| 摘要 |
PROBLEM TO BE SOLVED: To provide an enciphering scheme in which the risk of an enciphered message being decoded by a third party can almost be precluded, the data amount between a plain text and its enciphered text does not change at all, and whose processing speed is high. SOLUTION: In the enciphering scheme, the plain text to be enciphered is divided for every arbitrary number of bits, a plurality of blocks are successively selected according to the value of a register for determining the processing order of the objects, a random number is generated by a key scheduler from key block data obtained by dividing given key data for the same number of bits as the number of division bits of the plain text and position information focused on by the selected plain text block, and the plain text block is exchanged with the destination block using the value of the random number as the destination block number. Further, for this enciphering scheme, the following functions or the like can be used: the function of using the calculation result of the random number for next calculation; the function of selecting an exchange destination block number considering the value itself of the block focused on by the plain text block; the function of carrying out enciphering processing by setting the result obtained by carrying out an exclusive OR operation on the generated random number and a data block to the data block at the same position of the enciphered text. COPYRIGHT: (C)2005,JPO&NCIPI
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