| 摘要 |
<p>PROBLEM TO BE SOLVED: To generate a cipher whose effective period is set, and whose illegal use is difficult.SOLUTION: A time until the start time of an effective period is set as a start time specification time TS, and length from the start time to the end of the effective period is set as an effective time TM, and the start time specification time TS is divided by the effective time TM, and the quotient is set as an encryption key Q1, and the remainder is set as time correction information R. Then, the specific key code K and the encryption key Q1 are substituted in an encryption function to calculate an encryption element K', and a cipher including this is generated.</p> |
