A COMMUNICATION SYSTEM WITH CIPHERING KEY GENERATION

摘要

A communication system comprising: a communication channel (31); at one end of said channel (31): (i) a first cipher generator (3) for generating a succession of ciphers, said generator (3) including a first random number generator (5) for generating a sequence of random numbers, each cipher of said succession of ciphers being based on a respective successive portion of said sequence of random numbers; and (ii) a symmetric encryptor (37) for encrypting successive amounts of information for transmission to the other end of said channel (31), each amount of information being encrypted using a respective one of said succession of ciphers; and, at the other end of said channel (31): (i) a second cipher generator (35) for generating in synchronism with said first cipher generator (3) the same said succession of ciphers as the first cipher generator (3), said second cipher generator (35) including a second random number generator (5) for generating the same said sequence of random numbers as said first random number generator (5); and (ii) a symmetric decryptor (61) for decrypting the encrypted successive amounts of information received from said one end of said channel (31), each amount of information being decrypted using the same respective one of said succession of ciphers as was used to encrypt it by said encryptor (37) at said one end of said channel (31).