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DES加密算法实现（加解密代码C++）_des算法代码

作者：IT小白 | 2024-07-25 19:51:06

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des算法代码

参考博客：加密算法------DES加密算法详解_柯南的博客-CSDN博客_des加密算法

一、算法流程

 二、数据定义

数据名称

数据类型

数据描述

ExchangeRules

Int[56]

交换规则表

ShiftTable

Int[16]

移位表

PC_2

Int[48]

PC-2置换规则表

IP

Int[64]

IP置换规则表

E

Int[48]

E置换规则表

SBox

Int [8][4][16]

S盒置换规则表

P

Int[32]

P置换规则表

IP_1

Int[64]

IP_1置换规则表

三、方法说明 

方法名称

返回值类型

参数类型

方法描述

int2BinString

string

int

int转四位string  +  int十进制转string二进制

hexToTwo

string

string

string十六进制转string二进制

binToDec

int

string

string二进制转int十进制

str2Dec

int

string

01字符转十进制

Bin2Hex

string

string

64位密文转十六进制

exchange

string

String, int[], int

利用交换表进行置换

circleMove

string

String, int

依据移位表进行移位

spiltShift

string

String, int

左右两部分移位

XOR

string

String, string

string 异或

SBoxWork

string

String, int[][][]

S盒工作

四、效果呈现

五、代码实现（仅加密）

  1. #include <iostream>
  2. #include <bitset>
  3. #include <string>
  4. #include <cmath>
  5. #include<stdlib.h>
  6. using namespace std;
  7. /** 
  8. *函数声明 
  9. */
  10. string hexToTwo(string str);  //十六进制转二进制
  11.  
  12. string int2BinString(int n);  //int转四位string
  13.  
  14. string exchange(string str, int rule[], int x);  //置换
  15.  
  16. string circleMove(string str, int j);  //单步移位
  17.  
  18. string spiltShift(string str, int j);  // 左右分别移位
  19.  
  20. string XOR(string str1, string str2);  //异或
  21.  
  22. string SBoxWork(string str, int SBox[][4][16]);  //S盒工作
  23.  
  24. int binToDec(string bin);  //二进制转十进制
  25.  
  26. string Bin2Hex(string strBin);   //二进制转十六进制
  27.  
  28. int str2Dec(string str);
  29.  
  30. /**
  31. *全局变量
  32. */
  33. const int Key_SIZE = 16;
  34.  
  35. /**
  36. *8张表
  37. */
  38. //交换规则表（8*7）
  39. const int ExchangeRules_SIZE = 56;
  40. int ExchangeRules[56] = {
  41. 57, 49, 41, 33, 25, 17,  9,
  42.  1, 58, 50, 42, 34, 26, 18,
  43. 10,  2, 59, 51, 43, 35, 27,
  44. 19, 11,  3, 60, 52, 44, 36,
  45. 63, 55, 47, 39, 31, 23, 15,
  46.  7, 62, 54, 46, 38, 30, 22,
  47. 14,  6, 61, 53, 45, 37, 29,
  48. 21, 13,  5, 28, 20, 12,  4
  49. };
  50. //移位表
  51. const int ShiftTable_SIZE = 16;
  52. int ShiftTable[16] = {
  53. 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1
  54. };
  55. //PC-2（8*6）
  56. const int PC_2_SIZE = 48;
  57. int PC_2[48] = {
  58. 14, 17, 11, 24,  1,  5,
  59.  3, 28, 15,  6, 21, 10,
  60. 23, 19, 12,  4, 26,  8,
  61. 16,  7, 27, 20, 13,  2,
  62. 41, 52, 31, 37, 47, 55,
  63. 30, 40, 51, 45, 33, 48,
  64. 44, 49, 39, 56, 34, 53,
  65. 46, 42, 50, 36, 29, 32
  66. };
  67. //IP（8*8）
  68. const int IP_SIZE = 64;
  69. int IP[64] = {
  70. 58, 50, 42, 34, 26, 18, 10,  2,
  71. 60, 52, 44, 36, 28, 20, 12,  4,
  72. 62, 54, 46, 38, 30, 22, 14,  6,
  73. 64, 56, 48, 40, 32, 24, 16,  8,
  74. 57, 49, 41, 33, 25, 17,  9,  1,
  75. 59, 51, 43, 35, 27, 19, 11,  3,
  76. 61, 53, 45, 37, 29, 21, 13,  5,
  77. 63, 55, 47, 39, 31, 23, 15,  7
  78. };
  79. //扩展置换E（8*6）
  80. const int E_SIZE = 48;
  81. int E[48] = {
  82. 32,  1,  2,  3,  4,  5,
  83.  4,  5,  6,  7,  8,  9,
  84.  8,  9, 10, 11, 12, 13,
