A data structure that contains authentication and authorization information for a user. Windows creates the access token when the user logs on and the user's identity is confirmed. The access token contains the user's security ID (SID), the list of groups that the user is a member of, the list of privileges held by that user. Each process or thread started for the user inherits a copy of the access token. In some cases a user may have more than one access token, with different levels of authority.