概述
DES加密算法，算是密码学里入门的知识了，前段时间有兴趣搞了一下，但是没有做完。现在桌面实在是东西太多了，暂且丢到博客里，以后有空再来改一下。一共三个文件： data.h 各种表组成的头文件des.h DES加密算法的主要函数都在里边了test.cpp 测试各个函数的测试文件
贴代码：
/*下面是DES加密算法的各种置换表由Halfish整理，.12.13*///初始置换表IPint IP_Table[64] = { 57,49,41,33,25,17,9,1,59,51,43,35,27,19,11,3,61,53,45,37,29,21,13,5,63,55,47,39,31,23,15,7,56,48,40,32,24,16,8,0,58,50,42,34,26,18,10,2,60,52,44,36,28,20,12,4,62,54,46,38,30,22,14,6}; //逆初始置换表IP^-1int IP_1_Table[64] = {39,7,47,15,55,23,63,31,38,6,46,14,54,22,62,30,37,5,45,13,53,21,61,29,36,4,44,12,52,20,60,28,35,3,43,11,51,19,59,27,34,2,42,10,50,18,58,26,33,1,41,9,49,17,57,25,32,0,40,8,48,16,56,24 };//扩展置换表Eint E_Table[48] = {31, 0, 1, 2, 3, 4,3, 4, 5, 6, 7, 8,7, 8, 9,10,11,12,11,12,13,14,15,16,15,16,17,18,19,20,19,20,21,22,23,24,23,24,25,26,27,28,27,28,29,30,31, 0 };//置换选择1int PC_1[56] = {56,48,40,32,24,16,8,0,57,49,41,33,25,17,9,1,58,50,42,34,26,18,10,2,59,51,43,35,62,54,46,38,30,22,14,6,61,53,45,37,29,21,13,5,60,52,44,36,28,20,12,4,27,19,11,3};//置换选择2, 又叫做压缩置换int PC_2[48] = {13,16,10,23,0,4,2,27,14,5,20,9,22,18,11,3,25,7,15,6,26,19,12,1,40,51,30,36,46,54,29,39,50,44,32,46,43,48,38,55,33,52,45,41,49,35,28,31};//对左移次数的规定int left_move_times[16] = {1,1,2,2, 2,2,2,2, 1,2,2,2, 2,2,2,1};//置换函数Pint P_Table[32] = {15, 6,19,20,28,11,27,16,0,14,22,25, 4,17,30, 9,1, 7,23,13,31,26, 2, 8,18,12,29, 5,21,10, 3,24 };//S盒int S[8][64] ={//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}};
des.h
/** Halfish * December*/#include <iostream>#include <cstdio>#include <cstring>#include "data.h"using namespace std;const int EXTRA_BITS = 1;void mstrcpy(char to[], char from[], int offset) {for (int i = 0; i < offset; ++i){to[i] = from[i];}}// 初始置换void initial_permutation(char plain_block[]) {char temp[64 + EXTRA_BITS];mstrcpy(temp, plain_block, 64);for (int i = 0; i < 64; ++ i) {plain_block[i] = temp[IP_Table[i]];}}// 置换选择1: subkey[56] <-- key[64]void get_subkey(char subkey[], const char key[]) {for (int i = 0; i < 56; ++ i){subkey[i] = key[PC_1[i]];}}void shift_subkey(int shift, char subkey[], int size){char temp0 = subkey[0];char temp1 = subkey[1];switch(shift) {case 1:for (int i = 0; i < size - 1; ++ i) {subkey[i] = subkey[i + 1];}subkey[size - 1] = temp0;break;case 2:for (int i = 0; i < size - 1; ++ i) {subkey[i] = subkey[i + 2];}subkey[size - 2] = temp0;subkey[size - 1] = temp1;break;default:break;}}// 扩展置换 expand_block[48] <-- plain_right[32]void expand_permutation(char expand_block[], char plain_right[]) {for (int i = 0; i < 48; ++ i){expand_block[i] = plain_right[ E_Table[i] ];}}// 压缩置换后，得到48位的字密钥void compress_permutation(char comp_key[], char subkey[]) {for (int i = 0; i < 48; ++ i){comp_key[i] = subkey[ PC_2[i] ];}}int char2int(char a[], int index, int offset) {int base = 1;int ret = 0;for (int i = offset - 1; i >= 0; -- i){ret += (a[index + i] - '0') * base;base *= 2;}return ret;}void int2char(int num, char a[], int index, int offset){char temp[10];int i = 0;while(num) {temp[i] = num % 2 + '0';num = num / 2;++ i;}for (int j = 0; j < offset; ++ j){a[index + j] = '0';}for (int j = 0; j < i; ++ j){a[index + offset - j - 1] = temp[j];}//a[offset] = '\0';}// S-盒置换 sbox_block[32] <-- expand_block[48] void sbox_substitution(char sbox_block[], char expand_block[]) {for (int i = 0; i < 8; ++ i){int location = 0;char temp_int[2 + EXTRA_BITS];temp_int[0] = expand_block[i*6];temp_int[1] = expand_block[i*6 + 5];location += char2int(temp_int, 0, 2) * 16;location += char2int(expand_block, i * 6 + 1, 4);int2char(S[i][location], sbox_block, i * 4, 4);}}// P-盒置换 sboxvoid pbox_substitution(char pbox_block[], char sbox_block[]) {for (int i = 0; i < 32; ++ i){pbox_block[i] = sbox_block[ P_Table[i] ];}}void Xor(char c[], char a[], char b[], int size) {for (int i = 0; i < size; ++ i){// 异或操作，相同为0，不同为1c[i] = (a[i] == b[i]) ? '0' : '1' ;}}void final_permutation(char cipher_block[], char plain_block[]){for (int i = 0; i < 64; ++ i){cipher_block[i] = plain_block[ IP_1_Table[i] ];}}// for debugvoid myprint(const char *funcName, char *arr, int size, int columns) {cout << funcName << endl;for (int i = 0; i < size; ++ i){cout << *(arr ++) ;if ( (i + 1) % columns == 0) {cout << endl; }}cout << endl;}void encryption(char myplain_block[], char cipher_block[], char key[]) {char plain_block[64 + EXTRA_BITS];char plain_left[32 + EXTRA_BITS];char plain_right[32 + EXTRA_BITS];char subkey[56 + EXTRA_BITS];char comp_key[48 + EXTRA_BITS];char expand_block[48 + EXTRA_BITS];char sbox_block[32 + EXTRA_BITS];char pbox_block[32 + EXTRA_BITS];mstrcpy(plain_block, myplain_block, 64);// 初始置换initial_permutation(plain_block);strncpy(plain_left, plain_block, 32);strncpy(plain_right, plain_block + 32, 32);// 置换选择1, 得到初始子密钥get_subkey(subkey, key);for (int i = 0; i < 16; ++ i){// 将56位的subkey左移一位或者两位shift_subkey(left_move_times[i], subkey, 28);shift_subkey(left_move_times[i], subkey + 28, 28);// 压缩置换，又称为置换选择2，将56位的subkey压缩成48位的comp_keycompress_permutation(comp_key, subkey);// 扩展置换，将32位的 plain_right 扩展成48位expand_permutation(expand_block, plain_right);// 异或操作Xor(expand_block, expand_block, comp_key, 48);// S盒替换sbox_substitution(sbox_block, expand_block);if (i == 0){myprint("sbox_substitution", sbox_block, 32, 8);}// P盒替换pbox_substitution(pbox_block, sbox_block);if (i == 0){myprint("pbox_substitution", pbox_block, 32, 8);}char temp_right[32 + EXTRA_BITS];mstrcpy(temp_right, plain_right, 32);// 异或操作Xor(plain_right, pbox_block, plain_left, 32);if (i == 0){myprint("pbox_block", pbox_block, 32, 8);myprint("L0", plain_left, 32, 8);myprint("R1", plain_right, 32, 8);}mstrcpy(plain_left, temp_right, 32);if (i == 0 || i == 15){cout << i << endl;myprint("R1", plain_right, 32, 8);myprint("L1", plain_left, 32, 8);}}mstrcpy(plain_block, plain_left, 32);mstrcpy(plain_block + 32, plain_right, 32);// 末置换final_permutation(cipher_block, plain_block);}void decreption(char key[], char plain_block[], char cipher_block[]) {}
test.cpp
/** test.cpp* Halfish, , December*/#include <iostream>#include "des.h"using namespace std;int main(int argc, char const *argv[]){char plain_block[64 + EXTRA_BITS];// 明文块char cipher_block[64 + EXTRA_BITS];// 密文块char key[64 + EXTRA_BITS];// 密钥strcpy(plain_block, "0000000100100011010001010110011110001001101010111100110111101111"); strcpy(key, "0001001100110100010101110111100110011011101111001101111111110001");encryption(plain_block, cipher_block, key);myprint("plain_block", plain_block, 64, 8);myprint("key", key, 64, 8);myprint("cipher_block", cipher_block, 64, 8);return 0;}
