HOMOMORPHIC CRYPTOGRAPHIC PROCESSING METHOD AND CRYPTOGRAPHIC PROCESSING DEVICE FOR PATTERN MATCHING WITH SIMILARITIES COMPUTATION

摘要

PROBLEM TO BE SOLVED: To provide an encryption processing method of efficiently obtaining a result of an arithmetic operation of two vectors by performing a cipher arithmetic operation using an encryption polynomial.;SOLUTION: A memory unit 111 of an encryption processing device 101 stores a first vector. A production unit 112 uses a homomorphic public cipher key to encrypt a first polynomial which is associated with a first binary vector obtained by converting an element of the first vector in binary notation, and thus produces a first encrypted polynomial. A transmission unit 113 transmits cipher information, which represents the first encrypted polynomial, to a cipher arithmetic unit. The cipher arithmetic unit multiplies the first encrypted polynomial by a second encrypted polynomial, which is produced by encrypting a second polynomial associated with a second binary vector obtained by converting an element of a second vector in binary notation, and thus produces a third encrypted polynomial. The third encrypted polynomial is decoded using a secret key in order to obtain a third polynomial. A result of an arithmetic operation of the first vector and the second vector is obtained by assigning 2 to a variable in a predetermined part of the third polynomial.;SELECTED DRAWING: Figure 1;COPYRIGHT: (C)2016,JPO&INPIT