Windows CardSpace

Windows CardSpace (codenamed InfoCard), is Microsoft's client software for the Identity Metasystem. CardSpace is an instance of a class of identity client software called an Identity Selector. CardSpace stores references to users' digital identities for them, presenting them to users as visual Information Cards. CardSpace provides a consistent UI that enables people to easily use these identities in applications and web sites where they are accepted.

Overview

When an Information Card-enabled application or website wishes to obtain information about the user, the application or website requests a particular set of claims from the user. The CardSpace UI then appears, switching the display to the CardSpace service, which displays the user's stored identities as visual Information Cards. The user selects the InfoCard to use and the CardSpace software contacts the issuer of the identity to obtain a digitally signed XML token that contains the requested information. CardSpace also allows users to create "personal" (also known as "self-issued") Information Cards, which can contain one or more of 14 fields of telephone book-quality identity information (that is to say, labeled and categorized information, such as full name, address, etc., though most fields are optional). Other transactions may require a "managed" InfoCard; these are issued by a third party "identity provider" that makes the claims on the person's behalf, such as a bank, employer, or a government agency.

Windows CardSpace is built on top of the Web Services Protocol Stack, an open set of XML-based protocols, including WS-Security, WS-Trust, WS-MetadataExchange and WS-SecurityPolicy. This means that any technology or platform that supports WS-* protocols can integrate with CardSpace. In order to accept Information Cards, a website developer simply needs to declare an HTML