  85. 12, 13, 14, 15, 16, 17,
  86. 16, 17, 18, 19, 20, 21,
  87. 20, 21, 22, 23, 24, 25,
  88. 24, 25, 26, 27, 28, 29,
  89. 28, 29, 30, 31, 32,  1
  90. };
  91.  //S盒
  92.  int SBox[8][4][16] = {
  93. 	{
  94. 		{14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7},
  95. 		{0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8},
  96. 		{4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0},
  97. 		{15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13}
  98. 	},
  99. 	{
  100. 		{15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10},
  101. 		{3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5},
  102. 		{0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15},
  103. 		{13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9}
  104. 	},
  105. 	{
  106. 		{10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8},
  107. 		{13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1},
  108. 		{13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7},
  109. 		{1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12}
  110. 	},
  111. 	{
  112. 		{7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15},
  113. 		{13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9},
  114. 		{10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4},
  115. 		{3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14}
  116. 	},
  117. 	{
  118. 		{2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9},
  119. 		{14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6},
  120. 		{4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14},
  121. 		{11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3}
  122. 	},
  123. 	{
  124. 		{12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11},
  125. 		{10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8},
  126. 		{9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6},
  127. 		{4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13}
  128. 	},
  129. 	{
  130. 		{4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1},
  131. 		{13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6},
  132. 		{1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2},
  133. 		{6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12}
  134. 	},
  135. 	{
  136. 		{13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7},
  137. 		{1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2},
  138. 		{7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8},
  139. 		{2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11}
  140. 	}
  141. };
  142. //P盒（8*4）
  143. const int P_SIZE = 32;
  144. int P[32] = {
  145. 16,  7, 20, 21,
  146. 29, 12, 28, 17,
  147.  1, 15, 23, 26,
  148.  5, 18, 31, 10,
  149.  2,  8, 24, 14,
  150. 32, 27,  3,  9,
  151. 19, 13, 30,  6,
  152. 22, 11,  4, 25
  153. };
  154. //IP-1（8*8）
  155. const int IP_1_SIZE = 64;
  156. int IP_1[64] = {
  157. 40, 8, 48, 16, 56, 24, 64, 32,
  158. 39, 7, 47, 15, 55, 23, 63, 31,
  159. 38, 6, 46, 14, 54, 22, 62, 30,
  160. 37, 5, 45, 13, 53, 21, 61, 29,
  161. 36, 4, 44, 12, 52, 20, 60, 28,
  162. 35, 3, 43, 11, 51, 19, 59, 27,
  163. 34, 2, 42, 10, 50, 18, 58, 26,
