Encrypted text matching system, method, and computer readable medium

A method for encrypting a method comprising:

• generating first auxiliary data and second auxiliary data, respectively, which are for verification of matching between a first encrypted text that is obtained by encrypting at least one of a plurality of data segments into which input data is divided and that is registered with a storage device and a second encrypted text that is obtained by encrypting at least one of a plurality of data segments into which input data to be matched is divided, the verification being performed by using a Hamming distance between plaintexts;
• and
• taking a difference between the first encrypted text and the second encrypted text, and determining whether a Hamming distance between plaintexts that corresponds to the difference between the first encrypted text and the second encrypted text is equal to or less than a predetermined certain value by using the first auxiliary data and the second auxiliary data.

A non-transitory computer readable medium storing a program causing a computer to execute:

• a process which generates first auxiliary data and second auxiliary data, respectively, which are for verification of matching between a first encrypted text that is obtained by encrypting at least one of a plurality of data segments into which input data is divided and that is registered with a storage device and a second encrypted text that is obtained by encrypting at least one of a plurality of data segments into which input data to be matched is divided, the verification being performed by using a Hamming distance between plaintexts;
• and
• a process which takes a difference between the first encrypted text and the second encrypted text, and determines whether a Hamming distance between plaintexts that corresponds to the difference between the first encrypted text and the second encrypted text is equal to or less than a predetermined certain value by using the first auxiliary data and the second auxiliary data.