SYSTÈME, PROCÉDÉ ET PROGRAMME DE MISE EN CORRESPONDANCE DE TEXTES CHIFFRÉS

摘要

The present invention makes it possible, in encrypted text matching, to avoid leakage of the information in an original plain text and to ensure security. In the present invention, a system is provided with: a means for respectively generating first and second auxiliary data for verifying that a first encrypted text, which is input data that is encrypted and recorded in a storage device, and a second encrypted text, which is input data to be matched that has been encrypted, match using the Hamming distance of the plain texts; and a means for unidirectionally converting at least one portion of the first auxiliary data, unidirectionally converting intermediate data generated on the basis of the second auxiliary data and the difference between the first encrypted text and the second encrypted text, and using the unidrectionally converted first auxiliary data and the results of the unidirectional conversion of the intermediate data to determine whether or not the Hamming distance of the plain texts corresponding to the difference between the first encrypted text and the second encrypted text is at or below a predetermined designated value.