1. A method for authenticating, through use of a dispersed storage managing unit, a user transaction initiated within a dispersed storage network, the method comprising: receiving a first authentication request from external to the dispersed storage managing unit, the first authentication request containing information pertaining to a user that is requesting the user transaction; accessing a realm authentication list among a plurality of realm authentication lists stored in association with the dispersed storage managing unit; using realm information from the realm authentication list within the dispersed storage managing unit to validate the user as a valid user of the dispersed storage network; receiving a second authentication request from external to the dispersed storage managing unit, the second authentication request seeking authentication to process user data in a certain manner to further the user transaction; accessing access control list store information and user permission information to validate if the valid user can properly engage in the user transaction; and authorizing the continuation of the user transaction if the user is a valid user and the user transaction is a valid transaction for the valid user.