  164. 33, 1, 41,  9, 49, 17, 57, 25
  165. };
  166. int main()
  167. {
  168.     /**
  169.     *初始条件
  170.      **/
  171.  
  172.     /* 输入明文MingWen（十六进制），密钥Key（十六进制） */
  173.     string MingWen ;
  174.     string Key;
  175.  
  176.     cout<<"Welcome to DES encryption system! "<<endl;
  177.     cout<<"Please enter MingWen: "<<endl;
  178.     cin>>MingWen;
  179.     cout<<"Please enter your Key: "<<endl;
  180.     cin>>Key;
  181.     string M = hexToTwo(MingWen);
  182.     string K = hexToTwo(Key);
  183.  
  184.     /**
  185.     *处理密钥，生成16个子密钥 *
  186.     */
  187.  
  188.     /* 利用规则交换表（8*7）将K转换成 K0
  189.        K0(56位) = C0(28位) + D0(28位) */
  190.  
  191.     string KKK = exchange(K, ExchangeRules, ExchangeRules_SIZE);
  192.  
  193.     /* 利用移位表转换得C1D1----C16D16,存入K_arr */
  194.  
  195.     int i = 0;
  196.     string K_arr[Key_SIZE+1];
  197.     K_arr[0] = KKK;
  198.     for(i=1; i<=Key_SIZE; i++){
  199.         K_arr[i] = spiltShift(K_arr[i-1], ShiftTable[i-1]);
  200.     }
  201.  
  202.  
  203.     /* Kn（48位）= PC-2（8*6）处理 CnDn得16个子密钥，存入Key_arr */
  204.  
  205.     string Key_arr[Key_SIZE];
  206.     for(i=0; i<Key_SIZE; i++){
  207.         Key_arr[i] = exchange(K_arr[i+1], PC_2, PC_2_SIZE);
  208.     }
  209.  
  210.     /**
  211.     * 用子密钥对明文加密
  212.     **/
  213.  
  214.     /* 通过IP（8*8）处理M得L0（32位）  R0（32位） */
  215.     string IP_M = exchange(M, IP, IP_SIZE);
  216.  
  217.     /* Ln= R(n-1); Rn= L(n-1) + f(R(n- 1); Kn)迭代16次 */
  218.     string L[Key_SIZE+1];
  219.     string R[Key_SIZE+1];
  220.     L[0] = IP_M.substr(0, M.length()/2);
  221.     R[0] = IP_M.substr(M.length()/2);
  222.     string it = "";
  223.     for(i=1; i<=Key_SIZE; i++){
  224.  
  225.         //将R0通过扩展置换E（8*6）从32位扩展到48位
  226.         it = exchange(R[i-1], E, E_SIZE);
  227.  
  228.         //R0（48位）与 K1异或得E0（48位）
  229.         it = XOR(it, Key_arr[i-1]);
  230.  
  231.         //将E0（48位）通过S盒转换成32位
  232.         it = SBoxWork(it, SBox);
  233.  
  234.          //P盒（8*4）置换，得P0
  235.         it = exchange(it, P, P_SIZE);
  236.  
  237.         //P0与L0进行异或，得J0
  238.         it = XOR(it, L[i-1]);
  239.  
  240.         //左右交换位置，即R1 = J0; L1 = R0
  241.         L[i] = R[i-1];
  242.         R[i] = it;
  243.     }
  244.  
  245.  
  246.     /* 对R16 L16进行一次IP-1（8*8）排序得密文 */
  247.     string res = "";
  248.     res += R[16];
  249.     res += L[16];
  250.     string finalRes = Bin2Hex(exchange(res, IP_1, IP_1_SIZE));
  251.  
  252.     cout<<"DES encryption results are as follows: "<<endl;
  253.     cout<<finalRes<<endl;
  254.     return 0;
  255. }
  256.  
  257. /**
  258. *int转四位string  +  int十进制转string二进制
  259. **/
  260. string int2BinString(int n) {
  261.     bitset<4> bit(n);
  262.     return bit.to_string();
  263. }
  264. /**
  265. *string十六进制转string二进制
  266. **/
  267. string hexToTwo(string str){
  268.     string twoBin = "";
  269.     int i;
  270.     for(i=0; i<16; i++){
  271.         if(str[i]>='0'&&str[i]<='9')
  272.             twoBin.append(int2BinString(str[i]));
  273.         else if(str[i]>='A'&&str[i]<='Z')
  274.             twoBin.append(int2BinString(str[i]-'A'+10));
