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<tr><td class="header">Implementers' Draft</td><td class="header">A. Tom</td></tr>
<tr><td class="header"> </td><td class="header">Yahoo!</td></tr>
<tr><td class="header"> </td><td class="header">B. de Medeiros</td></tr>
<tr><td class="header"> </td><td class="header">Google</td></tr>
<tr><td class="header"> </td><td class="header">May 18, 2009</td></tr>
</table></td></tr></table>
<h1><br />OpenID User Interface Extension 1.0 - DRAFT 0.5</h1>
<h3>Abstract</h3>
<p>
This specification defines a mechanism to support OpenID user interfaces
optimized for different environments and languages.
</p><a name="toc"></a><br /><hr />
<h3>Table of Contents</h3>
<p class="toc">
<a href="#conv">1.</a>
Notation and Conventions<br />
<a href="#anchor1">2.</a>
Overview<br />
<a href="#anchor2">3.</a>
Extension Namespace<br />
<a href="#anchor3">4.</a>
Language Preference<br />
<a href="#anchor4">5.</a>
Requesting Authentication in a Popup<br />
<a href="#anchor5">5.1.</a>
Authentication Response in a Fragment<br />
<a href="#anchor6">6.</a>
Requesting Display of RP icons in the OP Approval UI<br />
<a href="#anchor7">7.</a>
Discovery<br />
<a href="#anchor8">8.</a>
Considerations<br />
<a href="#anchor9">9.</a>
Acknowledgements<br />
<a href="#rfc.references1">10.</a>
References<br />
<a href="#anchor11">Appendix A.</a>
Example Use of Experimental Mode<br />
<a href="#rfc.authors">§</a>
Authors' Addresses<br />
</p>
<br clear="all" />
<a name="conv"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.1"></a><h3>1.
Notation and Conventions</h3>
<p>The keywords MUST, MUST NOT, REQUIRED, SHALL,
SHALL NOT, SHOULD, SHOULD NOT, RECOMMENDED, MAY,
and OPTIONAL in this document are to be interpreted as
described in <a class='info' href='#RFC2119'>[RFC2119]<span> (</span><span class='info'>Bradner, B., “Key words for use in RFCs to Indicate Requirement Levels,” .</span><span>)</span></a>.
</p>
<p>
Unless otherwise noted, this specification is written as a direct
continuation of <a class='info' href='#OpenID 2.0'>[OpenID 2.0]<span> (</span><span class='info'>OpenID 2.0 Workgroup, “OpenID 2.0,” .</span><span>)</span></a>, inheriting the definitions and
guidelines set by it.
</p>
<a name="anchor1"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.2"></a><h3>2.
Overview</h3>
<p>
OpenID traditionally required the Relying Party to redirect the entire browser
window to the OpenID Provider for the user to authenticate before redirecting
the browser back to the Relying Party. It is believed that the User Experience (UX)
could be significantly improved if the authentication flow occurred within a separate
popup window, making the experience less disruptive to the user.
</p>
<p>
Although it is possible for Relying Parties to open a popup window for the user to
authenticate at the OpenID Provider using the Provider's default user interface,
the overall user experience can be optimized if the OP was aware that its UI was running
within a popup. For instance, an OP may want to resize the popup browser window when using
the popup interface, but would probably not want to resize the full browser
window when using the default redirect interface.
Another optimization is that the OP can close the popup, rather than
return a negative assertion if the user chooses to cancel the authentication request.
</p>
<p>
This extension also adds support for Relying Parties to indicate the user's language
preference to the OP, potentially making the transition from the RP to the OP less disruptive
to the user.
</p>
<a name="anchor2"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.3"></a><h3>3.
Extension Namespace</h3>
<p>
All OpenID 2.0 messages that contain a UI Extension element MUST
contain the following extension namespace declaration, as specified in the
Extensions section of <a class='info' href='#OpenID 2.0'>[OpenID 2.0]<span> (</span><span class='info'>OpenID 2.0 Workgroup, “OpenID 2.0,” .</span><span>)</span></a>.
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>
openid.ns.<alias>=http://specs.openid.net/extensions/ui/1.0
</pre></div>
<p>
The actual extension namespace alias should be determined on a per-message basis
by the party composing the messages, in such a manner as to avoid conflicts between
multiple extensions. For the purposes of this document, the extension namespace used
for all examples is "ui".
</p>
<a name="anchor3"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.4"></a><h3>4.
