Microsoft has postponed its Next-Generation Secure Computing Base (NGSCB) security plan, with only a sliver likely in the next version of Windows.

Microsoft unveiled NGSCB, formerly known as Palladium, in 2002. A year ago, it claimed it was "retooling" the technology so applications would not need to be rewritten, and promised an update by the end of 2004. Since then however, it has remained silent, fuelling speculation about its demise.

In its original form, NGSCB used a combination of software and hardware to increase PC security by allowing software to be isolated. It required changes to a PC's processor, chipset and graphics card, for which Microsoft said it had support from hardware makers including Intel and AMD.

To get the special protection, applications would have to be rebuilt to include a protected agent, run in a secured space on the system. Also, NGSCB would protect user data by encrypting it as it moves between hardware components.

NGSCB was scheduled to resurface at the Windows Hardware Engineering Conference (WinHEC) in Seattle this week. The preliminary agenda for the event listed two sessions that included NGSCB, including one titled "How to build NGSCB-enabled systems". But it is a no-show on the final conference calendar.

Microsoft staffers, however, argue that NGSCB is at WinHEC - in the form of Microsoft support for TPM (Trusted Platform Module) hardware and a feature in Longhorn called secure startup. TPM isn't new. PC vendors such as IBM and HP already support TPM for encrypted e-mail and hard drive partitions.

Secure startup is designed to protect data on a PC, for example when a user loses a laptop.

"That is really the first manifestation of the grand NGSCB plan," said Greg Sullivan, a lead product manager for Windows. "There are other products in the history of Microsoft where we have an ambitious vision that we invest in and the product manifestations end up being different than we thought," Sullivan said.