To solve the problem that a means for easily correcting an electronic document even when the status of dealings is changed is not available and an electronic ticket needs to be issued at a center or by using a storage medium after the dealings are completed.
A service issuer system 1100 generates an electronic signature for the ticket by using a secret key, ciphers the electronic signature by using a password, and provides the ticket and electronic signature for a user terminal 1200 and an open key for a service executor system 1400; when a charge collector system 1300 collects the charge for the ticket, the password is obtained from the service issuer system 1100 and provided for the user terminal 1200, the service executor system 1400 obtains the ticket, electronic signature, and password from the user terminal 1200, deciphers the electronic signature with the password, and applies the open key to the deciphered electronic signature to verify the adequacy of the ticket.
MATSUKI TAKESHI
TERADA SHUJI
KOJIMA TAKESHI
IWAMURA MITSURU
