Patent ID: 7260222

Claim:
A shared data purifying apparatus comprising: a block generating means for dividing temporarily-shared data that said shared data purifying apparatus temporarily shares with a transmitter according to a predetermined division rule so as to generate a first purification block and a first disposable block; a data mixing means for mixing the first purification block according to a predetermined data mixing rule so as to generate a first mixed block, according to the predetermined data mixing rule said data mixing means mixing each of two arbitrary digital data that are at a Hamming distance of 0 from each other so that two generated mixed data are at a Hamming distance of 0 from each other, and mixing each of two arbitrary digital data that are at a Hamming distance of 1 or more from each other so that two generated mixed data are at a have a Hamming distance of 1 or more from each other; a means for acquiring an encrypted block generated according to a predetermined encryption rule based on a second mixed block, which is generated by mixing a second purification block, which said transmitter generates together with a second disposable block by dividing temporarily-shared data being held by said transmitter according to the predetermined division rule, according to the predetermined data mixing rule, and based on the second disposable block; a decrypted block generating means for decrypting the encrypted block with the first disposable block according to a predetermined decrypting rule corresponding to the predetermined encryption rule so as to generate a decrypted block; and an identity judgment means for comparing the decrypted block with the first mixed block so as to judge whether the first purification block and the second purification block are identical with or different from each other according to a comparison result.