Encryption/decryption apparatus for data transmitted between telecommunication terminals over the public switched telephone network.

摘要

The data enciphering/deciphering apparatus comprises: a line interface (EILTC) linked to the switched telephone network (RTC); a modem (EMTC1) connected to the line interface (EILTC); processing means (EUT1) connected to the first modem module (EMTC1) and able to process the connections between the modem (EMTC1) and the line interface (EILTC); a line interface (EILEC) linked to the local telecommunication terminal (TEL1); a modem (EMTC2) connected to the line interface (EILEC), the connections between the modems (EMTC1 and EMTC2) being managed by the processing means (EUT1); processing means (EUT2) connected to the modem (EMTC2), providing for the connections between the modem (EMTC2) and the local telecommunication terminal and possessing a quiescent state and an active state, taken up on predetermined specific command. In their active state, the processing means (EUT2) decipher or encipher data coming from the remote telecommunication terminal in the receive phase via the modem (EMTC1) or which are addressed to the latter in the send phase via the modem (EMTC2), respectively. <IMAGE>