DES的加密解密在ECB上的使用(C语言实现)—

实验内容

实验原理

DES加密解密

ECB(电码本模式)

代码

DES函数的构建

RE_DES函数的构建

ECB函数的构建

RE_ECB的函数的构建

主函数的构建

总代码

测试结果

实验内容

输入一个文本文件，通过ECB和DES进行加密，再将内容储存在新的文本文件中，再通过ECB和DES解密，将内容储存在新的文本文件中

实验原理

DES加密解密

DES的加密与解密(C语言实现)——大三密码学实验_西瓜妹妹的唯一男朋友的博客-CSDN博客

ECB(电码本模式)

对明文分块后，每一块明文块都使用相同的密钥，通过加密器生成对应的密文块，每个明文块加密中不会受到彼此的影响

可以进行并行操作，一个密文块传输错误不会影响后续密文解密，但是缺点是无法避免重放攻击

代码

大部分代码都在这篇博客中说过

DES的加密与解密(C语言实现)——大三密码学实验_西瓜妹妹的唯一男朋友的博客-CSDN博客

主要把主函数中的DES加密定义成一个函数，解密定义成一个函数

DES函数的构建

void DES(unsigned char a[8],unsigned char b[8],unsigned char plus3[8])
{int m_a[64] = { 0 };int m_b[64];          //IP置换前后的明文 int s_a[64] = { 0 };int s_b[56];          //置换1前后的二进制密钥 int r;            //轮数int miwen[8] = { 0 };   //最终密文 int i, j = 0;int key_l[17][28];//16轮密钥 int key_r[17][28];int key_2[17][56];for (i = 0; i < 8; i++){shizhuaner(m_a, (int)a[i], i, 64);}for (i = 0; i < 8; i++){shizhuaner(s_a, (int)b[i], i, 64);}exchange(m_a, m_b, IP, 64); //明文进行初始置换 int min_l[17][32];int min_r[17][32];for (i = 0; i < 32; i++)//明文第0轮的左半部分 min_l[0][i] = m_b[i];for (i = 32; i < 64; i++)//明文的右半部分 min_r[0][i - 32] = m_b[i];exchange(s_a, s_b, zhihuan1, 56);//密钥进行PC-1置换  int run = 1;for (int i = 0; i < 28; i++) {key_l[0][i] = s_b[i];key_r[0][i] = s_b[i + 28];}int n;for (r = 1; r <= 16; r++) {n = get(r);left_move(key_l[run], key_l[run - 1], n);left_move(key_r[run], key_r[run - 1], n);run++;}//结合 for (r = 1; r <= 16; r++) {for (i = 0; i < 28; i++) {key_2[r][i] = key_l[r][i];key_2[r][i + 28] = key_r[r][i];}}//pc-2置换for (r = 1; r <= 16; r++) {exchange(key_2[r], key_3[r], zhihuan2, 48);}//真正的16轮密钥到此生成 int temp6[48], temp1[32];for (int r = 1; r <= 16; r++) {fuck(min_l[r], min_r[r - 1], 32);//左半部分等于上一轮右半部分 exchange(min_r[r - 1], temp6, e, 48);//E置换yihuo(temp6, key_3[r], 48);//准备S盒置换 s_box(temp1, temp6);//s盒替换完毕 exchange(temp1, temp6, p, 32);//P置换 yihuo(temp6, min_l[r - 1], 32);fuck(min_r[r], temp6, 32);}int plus1[64] = { 0 };int plus2[64] = { 0 };for (i = 0; i < 32; i++) {plus1[i] = min_r[16][i];plus1[i + 32] = min_l[16][i];}exchange(plus1, plus2, IP_1, 64);erzhuanshi(plus2, plus3, 64);//plus3是密文
}

输入：数组a（8字节明文）数组b（8字节密钥）数组plus3（8字节生成的密文）

最后结果是生成密文plus3

生成16轮密钥，再经过16轮Feistel体制，即可生成密文

RE_DES函数的构建

void RE_DES(unsigned char a[8],unsigned char b[8],unsigned char min_plus[8]) {//开始解密int plus2[64],plus1[64],min_l[17][32],min_r[17][32];for (int i = 0; i < 8; i++) {shizhuaner(plus2, int(a[i]), i, 64);}exchange(plus2, plus1, IP, 64);//IP_1置换 for (int i = 0; i < 32; i++) {min_l[16][i] = plus1[i + 32];min_r[16][i] = plus1[i];}cout << endl;for (int r = 16; r >= 1; r--) {fuck(min_r[r - 1], min_l[r], 32);//这一轮的左等于上一轮的右  exchange(min_r[r - 1], plus1, e, 48);//E扩展 yihuo(plus1, key_3[r], 48);//与密钥异或s_box(plus2, plus1);//S盒置换exchange(plus2, plus1, p, 32);//p盒置换fuck(min_l[r - 1], plus1, 32);yihuo(min_l[r - 1], min_r[r], 32);//异或 }for (int i = 0; i < 32; i++) {plus1[i + 32] = min_r[0][i];plus1[i] = min_l[0][i];}exchange(plus1, plus2, IP_1, 64);;erzhuanshi(plus2, min_plus, 64);//min_plus是明文
}