  275.         else if(str[i]>='a'&&str[i]<='z')
  276.             twoBin.append(int2BinString(str[i]-'a'+10));
  277.  
  278.     }
  279.     return twoBin;
  280. }
  281. /**
  282. * string二进制转int十进制
  283. **/
  284. int binToDec(string bin){
  285.     int sum = 0;
  286.     for(int i=0; i<bin.size(); i++){
  287.         if(bin[i]=='0' || bin[i]=='1'){
  288.             sum += (bin[i]-'0') * pow(2, bin.size()-i-1);
  289.         }else{
  290.             cout<<"非法二进制字符！"<<endl;
  291.             return 0;
  292.         }
  293.     }
  294.     return sum;
  295. }
  296.  
  297. /**
  298. * 01字符转十进制
  299. **/
  300. int str2Dec(string str) {
  301.     bitset<64> bst(str);
  302.     return (int)bst.to_ulong();
  303. }
  304. /**
  305. * 64位密文转十六进制
  306. **/
  307. //Bin2Hex转换表
  308. const static string Bin_Hex[16] {
  309.     "0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F"
  310. };
  311. string Bin2Hex(string strBin) {
  312.     string hex;
  313.     int a = strBin.length()/4;
  314.     string trans;
  315.     for(int i = 0; i < a; i++) {
  316.         trans.clear();
  317.         trans = strBin.substr(i*4, 4);
  318.         hex += Bin_Hex[str2Dec(trans)];
  319.     }
  320.     return hex;
  321. }
  322.  
  323. /**
  324. *利用交换表进行置换
  325. **/
  326. string exchange(string str, int rule[], int x){
  327.     string exchangedStr = "";
  328.     int i, temp;
  329.     for(i=0; i<x; i++){
  330.         temp = rule[i]-1;
  331.         exchangedStr.append(1, str[temp]);
  332.     }
  333.     return exchangedStr;
  334. }
  335.  
  336. /**
  337. *依据移位表进行移位
  338. **/
  339. string circleMove(string str, int j){
  340.  
  341.     string targetString = "";
  342.     targetString.append(str.substr(j));
  343.     targetString.append(str.substr(0, j));
  344.     return targetString;
  345. }
  346. /**
  347. *左右两部分移位
  348. **/
  349. string spiltShift(string str, int j){
  350.     string targetStr = "";
  351.     string leftString = str.substr(0, str.length()/2);
  352.     string rightString = str.substr(str.length()/2);
  353.     targetStr.append(circleMove(leftString, j));
  354.     targetStr.append(circleMove(rightString, j));
  355.     return targetStr;
  356. }
  357. /**
  358. * string 异或
  359. **/
  360. string XOR(string str1, string str2){
  361.     string targetString = "";
  362.     for(int j=0; j<str1.length(); j++){
  363.         targetString += ((str1[j] - '0') ^ (str2[j] - '0')) + '0';
  364.  
  365.     }
  366.     return targetString;
  367. }
  368. /**
  369. * S盒工作
  370. **/
  371. string SBoxWork(string str, int SBox[][4][16]){
  372.     string targetString = "";
  373.     string temp = "";
  374.     string x = "", y = "";
  375.     int col = 0, row = 0;
  376.     for(int i=0; i<str.size()/6; i++){
  377.         temp = str.substr(6*i, 6);
  378.         x = temp.substr(0, 1)+temp.substr(5, 1);
  379.         y = temp.substr(1, 4);
  380.         row = binToDec(x);
  381.         col = binToDec(y);
  382.         targetString.append(int2BinString(SBox[i][row][col]));
  383.     }
  384.     return targetString;
  385. }
  386.

