DES加密解密算法（简单、易懂、超等详细） - ToB企服应用市场:ToB评测及商务社交产业平台

string wen(string wenBinary[], int num)
{
int i, j;
string ipWenBinary[100]; //保存明文
string left[17], right[17], temp, result; //分为左右两个分支
for (i = 0; i < num; i++)
{
temp = ""; //一个暂存明文的字符串
//进行IP置换
for (j = 0; j < 64; j++) //明文为64bit
{
temp += wenBinary[i][ipTable[j] - 1];
}
ipWenBinary[i] = temp;
}
//进行左右分支，分为left:L0,,,right:R0
for (i = 0; i < num; i++)
{
left[0] = ipWenBinary[i].substr(0, 32);
right[0] = ipWenBinary[i].substr(32, 32);
//
for (j = 0; j < 16; j++) //进行16次循环
{
left[j + 1] = right[j]; // left: L1 = R0
//加密和解密的区别
// flag 为全局变量
if (flag == 1) // flage = 1进行加密，否则进行解密
right[j + 1] = xorAB(left[j], f(right[j], k[j]));
else
//倒着进行解密
right[j + 1] = xorAB(left[j], f(right[j], k[15 - j]));
}
temp = right[j] + left[j]; //经过16轮加密/解密，将左右32bit合并
//将加密后的密文进行最后的置换，实际上和初始置换是对称的~！
//每块的加密结果都和在result中,加密可以直接输出比特流
// 进行IP的逆置换
for (j = 0; j < 64; j++)
{
result += temp[ipReverseTable[j] - 1];
}
}
//解密结果输出的是字符
if (flag == 2)
{
string ch;
for (i = 0; i < num * 8; i++) //一个模块是8个bit
{
ch += binaryToInt(result.substr(8 * i, 8)); //每8bit进行一次二进制转整型
}
result = ch;
}
return result;
}

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//字符转二进制
string charToBinary(char c)
{
int i, b = c, k = 0, flag = 0;
string result;
//负数就是中文字符
if (b < 0)
{
b = -b;
flag = 1;
}
//英文字符转换成ASCII的倒序，所以后面需要进行逆序
while (k < 8) //这里的8表示char是1个字节=8bit
{
if (b) //这里将ASCII里的字符转换为二进制
{
result += ((b % 2) + '0'); // 其中这里+'0',表示将数字转换为字符
b /= 2;
}
else result += '0';
k++;
}
//汉字字符处理
if (flag)//判断是否为汉字
{
for (i = 0; i < result.length(); i++) //此时因为是负数，源码、反码、补码不相等，需要置换
{
if (result[i] == '0') result[i] = '1'; // 反码：最高最不变，其它的0->1,,1->0
else result[i] = '0';
}
for (i = 0; result[i] != '0'; i++)
{
result[i] = '0'; //补码：反码加+1
}
result[i] = '1';
}
reverse(result.begin(), result.end()); //将结果逆序，成为最终的二进制
return result;
}
//二进制转整型
int binaryToInt(string s)
{
int i, result = 0, p = 1;
for (i = s.length() - 1; i >= 0; i--)
{
result += ((s[i] - '0') * p); //数字字符转成字符
p *= 2;
}
return result;
}
//整型转二进制
string intToBinary(int i)
{
int k = 0;
string result;
while (k < 4) //此处，处理进入S盒后取出的数据转为2进制，此处最多用4bit
{
if (i)
{
result += ((i % 2) + '0');
i /= 2;
}
else result += '0';
k++;
}
reverse(result.begin(), result.end());
return result;
}

