實驗三 Hill 密碼
阿新 • • 發佈:2018-11-22
#include <stdio.h> #include <string.h> #include <stdlib.h> #define MAX 60 int main() { int K1[2][2] = {0}, K2[2][2] = {0}; int Temp1[2] = {0}, Temp2[2] = {0}; char P[MAX] = {0}, C[MAX] = {0}; int T1[MAX] = {0}, T2[MAX] = {0}; int len, flag=0, temp, temp1, i, j, num=0; printf("======= Hill 密碼 =======\n\n"); printf("請輸入祕鑰的值:\n"); for(i=0; i<2; i++) { for(j=0; j<2; j++) { scanf("%d", &K1[i][j]); } } printf("\n1. 加密\t 2. 解密\n請選擇:"); scanf("%d", &num); if(num == 1) { printf("請輸入明文:\n"); scanf("%s", P); len = strlen(P); // 當長度為奇數時補齊一位 if(len % 2 == 1) { P[len] = 'a'; len = strlen(P); flag = 1; } // 將大寫轉成小寫,並賦值給T1陣列 for(i=0; i<len; i++) { if(P[i] >= 'A' && P[i] <= 'Z') { P[i] = P[i] + 32; } T1[i] = P[i] - 'a'; } // 得到加密後結果,儲存在T2中 for(i=0; i<len; i+=2) { Temp1[0] = T1[i]; Temp1[1] = T1[i + 1]; // Temp2儲存密文int值 Temp2[0] = (Temp1[0] * K1[0][0] + Temp1[1] * K1[1][0]) % 26; Temp2[1] = (Temp1[0] * K1[0][1] + Temp1[1] * K1[1][1]) % 26; T2[i] = Temp2[0]; T2[i + 1] = Temp2[1]; } if(flag == 1) { len = len - 1; } printf("加密結果為:\n"); for(i=0; i<len; i++) { C[i] = T2[i] + 'a'; printf("%c ", C[i]); } printf("\n"); } else if(num == 2) { printf("請輸入密文:"); scanf("%s", C); len = strlen(C); // 當長度為奇數時補齊一位 if(len % 2 == 1) { C[len] = 'a'; len = strlen(C); flag = 1; } for(i=0; i<len; i++) { if(C[i] >= 'A' && C[i] <= 'Z') { C[i] = C[i] + 32; } T2[i] = C[i] - 'a'; } // 求K的逆 temp = -1; for(i=1; temp < 0; i++) { temp = (K1[0][0] * K1[1][1] - K1[0][1] * K1[1][0]) + 26 * i; } i = 1; while(1) { if((temp * i) % 26 == 1) { temp1 = i; break; } else { i++; } } K2[0][0] = K1[1][1] * temp1; K2[0][1] = (((-1 * K1[0][1]) + 26) * temp1) % 26; K2[1][0] = (((-1 * K1[1][0]) + 26) * temp1) % 26; K2[1][1] = K1[0][0] * temp1; // printf(" %d %d %d %d %d %d\n",temp, temp1, K2[0][0], K2[0][1], K2[1][0], K2[1][1]); // system("pause"); // printf(" %d %d %d %d %d %d\n",temp, temp1, K2[0][0]%26, K2[0][1]%26, K2[1][0]%26, K2[1][1]%26); // system("pause"); // 得到解密後結果,儲存在T2中 for(i=0; i<len; i+=2) { Temp2[0] = T2[i]; Temp2[1] = T2[i + 1]; // Temp1儲存明文int值 Temp1[0] = (Temp2[0] * K2[0][0] + Temp2[1] * K2[1][0]) % 26; Temp1[1] = (Temp2[0] * K2[0][1] + Temp2[1] * K2[1][1]) % 26; T1[i] = Temp1[0]; T1[i + 1] = Temp1[1]; } if(flag == 1) { len = len - 1; } printf("解密結果為:\n"); for(i=0; i<len; i++) { P[i] = T1[i] + 'a'; printf("%c ", P[i]); } printf("\n"); } else { printf("error!"); exit(0); } return 0; } [點選並拖拽以移動]