CRYPTOGRAPH, DECIPHERING DEVICE, AND ENCIPHERING/ DECIPHERING DEVICE

PROBLEM TO BE SOLVED: To provide a cryptograph and a deciphering device having enhanced safety and high processing speed. SOLUTION: The cryptograph enciphers block data BS using a common key KEY, and is provided with a random number for cipher generating section 1 for generating random numbers RND for cipher using a single or a plurality of random numbers CDn and the common key KEY, an enciphering processing section 3a for generating encrypted block data BCS by enciphering the block data BS using the common key KEY and the random numbers for cipher RND, and a control data generating section 2 for generating various kinds of control data to be used by the random number for cipher generating section 1 and the enciphering processing section 3a using the random numbers RND and the common key KEY. The deciphering device is provided with, in place of the enciphering processing section 3a, a deciphering processing section for deciphering the enciphering block data BCS using the common key KEY and the random number for cipher RND and generating block data BC. COPYRIGHT: (C)2004,JPO