1. A method for identification of an integrated circuit of a type comprising an indelibly stored identification number, the method comprising the steps of: writing, in a volatile register, a required number corresponding to an identification number of a required circuit; decoding, in the integrated circuit, the required number and supplying an information element representing the compatibility of the integrated circuit with the required circuit; and furnishing, during a reading of the identification number, the indelibly stored identification number of the integrated circuit which remains unchanged during the life thereof if the integrated circuit is not compatible with the required circuit or the required number if the integrated circuit is compatible with the required circuit.