Patent ID: 8090099
Filing Date: 2012-01-03
Classification: G06F,H04L

Abstract:
1. A non-transitory computer-readable recording medium recording a program for encryption/decryption with a Cyclic Vector Multiplication Algorithm which is configured, letting two elements A={a 0 , a 1 , a 2 , . . . , a m−1 } and B={b 0 , b 1 , b 2 , . . . , b m−1 } in an extension field F p of extension degree m with a prime number p as characteristic be plaintext data and an encryption key, or ciphertext data and a decryption key, to generate an element C={c 0 , c 1 , c 2 , . . . , c m−1 } of ciphertext data by multiplying the plaintext and the encryption key using an electronic computer, or to generate an element C={c 0 , c 1 , c 2 , . . . , c m−1 } of plaintext data by multiplying the ciphertext data and the decryption key, using an electronic computer, the program for encryption/decryption comprising: a first step of determining a positive integer k satisfying conditions that km+1 is a prime number and p is a primitive element in a finite field F a second step of multiplying said two elements A and B, regarding said two elements A and B as two elements in an extension field F a third step of obtaining a result of multiplication in an element of the extension field F wherein letting i, j, and t be integers, a M be a variable, K[t] be a t-th element of an array, q[<x>] be a <x>-th element of an array, <x> denoting x modulo (km+1), and ← be an assignment operator, the second step includes: a step of obtaining respective K[t]←<p a step of setting q[<i>]←0 respectively for 0≦i≦km; a step of obtaining q[<p a step of obtaining M←(a