Abstract: The invention concerns an apparatus comprising a device designed to encode an original message by means of a digital key whereof the apparatus manufacturer is the owner. The electronic equipment, to authenticate that a received message is a message coming from the apparatus authorized to certify said message, comprises a device designed to decode said received message with the digital key whereof the manufacturer of the apparatus is the owner. The method comprises: a first step whereby an encoded message is generated by means of the apparatus which encodes an original message by means of a digital key whereof the manufacturer of the apparatus is the owner; a second step whereby the encoded message is transmitted to the addressee electronic equipment; a third step whereby the encoded message is decoded with said digital key.

Abstract: To generate a tangible element of proof which guarantees that a specified transaction has been carried out using a specified microcircuit card, the method comprises steps in which a microprocessor, contained in the microcircuit, records, in an internal memory of the microcircuit, a cryptogram on the data of the transaction, as soon as it detects a confirming event for validating the transaction, the microprocessor then transmits a transaction validation signal out of the card, after having recorded the cryptogram in the internal memory.

Abstract: The invention concerns an authenticating device comprising an apparatus (1) for carrying out transactions. The apparatus (1) comprises a housing protected against breaches. In the housing are integrated an interface circuit (10) for receiving an identification support including an identification logic circuit, man-machine interface means (3, 4) for displaying transaction data and for receiving from the user identification data transmitted to the logic circuit via the interface circuit (10) and signature commands related to the transaction data displayed, a protected circuit (6) for delivering a first signature of transaction data in response to signature commands when the identification has been completed, said signature being obtained by encrypting part at least of the transaction data using a non-erasable private signature key stored in the protected circuit.