| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a system for time authentication that enable a transmission-side computer to obtain a certificate for the objective generation time of a generated electronic document and even a browsing-side computer to obtain it as well when an open key ciphering method is used. SOLUTION: The transmission-side computer transmits summary data etc., generated by applying a message summary function to an electronic document of a plaintext to an authentication-side computer. The authentication-side computer generates time certificate data by adding current time information data to the sent summary data and ciphering it with an authentication-side secret key and sends the generated time certificate data back to the transmission-side computer. The transmission-side computer deciphers the received time certificate data with the authentication-side open key to obtain time information data. Then it is confirmed whether the time information data and the generated time data which is previously recorded approximately match each other to obtain the generation time of the electronic document of the plaintext which is approximate, but objectively authenticated. COPYRIGHT: (C)2004,JPO |
