Future Web Service Security Technologies
In October 2001, Microsoft announced the Global XML Web Services Architecture (GXA), which builds on current Web service protocols such as SOAP, WSDL, and UDDI and adds additional building blocks, including security called WS-Security.
WS-Security provides a security language for Web services. It describes enhancements to SOAP messaging to provide three capabilities: credential exchange, message integrity, and message confidentiality. You can use these three mechanisms independently or in combination to accommodate a wide variety of authentication and cryptographic technologies.
The full specification is available at http://msdn.microsoft.com/ws/2001/10/Security.