Microsoft's CardSpace -- and the Infocard architecture that underlies it -- is an important development because it provides an easy way for users to store and manage identity information and because CardSpace and Infocards will be widely available through Windows Vista.

Microsoft provided open specifications for CardSpace and helped manage intellectual property issues that were raised when implementing the Infocard technology as open source, Olds said. Engineers from IBM also played a part in the solution, building token services for the project, said Paul Trevithick of Parity Communications, technical lead on the Higgins Project.

But optimistic "interoperability" demonstrations of federated user identities have been de rigueur at RSA for years now without any measurable decline in the number of user identities and passwords that users manage or the tangle of identity stores within enterprises, Olds and Trevithick admit.

One problem in realizing the vision of an open-source identity layer is that tends to commoditize existing identity management products, creating a perverse incentive for companies that are in a position to make interoperable identities work, Trevithick said.

"That may be the reason you hear about interoperability but still haven't seen it," he said. "Companies like Oracle and IBM and even Novell have no incentive to do it."