ENCRYPTING DEVICE OF SELF-SYNCHRONIZED STREAM CIPHER, DECRYPTING DEVICE, SELF-SYNCHRONIZED STREAM CIPHER SYSTEM, MAC GENERATING DEVICE, ENCRYPTING METHOD, DECRYPTING METHOD, MAC GENERATING METHOD, AND PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide an encrypting device, or the like of self-synchronized stream cipher capable of automatically executing synchronization recovery processing at a high speed. SOLUTION: An encrypting device of a self-synchronized stream cipher includes: a plurality of first nonlinear replacement functions of inputting a ciphertext, performing an exclusive-OR operation for the input ciphertext, and performing processing for nonlinear conversion; a compression function of inputting outputs of the plurality of nonlinear replacement functions, performing compression processing, and outputting one compression result; a plurality of registers connected through a plurality of second nonlinear replacement functions and storing the output of the compression function; a random number sequence generating function of generating a random number sequence; and an exclusive-OR computing element which performs an exclusive-OR operation between an input plaintext and the random number sequence generated by the random number sequence generating function to generate a ciphertext. COPYRIGHT: (C)2008,JPO&INPIT