An encryption processing method executed by a computer, the method includes converting a first vector using a first polynomial representation to acquire a first polynomial; converting an expression using a second polynomial representation to acquire a second polynomial, the expression being obtained based on a second vector and a random number corresponding to the first vector; converting the random number using at least one of the first polynomial representation and the second polynomial representation to acquire a random number polynomial; encrypting the first polynomial, the second polynomial, and the random polynomial using a homomorphic encryption scheme to acquire the encrypted first polynomial, the encrypted second polynomial, and the encrypted random polynomial; and collating the first vector and the second vector using the encrypted first polynomial, the encrypted second polynomial, and the encrypted random polynomial.