[Amin_Mansouri]

الان سی پلاس متاسفانه ندارم اما سورس بالای چیز ساده ای
یادمه گفتی واسه جای مهمی برنامه مینویسی
این کارتو انجام میده :

کد:

#include<conio.h>
#include <stdio.h>
#include<string.h>


int l[4],r[4],keys[2][8],ct[8];

void sbox(int sip[],int p[],int sbno,int i)
   {
    int sbox[2][4][4]={1,0,3,2,3,2,1,0,0,2,1,3,3,1,3,2,0,1,2,3,2,0,1,3,3,0,1,0,2,1,0,3};
    int rw,c,sop;
    rw = sip[3]+sip[0]*2;
    c = sip[2]+sip[1]*2;
    sop = sbox[sbno][rw][c]; //sop gives decimal value of S-Box Output
    for(;sop!=0;sop/=2)
        p[i--]=sop%2;
   }


void cmp_fun(int round)
   {
    int EP[]={4,1,2,3,2,3,4,1},i,epd[8];
    int slip[4],srip[4];
    int p[4]={0},p4[]={2,4,3,1},np[4];
    for(i=0;i<8;i++) // E/P Permutation
        epd[i]=r[EP[i]-1];
    for(i=0;i<8;i++)//Performing XOR with Key
        if(i<4)
            slip[i] = epd[i]^keys[round][i]; // usingKey1=>0
        else
            srip[i-4] = epd[i]^keys[round][i];
    sbox(slip,p,0,1);//Calling SBox 1, 0->SBOX 1
    sbox(srip,p,1,3);//Calling SBox 1, 1->SBOX 2
    for(i=0;i<4;i++) //P4 permutation
        np[i]=p[p4[i]-1];
    for(i=0;i<4;i++)
        l[i] = l[i]^np[i];
   }


void left_shift(int keyip[],int nob)
   {
    int t1,t2,i;
    while(nob>0)
           {
          t1=keyip[0],t2=keyip[5];
              for(i=0;i<9;i++)
         if(i<4)
                 keyip[i] =keyip[i+1];
             else if(i>4)
                     keyip[i] = keyip[i+1];
           keyip[4]=t1,keyip[9]=t2;
               nob--;
        }
    }


void Bin(int dec,int b[])
   {
      int i,a[8],j;
      for(i=0;i<8;i++)
        {
          while(dec!=0)
           {
             a[i]=dec%2;
             dec=dec/2;
             i++;
           }
          a[i]=0;
        }
      for(i=7,j=0;j<10;j++,i--)
        {
          if(i>=0)
         b[j]=a[i];
          else
         b[j]=0;
         }
   }


void ch_bin(unsigned char ch,int b[])
   {
      int i,a[8],j;
      int dec;
      dec=(int)ch;
      for(i=0;i<8;i++)
        {
          while(dec!=0)
            {
              a[i]=dec%2;
              dec=dec/2;
              i++;
             }
          a[i]=0;
        }
      for(i=7,j=0;j<8;j++,i--)
     b[j]=a[i];
   }


unsigned char bin_ch(int b[])
   {
      int i,j,p=1;
      int dec=0;
      unsigned char ch;
      for(i=7;i>=0;i--)
        {
          dec=dec+(b[i]*p);
          p=p*2;
        }
      ch=(unsigned char)dec;
      return ch;
   }


void pass_key(char *s,int key[])
   {
      int a[10],arr[10],ai[10],ar[10][10];
      int i,j,k;
      for(i=0;i<10;i++)
         {
            if(i<strlen(s))
          a[i]=(int)s[i];
            else
          a[i]=0;
            Bin(a[i],arr);
            for(k=0,j=0;k<10;k++,j++)
           ar[i][k]=arr[j];
         }
       k=0;
        for(i=0;i<10;i++)
           for(j=0;j<10;j++)
              if(i==j)
                {
                  key[k]=ar[i][j];
                  k++;
                 }
   }
    

void gen_keys(int key[])
   {
      int i,keyip[10];
      int p10[]={3,5,2,7,4,10,1,9,8,6},p8[]={6,3,7,4,8,5,10,9};
      
       for(i=0;i<10;i++) // Permutation P10
       keyip[i] = key[p10[i]-1];
       left_shift(keyip,1);     // Left Shifting (Array,No of bts)
       for(i=0;i<8;i++)             //Permuting P8 on key1
       keys[0][i] = keyip[p8[i]-1];// Key1 Generated!!
       left_shift(keyip,2);// Generating Key2 . .
       for(i=0;i<8;i++)
       keys[1][i] = keyip[p8[i]-1];// Key2 Generated!!
   }


void En_De(int pt[],int c)
   {
      int ip[]={2,6,3,1,4,8,5,7},ipi[]={4,1,3,5,7,2,8,6},t[8],i;
      for(i=0;i<8;i++)// Performing Permutation on input bits!!
      if(i<4)
         l[i]=pt[ip[i]-1];
      else
         r[i-4] = pt[ip[i]-1];
      cmp_fun(c);//Round 0+1 using key 0+1
      for(i=0;i<4;i++) //Swapping left & right
          r[i]=l[i]+r[i],l[i]=r[i]-l[i],r[i]=r[i]-l[i];
      cmp_fun(!c); // Round 1+1 wid key1+1 wid swapped bits
      for(i=0;i<8;i++)
      if(i<4)    
             t[i]=l[i];
      else    
             t[i]=r[i-4];
       for(i=0;i<8;i++)
       ct[i] = t[ipi[i]-1];
   }
      

void main()
    {
     int pt[8],i,j,choice,l;
     char s[10],name[20],target[20],pwd[20];
     char ch,chr,cha;
     int key[10],bin[8],key1[10];
    
