A system and method for taking control of process token creation in the Windows operating system to create conditional process tokens that define access to system resources for process running on a Windows computer. The system includes an LSA shim layer that intercepts standard Windows requests for authentication and authorization and an authentication agent that determines context for each request. A custom authentication and authorization (A&A) store determines authentication success and the amount of authorization based on context and supplied credentials. Once the custom A&A store determines a successful log-on and defines authorization for the user, it passes the elements of authorization through the authentication agent to the LSA shim layer, which passes them on to the LSA module, which in turn uses them to request a Windows process token from the Windows kernel. The Windows kernel assigns the token to a user's session on the computer, defining the level of resource access available to processes the user launches.