DES的加密与解密(C语言实现)——大三密码学实验
DES的描述DES：16轮，Feistel型结构明文长度：64比特密钥长度：64比特。实际使用56比特，另8位用作奇偶校验密文长度：64比特DES算法用Feistel体制作为框架进行设计，通过实现F函数和密钥扩展函数，并对Feistel进行初始置换和逆初始置换形成DES算法。DES的加密与解密(C语言实现)——大三密码学实验
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目录
DES的描述
DES：16轮，Feistel型结构
明文长度：64比特
密钥长度：64比特。实际使用56比特，另8位用作奇偶校验
密文长度：64比特
DES算法用Feistel体制作为框架进行设计，通过实现F函数和密钥扩展函数，并对Feistel进行初始置换和逆初始置换形成DES算法。
Feistel体制
即上一轮的R是下一轮的L，上一轮的R与那一轮对应的key经过F函数再与上一轮的L异或即是下一轮的R
密钥扩展函数
64比特密钥经过PC-1表进行置换，生成56比特密钥
然后把密钥分为两部分，左边28比特为C1，右边28比特为D1
接下来就是密钥扩展算法单轮结构
根据加密的轮数来确定Ci和Di左移几个比特
| 迭代轮次 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 |
| 移位次数 | 1 | 1 | 2 | 2 | 2 | 2 | 2 | 2 | 1 | 2 | 2 | 2 | 2 | 2 | 2 | 1 |
经过移位后再结合成56比特的密钥，再经过PC-2表置换，就生成对应轮的密钥
但是在下一轮时，使用的Ci和Di是上一轮的，而不是经过PC-2表生成的56比特密钥再平分的两个28比特密钥
至此经过16轮，所有密钥都已经生成
F函数
右半部分明文R经过E扩展，从32变为48位，再与对应的密钥异或，再经过S盒置换，生成32比特的密钥加，最会经过P置换就是F函数的最后输出。
难点在于S盒置换，S盒共8个表，每个表都是4*16的结构，每个S盒输入为6比特，输出为4比特，盒Si的输入为输入的分组的第 6i-5 到 6i 比特，盒Si的输入的第一位和最后一位组成一个2比特的二进制数来选择该盒的行，S盒输入的中间4位构成一个4比特的二进制数来选择该盒的列。
总流程
64比特密钥经过密钥扩展算法生成16轮密钥
明文先进行IP置换，再进行16轮迭代，再将最后生成的左密文与右密文对换顺序，结合后经过置换，即逆初始置换，就能够生成最后的64比特密文
代码
get函数的构建
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;
}根据要进行迭代的轮数得到密钥需要左移的比特位数
yihuo函数的构建
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;
}
}
}相同为0，不同为1，num为两个参数数组的大小
fuck函数的构建
void fuck(int a[64], int b[64], int n) {
for (int i = 0; i < n; i++) {
a[i] = b[i];
}
}fuck函数人不如其名，其实只是把一个数组赋值给另一个数组
left_move函数的构建
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
}
}即左移n位，先把数组S1赋值给S，防止后续对S造成更改
exchange函数的构建
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;
}
即置换函数，输出的第i位等于 输入的（第i位对应的表的位数）的位数
erzhuanshi函数的构建
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
}
}即把二进制数组转化为十进制数组
shizhuaner函数的构建
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;
}即把十进制数组转化为二进制数组
s_box函数的构建
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
}
}上面已经做过说明
主函数的构建
int main()
{
unsigned char a[8];//明文
unsigned char b[8];//密钥
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 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];
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
cout<<"* -------------- - DES加密-------------- *"<<endl<<endl;
printf("请输入需要加密的明文:\n");//将明文转化为2进制
for (i=0;i<8;i++)
{
cin>>a[i];
shizhuaner(m_a,(int)a[i],i,64);
}
cout<<endl<<"请输入加密的密钥:"<<endl;//将密钥转为2进制
for (i=0;i<8;i++)
{
cin>>b[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
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
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);
cout << "第" << r << "轮加密后的密文为" << endl;
for (i = 0; i < 32; i++) {
cout << min_l[r][i];
}
for (i = 0; i < 32; i++) {
cout << min_r[r][i];
}
cout << endl;
}
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];
}
unsigned char plus3[8];
exchange(plus1, plus2, IP_1, 64);
erzhuanshi(plus2, plus3, 64);
