The invention relates to an authorization verification method and devices suited therefor, which play back authorization data via a user interface (11) of an electronic playback device (1). During the playback of authorization data via the user interface (11) of a first playback device (1), the playback...http://www.google.de/patents/US7658328?utm_source=gb-gplus-sharePatent US7658328 - Authorization verification method and devices suited therefor
