Light-Weight Identity (LID) is a set of protocols and software implementations created by NetMesh Inc. for representing and using digital identities on the Internet without relying on any central authority. LID supports digital identities for humans, human organizations and non-humans (e.g. software agents, things, websites, etc.) It implements Yadis, a discovery service for interoperability with other URL-based identity systems like OpenID.

LID uses standard URLs as identifiers. For example, the URL http://lid.netmesh.org/liddemouser/ is the LID identifier for a hypothetical individual called Mr. LID Demo User. Anybody can host LID digital identities at a URL of their choosing, as long as they have control over the URL and the ability to run a program (CGI script) at that URL. For URLs where that is not possible, Yadis delegation allows a LID URL to point at one or more identity services hosted by different sites.

Unlike other digital identity systems, LID is organized in a base protocol called MinimumLID, and an ever-growing list of profiles on top of it. This enables LID to be a foundation for digital-identity related innovation by many parties. Any implementor chooses which or how many LID profiles to support to meet their needs.

Some of the already-defined profiles include:

• LID single sign-on
• LID for controlled profile data exchange using vCards -- define subsets of information for different clients
• LID for controlled, decentralized social networking using FOAF -- different subsets of information for different clients
• LID for authenticated messaging and blogging -- no more forged return addresses

LID relies on existing technologies to the maximum extent possible:

• XML and XPath (but not WS-*)
• REST
• PGP / GPG
• standard browsers without requiring plug-ins or extensions
• LID also supports OpenID authentication

Several implementations are available (including open source).

See also

• OpenID
• Yadis

External links

• Light-Weight Digital Identity (LID) - official site, LID-enabled itself
• Yadis - official Yadis site, LID-enabled
• Demo LID user
• mylid.net - a hosted LID service

Identity management systems