六、代码实现（加解密全）

  1. #include <iostream>
  2. #include <bitset>
  3. #include <string>
  4. #include <cmath>
  5. #include<stdlib.h>
  6. #include <cstdlib>
  7. using namespace std;
  8. /**
  9. *函数声明
  10. */
  11. string hexToTwo(string str);  //十六进制转二进制
  12.  
  13. string int2BinString(int n);  //int转四位string
  14.  
  15. string exchange(string str, int rule[], int x);  //置换
  16.  
  17. string circleMove(string str, int j);  //单步移位
  18.  
  19. string spiltShift(string str, int j);  // 左右分别移位
  20.  
  21. string XOR(string str1, string str2);  //异或
  22.  
  23. string SBoxWork(string str, int SBox[][4][16]);  //S盒工作
  24.  
  25. int binToDec(string bin);  //二进制转十进制
  26.  
  27. string Bin2Hex(string strBin);   //二进制转十六进制
  28.  
  29. int str2Dec(string str);  // string字符串转十进制
  30.  
  31. void printMenu();  //打印功能菜单
  32.  
  33. void controller();  //功能控制器
  34.  
  35. void encryption(); //加密
  36.  
  37. void decryption(); //解密
  38.  
  39. /**
  40. *全局变量
  41. */
  42. const int Key_SIZE = 16;
  43.  
  44. /**
  45. *8张表
  46. */
  47. //交换规则表（8*7）
  48. const int ExchangeRules_SIZE = 56;
  49. int ExchangeRules[56] =
  50. {
  51.     57, 49, 41, 33, 25, 17,  9,
  52.     1, 58, 50, 42, 34, 26, 18,
  53.     10,  2, 59, 51, 43, 35, 27,
  54.     19, 11,  3, 60, 52, 44, 36,
  55.     63, 55, 47, 39, 31, 23, 15,
  56.     7, 62, 54, 46, 38, 30, 22,
  57.     14,  6, 61, 53, 45, 37, 29,
  58.     21, 13,  5, 28, 20, 12,  4
  59. };
  60. //移位表
  61. const int ShiftTable_SIZE = 16;
  62. int ShiftTable[16] =
  63. {
  64.     1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1
  65. };
  66. //PC-2（8*6）
  67. const int PC_2_SIZE = 48;
  68. int PC_2[48] =
  69. {
  70.     14, 17, 11, 24,  1,  5,
  71.     3, 28, 15,  6, 21, 10,
  72.     23, 19, 12,  4, 26,  8,
  73.     16,  7, 27, 20, 13,  2,
  74.     41, 52, 31, 37, 47, 55,
  75.     30, 40, 51, 45, 33, 48,
  76.     44, 49, 39, 56, 34, 53,
  77.     46, 42, 50, 36, 29, 32
  78. };
  79. //IP（8*8）
  80. const int IP_SIZE = 64;
  81. int IP[64] =
  82. {
  83.     58, 50, 42, 34, 26, 18, 10,  2,
  84.     60, 52, 44, 36, 28, 20, 12,  4,
  85.     62, 54, 46, 38, 30, 22, 14,  6,
  86.     64, 56, 48, 40, 32, 24, 16,  8,
  87.     57, 49, 41, 33, 25, 17,  9,  1,
  88.     59, 51, 43, 35, 27, 19, 11,  3,
  89.     61, 53, 45, 37, 29, 21, 13,  5,
  90.     63, 55, 47, 39, 31, 23, 15,  7
  91. };
  92. //扩展置换E（8*6）
  93. const int E_SIZE = 48;
  94. int E[48] =
  95. {
  96.     32,  1,  2,  3,  4,  5,
  97.     4,  5,  6,  7,  8,  9,
  98.     8,  9, 10, 11, 12, 13,
  99.     12, 13, 14, 15, 16, 17,
  100.     16, 17, 18, 19, 20, 21,
  101.     20, 21, 22, 23, 24, 25,
  102.     24, 25, 26, 27, 28, 29,
  103.     28, 29, 30, 31, 32,  1
  104. };
  105. //S盒
  106. int SBox[8][4][16] =
  107. {
  108.     {
  109.         {14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7},
  110.         {0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8},
  111.         {4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0},
  112.         {15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13}
  113.     },
  114.     {
  115.         {15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10},
  116.         {3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5},
  117.         {0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15},
  118.         {13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9}
  119.     },
  120.     {
  121.         {10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8},
  122.         {13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1},
  123.         {13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7},
  124.         {1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12}
  125.     },
  126.     {
  127.         {7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15},
  128.         {13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9},
  129.         {10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4},
  130.         {3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14}
  131.     },
