四种古典密码的C++实现（2）—–Virginia密码

1 //Virginia密码
  2 /*理解算法最重要，最好自己动手实现试试看，可以使用MFC写一个简单的交互界面*/
  3 #include<iostream> 
  4 #include<cstring> 
  5 
  6 using namespace std; 
  7 #define MINCHAR 32 
  8 #define CHARSUM 94 
  9 char table[CHARSUM][CHARSUM]; 
 10 bool Init(); 
 11 bool Encode(char* key, char* source, char* dest); 
 12 bool Dncode(char* key, char* source, char* dest); 
 13 int main() 
 14 { 
 15 if(!Init()) 
 16 { 
 17 cout << "初始化错误！" << endl; 
 18 return 1; 
 19 } 
 20 char key[256]; 
 21 char str1[256]; 
 22 char str2[256]; 
 23 int operation; 
 24 while(1) 
 25 { 
 26 do 
 27 { 
 28  cout << "请选择一个操作：1. 加密； 2. 解密； -1. 退出\n"; 
 29  cin >> operation; 
 30 }while(operation != -1 && operation != 1 && operation != 2); 
 31 if(operation == -1) 
 32 return 0; 
 33 else if(operation == 1)//加密 
 34 { 
 35  cout << "请输入密钥："; 
 36  cin >> key; 
 37  cout << "请输入待加密字符串："; 
 38  cin >> str1; 
 39  Encode(key, str1, str2); 
 40  cout << "加密后的字符串：" << str2 << endl; 
 41 } 
 42 else if(operation == 2)//解密 
 43 { 
 44  cout << "请输入密钥："; 
 45  cin >> key; 
 46  cout << "请输入待解密字符串："; 
 47  cin >> str1; 
 48  Dncode(key, str1, str2); 
 49  cout << "解密后的字符串：" << str2 << endl; 
 50 } 
 51 cout << endl; 
 52 } 
 53 return 0; 
 54 } 
 55 // 初始化维吉尼亚方阵 
 56 bool Init() 
 57 { 
 58  int i, j; 
 59  for(i = 0; i < CHARSUM; i++) 
 60  { 
 61   for(j = 0; j < CHARSUM; j++) 
 62   { 
 63    table[i][j] = MINCHAR + (i + j) % CHARSUM; 
 64   } 
 65  } 
 66  return true; 
 67 } 
 68 // 加密 
 69 // key：密钥 
 70 // source：待加密的字符串 
 71 // dest：经过加密后的字符串 
 72 bool Encode(char* key, char* source, char* dest) 
 73 { 
 74  char* tempSource = source; 
 75  char* tempKey = key; 
 76  char* tempDest = dest; 
 77  do 
 78  { 
 79   *tempDest = table[(*tempKey) - MINCHAR][(*tempSource) - MINCHAR]; 
 80   tempDest++; 
 81   if(!(*(++tempKey))) 
 82    tempKey = key; 
 83  }while(*tempSource++); 
 84  dest[strlen(source)] = 0; 
 85  return true; 
 86 } 
 87 // 解密 
 88 // key：密钥 
 89 // source：待解密的字符串 
 90 // dest：经过解密后的字符串 
 91 bool Dncode(char* key, char* source, char* dest) 
 92 { 
 93  char* tempSource = source; 
 94  char* tempKey = key; 
 95  char* tempDest = dest; 
 96  char offset; 
 97  do 
 98  { 
 99   offset = (*tempSource) - (*tempKey); 
100   offset = offset >= 0 ? offset : offset + CHARSUM; 
101   *tempDest = MINCHAR + offset; 
102   tempDest++; 
103   if(!(*(++tempKey))) 
104    tempKey = key; 
105  }while(*++tempSource); 
106  dest[strlen(source)] = 0; 
107  return true; 
108 }

原文链接: https://www.cnblogs.com/nanashi/p/6700981.html

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