ELECTRONIC JOINT SIGNATURE DOCUMENT EXCHANGE SYSTEM, ELECTRONIC JOINT SIGNATURE DOCUMENT EXCHANGE METHOD AND PROGRAM

摘要

PROBLEM TO BE SOLVED: To make joint signatures without exchanging an electronic document and to enable a third person to guarantee the actions of the joint signatures while keeping the secrecy of the electronic document in an electronic joint signature document exchange system in which a plurality of users electronically sign one and the same electronic document via a network.;SOLUTION: User devices 10-1 and 10-2 for performing the electronic signatures to one and the same electronic document encrypt electronic summary data summarizing the electronic document as a target of joint signatures by using their own original secret keys, create the electronic signatures by further adding data intrinsic for the users and transmit the created electronic signatures to a joint signature creation center device 20. The joint signature creation center device 20 decrypts the electronic signatures from the respective user devices 10-1 and 10-2 by using public keys original for the user devices of transmission sources and when the decrypted results of the same contents are obtained as many as the number of results required for the joint signatures, the joint signatures are created and returned to the user devices of targets of the joint signatures. Besides, the created joint signatures are stored.;COPYRIGHT: (C)2003,JPO