Language Preference</h3>
<p>
When requesting OpenID authentication using the checkid_setup mode, the Relying Party MAY send the
OP a hint regarding the user's preferred language by sending the following parameters:
</p>
<p>
</p>
<blockquote class="text"><dl>
<dt>openid.ns.ui</dt>
<dd>
REQUIRED. Value: "http://specs.openid.net/extensions/ui/1.0"
</dd>
<dt>openid.ui.lang</dt>
<dd>
REQUIRED. The user's preferred languages as a <a class='info' href='#BCP 47'>[BCP 47]<span> (</span><span class='info'>Phillips, A. and M. Davis, “Tags for Identifying Languages,” .</span><span>)</span></a> language priority list,
represented as a comma-separated list of BCP 47 basic language ranges in descending priority order.
For instance, the value "fr-CA,fr-FR,en-CA" represents the preference for French spoken in Canada,
French spoken in France, followed by English spoken in Canada.
</dd>
</dl></blockquote><p>
</p>
<p>
The language preference hint SHOULD take precedence over the Accept-Language
HTTP header sent by the user's browser, and SHOULD take precedence over the language
preference inferred by the user's IP address.
</p>
<a name="anchor4"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.5"></a><h3>5.
Requesting Authentication in a Popup</h3>
<p>
The Relying Party SHOULD first request authentication using the checkid_immedidate mode if the Relying Party
has reason to believe that user had previously authenticated at the Relying Party and can determine
the user's OpenID Provider.
</p>
<p>
When requesting OpenID authentication using the checkid_setup mode, the Relying Party MUST send
the following parameters:
</p>
<p>
</p>
<blockquote class="text"><dl>
<dt>openid.ns.ui</dt>
<dd>
REQUIRED. Value: "http://specs.openid.net/extensions/ui/1.0"
</dd>
<dt>openid.ui.mode</dt>
<dd>
REQUIRED. Value: "popup".
New modes may be defined in future versions of this extension. Any mode starting with the prefix "x-" should be
considered experimental. If an OpenID provider receives a request containing an experimental mode, and it does
not recognize that mode, it SHOULD NOT throw an error or invalidate further processing of this extension. If no other
parameters are present, then the OpenID provider receiving an experimental mode SHOULD continue processing the OpenID
request as if this extension were not included in it.
</dd>
</dl></blockquote><p>
</p>
<p>
The RP SHOULD create the popup to be 450 pixels wide and 500 pixels tall.
The popup MUST have the address bar displayed, and MUST be in a standalone browser
window. The contents of the popup MUST NOT be framed by the RP.
</p>
<p>
The RP SHOULD open the popup centered above the main browser window, and SHOULD dim
the contents of the parent window while the popup is active. The RP SHOULD ensure
that the user is not surprised by the appearance of the popup, and understands
how to interact with it.
</p>
<p>
To keep the user popup user experience consistent, it is RECOMMENDED that
the OP does not resize the popup window unless the OP requires additional
space to show special features that are not usually displayed as part of the
default popup user experience.
</p>
<p>
The OP MAY close the popup without returning a response to the RP.
Closing the popup without sending a response should be interpreted as a
negative assertion.
</p>
<p>
The response to an authentication request in a popup is unchanged from
<a class='info' href='#OpenID 2.0'>[OpenID 2.0]<span> (</span><span class='info'>OpenID 2.0 Workgroup, “OpenID 2.0,” .</span><span>)</span></a>.
Relying Parties detecting that the popup was closed without receiving an authentication response
SHOULD interpret the close event to be a negative assertion.
</p>
<a name="anchor5"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.5.1"></a><h3>5.1.
Authentication Response in a Fragment</h3>
<p>
The user experience can be optimized by returning the authentication response parameters in
the fragment portion of the Relying Party's return_to URL, allowing the content of the return_to
URL to be returned from the browser's cache, if already present. To use this
technique, the Relying Party MUST include the fragment delimiter (the "#" character) in the return_to
URL in the authentication request. If the fragment delimiter character is present in the return_to URL,
the OpenID Provider SHOULD return the response parameters in the fragment portion of the URL. If the
return_to URL already contains a question mark "?", the first response parameter MUST be prefixed
with an ampersand "&", otherwise the first response parameter MUST be prefixed with a question mark "?".
</p>
<a name="anchor6"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.6"></a><h3>6.
Requesting Display of RP icons in the OP Approval UI</h3>
<p>
When requesting authentication, the Relying Party MAY indicate to the OpenID Provider
the availability of graphical resources to represent the Relying Party brand at the OpenID Provider's approval UI.
