[DESN演算法] 資訊保安概論
阿新 • • 發佈：2018-11-22
//通訊雙方同時掌握一個金鑰，加密解密都是一個金鑰完成的。通訊雙方協定一個金鑰，不予公開。通訊雙方掌握不同金鑰，不同方向加解密由 //不同祕鑰完成 //對稱加密演算法代表 DES演算法 // 利用58＋8奇偶校驗位 8,16,24,32,30,48,56,64 位的金鑰對以64位為單位的塊數進行加密。 #include <iostream> #include <string> using namespace std; // IP 初始置換表 const static int IP_TABLE[64] = { 58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4, 62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8, 57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3, 61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7 }; // E 擴充套件表 const static int E_TABLE[48] = { 32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 9, 10, 11, 12, 13, 12, 13, 14, 15, 16, 17, 16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 24, 25, 24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1 }; // P 盒 const static int P_TABLE[32] = { 16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5, 18, 31, 10, 2, 8, 24, 14, 32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4, 25 }; // IP 逆置換表 const static int IPR_TABLE[64] = { 40, 8, 48, 16, 56, 24, 64, 32, 39, 7, 47, 15, 55, 23, 63, 31, 38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45, 13, 53, 21, 61, 29, 36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11, 51, 19, 59, 27, 34, 2, 42, 10, 50, 18, 58, 26, 33, 1, 41, 9, 49, 17, 57, 25 }; // 金鑰第一次置換表 const static int PC1_TABLE[56] = { 57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18, 10, 2, 59, 51, 43, 35, 27, 19, 11, 3, 60, 52, 44, 36, 63, 55, 47, 39, 31, 23, 15, 7, 62, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 28, 20, 12, 4 }; // 金鑰第二次置換表 const int PC2_TABLE[48] = { 14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10, 23, 19, 12, 4, 26, 8, 16, 7, 27, 20, 13, 2, 41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48, 44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32 }; // S 盒 const static int S_BOX[8][4][16] = { // s1 { 14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7, 0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8, 4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0, 15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13 }, // s2 { 15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10, 3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5, 0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15, 13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9 }, // s3 { 10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8, 13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1, 13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7, 1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12 }, // s4 { 7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15, 13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9, 10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4, 3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14 }, // s5 { 2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9, 14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6, 4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14, 11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3 }, // s6 { 12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11, 10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8, 9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6, 4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13 }, // s7 { 4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1, 13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6, 1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2, 6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12 }, // s8 { 13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7, 1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2, 7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8, 2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11 } }; // 生成的 sub key，在第 1、2、9、16 輪迴圈左移 1 位，其他輪迴圈左移 2 位 // 這裡為了使下標對應迴圈次數，在開頭設定一位無用的0 const static int LEFT_SHIFT_TIMES[17] = { 0, 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 }; /* * 將 char 型轉化為二進位制形式 */ void char_to_bits(const char input[8], int output[64]) { for (int i = 0; i < 8; i++) { for (int j = 0; j < 8; j++) { output[7 * (i + 1) - j + i] = (input[i] >> j) & 1; } } } /* * 將二進位制形式轉化為 char 型 */ void bits_to_char(const int input[64], char output[8]) { for (int i = 0; i < 8; i++) { for (int j = 0; j < 8; j++) { output[i] = (char) (output[i] * 2 + input[8 * i + j]); } } } /* * 異或函式 * 將陣列 arr_1 和 arr_2 進行異或操作，並且儲存在 arr_1 中 * op_len 是進行異或的位數 */ void arr_xor(int *arr_1, const int *arr_2, const int op_len) { for (int i = 0; i < op_len; i++) { arr_1[i] = arr_1[i] ^ arr_2[i]; } } /* * IP 初始置換函式 * IP 根據 IP 初始置換表進行初始置換 */ void pass_ip(const int input[64], int output[64]) { for (int i = 0; i < 64; i++) { output[i] = input[IP_TABLE[i] - 