解密过程

输入：

输入：数组a（8字节密文）数组b（8字节密钥）数组plus3（8字节生成的明文）

最后结果是生成明文plus3

ECB函数的构建

int ECB(unsigned char b[8]) {FILE* input = fopen("C:\\Users\\Administrator\\Desktop\\ECB.txt", "r");FILE* output = fopen("C:\\Users\\Administrator\\Desktop\\ECB_1.txt", "a");int size,size1;unsigned char a[8],plus3[8];fseek(input, 0, SEEK_END);size = ftell(input);fseek(input, 0, SEEK_SET);for (int i = 0; i < size/8; i++) {fread(a, 8, 1, input);DES(a, b, plus3);fwrite(plus3, 8, 1, output);}size1 = size % 8;fread(a, size1, 1, input);for (int i = size1; i < 8 ; i++) {a[size1] = '0';}DES(a, b, plus3);fwrite(plus3, 8, 1, output);fclose(input);fclose(output);return size;
}

ECB函数是读取一个文件，对其加密，结果存储在新的文本文件中

输入为数组b，即密钥

input是读取明文文件的指针，output是要写入密文文本的指针，size是明文文件的大小

每次读取八字节作为明文，通过DES算法生成密文并存储在文本中

如果最后读取的字节少于八字节，就对明文补"0"，使其够8字节，再进行DES算法并存储

RE_ECB的函数的构建

void RE_ECB(unsigned char b[8],int size) {FILE* input1 = fopen("C:\\Users\\Administrator\\Desktop\\ECB_1.txt", "r");FILE* output1 = fopen("C:\\Users\\Administrator\\Desktop\\ECB_2.txt", "a");unsigned char min_plus[8];int size1;unsigned char a[8];fseek(input1, 0, SEEK_END);size1 = ftell(input1);fseek(input1, 0, SEEK_SET);for (int i = 0; i < size/8; i++) {fread(a, 8, 1, input1);RE_DES(a, b, min_plus);fwrite(min_plus, 8, 1, output1);}size1 = 8-(size1 - size);fread(a, 8, 1, input1);RE_DES(a, b, min_plus);fwrite(min_plus, size1, 1, output1);fclose(input1);fclose(output1);
}

RE_ECB函数是读取一个密文文件，对其解密，结果存储在新的文本文件中

输入：密钥b，原明文的字节数size

每次读取八字节进行解密，由于密文文件字节数是8的整数倍，而我们需要的解密文件不是8的整数倍，则读到最后一个9字节密文时，解密出来的明文选取合适的字节储存进去即可

主函数的构建

int main() {unsigned char b[8];int size;cout << "请输入密钥" << endl;for (int i = 0; i < 8; i++) {cin >> b[i];}size=ECB(b);RE_ECB(b,size);FILE* min = fopen("C:\\Users\\Administrator\\Desktop\\ECB_2.txt", "r ");FILE* min1 = fopen("C:\\Users\\Administrator\\Desktop\\ECB.txt", "r");char p, q;int flag = 0;for (int i = 0; i < size; i++) {fread(&p, 1, 1, min);fread(&q, 1, 1, min1);if (p != q) {flag = 1;break;}}if (flag==0) {cout << "解密成功";}else {cout<<"解密失败";}return 0;
}

