It is presented a key device comprising: a mechanical interface for mechanically maneuvering a lock device upon successful access control. The mechanical interface comprises a connector for powering the lock device and for communication with the lock device such that the lock device is able to perform electronic access control using the key device. The key device further comprises a clock; a memory; a radio communication module; and a controller arranged to, using the radio communication module communicate online with an access control device and use the memory as temporary storage for offline communication between the access control device and one or more lock devices. A corresponding method, computer program and computer program product are also presented.