DES加密解密算法C++实现

DES加密算法并不难，是由一些简单的变换得来的，难的是要有足够的耐心。蒟蒻并不想说自己用了多久才把代码写好的。

代码：

我真的太难了QAQ

 #include<iostream>
 using namespace std;

 int jiami(){

     // 明文
     int mingwen[];

     cout<<"请输入16位十六进制的明文:";
     string  kk;
     cin>>kk;
     int len=kk.length();

     while(len!=){
         cout<<"请重新输入16位十六进制的明文:";
         cin>>kk;
         len=kk.length();
     }

     int jishu=;
     for(int i=;i<;i++){
         int a;
         if(kk[i]>=''&&kk[i]<='')
            a=kk[i]-'';
         else
            a=kk[i]-'A'+;

         int n[]={};
         int f=;
         while(a){
             n[f]=a%;
             a=a/;
             f++;
         }
         mingwen[jishu*]=n[];
         mingwen[jishu*+]=n[];
         mingwen[jishu*+]=n[];
         mingwen[jishu*+]=n[];
         jishu++;
     } 

     //初始置换IP
     int IP[]={, , , , , , , ,
                 , , , , , , , ,
                 , , , , , , , ,
                 , , , , , , , ,
                 , , , , , ,  , ,
                 , , , , , , , ,
                 , , , , , , , ,
                 , , , , , , , };

     // 选择运算E   32位明文扩充为48位
     int E[]={ ,  ,  ,  ,  ,  ,
                 ,  ,  ,  ,  ,  ,
                 ,  , , , , ,
                , , , , , ,
                , , , , , ,
                , , , , , ,
                , , , , , ,
                , , , , ,   }; 

     //64位秘钥     0123456789ABCDEF    56位的秘钥+8位校验码
     int miyao[];
     cout<<"请输入16位十六进制的秘钥:";
     string  k_2;
     cin>>k_2;
     int len_2=k_2.length();

     while(len_2!=){
         cout<<"请重新输入16位十六进制的秘钥:";
         cin>>k_2;
         len_2=k_2.length();
     }

     int jishu_2=;
     for(int i=;i<;i++){
         int a;
         if(k_2[i]>=''&&k_2[i]<='')
            a=k_2[i]-'';
         else
            a=k_2[i]-'A'+;

         int n[]={};
         int f=;
         while(a){
             n[f]=a%;
             a=a/;
             f++;
         }
         miyao[jishu_2*]=n[];
         miyao[jishu_2*+]=n[];
         miyao[jishu_2*+]=n[];
         miyao[jishu_2*+]=n[];
         jishu_2++;
     }      

     //置换选择1
     int IP_1[]={, , , , , ,  ,
                    , , , , , , ,
                   ,  , , , , , ,
                   , ,  , , , , ,
                   , , , , , , ,
                    , , , , , , ,
                   ,  , , , , , ,
                   , ,  , , , ,  };

     //16次左移对应的位数
     int weiyi[]={,,,,,,,,,,,,,,,};
     // 置换选择2 秘钥56->48位压缩
     int IP_2[]={, , , ,  ,  ,
                    , , ,  , , ,
                   , , ,  , ,  ,
                   ,  , , , ,  ,
                   , , , , , ,
                   , , , , , ,
                   , , , , , ,
                   , , , , , };

      //S盒

     int s[][]=
 {
     {
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,
     },
     {
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,
     },
     {
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,
     },
     {
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,
     },
     {
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,
     },
     {
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,
     },
     {
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,
     },
     {
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,
     }
 };

      //P置换
      int P[]={,  , , , , , , ,
                 , , , ,  , , , ,
                 ,  , , , , ,  ,  ,
                 , , ,  , , ,  ,  }; 

     //1初始置换
     //1.1  64明文进行初始置换分左右
     int mingwen_1[];
     int l[],r[];
     for (int i=;i<;i++){
         mingwen_1[i]=mingwen[IP[i]-];
     }
     for(int i=;i<;i++){
         l[i]=mingwen_1[i];
         r[i]=mingwen_1[i+];
     }
     cout<<"明文初始置换M   =";
     for(int i=;i<;i++){
         if(i%==) cout<<" ";
         cout<<mingwen_1[i];
     }
     cout<<endl;

