CIPHERING METHOD, DECODING METHOD, CIPHER COMMUNICATION METHOD, CIPPHERING AND DECODING DEVICE, CIPHER COMMUNICATION SYSTEM AND RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide a ciphering method capable of performing a high-speed processing by a multiplication type knapsack ciphering system and a cipher communication system using the same method. ;SOLUTION: When a plain text (x) of a binary series is converted into a ciphered text C, the plain text (x) is divided into (y) pieces of divided plain texts xk (k=1, 2, ..., y) and these divided plain texts xk are converted into weight limited divided plain texts sk in which weights of these divided plain texts xk are limited and a weight limited plain text (s) is obtained by continuously connecting these divided plain texts sk and, then, the ciphered text C is prepared by using the weight limited plain text (s).;COPYRIGHT: (C)2001,JPO