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//f函数
string f(string right, string k) //其中right 为明文的右分支R0--R16，k当前加密轮密钥
{
int i, temp;
string extendBinary, result, b0; //extendBinary用来存放E扩展32bit~48bit的内容
string b[8], row, col;
string b8, pb;
for (i = 0; i < 48; i++)
{
extendBinary += right[extendTable[i] - 1];
}
b0 = xorAB(extendBinary, k);//扩展后的内容与此轮密钥异或操作并将结果存入b0中
for (i = 0; i < 8; i++) //将b0的内容分成八份，每份六bit，为进入S盒做准备
{
b[i] = b0.substr(i * 6, 6);
}
for (i = 0; i < 8; i++)
{
//6bit的第一位和第六位作为行坐标
row = b[i].substr(0, 1) + b[i].substr(5, 1);
//6bit的第二至五位作为纵坐标
col = b[i].substr(1, 4);
//进行查表
temp = sBox[i][binaryToInt(row)][binaryToInt(col)];
//转到b8中合并----48bit压缩到32bit
b[i] = intToBinary(temp);
b8 += b[i];
}
//进行P盒置换
for (i = 0; i < 32; i++)
{
pb += b8[pTable[i] - 1];
}
//f轮函数结束，返回pb
return pb;
}

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void miyao()
{
int i, j;
string miyao, miyaoBinary, pc1MiyaoBinary;
string c[17], d[17], temp, pc2Temp;
cout << "请输入密钥：";
while (cin >> miyao)
{
if (miyao.length() < 9) break;
else cout << "密钥不能超过8位，请重新输入：";
}
for (i = 0; i < miyao.length(); i++)
{
miyaoBinary += charToBinary(miyao[i]);
}
//密钥长度不足64bit，补'0'
//64位中，只有56位参与运算，其中8位为校验位
while (miyaoBinary.length() % 64 != 0)
{
miyaoBinary += '0';
}
//从64bit密钥中依据PC-1盒子取出56bit
for (i = 0; i < 56; i++)
{
pc1MiyaoBinary += miyaoBinary[pc1Table[i] - 1];
}
//56bit分成左右两部分
// 左右两部分都为28bit
c[0] = pc1MiyaoBinary.substr(0, 28);
d[0] = pc1MiyaoBinary.substr(28, 28);
产生16轮加密需要的密钥，存入全局变量k[]中
for (i = 1; i <= 16; i++)
{
//根据循环移位表，确定生成该轮密钥移位数目
c[i] = c[i - 1].substr(loopTable[i - 1], 28 - loopTable[i - 1]) + c[i - 1].substr(0, loopTable[i - 1]);
d[i] = d[i - 1].substr(loopTable[i - 1], 28 - loopTable[i - 1]) + d[i - 1].substr(0, loopTable[i - 1]);
//移位后将其合并
temp = c[i] + d[i];
pc2Temp = "";
// 通过PC2成为48bit密钥
for (j = 0; j < 48; j++)
{
pc2Temp += temp[pc2Table[j] - 1];
}
k[i - 1] = pc2Temp;//从1`16
}
}

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#pragma once
#include<iostream>
#include<cstdio>
#include<string>
#include<algorithm>
using namespace std;
//字符转二进制
string charToBinary(char c);
//二进制转整型
int binaryToInt(string s);
//整型转二进制
string intToBinary(int i);
//异或运算
string xorAB(string a, string b);
//f函数
string f(string right, string k);
//明文/密文处理
string wen(string wenBinary[], int num);
//密钥处理
void miyao();
//DES 算法测试
void DES();