1]; } } /* * E 擴充套件置換函式 * 根據 E 擴充套件表進行擴充套件 */ void pass_ext(const int input[32], int output[48]) { for (int i = 0; i < 48; i++) { output[i] = input[E_TABLE[i] - 1]; } } /* * P 置換函式 * 根據 P 盒進行置換 */ void pass_p_box(const int input[32], int output[32]) { for (int i = 0; i < 32; i++) { output[i] = input[P_TABLE[i] - 1]; } } /* * IP 逆置換函式 * IP 根據 IP 逆置換表進行置換 */ void pass_ipr(const int input[64], int output[64]) { for (int i = 0; i < 64; i++) { output[i] = input[IPR_TABLE[i] - 1]; } } /* * 密匙第一次置換函式 * 根據密匙第一次置換表進行置換 */ void pass_pc_1(const int input[64], int output[56]) { for (int i = 0; i < 56; i++) { output[i] = input[PC1_TABLE[i] - 1]; } } /* * 密匙第二次置換函式 * 根據密匙第二次置換表進行置換 */ void pass_pc_2(const int input[56], int output[48]) { for (int i = 0; i < 48; i++) { output[i] = input[PC2_TABLE[i] - 1]; } } /* * S 盒壓縮函式 * 根據 8 個 S 盒進行壓縮 */ void pass_s_box(const int input[48], int output[32]) { int INT[8]; for (int i = 0, j = 0; i < 48; i = i + 6, j++) { int row = (input[i] << 1) + (input[i + 5]); int column = (input[i + 1] << 3) + (input[i + 2] << 2) + (input[i + 3] << 1) + (input[i + 4]); INT[j] = S_BOX[j][row][column]; } for (int j = 0; j < 8; j++) { for (int i = 0; i < 4; i++) { output[3 * (j + 1) - i + j] = (INT[j] >> i) & 1; } } } /* * 輪迭代函式 */ void f_func(const int input[32], int output[32], int sub_key[48]) { int after_ext[48] = {0}; int after_s_box[32] = {0}; pass_ext(input, after_ext); arr_xor(after_ext, sub_key, 48); pass_s_box(after_ext, after_s_box); pass_p_box(after_s_box, output); } /* * 密匙迴圈左移函式 * 密匙在不同輪數都要進行不同的左移操作 */ void rotate_left_shift(const int input[28], int output[28], int leftCount) { for (int i = 0; i < 28; i++) { output[i] = input[(i + leftCount) % 28]; } } /* * 子密匙生成函式 * 生成 subKey，在第 1、2、9、16 輪迴圈左移 1 位，其他輪迴圈左移 2 位 */ void gen_sub_key(const int input[64], int sub_keys[16][48]) { int c[28], d[28]; int pc_1[56] = {0}; int pc_2[16][56] = {0}; int rotate_l_c[16][28] = {0}; int rotate_l_d[16][28] = {0}; // 經過第一次 pc 置換 pass_pc_1(input, pc_1); for (int i = 0; i < 28; i++) { c[i] = pc_1[i]; d[i] = pc_1[i + 28]; } // 迴圈左移 for (int i = 1; i < 17; i++) { rotate_left_shift(c, rotate_l_c[i - 1], LEFT_SHIFT_TIMES[i]); rotate_left_shift(d, rotate_l_d[i - 1], LEFT_SHIFT_TIMES[i]); } // 合併 for (int i = 0; i < 16; i++) { for (int j = 0; j < 28; j++) { pc_2[i][j] = rotate_l_c[i][j]; pc_2[i][j + 28] = rotate_l_d[i][j]; } } // 經過第二次 pc 置換 for (int i = 0; i < 16; i++) { pass_pc_2(pc_2[i], sub_keys[i]); } } /* * DES 加密函式 * 傳入明文 input 和密匙 inKey，獲取 64 位二進位制密文 output */ void encrypt(const char input[8], char key[8], int output[64]) { int ip[64] = {0}; int output_1[64] = {0}; int sub_keys[16][48]; int char_to_bit[64] = {0}; int bin_key[64]; int l[17][32], r[17][32]; char_to_bits(input, char_to_bit); pass_ip(char_to_bit, ip); char_to_bits(key, bin_key); gen_sub_key(bin_key, sub_keys); for (int i = 0; i < 32; i++) { l[0][i] = ip[i]; r[0][i] = ip[32 + i]; } for (int j = 1; j < 17; j++) { for (int k = 0; k < 32; k++) { if (j == 16) { // 第 16 輪迭代特殊處理 r[j][k] = r[j - 1][k]; } else { l[j][k] = r[j - 1][k]; } } if (j == 16) { // 第 16 輪迭代特殊處理 f_func(r[j - 1], l[j], sub_keys[j - 1]); arr_xor(l[j], l[j - 1], 32); } else { f_func(r[j - 1], r[j], sub_keys[j - 1]); arr_xor(r[j], l[j - 1], 32); } } for (int t = 0; t < 32; t++) { output_1[t] = l[16][t]; output_1[32 + t] = r[16][t]; } pass_ipr(output_1, output); } /* * DES 解密函式 * 傳入 64 位二進位制密文 input 和密匙 key 獲取明文 output */ void decrypt(const int input[64], const char key[64], char output[64]) { int after_ip[64] = {0}; int output_1[64] = {0}; int output_2[64] = {0}; int sub_keys[16][48]; int bin_key[64]; int l[17][32], r[17][32]; pass_ip(input, after_ip); char_to_bits(key, bin_key); gen_sub_key(bin_key, sub_keys); for (int i = 0; i < 32; i++) { l[0][i] = after_ip[i]; r[0][i] = after_ip[32 + i]; } // 16次迭代處理 for (int j = 1; j < 17; j++) { for (int k = 0; k < 32; k++) { if (j == 16) { // 第 16 輪迭代特殊處理 r[j][k] = r[j - 1][k]; } else { l[j][k] = r[j - 1][k]; } } if (j == 16) { // 第 16 輪迭代特殊處理 // 解密時，子金鑰反過來用 f_func(r[j - 1], l[j], sub_keys[16 - j]); arr_xor(l[j], l[j - 1], 32); } else { // 解密時，子金鑰反過來用 f_func(r[j - 1], r[j], sub_keys[16 - j]); arr_xor(r[j], l[j - 1], 32); } } for (int t = 0; t < 32; t++) { output_1[t] = l[16][t]; output_1[32 + t] = r[16][t]; } pass_ipr(output_1, output_2); bits_to_char(output_2, output); } int main() { int encrypted[64] = {0}; // 字元陣列最後要有一個'\0' 因此長一位 char origin[9] = {0}; char key[9] = {0}; cout << "請輸入8位明文: " << endl; cin >> origin; cout << "請輸入8位金鑰: " << endl; cin >> key; encrypt(origin, key, encrypted); cout << "加密後: " << endl; for (int i = 0; i < 4; i++) { for (int j = 0; j < 16; j++) { cout << encrypted[i * 4 + j]; } cout << endl; } decrypt(encrypted, key, origin); cout << "解密後: " << endl; cout << origin; return 0; }