先输入密钥，再ECB加密，解密，然后将解密后的文件与原明文的文件进行比较

如果相同则解密成功，否则解密失败

总代码

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <iostream>
using namespace std;
int key_3[17][48];
int zhihuan2[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 };  //置换2
int e[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 };    //E盒
int p[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 };     //P盒
int zhihuan1[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 };      //置换1
int IP[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 };    //IP置换
int IP_1[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 };    //IP_1置换
int get(int r)         //得到第r轮的移位数
{int i;if (r == 1 || r == 2 || r == 9 || r == 16) {i = 1;}else {i = 2;}return i;
}void yihuo(int* a, int* b, int num)      //异或
{int i;for (i = 0; i < num; i++){if (a[i] == b[i]) {//相同为0 a[i] = 0;}else {//不同为1 a[i] = 1;}}
}void fuck(int a[64], int b[64], int n) {for (int i = 0; i < n; i++) {a[i] = b[i];}
}
void left_move(int s[28], int s1[28], int n) //左移
{int i, t, temp;fuck(s, s1, 28);for (i = 0; i < n; i++) {temp = s[0];for (t = 0; t < 27; t++) {s[t] = s[t + 1];}s[27] = temp;//原先的左半部分第一位赋给最后一位 }
}
void exchange(int* a, int* b, int* biao, int n)    //置换
{int i, loc;for (i = 0; i < n; i++)//输入的第biao[i]位是输出的第i位 {loc = biao[i];b[i] = a[loc - 1];}return;
}void erzhuanshi(int* a, unsigned char* b, int n)
// a是二进制数组，b是存放十六进制的数组，n是二进制数组的大小
{int i, j;n = n / 8;for (i = 0; i < n; i++){j = 128 * a[8 * i] + 64 * a[8 * i + 1] + 32 * a[8 * i + 2] + 16 * a[8 * i + 3] + 8 * a[8 * i + 4] + 4 * a[8 * i + 5] + 2 * a[8 * i + 6] + 1 * a[8 * i + 7];//先转换为十进制 b[i] = (char)j;//转换为char型字符 }
}
void shizhuaner(int* a, int x, int i, int n)
// a是存放二进制的数组，x是需要进行转换的十进制数，i是第i个十进制数，n是数组大小
{int j; n = n / 8; j = n - 1;do {a[i * n + j] = x % 2;//x的2进制最后一位，0or1 x = x / 2;//右移 j--;} while (x != 0);while (j >= 0)//如果右移后出现000....的情况 {a[i * n + j] = 0;j--;}return;
}void s_box(int a[32], int b[48])         //S盒
{int i, r, c, s;int s1[4][16] = { { 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[4][16] = { { 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[4][16] = { { 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[4][16] = { { 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, 3 },{ 3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14 } },s5[4][16] = { { 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[4][16] = { { 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][16] = { { 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[4][16] = { { 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 } };for (i = 0; i < 8; i++){r = 2 * b[6 * i] + b[6 * i + 5];//第一位和最后一位构建行  c = 8 * b[6 * i + 1] + 4 * b[6 * i + 2] + 2 * b[6 * i + 3] + b[6 * i + 4];//中间四位构建列 switch (i) //选择盒子 {case 0:s = s1[r][c]; break;case 1:s = s2[r][c]; break;case 2:s = s3[r][c]; break;case 3:s = s4[r][c]; break;case 4:s = s5[r][c]; break;case 5:s = s6[r][c]; break;case 6:s = s7[r][c]; break;case 7:s = s8[r][c]; break;}shizhuaner(a, s, i, 32); //转化为二进制 }
}void DES(unsigned char a[8],unsigned char b[8],unsigned char plus3[8])