  132.     {
  133.         {2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9},
  134.         {14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6},
  135.         {4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14},
  136.         {11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3}
  137.     },
  138.     {
  139.         {12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11},
  140.         {10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8},
  141.         {9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6},
  142.         {4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13}
  143.     },
  144.     {
  145.         {4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1},
  146.         {13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6},
  147.         {1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2},
  148.         {6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12}
  149.     },
  150.     {
  151.         {13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7},
  152.         {1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2},
  153.         {7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8},
  154.         {2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11}
  155.     }
  156. };
  157. //P盒（8*4）
  158. const int P_SIZE = 32;
  159. int P[32] =
  160. {
  161.     16,  7, 20, 21,
  162.     29, 12, 28, 17,
  163.     1, 15, 23, 26,
  164.     5, 18, 31, 10,
  165.     2,  8, 24, 14,
  166.     32, 27,  3,  9,
  167.     19, 13, 30,  6,
  168.     22, 11,  4, 25
  169. };
  170. //IP-1（8*8）
  171. const int IP_1_SIZE = 64;
  172. int IP_1[64] =
  173. {
  174.     40, 8, 48, 16, 56, 24, 64, 32,
  175.     39, 7, 47, 15, 55, 23, 63, 31,
  176.     38, 6, 46, 14, 54, 22, 62, 30,
  177.     37, 5, 45, 13, 53, 21, 61, 29,
  178.     36, 4, 44, 12, 52, 20, 60, 28,
  179.     35, 3, 43, 11, 51, 19, 59, 27,
  180.     34, 2, 42, 10, 50, 18, 58, 26,
  181.     33, 1, 41,  9, 49, 17, 57, 25
  182. };
  183. int main()
  184. {
  185.     printMenu();
  186.     return 0;
  187. }
  188. /**
  189. *打印功能菜单
  190. **/
  191. void printMenu()
  192. {
  193.     cout<<"Welcome to DES encryption system! "<<endl;
  194.     cout<<"The following are the functions of the system: "<<endl;
  195.     cout<<"1. encryption"<<endl;
  196.     cout<<"2. decryption"<<endl;
  197.     cout<<"3. exit"<<endl;
  198.     controller();
  199. }
  200. /**
  201. *功能控制器
  202. **/
  203. void controller()
  204. {
  205.     cout<<"Please select the action you want to take: "<<endl;
  206.  
  207.     int choice;
  208.     cin>>choice;
  209.  
  210.     if(choice == 1) encryption();
  211.     else if(choice == 2) decryption();
  212.     else if(choice == 3) {
  213.         cout<<"Looking forward to your use again!"<<endl;
  214.         cout<<"Bye Bye!"<<endl;
  215.         exit(0);
  216.     }
  217.     else
  218.     {
  219.         cout<<"Error! This option is not recognized. Please reselect it!"<<endl;
  220.         controller();
  221.     }
  222. }
  223.  
  224. /**
  225. *加密
  226. **/
  227. void encryption()
  228. {
  229.     /**
  230.     *初始条件
  231.     **/
  232.  
  233.     /* 输入明文MingWen（十六进制），密钥Key（十六进制） */
  234.     string MingWen ;
  235.     string Key;
  236.  
  237.     cout<<"Please enter MingWen: "<<endl;
  238.     cin>>MingWen;
  239.     cout<<"Please enter your Key: "<<endl;
  240.     cin>>Key;
  241.  
  242.     string M = hexToTwo(MingWen);
  243.     string K = hexToTwo(Key);
  244.  
  245.     /**
  246.     *处理密钥，生成16个子密钥 *
  247.     */
  248.  
  249.     /* 利用规则交换表（8*7）将K转换成 K0 ;  K0(56位) = C0(28位) + D0(28位) */
  250.  
  251.     string KKK = exchange(K, ExchangeRules, ExchangeRules_SIZE);
  252.  
  253.     /* 利用移位表转换得C1D1----C16D16,存入K_arr */
  254.  
  255.     int i = 0;
  256.     string K_arr[Key_SIZE+1];
  257.     K_arr[0] = KKK;
  258.     for(i=1; i<=Key_SIZE; i++)
  259.     {
  260.         K_arr[i] = spiltShift(K_arr[i-1], ShiftTable[i-1]);
  261.     }
  262.  
  263.  
