CIPHER COMMUNICATION SYSTEM, CRYPTOGRAPHIC KEY DETERMINING METHOD AND COMPUTER READABLE STORAGE MEDIUM RECORDING PROGRAM FOR COMPUTER TO EXECUTE THE SAME METHOD

摘要

PROBLEM TO BE SOLVED: To provide a cipher communication system, a cryptographic key determining method and a storage medium with which a common cryptographic key can be easily and efficiently set before cipher communication. SOLUTION: The cryptographic key and an identifier for uniquely determining the cryptographic key are correspondently stored in a cryptographic key managing table 11f and when a data transmission request is received from a work station(WS) 14, a notice frame containing the identifier corresponding to the cryptographic key to be used for enciphering relevant data is transmitted to an enciphering device on the side of party. Based on the identifier contained in this notice frame, the cryptographic key to be used for deciphering is determined by the enciphering device on the side of party.