Microsoft Corp is supporting a multi-vendor web services security specification, opening the door on interoperability with rivals, Gavin Clarke writes.

The Redmond, Washington-based company said it will adopt Security Assertion Mark-up Language (SAML), officially launched yesterday, as it relates to WS-Security - developed by Microsoft and IBM with VeriSign Inc.

SAML was developed by 12 members of the Organization for Advancement of Structured Information Standards (OASIS).

SAML support raises the possibility of interoperability between systems based on WS-Security and specifications from the Sun Microsystems Inc-backed Liberty Alliance Project, the first version of which were also launched yesterday.

Microsoft architect Kim Cameron disclosed Microsoft's plans at the Burton Group Catalyst 2002 Conference in San Francisco, California, yesterday.

Adam Sohn, .NET platform strategy group product manager, said Microsoft would support multiple assertion types in WS-Security and so too - ultimately - would Windows and Active Directory. Other assertions that could also be supported are PKI, Kerberos and XRML, Sohn said.

He said Microsoft's backing for SAML "boded well" for future interoperability with Liberty specifications, given Sun's recent support for WS-Security's submission to OASIS. Sohn supported SAML following last year's Catalyst conference.

Members of OASIS are already working on extensions to SAML that work with WS-Security. It is unclear whether Microsoft would work through OASIS or the Web Services Interoperability (WS-I) organization, which aggregates specifications.

SAML provides security assertions - which identify a user. WS-Security provides a framework for different security assertions and certificates, such as SAML, Kerberos, 501 certificates and PKI to operate and exchange data in a standards-based way.

SAML is the basis for the Liberty specifications, version 1.0 of which were launched at yesterday's conference. Version 1.0 outlines a standards-based way to exchange user identity across different web sites, domains and servers.

Version 1.0 of Liberty builds on SAML with additional features. These are ability for a user to link accounts held by different service providers, once a user's accounts are linked ability to authenticate across these accounts, ability to communicate information between accounts, log-out across all sites, and a client.

Unlike Microsoft's .NET Passport, data is not held by a single company or service provider but remains with the user or multiple service providers - like banks or retailers.

Vendors are already lining-up behind both Liberty and SAML. Seven vendors announced Liberty products, including Sun which plans product announcements today, Novell Inc which announced Project Saturn to Liberty-enable versions of its eDirectory and iChain this year, and RSA Security Inc which plans products that create and provide Liberty identities and consume identities.

Those backing SAML include Baltimore Technologies, CrossLogix, Entegrity Solutions, ePeople, Novell, Oblix and Sun and Sigba.

Version 2.0 of Liberty is expected in 2002. That version will focus on privacy and enable users to specify what types of personal information they share between sites, such as name, address, or credit card.

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