Although administrators can configure a system to restrict access to resources, in a mass-market setting they cannot be sure of the kernel's integrity. The commercial need for an open software and hardware architecture leads to huge and complex operating systems. A single programming error or intentional back door in this code base can open the way for an attack that renders the access-control system ineffective.

The authors describe Microsoft?s next-generation secure computing base, a system that offers robust access control through mechanisms for code authentication.