Patent ID: 7627763

Claim:
A multi-signature verification system configured to add an additional data to an original data previously created and configured to verify the original data and the additional data, the system comprising: an electronic signature attaching apparatus including an electronic signature attaching unit configured to attach an electronic signature to the original data previously created, to a first trapdoor hash value created by a data addition apparatus, and to an identification information; the data addition apparatus including: a data adding unit configured to add additional data including at least new created data to the original data; and a determination value calculating unit configured to calculate a determination value distinct from the electronic signature, such that an output of a trapdoor hash function using the determination value and the additional data as an input is equal to the first trapdoor hash value created by the data addition apparatus; and an electronic signature verification apparatus including: a trapdoor hash value calculating unit configured to calculate a second trapdoor hash value based on the additional data and the determination value; and a verifying unit configured to verify the additional data by comparing the second trapdoor hash value calculated by the trapdoor hash value calculating unit and the first trapdoor hash value created by the data addition apparatus, wherein the identification information identifies the data addition apparatus which has created the first trapdoor hash value.