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#define _CRT_SECURE_NO_WARNINGS 1#include "DES.h"//进行标志选择int flag;string k[16]; //16轮密钥存储//PC1选位表int pc1Table[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};//左移位数表int loopTable[16] ={ 1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1};//PC2选位表int pc2Table[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IP表int ipTable[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扩展置换表int extendTable[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};//S盒int sBox[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};//P换位表int pTable[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};//逆置换IP^-1表int ipReverseTable[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};//将输入的东西全部看成字符//字符转二进制
string charToBinary(char c)
{
int i, b = c, k = 0, flag = 0;
string result;
//负数就是中文字符
if (b < 0)
{
b = -b;
flag = 1;
}
//英文字符转换成ASCII的倒序，所以后面需要进行逆序
while (k < 8) //这里的8表示char是1个字节=8bit
{
if (b) //这里将ASCII里的字符转换为二进制
{
result += ((b % 2) + '0'); // 其中这里+'0',表示将数字转换为字符
b /= 2;
}
else result += '0';
k++;
}
//汉字字符处理
if (flag)//判断是否为汉字
{
for (i = 0; i < result.length(); i++) //此时因为是负数，源码、反码、补码不相等，需要置换
{
if (result[i] == '0') result[i] = '1'; // 反码：最高最不变，其它的0->1,,1->0
else result[i] = '0';
}
for (i = 0; result[i] != '0'; i++)
{
result[i] = '0'; //补码：反码加+1
}
result[i] = '1';
}
reverse(result.begin(), result.end()); //将结果逆序，成为最终的二进制
return result;
}
//二进制转整型
int binaryToInt(string s)
{
int i, result = 0, p = 1;
for (i = s.length() - 1; i >= 0; i--)
{
result += ((s[i] - '0') * p); //数字字符转成字符
p *= 2;
}
return result;
}
//整型转二进制
string intToBinary(int i)
{
int k = 0;
string result;
while (k < 4) //此处，处理进入S盒后取出的数据转为2进制，此处最多用4bit
{
if (i)
{
result += ((i % 2) + '0');
i /= 2;
}
else result += '0';
k++;
}
reverse(result.begin(), result.end());
return result;
}//异或运算string xorAB(string a, string b){ int i; string result; for (i = 0; i < a.length(); i++) { //+'0':表示数字转化为数字字符 result += (((a[i] - '0') ^ (b[i] - '0')) + '0'); // -'0':表示数字字符转化为数字 } return result;}//f函数
string f(string right, string k) //其中right 为明文的右分支R0--R16，k当前加密轮密钥
{
int i, temp;
string extendBinary, result, b0; //extendBinary用来存放E扩展32bit~48bit的内容
string b[8], row, col;
string b8, pb;
for (i = 0; i < 48; i++)
{
extendBinary += right[extendTable[i] - 1];
}
b0 = xorAB(extendBinary, k);//扩展后的内容与此轮密钥异或操作并将结果存入b0中
for (i = 0; i < 8; i++) //将b0的内容分成八份，每份六bit，为进入S盒做准备
{
b[i] = b0.substr(i * 6, 6);
}
for (i = 0; i < 8; i++)
{
//6bit的第一位和第六位作为行坐标
row = b[i].substr(0, 1) + b[i].substr(5, 1);
//6bit的第二至五位作为纵坐标
col = b[i].substr(1, 4);
//进行查表
temp = sBox[i][binaryToInt(row)][binaryToInt(col)];
//转到b8中合并----48bit压缩到32bit
b[i] = intToBinary(temp);
b8 += b[i];
}
//进行P盒置换
for (i = 0; i < 32; i++)
{
pb += b8[pTable[i] - 1];
}
//f轮函数结束，返回pb
return pb;
}//明文/密文处理string wen(string wenBinary[], int num)
{
int i, j;
string ipWenBinary[100]; //保存明文
string left[17], right[17], temp, result; //分为左右两个分支
for (i = 0; i < num; i++)
{
temp = ""; //一个暂存明文的字符串
//进行IP置换
for (j = 0; j < 64; j++) //明文为64bit
{
temp += wenBinary[i][ipTable[j] - 1];
}
ipWenBinary[i] = temp;
}
//进行左右分支，分为left:L0,,,right:R0
for (i = 0; i < num; i++)
{
left[0] = ipWenBinary[i].substr(0, 32);
right[0] = ipWenBinary[i].substr(32, 32);
//
for (j = 0; j < 16; j++) //进行16次循环
{
left[j + 1] = right[j]; // left: L1 = R0
//加密和解密的区别
// flag 为全局变量
if (flag == 1) // flage = 1进行加密，否则进行解密