This is indicated by including the following parameter:
</p>
<blockquote class="text"><dl>
<dt>openid.ui.icon</dt>
<dd>
REQUIRED. Value: "true"
</dd>
</dl></blockquote><p>
In order to retrieve the indicated graphical resources, the OpenID Provider performs discovery on the Relying Party, as specified
in <a class='info' href='#OpenID 2.0'>[OpenID 2.0]<span> (</span><span class='info'>OpenID 2.0 Workgroup, “OpenID 2.0,” .</span><span>)</span></a> (or future versions of the OpenID protocol specification).
The RP SHOULD indicate the location of the graphical resource by adding an entry to its XRDS document:
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>
<Service xmlns="xri://$xrd*($v*2.0)">
<Type>http://specs.openid.net/extensions/ui/icon</Type>
<URI>http://consumer.example.com/images/image.jpg</URI>
</Service>
<Service xmlns="xri://$xrd*($v*2.0)">
<Type>http://specs.openid.net/extensions/ui/icon</Type>
<URI>http://consumer.example.com/favicon.ico</URI>
</Service>
</pre></div>
<p>
If the Relying Party indicates availability of graphical resources using the "icon" parameter but the OpenID Provider
does not succeed in obtaining a discovery document at the Relying Party, the OpenID Provider MAY attempt to locate a graphical
resource at the domain indicated by "openid.realm", under the path "/favicon.ico". If the realm contains the wildcard "*" for the host,
the OpenID Provider should replace it with "www".
In this case, the OpenID provider MAY restrict
the display of the resource to 16x16 format, and the Relying Party SHOULD ensure that the resource displays well in 16x16 format.
</p>
<p>
It is RECOMMENDED that the OpenID Provider do not inline graphical resources from the Relying Party without verification. Instead,
the OpenID Provider SHOULD proxy the icons after performing appropriate sanitization. Proxying is also necessary to avoid mixed-content
warnings if the OpenID Provider approval page is served over HTTPS but the graphical resource is only available over HTTP.
</p>
<a name="anchor7"></a><br /><hr />
<table summary="layout" cellpadding="0" cellspacing="2" class="TOCbug" align="right"><tr><td class="TOCbug"><a href="#toc"> TOC </a></td></tr></table>
<a name="rfc.section.7"></a><h3>7.
Discovery</h3>
<p>
OpenID Providers supporting the User Interface Extension SHOULD advertise their support of the
Extension using OpenID Discovery as defined in Section 7.3 of <a class='info' href='#OpenID 2.0'>[OpenID 2.0]<span> (</span><span class='info'>OpenID 2.0 Workgroup, “OpenID 2.0,” .</span><span>)</span></a>.
</p>
<p>
OpenID Providers supporting the language preference functionality SHOULD define
http://specs.openid.net/extensions/ui/1.0/lang-pref as a <xrd:Type> child element of the <xrd:Service> element
in the XRDS discovery document.
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>
<Type>http://specs.openid.net/extensions/ui/1.0/lang-pref</Type>
</pre></div>
<p>
OpenID Providers supporting the popup functionality SHOULD define
http://specs.openid.net/extensions/ui/1.0/mode/popup as a <xrd:Type> child element
of the <xrd:Service> element in the
XRDS discovery document.
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>
<Type>http://specs.openid.net/extensions/ui/1.0/mode/popup</Type>
</pre></div>
<p>
OpenID Providers supporting the graphical RP representation functionality SHOULD define
http://specs.openid.net/extensions/ui/1.0/icon as a <xrd:Type> child element of the <xrd:Service> element
in the XRDS discovery document.
</p><div style='display: table; width: 0; margin-left: 3em; margin-right: auto'><pre>
<Type>http://specs.openid.net/extensions/ui/1.0/icon</Type>
</pre></div>
<a name="anchor8"></a><br /><hr />
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<a name="rfc.section.8"></a><h3>8.
Considerations</h3>
<p>
OpenID Providers SHOULD use HTTPS for all their authentication screens, and educate
their users to always check their browser's address bar before entering their
credentials. OPs SHOULD implement Javascript framebusting code to prevent their UI from
being framed.
</p>
<p>
Credential verification and approval screens SHOULD always be in an independent browser
window to protect the user's credentials and approval from clickjacking exploits.
</p>
<a name="anchor9"></a><br /><hr />
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<a name="rfc.section.9"></a><h3>9.