     FILE *fin;
     FILE *fout;
    
     start:

     clrscr();    
     printf("\n\n\t\t\t");
     textcolor(11);
     cprintf("Program on Encryption and Decryption");
     printf("\n\n\n\t");
     textcolor(6);
     cprintf("0. To Exit !");
     textcolor(7);
     printf("\n\t1. encrypt the Text file ");
     printf("\n\t2. Decrypt the encrypted file");
     printf("\n\t3. Help");
     printf("\n\tEnter your choice :");
     scanf("%d",&choice);
     switch(choice)
      {
      case 1:
       {
         printf("\n\t Enter the Password \n\t");
         scanf("%s",&s);
         pass_key(s,key);//conversion of password to 10 bit key
         gen_keys(key); // Generating Keys key1 & key2
         printf("\n\nEnter The Path Of A File Which Is To Be Encrypted : \n\t");
     fflush(stdin);
     gets(name);
         fin=fopen(name,"r");     //Open TheInput File In A Binary Mode
         if(!fin)
           {                                                          //ShowErrorOccur If File Does Not Exist
         printf("Error In Openinig Of A File : \n\t");                 //Or AnyErrorOccurs
         printf("Re-Enter the file path.......\n\t");
         getch();
         goto start;
           }
         printf("Enter The New Encrypted File Name : \n\t");
     fflush(stdin);
     gets(target);
         fout=fopen(target,"w+");                         //Open TheOutPut File In A Binary Mode
         if(!fout)
           {
          fclose(fin);
         printf("Error In Opening Of Target File :\n\t"); //Show ErrorIfAny Error Occrs In Opening Of A File
         printf("RE-Enter the target file name......\n\t");
         getch();
         goto start;
           }
     fputs(s,fout);
         while(fin)
           {
         ch=fgetc(fin);
         if(ch==EOF)
           {
            fclose(fin);
            fclose(fout);
            break;
           }
         ch_bin(ch,bin);
         En_De(bin,0);
         chr=bin_ch(ct);
         fputc(chr,fout);
           }
         getch();
        goto start;
      }

    case 2:
       {
         printf("\n\nEnter The Path Of A File Which Is To Be decrypted : \n\t");
         fflush(stdin);
         gets(name);
         fin=fopen(name,"r");                              //Open TheInput File In A Binary Mode
         if(!fin)
           {                                      //ShowErrorOccur If File Does Not Exist
          printf("Error In Openinig requested File...... \n\t");
      printf("Re-Enter the File path......\n\t");
      getch();                //Or AnyErrorOccurs
          goto start;
           }
          printf("enter the length of password\n\t");
      scanf("%d",&l);
         fgets(s,l+1,fin);

         printf("\n\tEnter the password.......\n\t");
         BACK5:
      scanf("%s",&pwd);
         if(strcmp(s,pwd)==0)
         {
         pass_key(pwd,key);
         gen_keys(key); // Generating Keys key1 & key2
         printf("\nEnter The New decrypted File Name : \n\t");
         fflush(stdin);
     gets(target);
         fout=fopen(target,"w+");                         //Open TheOutPut File In A Binary Mode
         if(!fout)
           {
          fclose(fin);
          printf("Error In Opening Of Target File :\n\t");       //Show ErrorIfAny Error Occrs In Opening Of A File
          printf("Re-Enter the file name.......\n\t");
          getch();
          goto start;
           }
         while(fin)
      {
           cha=fgetc(fin);
           if(cha==EOF)
            {
             fclose(fin);
             fclose(fout);
             break;
            }
       ch_bin(cha,bin);
           En_De(bin,1);
       chr=bin_ch(ct);
       fputc(chr,fout);
      }
    }
       else
     {
        printf("\nre-enter the password\n\t");
        goto BACK5;
     }
     getch();
    goto start;
    }

    case 3:
     {
     printf("\n\n\n\t1. This program is to encrypt and decrypt the text file.");
     printf("\n\n\t2. enter the path for text file you wants to encrypt and decrypt.");
     printf("\n\n\t3. The program may not give correct results in fullsreen.");
     getch();
     goto start;
     }
    case 0:
    {
    clrscr();
    textcolor(14);
     cprintf("\n\n\n     --Thank U for using this software program-- ");
     printf("\n\n\n");
    getch();
      break;
    }
    default:
    textcolor(9);
    cprintf("\n       Invalid choice !");
    getch();
    textcolor(7);
    goto start;
     }
}

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