right[j + 1] = xorAB(left[j], f(right[j], k[j]));
else
//倒着进行解密
right[j + 1] = xorAB(left[j], f(right[j], k[15 - j]));
}
temp = right[j] + left[j]; //经过16轮加密/解密，将左右32bit合并
//将加密后的密文进行最后的置换，实际上和初始置换是对称的~！
//每块的加密结果都和在result中,加密可以直接输出比特流
// 进行IP的逆置换
for (j = 0; j < 64; j++)
{
result += temp[ipReverseTable[j] - 1];
}
}
//解密结果输出的是字符
if (flag == 2)
{
string ch;
for (i = 0; i < num * 8; i++) //一个模块是8个bit
{
ch += binaryToInt(result.substr(8 * i, 8)); //每8bit进行一次二进制转整型
}
result = ch;
}
return result;
}//密钥处理void miyao()
{
int i, j;
string miyao, miyaoBinary, pc1MiyaoBinary;
string c[17], d[17], temp, pc2Temp;
cout << "请输入密钥：";
while (cin >> miyao)
{
if (miyao.length() < 9) break;
else cout << "密钥不能超过8位，请重新输入：";
}
for (i = 0; i < miyao.length(); i++)
{
miyaoBinary += charToBinary(miyao[i]);
}
//密钥长度不足64bit，补'0'
//64位中，只有56位参与运算，其中8位为校验位
while (miyaoBinary.length() % 64 != 0)
{
miyaoBinary += '0';
}
//从64bit密钥中依据PC-1盒子取出56bit
for (i = 0; i < 56; i++)
{
pc1MiyaoBinary += miyaoBinary[pc1Table[i] - 1];
}
//56bit分成左右两部分
// 左右两部分都为28bit
c[0] = pc1MiyaoBinary.substr(0, 28);
d[0] = pc1MiyaoBinary.substr(28, 28);
产生16轮加密需要的密钥，存入全局变量k[]中
for (i = 1; i <= 16; i++)
{
//根据循环移位表，确定生成该轮密钥移位数目
c[i] = c[i - 1].substr(loopTable[i - 1], 28 - loopTable[i - 1]) + c[i - 1].substr(0, loopTable[i - 1]);
d[i] = d[i - 1].substr(loopTable[i - 1], 28 - loopTable[i - 1]) + d[i - 1].substr(0, loopTable[i - 1]);
//移位后将其合并
temp = c[i] + d[i];
pc2Temp = "";
// 通过PC2成为48bit密钥
for (j = 0; j < 48; j++)
{
pc2Temp += temp[pc2Table[j] - 1];
}
k[i - 1] = pc2Temp;//从1`16
}
}// 输出函数void DES(){ int i, j, num; string wenString, wenBinary[100], temp; while (1) { cout << "----------------------------------------------" << endl; cout << "***** 请选择所需功能： *****" << endl; cout << "***** 1. 加密 *****" << endl; cout << "***** 2. 解密 *****" << endl; cout << "***** 0.退出程序 *****"<< endl; cout << "----------------------------------------------" << endl; cin >> flag; if (!flag) break; else if ((flag != 1) && (flag != 2)) { cout << "输入不正当，请重新输入！" << endl << endl; continue; } num = 0; miyao(); getchar(); switch (flag) { case 1: cout << "请输入明文："; getline(cin, wenString);//输入明文 //将明文转成二进制 for (i = 0; i < wenString.length(); i++) { temp += charToBinary(wenString[i]); //字符每满8bit为一组，最后一组可以不满8bit，后面会补0 if (((i + 1) % 8 == 0) || (((i + 1) % 8 != 0) && (i == wenString.length() - 1))) { wenBinary[num++] = temp; temp = ""; } } //最后一组不满64位就补零，补的零，肯定是八的整数倍，二进制00000000为null空字符，不输出 while (wenBinary[num - 1].length() % 64 != 0) { wenBinary[num - 1] += '0'; } cout << "加密结果为（二进制）：" << wen(wenBinary, num) << endl << endl; break; case 2: cout << "请输入密文（二进制）："; cin >> wenString; for (i = 0; i * 64 < wenString.length(); i++) { wenBinary[num++] = wenString.substr(i * 64, 64); } cout << "解密结果为（字符）：" << wen(wenBinary, num) << endl << endl; break; case 3: exit(0); default : cout << "输入错误，请重新输入" << endl; } }}

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#define _CRT_SECURE_NO_WARNINGS 1
#include "DES.h"
void menu()
{
cout << "**********************************************" << endl;
cout << "**********************************************" << endl;
cout << "***********欢迎来到DES加密测试系统************" << endl;
cout << "**********************************************" << endl;
cout << "**********************************************" << endl;
}
int main()
{
menu();
DES();
return 0;
}

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