Patent ID: 7079655

Claim:
An encryption algorithm management system, comprising: a terminal unit; and a center unit, the terminal unit and the center unit having a common cipher-key, said terminal unit comprising: a transmitter configured to transmit a demand to said center unit for obtaining an encrypted data needed for decrypting a ciphered encryption algorithm, an encryption controller configured to renew said common cipher-key in every case of receiving said encrypted data from said center unit in response to said demand, decrypt a cipher-key for the ciphered encryption algorithm from the encrypted data with the renewed common cipher-key, and decrypt an encryption algorithm from the ciphered encryption algorithm with the cipher-key for the ciphered encryption algorithm, and an encryption unit configured to encrypt a message with the encryption algorithm and send the encrypted message to a second terminal; said center unit comprising: a key controller configured to renew said common cipher-key so as to be identical with said renewed common cipher-key in case of receiving said demand from said transmitter, and an encoder configured to produce said encrypted data by encrypting the cipher-key for the ciphered encryption algorithm with said renewed common cipher-key and transmit said encrypted data to said terminal unit.