{int m_a[64] = { 0 };int m_b[64];          //IP置换前后的明文 int s_a[64] = { 0 };int s_b[56];          //置换1前后的二进制密钥 int r;            //轮数int miwen[8] = { 0 };   //最终密文 int i, j = 0;int key_l[17][28];//16轮密钥 int key_r[17][28];int key_2[17][56];for (i = 0; i < 8; i++){shizhuaner(m_a, (int)a[i], i, 64);}for (i = 0; i < 8; i++){shizhuaner(s_a, (int)b[i], i, 64);}exchange(m_a, m_b, IP, 64); //明文进行初始置换 int min_l[17][32];int min_r[17][32];for (i = 0; i < 32; i++)//明文第0轮的左半部分 min_l[0][i] = m_b[i];for (i = 32; i < 64; i++)//明文的右半部分 min_r[0][i - 32] = m_b[i];exchange(s_a, s_b, zhihuan1, 56);//密钥进行PC-1置换  int run = 1;for (int i = 0; i < 28; i++) {key_l[0][i] = s_b[i];key_r[0][i] = s_b[i + 28];}int n;for (r = 1; r <= 16; r++) {n = get(r);left_move(key_l[run], key_l[run - 1], n);left_move(key_r[run], key_r[run - 1], n);run++;}//结合 for (r = 1; r <= 16; r++) {for (i = 0; i < 28; i++) {key_2[r][i] = key_l[r][i];key_2[r][i + 28] = key_r[r][i];}}//pc-2置换for (r = 1; r <= 16; r++) {exchange(key_2[r], key_3[r], zhihuan2, 48);}//真正的16轮密钥到此生成 int temp6[48], temp1[32];for (int r = 1; r <= 16; r++) {fuck(min_l[r], min_r[r - 1], 32);//左半部分等于上一轮右半部分 exchange(min_r[r - 1], temp6, e, 48);//E置换yihuo(temp6, key_3[r], 48);//准备S盒置换 s_box(temp1, temp6);//s盒替换完毕 exchange(temp1, temp6, p, 32);//P置换 yihuo(temp6, min_l[r - 1], 32);fuck(min_r[r], temp6, 32);}int plus1[64] = { 0 };int plus2[64] = { 0 };for (i = 0; i < 32; i++) {plus1[i] = min_r[16][i];plus1[i + 32] = min_l[16][i];}exchange(plus1, plus2, IP_1, 64);erzhuanshi(plus2, plus3, 64);//plus3是密文
}
void RE_DES(unsigned char a[8],unsigned char b[8],unsigned char min_plus[8]) {//开始解密int plus2[64],plus1[64],min_l[17][32],min_r[17][32];for (int i = 0; i < 8; i++) {shizhuaner(plus2, int(a[i]), i, 64);}exchange(plus2, plus1, IP, 64);//IP_1置换 for (int i = 0; i < 32; i++) {min_l[16][i] = plus1[i + 32];min_r[16][i] = plus1[i];}cout << endl;for (int r = 16; r >= 1; r--) {fuck(min_r[r - 1], min_l[r], 32);//这一轮的左等于上一轮的右     exchange(min_r[r - 1], plus1, e, 48);//E扩展 yihuo(plus1, key_3[r], 48);//与密钥异或s_box(plus2, plus1);//S盒置换exchange(plus2, plus1, p, 32);//p盒置换fuck(min_l[r - 1], plus1, 32);yihuo(min_l[r - 1], min_r[r], 32);//异或 }for (int i = 0; i < 32; i++) {plus1[i + 32] = min_r[0][i];plus1[i] = min_l[0][i];}exchange(plus1, plus2, IP_1, 64);;erzhuanshi(plus2, min_plus, 64);//min_plus是明文
}
int ECB(unsigned char b[8]) {FILE* input = fopen("C:\\Users\\Administrator\\Desktop\\ECB.txt", "r");FILE* output = fopen("C:\\Users\\Administrator\\Desktop\\ECB_1.txt", "a");int size,size1;unsigned char a[8],plus3[8];fseek(input, 0, SEEK_END);size = ftell(input);fseek(input, 0, SEEK_SET);for (int i = 0; i < size/8; i++) {fread(a, 8, 1, input);DES(a, b, plus3);fwrite(plus3, 8, 1, output);}size1 = size % 8;fread(a, size1, 1, input);for (int i = size1; i < 8 ; i++) {a[size1] = '0';}DES(a, b, plus3);fwrite(plus3, 8, 1, output);fclose(input);fclose(output);return size;
}
void RE_ECB(unsigned char b[8],int size) {FILE* input1 = fopen("C:\\Users\\Administrator\\Desktop\\ECB_1.txt", "r");FILE* output1 = fopen("C:\\Users\\Administrator\\Desktop\\ECB_2.txt", "a");unsigned char min_plus[8];int size1;unsigned char a[8];fseek(input1, 0, SEEK_END);size1 = ftell(input1);fseek(input1, 0, SEEK_SET);for (int i = 0; i < size/8; i++) {fread(a, 8, 1, input1);RE_DES(a, b, min_plus);fwrite(min_plus, 8, 1, output1);}size1 = 8-(size1 - size);fread(a, 8, 1, input1);RE_DES(a, b, min_plus);fwrite(min_plus, size1, 1, output1);fclose(input1);fclose(output1);
}
int main() {unsigned char b[8];int size;cout << "请输入密钥" << endl;for (int i = 0; i < 8; i++) {cin >> b[i];}size=ECB(b);RE_ECB(b,size);FILE* min = fopen("C:\\Users\\Administrator\\Desktop\\ECB_2.txt", "r ");FILE* min1 = fopen("C:\\Users\\Administrator\\Desktop\\ECB.txt", "r");char p, q;int flag = 0;for (int i = 0; i < size; i++) {fread(&p, 1, 1, min);fread(&q, 1, 1, min1);if (p != q) {flag = 1;break;}}if (flag==0) {cout << "解密成功";}else {cout<<"解密失败";}return 0;
}

测试结果

明文文件

密文文件

解密文件

最终结果