12345678................................................X..........................................................Z........Y x ......... .......................................................................(x+n)
12345678................................................X..........................................................Z........Y x ......... .......................................................................(x+n) X = [(x+n) / Y]の余り X = (x+n) mod Y Z = [(x-n) / Y]の余り Z = (x−n) mod Y 暗号化 復号