ANONYMOUS COUNTING SYSTEM OF DATA ITEM FOR STATISTIC PURPOSE

摘要

PROBLEM TO BE SOLVED: To secure a certain measure of secrecy of information related to a user by dividing a function for verifying the identity/genuineness of an information source between two separated units. SOLUTION: A determination unit ciphers a source information item S and a random data item R1 by a disclosure key PKC stored in a counting unit, ciphers the ciphered result X by using an individual data item (d), signs a message X2 by the use of a signature SiD, and transmits a final message M1 to a verification unit. The verification unit verifies the signature of the message X2 by using a signature related to identity Id, and when both the signatures are matched with each other, verifies the unvoted state of a voter and then registers the voter in a data base B1. The identity Id is related to a random data item R2 in each voter, a message M2 constituted of the signatures of the items X1, R2 is sent to the counting unit by the use of an indivisual signature SiV and the counting unit verifies the signature and decodes the message X1 by the use of an individual secret key SKC to obtain the value S.