Microsoft has revised its Next-Generation Secure Computing Base (NGSCB) security technology planned to ship as part of Longhorn.

Microsoft unveiled NGSCB, formerly codenamed Palladium, in 2002, and published a beta last October.

NGSCB uses a new software component called a 'nexus' to shield applications from each other and the operating system. A new chip, the trusted platform module, encrypts data streams between the operating system and applications.

The encryption ensures that even when a virus is able to penetrate defences it will be contained in that application, having no way of accessing any other data or applications.

The original plans required users to update both their hardware and software.

But Peter Biddle, product unit manager for Microsoft's security business, told delegates at the WinHEC show: "Customers have told us that they require the benefits 'out of the box', without having to write or rewrite applications."

As a result, NGSCB will not shield individual applications but will create 'secure compartments'. The operating system will contain compartments for elements such as the actual operating system, computing tasks and administration and management.

Software that is designed for NGSCB will still get the same level of security as the original plans intended.

Other enhancements requested by users include ease of deployment and migration to the new secure system, and a user experience that holds a closer resemblance to existing Windows software.