A transponder is provided, in particular a passive and/or backscatter-based transponder, for an RFID system, wherein at least one first piece of information can be stored in a first memory area on the transponder that is accessible in clear text only by a read access internal to the transponder, and a second piece of information can be stored in a second memory area that is accessible in clear text through an air interface for read access, and the second piece of information is generated from the first piece of information using an asymmetric encryption method. The invention further relates to an RFID system for wireless data exchange comprising a transponder and a base station, and a method for requesting write and/or read access to a transponder, in particular a passive and/or backscatter-based transponder.