초록 ▼

A system for transmitting information between an emitting center and receiving stations, comprising: a subscription administration center generating a plurality of subscriber\s keys Ci changing randomly at relatively long intervals of the order of a month; in the emitting center: a generator of an o

A system for transmitting information between an emitting center and receiving stations, comprising: a subscription administration center generating a plurality of subscriber\s keys Ci changing randomly at relatively long intervals of the order of a month; in the emitting center: a generator of an operating key K changing randomly at relatively short intervals of the order of a few minutes; a circuit for forming messages Mi obtained from said subscriber\s keys Ci and from the operating key K by means of an algorithm, all the messages Mi then being directed towards the emitting center; and automatic encryption means using the operating key K, in each receiving station: a subscription holder on which is recorded a signal corresponding to at least one of the subscriber\s keys Ci; a circuit for restoring the operating key receiving the messages Mi and the subscriber\s key Ci, this circuit working out an algorithm for restoring the signal corresponding to the operating key K used in the emitting center; an automatic decryption means; and at least one charging station capable of temporarily receiving the subscription holders and permanently recording one of the subscriber\s key Ci thereon.

대표청구항 ▼

A system for transmitting information between an emitting center and receiving stations, the emitting center comprising a circuit for forming signals carrying said information and means for emitting said signals, each receiving station comprising means for receiving the signals transmitted and means

A system for transmitting information between an emitting center and receiving stations, the emitting center comprising a circuit for forming signals carrying said information and means for emitting said signals, each receiving station comprising means for receiving the signals transmitted and means for displaying the information, wherein it also comprises: (A) a subscription administration center generating a plurality of signals constituting subscriber\s keys Ci, these subscriber\s keys changing randomly at relatively long intervals of the order of a month; (B) in the emitting center: (a) a generator of a signal constituting an operating key K, this key changing randomly at relatively short intervals of the order of a few minutes, (b) a circuit for forming messages Mi obtained from said subscriber\s keys Ci and from the operating key K by means of an algorithm the parameters of which are provided by the subscriber\s keys, namely Mi=FCi (K), this circuit delivering as many messages as there are subscriber\s keys, these messages changing with the operating key, all the messages Mi then being directed towards the emitter means, (c) an automatic encryption means using the operating key K, this automatic means receiving signals carrying the information and delivering encrypted signals which are then directed towards the emitter means, (c) in each receiving station: (a) a subscription holder on which is recorded a signal corresponding to at least one of the subscriber\s keys Ci, (b) a circuit for restoring the operating key, receiving on the one hand the messages Mi received and, on the other hand, the subscriber\s key Ci, this circuit working out an algorithm K=GCi (Mi) for restoring the signal corresponding to the operating key K used in the emitting station from the messages Mi received and from the subscriber\s key Ci, (c) an automatic decryption means which is connected, on the one hand, to the receiving means from which it receives the encrypted signals and, on the other hand, to the restoring circuit from which it receives the operating key K, this automatic means decrypting the encrypted signals, by using the operating key, and delivering decrypted signals which are then directed towards the information display means, (D) at least one charging station for the subscription holders, this station being connected to the subscription administration center from which it receives the signals corresponding to the different subscriber\s keys Ci generated by this center, each station being capable of temporarily receiving the subscription holders and permanently recording one of the subscriber\s key Ci thereon.