A system and method for tracking user security credentials in a distributed computing environment. The security credentials of an authenticated user includes not just his unique user identifier, but also a set of security attributes such as the time of authentication, the location where the user is authenticated (i.e., intranet user v. internet user), the authentication strength, and so on. The security attributes are used in access control decisions. The same user can be given different authorization if he has a different security attribute value. Security credentials may be generated either by WebSphere security code or by third party security provider code. This invention stores the user credentials in a distributed cache and provides a system and method to compute the unique key based on the dynamic security credentials for cache lookup.