58 Fundamentals Review Vol.1 No.3 n 1 n n CAIRN 1422 = {1, 2, . . . } = {. . . 2, 1 0 1 2 . . . , } n a, b n a, b n a b mod n n x2 y2 mod n �, � �� ��� x2 y2 n x2 y2 = x + y x y n x+y x y gcd n x+y n n = 187 = 11 17 x = 73 y = 158 gcd n, x + y = gcd 187, 231 = 11 1 n 11 x y z2 q1 e1 · · · qt et mod n z q1 . . . , qt q1 = 2, q2 = 3, q3 = 5 . . . factor base n = 187 16 24 26 2 3 5 23 2 mod n 2 732 ≡