| 摘要 |
<p>In the encryption/decryption method, a random number sequence äriü is generated on the basis of a given multi-affine key system K and encryption is performed by an exclusive OR of the random number sequence äriü with a plain text (ABC). Further, the multi-affine key system K is automatically sequentially rewritten into a series (K', K", ...) of new multi-affine key systems each time when the number of use times of the multi-affine key system reaches a predetermined number and encryption of plain texts (DEF) thereafter is continued while generating random numbers using the series of the rewritten multi-affine key systems. Likewise, in decryption as well, since decryption is performed using a multi-affine key system automatically rewritten each time when the number of use times reaches a predetermined number, a third party cannot reproduce the multi-affine key system and therefore cannot decipher a cipher text. <IMAGE></p> |
