device and procedure for examination of the legal authority for zugangskontrolleinrichtungen, especially schliesseinrichtungen for vehicles

摘要

The device has a controller (A) with a stored code on the access side, a user key (B) containing a transponder (T) and a comparator (V) in the controller which determines validity for releasing the access device by comparing the information transmitted by the transponder with information in the controller. The controller stores a secret key and a user code which are placed in the key transponder. The information transmitted by the transponder consists of the user code encoded with the secret key. The key contains a comparator coupled with lock bits for the secret key so that a partial release is effected to enable overwriting of the secret key stored in the key, if the further comparator detects coincidence between the transmitted user code and a stored user code.