Patent EA-001187-B1 (EA)
Title: Process for allowing direct encrypted communication between two terminals of a mobile radio network and groupings of stations and terminals involved
Inventor: TOTARO ANTONINE
IPC: H04L9/08
Filed: 1998-05-20
Abstract: 1. A process allowing direct encrypted communication such as direct simple communication between terminals of a mobile radio network via satellite(s) and/or type GSM/DCS after establishing a call by one of them via a stationary station of the mobile radio communication, characterized in that  during the first phase of encrypting which is realized by common way after an identification an appealing user by a signed response (SRES), provided with an individual identification card of this user via an appealing terminal with which the card is associated, receiving an arbitrary number (RAND), transmitted by the station to the appealing terminal, whereby a ciphering key (Kc1) is simultaneously generated by the card associated with the appealing terminal and the structure of the network control for encrypting/decrypting of data, transmitted by radio communication between the appealing terminal and the station, the ciphering key is stored in the memory unit of the station, then the key is transmitted to the terminal, which was called from the station when setting up radio communication between the station and the terminal, and which was called for communication appealed by the calling terminal for encrypting/decrypting of datum, which are exchanged with this terminal. 2. The process as claimed in claim 1, characterized in that the ciphering key (Kc1) includes in a message of the establishment of communication, which the station transmits for the called terminal whilst setting up radio communication with the called terminal. 3. The process as claimed in claim 1, characterized in that the ciphering key (Kc1) is transmitted in a special message, transmitted by the station separately from the message of the establishing of communication, which transmits this station to the called terminal when setting up radio communication with the called terminal. 4. A station of radio communication with movable users of the radio network via satellite(s) and/or type GSM/DCS to realize the method as claimed in any one of the preceding claims, characterized in that comprises a means for temporary storing the ciphering key for transmitting by the network control unit for exchanging between data between the station and the terminal, a means allowing to direct the ciphering key from the station to the called terminal so that each of these terminals is permitted to encrypt/decrypt datum, transmitted by another terminal, using one ciphering key when setting up their direct communication and in the process of this communication. 5. A terminal of mobile radio communication network via satellite(s) and/or type GSM/DCS to realize the method as claimed in any claims 1, 2 and 3, characterized in that comprises a means allowing to store successively the ciphering key for each call, received from one station of the mobile radio communication network when calling the terminal, a means allowing to use the key for encrypting/decrypting datum, which the key exchanges during a direct communication with the terminal, which called it via this station.