| 摘要 |
<p>PROBLEM TO BE SOLVED: To allow only one certifying means to succeed in authentication with a verifying means even in environment wherein more than one certifying means is able to access the verifying means at the same time. SOLUTION: The verifying means 200 generates and sends a challenge to a certifying means 100. The certifying means 100 generates a response to the challenge, determines the time when time information is sent, and ciphers and sends the response and time information to the verifying means 200. The verifying means 200 deciphers the response and time information to authenticate the challenge response. At corresponding time, the certifying means 100 sends the time information to the verifying means 200. The verifying means 200 receives the time information and confirms whether or not the contents match the time information held in its storage means 201 and the time when the time information is received is within a predetermined error permissible time. The above services are provided.</p> |
