仿射代码的加密与解密 Z26
int dx, y, q; void extend_Eulid(int aa, int bb) { if (bb == 0) { dx = 1; y = 0; q = aa; } else { extend_Eulid(bb, aa % bb); int temp = dx; dx = y; y = temp - aa / bb * y; } } int main() { int a, b, YN, i, l; char c[100]; int x[100], y[100]; char ex[100]; cout << "请依次输入k =( a, b )的a, b值，其中 a,b ∈ Z/(26)，gcd( a,26) = 1 ：" << endl; cin >> a >> b; cout << "那么你的加密函数就是 ex = " << a << "*x + " << b << endl; cout << endl << "接下来输入你要加密的明文(小写字母)：" << endl; cin >> c;//明文 l = strlen(c); for (i = 0; i < l; i++) { x[i] = c[i] - 'a'; ex[i] = (a * x[i] + b) % 26;//数字 } cout << "加密后的字母为："; for (i = 0; i < l; i++) { cout << char(ex[i] + 'a');//转字符 } cout << endl << endl; cout << "是否要解密原文（输入1则确定，输入其他则取消）:"; cin >> YN; while (YN == 1) { extend_Eulid(a, 26);//取逆 dx = (dx + 26) % 26; for (i = 0; i < l; i++) { y[i] = (dx * int(ex[i]) - dx * b) % 26; y[i] = (y[i] + 26) % 26;//+26取正 cout << char(y[i] + 'a'); } break; } system("pause"); }