An authentication method authenticates a first party to a second party, where an operation is performed on condition that the authentication succeeds. If the first party is not authenticated, then if the first party qualifies for a sub-authorization, the operation is still performed. Further, a device that includes a first memory area holding a comparison measure, which is associated with time, and which is also used in said authentication procedure, a second memory area holding a limited list of other parties which have been involved in an authentication procedure with the device, and a third memory area, holding compliance certificates concerning parties of said list.