Providing a user apparatus access to a computer system including services and authentication levels. A service request is determined for at least one of the services from a user apparatus. A distributed authentication provider is negotiated with to provide an authentication level based access control for the plurality of authentication levels associated with the plurality of services. The user apparatus to is redirected to access the distributed authentication provider such that the user apparatus authenticates itself at the distributed authentication provider for the authentication level associated with the at least one of the services within the service request. The user apparatus is provided access to the at least one of the services within the service request based on a successful authentication at the distributed authentication provider for the authentication level associated with the at least one of the services within the service request.