Patent ID: 6754345
Filing Date: 2004-06-22
Classification: G06F

Abstract:
A data communication system comprising a first and a second cipher keys generation circuits which generate a first and a second cipher keys, respectively, an enciphering circuit which enciphers original data to enciphered data based on said first cipher key, and a deciphering circuit which deciphers said enciphered data to deciphered data based on said second cipher key,said first cipher key generation circuit including a first pseudorandom number generation circuit generating a first pseudorandom number, a first clock generator generating a first clock signal based on said first pseudorandom number, a second pseudorandom number generation circuit generating a second pseudorandom number in response to said first clock signal, and means for supplying said second pseudorandom number to said enciphering circuit as said first cipher key, said second cipher key generation circuit including a third pseudorandom number generation circuit generating a third pseudorandom number, a second clock generator generating a second clock signal based on said third pseudorandom number, a fourth pseudorandom number generation circuit generating a fourth pseudorandom number in response to said second clock signal, and means for supplying said fourth pseudorandom number to said deciphering circuit as said second cipher key.