     //1.2 56位秘钥初始置换分左右 

     cout<<"秘钥初始置换k0  =";
     for(int i=;i<;i++){
         if(i%==) cout<<" ";
         cout<<miyao[i];
     }
     cout<<endl;

     int ml[],mr[];
     int miyao_0[];
     for(int i=;i<;i++){
         miyao_0[i]=miyao[IP_1[i]-];
     }
     for(int i=;i<;i++){
         ml[i]=miyao_0[i];
         mr[i]=miyao_0[i+];
     }

     //2.循环加密
     for (int i=;i<;i++){

         cout<<"-------------------------------第"<<i+<<"轮循环-----------------------------------" <<endl;

         //2.1明文左右交换
         int new_l[],new_r[];
         for(int j=;j<;j++){
             new_l[j]=r[j];
         }

         //2.2 右边32位拓展变换成48位
         for(int j=;j<;j++){
             new_r[j]=r[E[j]-];
         }

         //2.3 左右秘钥 左移
         int new_ml[],new_mr[];
          for(int j=;j<;j++){
              new_ml[j]=ml[(j++weiyi[i])%];
              new_mr[j]=mr[(j++weiyi[i])%];
          }

         //2.4  重新合并成56位的秘钥
         int miyao_1[];
         for(int j=;j<;j++){
             miyao_1[j]=new_ml[j];
             miyao_1[j+]=new_mr[j];
         }
         //2.5  IP_2 56位秘钥压缩成48位的秘钥
         int k[];
         for (int j=;j<;j++){
             k[j]=miyao_1[IP_2[j]-];
         } 

         cout<<"k"<<i+<<"             =";
         for(int j=;j<;j++){
           if(j%==) cout<<" ";
           cout<<k[j];
        }
         cout<<endl;

         cout<<"R"<<i<<"            "<<"=";
         for(int j=;j<;j++){
           if(j%==) cout<<" ";
           cout<<new_r[j];
        }
         cout<<endl;

         //2.6   2.2和2.5XOR
         int new_r2[];
         for(int j=;j<;j++){
             new_r2[j]=new_r[j] ^ k[j];
         } 

         cout<<"R(i-1)^ki      "<<"=";
         for(int j=;j<;j++){
           if(j%==) cout<<" ";
           cout<<new_r2[j];
        }
         cout<<endl;

         //2.7 s盒
         int new_r3[];
         int b1,b2,b3,b4,b5,b6;
         int m=;
         for(int j=;j<;j++){
             int row = ((new_r2[j*])<<)+(new_r2[j*+]);   //第1，6位组成行号
             int col = ((new_r2[j*+])<<)+((new_r2[j*+])<<)+((new_r2[j*+])<<)+(new_r2[j*+]);  //第2，3，4，5位组成列号
               //找到s盒对应的数
             int a=s[j][*row+col];

             //转成对应的2进制
             int n[]={};
             int f=;
             while(a){
                 n[f]=a%;
                 a=a/;
                 f++;
             }

             new_r3[m*]=n[];
             new_r3[m*+]=n[];
             new_r3[m*+]=n[];
             new_r3[m*+]=n[];
             m++;
         }

         cout<<"第"<<i+<<"轮s盒"<<"       =";
         for(int j=;j<;j++){
           if(j%==) cout<<" ";
           cout<<new_r3[j];
        }
         cout<<endl;

         //2.8 P置换
         int new_r4[];
         for(int j=;j<;j++){
             new_r4[j]=new_r3[P[j]-];
         } 

         cout<<"P置换          "<<"=";
         for(int j=;j<;j++){
           if(j%==) cout<<" ";
           cout<<new_r4[j];
        }
         cout<<endl;

         //2.9 明文左边32位和2.8 new_r4[32] XOR
         int new_r5[];
         for(int j=;j<;j++){
             new_r5[j]=l[j] ^ new_r4[j];
             //更新左右明文，以便于下次循环
             l[j]=new_l[j];
             r[j]=new_r5[j];
         } 

         cout<<"R"<<i+<<"             =";
         for(int j=;j<;j++){
           if(j%==) cout<<" ";
           cout<<new_r5[j];
        }
         cout<<endl;
         cout<<"L"<<i+<<"             =";
         for(int j=;j<;j++){
           if(j%==) cout<<" ";
           cout<<new_l[j];
        }
         cout<<endl;
         //2.10 更新左右秘钥，以便于下次循环
          for(int j=;j<;j++){
              ml[j]=new_ml[j];
              mr[j]=new_mr[j];
          } 

          cout<<"----------------------------------------------------------------------------"<<endl<<endl<<endl; 

