| 摘要 |
<P>PROBLEM TO BE SOLVED: To further prevent leakage of information to a third party. <P>SOLUTION: A pseudo random number D1 is generated by using a result derived on the basis of prescribed information used in a prescribed communication protocol as seeds, and a partial random number D3 or a hash value D4 is generated by changing the state of a random number sequence in the pseudo random number D1 by providing the pseudo random number D1 with a signal processing to reduce the information amount of the pseudo random number D1. Consequently, even when the partial random number D3 (or the hash value D4) is illegally obtained during transmission, it is possible to prevent the third party from guessing the pseudo random number D1 which is the generating source of the same without allowing the third party to find the pseudo random number D1 on the basis of the partial random number D3 (or the hash value D4). In this way, leakage of information to the third party can be further prevented. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