  264.     /* Kn（48位）= PC-2（8*6）处理 CnDn得16个子密钥，存入Key_arr */
  265.  
  266.     string Key_arr[Key_SIZE];
  267.     for(i=0; i<Key_SIZE; i++)
  268.     {
  269.         Key_arr[i] = exchange(K_arr[i+1], PC_2, PC_2_SIZE);
  270.     }
  271.  
  272.     /**
  273.     * 用子密钥对明文加密
  274.     **/
  275.  
  276.     /* 通过IP（8*8）处理M得L0（32位）  R0（32位） */
  277.     string IP_M = exchange(M, IP, IP_SIZE);
  278.  
  279.     /* Ln= R(n-1); Rn= L(n-1) + f(R(n- 1); Kn)迭代16次 */
  280.     string L[Key_SIZE+1];
  281.     string R[Key_SIZE+1];
  282.     L[0] = IP_M.substr(0, M.length()/2);
  283.     R[0] = IP_M.substr(M.length()/2);
  284.     string it = "";
  285.     for(i=1; i<=Key_SIZE; i++)
  286.     {
  287.  
  288.         //将R0通过扩展置换E（8*6）从32位扩展到48位
  289.         it = exchange(R[i-1], E, E_SIZE);
  290.  
  291.         //R0（48位）与 K1异或得E0（48位）
  292.         it = XOR(it, Key_arr[i-1]);
  293.  
  294.         //将E0（48位）通过S盒转换成32位
  295.         it = SBoxWork(it, SBox);
  296.  
  297.         //P盒（8*4）置换，得P0
  298.         it = exchange(it, P, P_SIZE);
  299.  
  300.         //P0与L0进行异或，得J0
  301.         it = XOR(it, L[i-1]);
  302.  
  303.         //左右交换位置，即R1 = J0; L1 = R0
  304.         L[i] = R[i-1];
  305.         R[i] = it;
  306.     }
  307.  
  308.  
  309.     /* 对R16 L16进行一次IP-1（8*8）排序得密文 */
  310.     string res = "";
  311.     res += R[16];
  312.     res += L[16];
  313.     string finalRes = Bin2Hex(exchange(res, IP_1, IP_1_SIZE));
  314.  
  315.     cout<<"DES encryption results are as follows: "<<endl;
  316.     cout<<finalRes<<endl;
  317.     cout<<"------------------------"<<endl;
  318.     printMenu();
  319. }
  320.  
  321. /**
  322. *解密
  323. **/
  324. void decryption()
  325. {
  326.     string MiWen;
  327.     string Key;
  328.  
  329.     cout<<"Please enter MiWen: "<<endl;
  330.     cin>>MiWen;
  331.     cout<<"Please enter your Key: "<<endl;
  332.     cin>>Key;
  333.  
  334.     string M = hexToTwo(MiWen);
  335.     string K = hexToTwo(Key);
  336.  
  337.     /**
  338.     *处理密钥，生成16个子密钥 *
  339.     */
  340.  
  341.     /* 利用规则交换表（8*7）将K转换成 K0 ; K0(56位) = C0(28位) + D0(28位) */
  342.  
  343.     string KKK = exchange(K, ExchangeRules, ExchangeRules_SIZE);
  344.  
  345.     /* 利用移位表转换得C1D1----C16D16,存入K_arr */
  346.  
  347.     int i = 0;
  348.     string K_arr[Key_SIZE+1];
  349.     K_arr[0] = KKK;
  350.     for(i=1; i<=Key_SIZE; i++)
  351.     {
  352.         K_arr[i] = spiltShift(K_arr[i-1], ShiftTable[i-1]);
  353.     }
  354.  
  355.  
  356.     /* Kn（48位）= PC-2（8*6）处理 CnDn得16个子密钥，存入Key_arr */
  357.  
  358.     string Key_arr[Key_SIZE];
  359.     for(i=0; i<Key_SIZE; i++)
  360.     {
  361.         Key_arr[i] = exchange(K_arr[i+1], PC_2, PC_2_SIZE);
  362.     }
  363.  
  364.     /**
  365.     * 用子密钥对明文加密
  366.     **/
  367.  
  368.     /* 通过IP（8*8）处理M得L0（32位）  R0（32位） */
  369.     string IP_M = exchange(M, IP, IP_SIZE);
  370.  
  371.     /* Ln= R(n-1); Rn= L(n-1) + f(R(n- 1); Kn)迭代16次 */
  372.     string L[Key_SIZE+1];
  373.     string R[Key_SIZE+1];
  374.     L[0] = IP_M.substr(0, M.length()/2);
  375.     R[0] = IP_M.substr(M.length()/2);
  376.     string it = "";
  377.     for(i=1; i<=Key_SIZE; i++)
  378.     {
  379.  
  380.         //将R0通过扩展置换E（8*6）从32位扩展到48位
  381.         it = exchange(R[i-1], E, E_SIZE);
  382.  
  383.         //R0（48位）与 K1异或得E0（48位）
  384.         it = XOR(it, Key_arr[16-i]);
  385.  
  386.         //将E0（48位）通过S盒转换成32位
  387.         it = SBoxWork(it, SBox);
  388.  
  389.         //P盒（8*4）置换，得P0
  390.         it = exchange(it, P, P_SIZE);
  391.  
  392.         //P0与L0进行异或，得J0
  393.         it = XOR(it, L[i-1]);
  394.  
  395.         //左右交换位置，即R1 = J0; L1 = R0
  396.         L[i] = R[i-1];
  397.         R[i] = it;
  398.     }
  399.  
  400.     /* 对R16 L16进行一次IP-1（8*8）排序得密文 */
  401.     string res = "";
  402.     res += R[16];
  403.     res += L[16];
  404.     string finalRes = Bin2Hex(exchange(res, IP_1, IP_1_SIZE));
  405.  
  406.     cout<<"DES decryption results are as follows: "<<endl;
  407.     cout<<finalRes<<endl;