     }

     //3.  循环加密之后的明文mingwen_1[64]
     for(int i=;i<;i++){
         mingwen_1[i]=r[i];
         mingwen_1[i+]=l[i];
     } 

 //    cout<<"逆置换前=";
 //    for(int i=0;i<64;i++){
 //        cout<<mingwen_1[i];
 //    }
 //    cout<<endl<<endl;

     //4.  逆置换
     int miwen[];
     for(int i=;i<;i++){
         miwen[IP[i]-]=mingwen_1[i];
     } 

     //5.输出

     cout<<"原明文为：";
     for(int i=;i<;i++){
         if(i%==) cout<<endl;
         cout<<mingwen[i];
     }
     cout<<endl<<endl;
     cout<<"秘钥为：";
     for(int i=;i<;i++){
         if(i%==) cout<<endl;
         cout<<miyao[i];
     }
     cout<<endl<<endl;
     cout<<"密文为：";
     for(int i=;i<;i++){
         if(i%==) cout<<endl;
         cout<<miwen[i];
     }
      //是否将密文转换成十六进制？（Y  or  N)

     cout<<endl<<endl<<"是否将密文转换成十六进制？（Y  or  N)：";
     char YN;
     cin>>YN;
     cout<<endl<<"十六进制密文表示：";
     if(YN=='Y'){
         for(int i=;i<;i++){
             int q=miwen[i*]*+miwen[i*+]*+miwen[i*+]*+miwen[i*+];
             if(q>= && q<= ){
                 cout<<q;
             }
             else{
                 cout<<hex<<uppercase<<q;
             }
         }
     }
     cout<<endl<<endl<<"！！！！皆大欢喜，普天同庆！！！！"<<endl;
     return ;
 }

 int jiemi(){
     // 密文
     int miwen[];

     cout<<"请输入16位十六进制的密文:";
     string  kk;
     cin>>kk;
     int len=kk.length();

     while(len!=){
         cout<<"请重新输入16位十六进制的密文:";
         cin>>kk;
         len=kk.length();
     }

     int jishu=;
     for(int i=;i<;i++){
         int a;
         if(kk[i]>=''&&kk[i]<='')
            a=kk[i]-'';
         else
            a=kk[i]-'A'+;

         int n[]={};
         int f=;
         while(a){
             n[f]=a%;
             a=a/;
             f++;
         }
         miwen[jishu*]=n[];
         miwen[jishu*+]=n[];
         miwen[jishu*+]=n[];
         miwen[jishu*+]=n[];
         jishu++;
     } 

     //初始置换IP
     int IP[]={, , , , , , , ,
                 , , , , , , , ,
                 , , , , , , , ,
                 , , , , , , , ,
                 , , , , , ,  , ,
                 , , , , , , , ,
                 , , , , , , , ,
                 , , , , , , , };

     // 选择运算E   32位明文扩充为48位
     int E[]={ ,  ,  ,  ,  ,  ,
                 ,  ,  ,  ,  ,  ,
                 ,  , , , , ,
                , , , , , ,
                , , , , , ,
                , , , , , ,
                , , , , , ,
                , , , , ,   }; 

     //64位秘钥     0123456789ABCDEF    56位的秘钥+8位校验码
     int miyao[];
     cout<<"请输入16位十六进制的秘钥:";
     string  k_2;
     cin>>k_2;
     int len_2=k_2.length();

     while(len_2!=){
         cout<<"请重新输入16位十六进制的秘钥:";
         cin>>k_2;
         len_2=k_2.length();
     }

     int jishu_2=;
     for(int i=;i<;i++){
         int a;
         if(k_2[i]>=''&&k_2[i]<='')
            a=k_2[i]-'';
         else
            a=k_2[i]-'A'+;

         int n[]={};
         int f=;
         while(a){
             n[f]=a%;
             a=a/;
             f++;
         }
         miyao[jishu_2*]=n[];
         miyao[jishu_2*+]=n[];
         miyao[jishu_2*+]=n[];
         miyao[jishu_2*+]=n[];
         jishu_2++;
     }      

     //置换选择1
     int IP_1[]={, , , , , ,  ,
                    , , , , , , ,
                   ,  , , , , , ,
                   , ,  , , , , ,
                   , , , , , , ,
                    , , , , , , ,
                   ,  , , , , , ,
                   , ,  , , , ,  };