Acknowledgements</h3>
<p>
Allen Tom (atom@yahoo-inc.com)
</p>
<p>
Breno de Medeiros (breno@google.com)
</p>
<p>
Brian Ellin (brian@janrain.com)
</p>
<p>
Chris Messina (chris@citizenagency.com)
</p>
<p>
David Recordon (david@sixapart.com)
</p>
<a name="rfc.references1"></a><br /><hr />
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<h3>10. References</h3>
<table width="99%" border="0">
<tr><td class="author-text" valign="top"><a name="BCP 47">[BCP 47]</a></td>
<td class="author-text">Phillips, A. and M. Davis, “Tags for Identifying Languages,” BCP 47.</td></tr>
<tr><td class="author-text" valign="top"><a name="Language Preference Attribute">[Language Preference Attribute]</a></td>
<td class="author-text">axschema.org, “<a href="http://axschema.org/pref/language">Language Preference Attribute</a>.”</td></tr>
<tr><td class="author-text" valign="top"><a name="OpenID 2.0">[OpenID 2.0]</a></td>
<td class="author-text">OpenID 2.0 Workgroup, “<a href="http://openid.net">OpenID 2.0</a>.”</td></tr>
<tr><td class="author-text" valign="top"><a name="OpenID Attribute Exchange">[OpenID Attribute Exchange]</a></td>
<td class="author-text">Hardt, D., Bufu, J., and J. Hoyt, “<a href="http://openid.net/specs/openid-attribute-exchange-1_0.html">OpenID Attribute Exchange 1.0</a>.”</td></tr>
<tr><td class="author-text" valign="top"><a name="RFC2119">[RFC2119]</a></td>
<td class="author-text">Bradner, B., “<a href="http://tools.ietf.org/html/rfc2119">Key words for use in RFCs to Indicate Requirement Levels</a>,” RFC 2119.</td></tr>
</table>
<a name="anchor11"></a><br /><hr />
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<a name="rfc.section.A"></a><h3>Appendix A.
Example Use of Experimental Mode</h3>
<p>
In OpenID authentication, when using the checkid_immediate mode, there is no mechanism to indicate that there is a user logged in at the OpenID Provider.
Therefore, the Relying Party does not know if the checkid_immediate request failed because:
</p>
<ol class="text">
<li>The user does not have an account at the OpenID Provider (or is not logged in at the Provider), or:
</li>
<li>The user is logged in to the OpenID Provider but has not yet approved transparent login with the Relying Party.
</li>
</ol><p>
This makes it difficult for the RP to optimize the OpenID
user experience by, for instance, displaying a prominent button for the OpenID Provider in case (2). The following example shows how an experimental mode can be sent with
checkid_immediate requests to obtain this information.
</p>
<p>
</p>
<blockquote class="text"><dl>
<dt>openid.ns.ui</dt>
<dd>
REQUIRED. Value: "http://specs.openid.net/extensions/ui/1.0"
</dd>
<dt>openid.ui.mode</dt>
<dd>
REQUIRED. Value: "x-has-session".
</dd>
</dl></blockquote><p>
</p>
<p>
To respond, the OpenID provider sends identical parameters in the "setup_needed" response to answer affirmatively (i.e., there IS an authenticated browser session):
</p>
<blockquote class="text"><dl>
<dt>openid.ns.ui</dt>
<dd>
REQUIRED. Value: "http://specs.openid.net/extensions/ui/1.0"
</dd>
<dt>openid.ui.mode</dt>
<dd>
REQUIRED. Value: "x-has-session".
</dd>
</dl></blockquote><p>
Alternative, if the OpenID provider needs to indicate the LACK of a session, it sends simply the UI namespace, without a mode, in the "setup_needed" response:
</p>
<blockquote class="text"><dl>
<dt>openid.ns.ui</dt>
<dd>
REQUIRED. Value: "http://specs.openid.net/extensions/ui/1.0"
</dd>
</dl></blockquote><p>
</p>
<a name="rfc.authors"></a><br /><hr />
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<h3>Authors' Addresses</h3>
<table width="99%" border="0" cellpadding="0" cellspacing="0">
<tr><td class="author-text"> </td>
<td class="author-text">Allen Tom</td></tr>
<tr><td class="author-text"> </td>
<td class="author-text">Yahoo!</td></tr>
<tr><td class="author" align="right">Email: </td>
<td class="author-text"><a href="mailto:atom@yahoo-inc.com">atom@yahoo-inc.com</a></td></tr>
<tr cellpadding="3"><td> </td><td> </td></tr>
<tr><td class="author-text"> </td>
<td class="author-text">Breno de Medeiros</td></tr>
<tr><td class="author-text"> </td>
<td class="author-text">Google</td></tr>
<tr><td class="author" align="right">Email: </td>
<td class="author-text"><a href="mailto:breno@google.com">breno@google.com</a></td></tr>
</table>
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