  408.  
  409.     cout<<"------------------------"<<endl;
  410.     printMenu();
  411.  
  412.  
  413. }
  414.  
  415. /**
  416. *int转四位string  +  int十进制转string二进制
  417. **/
  418. string int2BinString(int n)
  419. {
  420.     bitset<4> bit(n);
  421.     return bit.to_string();
  422. }
  423. /**
  424. *string十六进制转string二进制
  425. **/
  426. string hexToTwo(string str)
  427. {
  428.     string twoBin = "";
  429.     int i;
  430.     for(i=0; i<16; i++)
  431.     {
  432.         if(str[i]>='0'&&str[i]<='9')
  433.             twoBin.append(int2BinString(str[i]));
  434.         else if(str[i]>='A'&&str[i]<='Z')
  435.             twoBin.append(int2BinString(str[i]-'A'+10));
  436.         else if(str[i]>='a'&&str[i]<='z')
  437.             twoBin.append(int2BinString(str[i]-'a'+10));
  438.  
  439.     }
  440.     return twoBin;
  441. }
  442. /**
  443. * string二进制转int十进制
  444. **/
  445. int binToDec(string bin)
  446. {
  447.     int sum = 0;
  448.     for(int i=0; i<bin.size(); i++)
  449.     {
  450.         if(bin[i]=='0' || bin[i]=='1')
  451.         {
  452.             sum += (bin[i]-'0') * pow(2, bin.size()-i-1);
  453.         }
  454.         else
  455.         {
  456.             cout<<"非法二进制字符！"<<endl;
  457.             return 0;
  458.         }
  459.     }
  460.     return sum;
  461. }
  462.  
  463. /**
  464. * 01字符转十进制
  465. **/
  466. int str2Dec(string str)
  467. {
  468.     bitset<64> bst(str);
  469.     return (int)bst.to_ulong();
  470. }
  471. /**
  472. * 64位密文转十六进制
  473. **/
  474. //Bin2Hex转换表
  475. const static string Bin_Hex[16]
  476. {
  477.     "0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F"
  478. };
  479. string Bin2Hex(string strBin)
  480. {
  481.     string hex;
  482.     int a = strBin.length()/4;
  483.     string trans;
  484.     for(int i = 0; i < a; i++)
  485.     {
  486.         trans.clear();
  487.         trans = strBin.substr(i*4, 4);
  488.         hex += Bin_Hex[str2Dec(trans)];
  489.     }
  490.     return hex;
  491. }
  492.  
  493. /**
  494. *利用交换表进行置换
  495. **/
  496. string exchange(string str, int rule[], int x)
  497. {
  498.     string exchangedStr = "";
  499.     int i, temp;
  500.     for(i=0; i<x; i++)
  501.     {
  502.         temp = rule[i]-1;
  503.         exchangedStr.append(1, str[temp]);
  504.     }
  505.     return exchangedStr;
  506. }
  507.  
  508. /**
  509. *依据移位表进行移位
  510. **/
  511. string circleMove(string str, int j)
  512. {
  513.  
  514.     string targetString = "";
  515.     targetString.append(str.substr(j));
  516.     targetString.append(str.substr(0, j));
  517.     return targetString;
  518. }
  519. /**
  520. *左右两部分移位
  521. **/
  522. string spiltShift(string str, int j)
  523. {
  524.     string targetStr = "";
  525.     string leftString = str.substr(0, str.length()/2);
  526.     string rightString = str.substr(str.length()/2);
  527.     targetStr.append(circleMove(leftString, j));
  528.     targetStr.append(circleMove(rightString, j));
  529.     return targetStr;
  530. }
  531. /**
  532. * string 异或
  533. **/
  534. string XOR(string str1, string str2)
  535. {
  536.     string targetString = "";
  537.     for(int j=0; j<str1.length(); j++)
  538.     {
  539.         targetString += ((str1[j] - '0') ^ (str2[j] - '0')) + '0';
  540.  
  541.     }
  542.     return targetString;
  543. }
  544. /**
  545. * S盒工作
  546. **/
  547. string SBoxWork(string str, int SBox[][4][16])
  548. {
  549.     string targetString = "";
  550.     string temp = "";
  551.     string x = "", y = "";
  552.     int col = 0, row = 0;
  553.     for(int i=0; i<str.size()/6; i++)
  554.     {
  555.         temp = str.substr(6*i, 6);
  556.         x = temp.substr(0, 1)+temp.substr(5, 1);
  557.         y = temp.substr(1, 4);
  558.         row = binToDec(x);
  559.         col = binToDec(y);
  560.         targetString.append(int2BinString(SBox[i][row][col]));
  561.     }
  562.     return targetString;
  563. }
  564.

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