WS-Trust comprises a protocol for systems and applications to use when requesting a service to issue, validate, and exchange security tokens. Organizations can leverage this protocol to centralize their security-token processing.
The WS-Trust specification also defines the role of a Security Token Service as the entity responsible for responding to requests using the protocol. In this role, the STS creates new security tokens, validates existing security tokens, and/or exchanges security tokens of one type for those of another.
WS-Trust was created by a consortium of leading platform and security vendors who have contributed the protocol to the OASIS standards organization, where it is managed by the WS-SX (Secure Exchange) technical committee (see www.oasis-open.org/committees/tc_home.php?wg_abbrev=ws-sx.)