
</appendix>
<appendix title="Calculating Signature Value">
<t>
HMAC-SHA1 produces the following <spanx style="verb">digest</spanx> value as a base64-encoded
string (using the signature base string as <spanx style="verb">text</spanx> and
<spanx style="verb">kd94hf93k423kf44&pfkkdhi9sl3r4s00</spanx> as <spanx style="verb">key</spanx>):
<figure>
<artwork>
tR3+Ty81lMeYAr/Fid0kMTYa/WM=
</artwork>
</figure>
</t>
</appendix>
<appendix title="Requesting protected resource">
<t>
All together, the client request for the photo is:
<figure>
<artwork>
GET /photos?file=vacation.jpg&size=original HTTP/1.1
Host: photos.example.com
Authorization: OAuth realm="http://photos.example.net/",
oauth_consumer_key="dpf43f3p2l4k3l03",
oauth_token="nnch734d00sl2jdk",
oauth_signature_method="HMAC-SHA1",
oauth_signature="tR3%2BTy81lMeYAr%2FFid0kMTYa%2FWM%3D",
oauth_timestamp="1191242096",
oauth_nonce="kllo9940pd9333jh",
oauth_version="1.0"
</artwork>
</figure>
</t>
<t>
The photos.example.net sever validates the request and responds with the requested
photo.
</t>
</appendix>
</appendix>
</appendix>
<appendix title="Acknowledgments">
<t>
This specification is directly based on the <xref target="OAuth Core 1.0 Revision A" /> community
specification which was the product of the OAuth community. OAuth was modeled after
existing proprietary protocols and best practices that have been independently implemented
by various web sites. This specification was orignially 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>
</appendix>
<appendix title="Document History">
<t>
[[ To be removed by the RFC editor before publication as an RFC. ]]
</t>
<t>
-01
<list style="symbols">
<t>
Moved all subsection from section 3 to the document root.
</t>
</list>
</t>
<t>
-00
<list style="symbols">
<t>
Transitioned from the individual submission draft-hammer-oauth-02 to working group draft.
</t>
<t>
Split draft-hammer-oauth-02 into two drafts, one dealing with web delegation (this draft)
and another dealing with authentication draft-ietf-oauth-web-authentication.
</t>
<t>
Updated draft with changes from OAuth Core 1.0 Revision A to fix a session fixation exploit.
</t>
</list>
</t>
</appendix>
</middle>
<back>
<references title="Normative References">
<?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.3986.xml"?>
<?rfc include="http://xml.resource.org/public/rfc/bibxml4/reference.W3C.REC-html40-19980424.xml"?>
<reference anchor="draft-ietf-oauth-authentication">
<front>
<title>The OAuth Protocol: Authentication</title>
<author initials="E" surname="Hammer-Lahav" fullname="Eran Hammer-Lahav" role="editor">
<organization>
Yahoo!
</organization>
<address>
<email>eran@hueniverse.com</email>
<uri>http://hueniverse.com</uri>
</address>
</author>
</front>
<format type="TXT" target="http://www.ietf.org/internet-drafts/draft-ietf-oauth-authentication-01.txt" />
</reference>
</references>
<references title="Informative References">
<reference anchor="OAuth Core 1.0 Revision A">
<front>
<title>OAuth Core 1.0</title>
<author initials="OCW" surname="OAuth" fullname="OAuth Core Workgroup">
<organization />
</author>
</front>
<format type="HTML" target="http://oauth.net/core/1.0a" />
</reference>
</references>
</back>
</rfc>| PAFTECH AB 2003-2026 | 2026-04-23 08:36:19 |