The aim of the present invention is to ensure that a security module SC or CAM is used with an authorized receiver device. A security device for Pay-TV receiver decoder, in charge of processing the security messages and to extract the keys or rights from the security messages, this security device comprising a memory to store at least one reference identifier of the receiver/decoder, characterized in that, it further comprises a wireless reader to read a wireless tag containing a receiver/decoder identifier with which it is connected, and means to compare this identifier with the reference identifier, said security device modifying the processing of the security messages in function of the comparison result.