cout << "最终密文为" << endl;
for (i = 0; i < 8; i++) {
cout << plus3[i];
}
//开始解密
exchange(plus2, plus1, IP, 64);//IP_1置换
for (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
cout << "第" << 17 - r << "轮解密后的密文为" << endl;
for (i = 0; i < 32; i++) {
cout << min_l[r - 1][i];
}
for (i = 0; i < 32; i++) {
cout << min_r[r - 1][i];
}
cout << endl;
}
for (i = 0; i < 32; i++) {
plus1[i + 32] = min_r[0][i];
plus1[i] = min_l[0][i];
}
exchange(plus1, plus2, IP_1, 64);
cout << "解密后的密文为" << endl;
int min_re[64];
unsigned char min_plus[16];
erzhuanshi(plus2, min_plus, 64);
for (i = 0; i < 8; i++) {
cout << min_plus[i];
}
cout << endl;
fuck(min_re, plus2, 64);
int flag = 0;
for (i = 0; i < 64; i++) {
if (m_a[i] != min_re[i]) {
flag = 1;
break;
}
}
if (flag == 0) {
cout << "解密成功";
}
else {
cout << "解密失败";
}
}没什么好解释的，就是跟着16轮迭代来呗，里面也加了注释
所谓解密就是加密的逆过程，大家都是大佬，我就不做过多解释
此外太冷了，写不下去了
总函数
#include <stdio.h>
#include <iostream>
using namespace std;
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
}
}
int main()
{
unsigned char a[8];//明文
unsigned char b[8];//密钥
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 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];
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
cout<<"* -------------- - DES加密-------------- *"<<endl<<endl;
printf("请输入需要加密的明文:\n");//将明文转化为2进制
for (i=0;i<8;i++)
{
cin>>a[i];
shizhuaner(m_a,(int)a[i],i,64);
}
cout<<endl<<"请输入加密的密钥:"<<endl;//将密钥转为2进制
for (i=0;i<8;i++)
{
cin>>b[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
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
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);
cout << "第" << r << "轮加密后的密文为" << endl;
for (i = 0; i < 32; i++) {
cout << min_l[r][i];
}
for (i = 0; i < 32; i++) {
cout << min_r[r][i];
}
cout << endl;
}
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];
}
unsigned char plus3[8];
exchange(plus1, plus2, IP_1, 64);
erzhuanshi(plus2, plus3, 64);
cout << "最终密文为" << endl;
for (i = 0; i < 8; i++) {
cout << plus3[i];
}
//开始解密
exchange(plus2, plus1, IP, 64);//IP_1置换
for (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
cout << "第" << 17 - r << "轮解密后的密文为" << endl;
for (i = 0; i < 32; i++) {
cout << min_l[r - 1][i];
}
for (i = 0; i < 32; i++) {
cout << min_r[r - 1][i];
}
cout << endl;
}
for (i = 0; i < 32; i++) {
plus1[i + 32] = min_r[0][i];
plus1[i] = min_l[0][i];
}
exchange(plus1, plus2, IP_1, 64);
cout << "解密后的密文为" << endl;
int min_re[64];
unsigned char min_plus[16];
erzhuanshi(plus2, min_plus, 64);
for (i = 0; i < 8; i++) {
cout << min_plus[i];
}
cout << endl;
fuck(min_re, plus2, 64);
int flag = 0;
for (i = 0; i < 64; i++) {
if (m_a[i] != min_re[i]) {
flag = 1;
break;
}
}
if (flag == 0) {
cout << "解密成功";
}
else {
cout << "解密失败";
}
}运行结果示例
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