communications protocol A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchr ...

OpenID OpenID is an open standard and decentralized authentication protocol promoted by the non-profit OpenID Foundation. It allows users to be authenticated by co-operating sites (known as relying parties, or RP) using a third-party identity provider ...

OAuth OAuth (short for "Open Authorization") is an open standard for access delegation, commonly used as a way for internet users to grant websites or applications access to their information on other websites but without giving them the passwords. T ...

digital identity A digital identity is information used by computer systems to represent an external agent – a person, organization, application, or device. Digital identities allow access to services provided with computers to be automated and make it possibl ...

i-name I-names are one form of an XRI — an OASIS open standard for digital identifiers designed for sharing resources and data across domains and applications.XRDS format and connects several services, like authentication or authorization to the Yadis URL. Each service description can have further parameters.

Modular architecture

Yadis follows the

REST Rest or REST may refer to: Relief from activity * Sleep ** Bed rest * Kneeling * Lying (position) * Sitting * Squatting position Structural support * Structural support ** Rest (cue sports) ** Armrest ** Headrest ** Footrest Arts and enter ...

-ful, "small pieces loosely joined" paradigm that has proven to be successful in the development of the web. The basic assumption is that identities can be addressed with URLs or with other identifiers (such as XRI

i-name I-names are one form of an XRI — an OASIS open standard for digital identifiers designed for sharing resources and data across domains and applications.XRDS document (an XML-based capability file) with each URL that expresses the associated capabilities or services. The owner of a Yadis identifier can choose which services he wishes to use in his XRDS document. After retrieving this document, a relying party such as a website accepting Yadis identifiers can select an appropriate services of the XRDS document, e.g. a protocol to use for authentication. This can allow existing web sites, like blogs, to easily implement basic Yadis functionality (for instance, redirecting users who arrive at a blog to relevant information about the person the blog belongs to) while also making it possible to build more advanced applications (for example, allowing complex queries of a site-owner's information to be submitted directly to the Yadis site).

Discovery of the Yadis Resource Descriptor

The capability document associated with an identity URL is found either: # By following a custom HTTP response header called X-XRDS-Location, # By an equivalent entry in the HTML HEAD section, called
<meta http-equiv="X-XRDS-Location" content="http://example.com/yadis.xml">, or # By requesting a special mime type called application/xrds+xml when performing an HTTP GET on the identity URL. Developers can choose which of the alternatives to implement, based on factors such as whether they can run software at the identity URL or not.

XRDS documents

Here is an example XRDS capability document: http://openid.net/signon/1.0 http://www.myopenid.com/server http://smoker.myopenid.com/ http://openid.net/signon/1.0 http://www.livejournal.com/openid/server.bml http://www.livejournal.com/users/frank/ http://lid.netmesh.org/sso/2.0 http://mylid.net/liddemouser http://lid.netmesh.org/sso/1.0 If this XRDS document was returned, using one of the listed mechanisms, for a URL, it would express the following information: * The URL is a Yadis identity URL. * This URL supports the

OpenID OpenID is an open standard and decentralized authentication protocol promoted by the non-profit OpenID Foundation. It allows users to be authenticated by co-operating sites (known as relying parties, or RP) using a third-party identity provider ...

protocol, through two servers and two delegates. * This URL supports version 1.0 and version 2.0 of the

LID A lid, also known as a cover, is part of a container, and serves as the closure or seal, usually one that completely closes the object. Lids can be placed on small containers such as tubs as well as larger lids for open-head pails and drums. S ...

protocol, with a delegate. * The owner of this identity URL prefers to sign-on using their LiveJournal account and the

OpenID OpenID is an open standard and decentralized authentication protocol promoted by the non-profit OpenID Foundation. It allows users to be authenticated by co-operating sites (known as relying parties, or RP) using a third-party identity provider ...

protocol (priority 10). If that is not possible (e.g. because a relying party does not support OpenID, or because the LiveJournal server is unavailable), the owner would like to use the

LID A lid, also known as a cover, is part of a container, and serves as the closure or seal, usually one that completely closes the object. Lids can be placed on small containers such as tubs as well as larger lids for open-head pails and drums. S ...

URL http://mylid.net/liddemouser (priority 20), followed by the MyOpenID service (priority 50).

LID, OpenID and the developer community

Yadis was initiated by developers of the Light-weight Identity (LID) and

OpenID OpenID is an open standard and decentralized authentication protocol promoted by the non-profit OpenID Foundation. It allows users to be authenticated by co-operating sites (known as relying parties, or RP) using a third-party identity provider ...

protocols. This collaboration was then joined by members of the OASIS XRI Technical Committee, particularly those working on

i-name I-names are one form of an XRI — an OASIS open standard for digital identifiers designed for sharing resources and data across domains and applications.XRDS lightweight capabilities description, making possible a "mix and match" approach to building Yadis-enabled applications, enabling application developers to choose their own balance between ease of implementation on one hand, and range of features on the other.

External links

Yadis Documentation
Federated identity

Modular architecture

Discovery of the Yadis Resource Descriptor

XRDS documents

LID, OpenID and the developer community

See also

External links