     //16次左移对应的位数
     int weiyi[]={,,,,,,,,,,,,,,,};
     // 置换选择2 秘钥56->48位压缩
     int IP_2[]={, , , ,  ,  ,
                    , , ,  , , ,
                   , , ,  , ,  ,
                   ,  , , , ,  ,
                   , , , , , ,
                   , , , , , ,
                   , , , , , ,
                   , , , , , };

      //S盒
     int s[][]=
 {
     {
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,
     },
     {
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,
     },
     {
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,
     },
     {
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,
     },
     {
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,
     },
     {
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,
     },
     {
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,
     },
     {
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,,
         ,,,,,,,,,,,,,,,
     }
 };

      //P置换
      int P[]={,  , , , , , , ,
                 , , , ,  , , , ,
                 ,  , , , , ,  ,  ,
                 , , ,  , , ,  ,  }; 

     //1初始置换    

     //1.1  64密文进行逆置换分左右
     int miwen_1[];
     int l[],r[];
     for (int i=;i<;i++){
         miwen_1[i]=miwen[IP[i]-];
     }
     for(int i=;i<;i++){
         r[i]=miwen_1[i];
         l[i]=miwen_1[i+];
     }
     cout<<"密文逆置换     =";
     for(int i=;i<;i++){
         if(i%==) cout<<" ";
         cout<<miwen_1[i];
     }
     cout<<endl;

     //1.2 56位秘钥初始置换分左右 

     cout<<"秘钥初始置换k0 =";
     for(int i=;i<;i++){
         if(i%==) cout<<" ";
         cout<<miyao[i];
     }
     cout<<endl;

     int ml_0[],mr_0[];
     int miyao_0[];
     for(int i=;i<;i++){
         miyao_0[i]=miyao[IP_1[i]-];
     }
     for(int i=;i<;i++){
         ml_0[i]=miyao_0[i];
         mr_0[i]=miyao_0[i+];
     }

     // 因为加密过程一共左移了28位，回到了原来的位置，
     //所以我们要先将原始秘钥左移一次。

     int ml[],mr[];
     for(int j=;j<;j++){
         ml[j]=ml_0[(j++)%];
         mr[j]=mr_0[(j++)%];
     }    

     //2.循环解密
     for (int i=;i<;i++){

         cout<<"-------------------------------第"<<i+<<"轮循环解密-----------------------------------" <<endl;

         //2.1密文左右交换
         int new_l[],new_r[];
         for(int j=;j<;j++){
             new_r[j]=l[j];
         }

         //2.2 左边32位拓展变换成48位
         for(int j=;j<;j++){
             new_l[j]=new_r[E[j]-];
         }

         //2.3 左右秘钥 右移

         int new_ml[],new_mr[];
          for(int j=;j<;j++){
              new_ml[j]=ml[(j+-weiyi[-i])%];
              new_mr[j]=mr[(j+-weiyi[-i])%];
          }

         //2.4  重新合并成56位的秘钥
         int miyao_1[];
         for(int j=;j<;j++){
             miyao_1[j]=new_ml[j];
             miyao_1[j+]=new_mr[j];
         }
         //2.5  IP_2 56位秘钥压缩成48位的秘钥
         int k[];
         for (int j=;j<;j++){
             k[j]=miyao_1[IP_2[j]-];
         } 

         cout<<"k"<<-i<<"             =";
         for(int j=;j<;j++){
           if(j%==) cout<<" ";
           cout<<k[j];
        }
         cout<<endl;

         cout<<"L"<<-i<<"             "<<"=";
         for(int j=;j<;j++){
           if(j%==) cout<<" ";
           cout<<new_l[j];
        }
         cout<<endl;

         //2.6   2.2和2.5XOR
         int new_l2[];
         for(int j=;j<;j++){
             new_l2[j]=new_l[j] ^ k[j];
         } 

         cout<<"Li^ki         "<<"=";
         for(int j=;j<;j++){
           if(j%==) cout<<" ";
           cout<<new_l2[j];
        }
         cout<<endl;

         //2.7 s盒
         int new_l3[];
         int b1,b2,b3,b4,b5,b6;
         int m=;
         for(int j=;j<;j++){
             int row = ((new_l2[j*])<<)+(new_l2[j*+]);   //第1，6位组成行号
             int col = ((new_l2[j*+])<<)+((new_l2[j*+])<<)+((new_l2[j*+])<<)+(new_l2[j*+]);  //第2，3，4，5位组成列号
               //找到s盒对应的数
             int a=s[j][*row+col];

             //转成对应的2进制
             int n[]={};
             int f=;
             while(a){
                 n[f]=a%;
                 a=a/;
                 f++;
             }

             new_l3[m*]=n[];
             new_l3[m*+]=n[];
             new_l3[m*+]=n[];
             new_l3[m*+]=n[];
             m++;
         }

         cout<<"第"<<-i<<"轮s盒"<<"       =";
         for(int j=;j<;j++){
           if(j%==) cout<<" ";
           cout<<new_l3[j];
        }
         cout<<endl;

         //2.8 P置换
         int new_l4[];
         for(int j=;j<;j++){
             new_l4[j]=new_l3[P[j]-];
         } 

         cout<<"P置换          "<<"=";
         for(int j=;j<;j++){
           if(j%==) cout<<" ";
           cout<<new_l4[j];
        }
         cout<<endl;

         //2.9 密文右边32位和2.8 new_l4[32] XOR
         int new_l5[];
         for(int j=;j<;j++){
             new_l5[j]=r[j] ^ new_l4[j];
             //更新左右明文，以便于下次循环
             r[j]=new_r[j];
             l[j]=new_l5[j];
         } 

         cout<<"L"<<-i-<<"            =";
         for(int j=;j<;j++){
           if(j%==) cout<<" ";
           cout<<new_l5[j];
        }
         cout<<endl;
         cout<<"R"<<-i-<<"            =";
         for(int j=;j<;j++){
           if(j%==) cout<<" ";
           cout<<new_r[j];
        }
         cout<<endl;

         //2.10 更新左右秘钥，以便于下次循环
          for(int j=;j<;j++){
              ml[j]=new_ml[j];
              mr[j]=new_mr[j];
          } 

          cout<<"ml"<<-i<<"=";
          for(int j=;j<;j++){
              cout<<ml[j];
          }
          cout<<endl;
          cout<<"mr"<<-i<<"=";
          for(int j=;j<;j++){
              cout<<mr[j];
          }
          cout<<endl;

          cout<<"------------------------------------------------------------------------------"<<endl<<endl<<endl; 

     }

     //3.  循环解密之后的密文miwen_1[64]
     for(int i=;i<;i++){
         miwen_1[i]=l[i];
         miwen_1[i+]=r[i];
     }
     //4.  初始置换
     int mingwen[];
     for(int i=;i<;i++){
         mingwen[IP[i]-]=miwen_1[i];
     } 

     //5.输出

     cout<<"原密文为：";
     for(int i=;i<;i++){
         if(i%==) cout<<endl;
         cout<<miwen[i];
     }
     cout<<endl<<endl;
     cout<<"秘钥为：";
     for(int i=;i<;i++){
         if(i%==) cout<<endl;
         cout<<miyao[i];
     }
     cout<<endl<<endl;
     cout<<"明文为：";
     for(int i=;i<;i++){
         if(i%==) cout<<endl;
         cout<<mingwen[i];
     }
      //是否将明文转换成十六进制？（Y  or  N)

     cout<<endl<<endl<<"是否将明文转换成十六进制？（Y  or  N)：";
     char YN;
     cin>>YN;
     cout<<endl<<"十六进制明表示：";
     if(YN=='Y'){
         for(int i=;i<;i++){
             int q=mingwen[i*]*+mingwen[i*+]*+mingwen[i*+]*+mingwen[i*+];
             if(q>= && q<= ){
                 cout<<q;
             }
             else{
                 cout<<hex<<uppercase<<q;
             }
         }
     }
     cout<<endl<<endl<<"！！！！皆大欢喜，普天同庆！！！！"<<endl;
     return ;
 } 

 int main(){

     while(){
     int number;
     cout<<"===欢迎来到DES加密算法系统==="<<endl;
     cout<<"                  Author:十七"<<endl;
     cout<<"目前支持的操作有："<<endl;
     cout<<"  1.加密操作；"<<endl;
     cout<<"  2.解密操作；"<<endl;
     cout<<"  0.退出。"<<endl;
     cout<<"============================="<<endl;
     cout<<"请选择您项进行的操作：";
     cin>>number;
     cout<<endl;

     if(number==){
         jiami();
     }
     else if(number==){
         jiemi();
     }
     else{
         cout<<"您已成功退出系统，如果您对本次服务感到满意，欢迎五星好评^_^"<<endl;
         return ;
      }
     }
     return ;
 } 

运行结果截图：

......

......