One Time Pad Encryption Algorithm in C

This post is about implementation of One Time Pad cipher algorithm in c.

Hope that this will help you to understand the concept One Time Pad cipher algorithm.

For any query regarding c/c++ concept please send me at khimanichirag@gmail.com.I will try my best to solve it.

     #include<stdio.h>  
     #include<conio.h>  
     #include<stdlib.h>  
     #include<time.h>  
     #include<string.h>  
     char s[30],cp[30];  
     void main()  
     {  
          char c[26],k[30];  
          int i,index,max=26;  
          clrscr();  
          for(i=97;i<=122;i++)  
          {  
               c[i-97]=i;  
          }  
          printf("Enter plain text: ");  
          gets(s);  
          printf("Your key is: ");  
          randomize();  
          for(i=0;i<strlen(s);i++)  
          {  
               index=random(max)%26;  
               k[i]=c[index];  
          }  
          k[i]='\0';  
          puts(k);  
          getch();  
      }  

Polyalphabetic Algorithm in C

This blog is about implementation of Polyalphabetic cipher algorithm in c.

Hope that this will help to understand the concept of Polyalphabetic cipher cipher algorithm.

For any query regarding c/c++ please contact me at khimanichirag@gmail.com

     #include<stdio.h>  
     #include<conio.h>  
     #include<string.h>  
     void main()  
     {  
           char s[30],k[27],c[30];  
           int i,j=0;  
           clrscr();  
           printf("Enter plain text:");  
           gets(s);  
           printf("Enter key value:");  
           gets(k);  
           for(i=0;i<strlen(s);i++)  
           {  
               c[i]=s[i]+(k[j]-97);  
               j++;  
               if(j==strlen(k))  
               {  
                   j=0;  
               }  
           }  
           printf("Your cipher text is: %s",c);  
           getch();  
      }  

Monoalphabetic Algorithm in C

This blog is about implementation of Monoalphabetic cipher algorithm in c.

Hope that this will help to understand the concept Monoalphabetic cipher algorithm.

For any query regarding c/c++ concept please contact me at khimanichirag@gmail.com

     #include<stdio.h>  
     #include<conio.h>  
     #include<string.h>  
     void main()  
     {  
           char s[30],k[27],c[30];  
           int i, index;  
           clrscr();  
           printf("Enter plain text: ");  
           gets(s);  
           printf("\nEnter key with 26 character:");  
           for(i=0;i<26;i++)  
           {  
                printf("\n%c",i+97);  
                k[i]=getch();  
                printf("%c",k[i]);  
           }  
           for(i=0;i<strlen(s);i++)  
           {  
                index=s[i]-97;  
                c[i]=k[index];  
           }  
           printf("Your cipher text is:");  
           for(i=0;i<strlen(s);i++)  
           {  
               printf("%c",c[i]);  
           }  
            getch();  
      }  

Caesar Cipher Algorithm in C

This blog is about implementation of Caesar cipher algorithm in c.

Hope that this will help to understand the concept of Caesar cipher algorithm.

For any query regarding c/c++ concept please contact me at khimanichirag@gmail.com

     #include<stdio.h>  
     #include<conio.h>  
     #include<string.h>  
     #include<graphics.h>  
     void main()  
     {  
           int key,i;  
          char data[30];  
          clrscr();  
          printf("\nEnter the plain text: ");  
          gets(data);  
          printf("\nEnter the key value: ");  
          scanf("%d",&key);  
         for(i=0;i<strlen(data);i++)  
         {     
               if(data[i]!=' ')   
              {  
                   if(data[i]>= data[strlen(data)-1-key])  
                   {  
                       data[i]=data[i]-26;  
                   }  
                   data[i]=data[i]+key;  
              }  
         }  
          printf("Your cipher text is: %s",data);  
          getch();  
     }  

Playfair Cipher in C

Hello friends, I am very happy to write my first post about implementation of Playfair cipher algorithm in c. 

For any query regarding c/c++ feel free to contact me on khimanichirag@gmail.com. I try my best to solve it.

     #include<stdio.h>   
     #include<conio.h>  
     #include<string.h>  
     #include<graphics.h>  
     void line(int a)  
     {  
          int i;  
           printf("\n");  
           for(i=0;i<a;i++)  
           {  
                printf("*");  
           }  
           printf("\n");  
     }  
     char s[30];  
     void main()  
     {  
         char c[27],k[30],temp[40],matrix[5][5],first,second;  
         int i,index,j,t,t1,p,p1,gd,gm;  
         initgraph(&gm,&gd, "c:\\tc\\bgi");  
         clrscr();  
         cleardevice();  
 //-------------------------ABCD in c[]---------------------------------  
         setcolor(2);  
         outtextxy(400,460,"Prepared By:Khimani Chirag");  
         setcolor(2);  
         outtextxy(150,10,"Welcome To Playfair Cipher Encryption");  
         for(i=97;i<=122;i++)  
         {  
               c[i-97]=i;  
         }  
 //---------------------------------------------------------------------  
           printf("\n\n");  
           line(50);  
           printf("enter the plain text: ");  
           gets(s);  
           printf("\nenter key for playfair cipher: ");  
           gets(k);  
           line(50);  
 //---------------------------put c[]<--* when key-----------------------  
           for(i=0;k[i]!='\0';i++)  
           {  
              index=k[i]-97;  
                if(c[index]=='*')  
                {  
                   k[i]='*';  
                }  
                else  
                {  
                   c[index]='*';  
                }  
           }  
 //------------------------------put key[] in variable-------------------  
         i=0;  
         j=0;  
           while(k[i] !='\0')  
           {  
             if(k[i]!='*' )  
             {  
                   temp[j]=k[i];  
                   j++;  
             }  
               i++;  
           }  
 //-----------------------------put c[] in temp variable------------------            
         i=0;  
         while(c[i] !='\0')  
           {  
                 if(c[i]!='*' && c[i]!='j' )  
                 {  
                 temp[j]=c[i];  
                 j++;  
                 }  
                 i++;  
           }  
          printf("\nyour matrix is:\n");  
          line(20);  
 //-----------------------------matrix printing---------------------------  
         t=0;  
         for(i=0;i<5;i++)  
         {  
                printf("*  ");  
               for(j=0;j<5;j++)  
               {  
                 printf("%c ",temp[t]);  
                 matrix[i][j]=temp[t];  
                 t++;  
               }  
                   printf("  *");  
                   if(i!=4)  
                        printf("\n");  
          }  
          line(20);  
          printf("\nyour cipher text is: ");  
 //------------------------------------------------------------------------  
         i=0;  
            if(strlen(s)%2!=0)  
            {  
               while(s[i]!='\0')  
               {  
                    i++;  
               }  
               s[i]='x';  
               s[i+1]='\0';  
            }  
           for(index=0;index<strlen(s);index+=2)  
           {  
                 first=s[index];  
                 second=s[index+1];  
              for(i=0;i<5;i++)  
              {  
                   for(j=0;j<5;j++)  
                   {  
                        if(matrix[i][j]==first)  
                       {  
                             t=i;  
                             t1=j;  
                       }  
                       if(matrix[i][j]==second)  
                       {  
                            p=i;  
                            p1=j;  
                       }  
                   }  
              }  
               if(p==t)  
               {  
                    if(p1==4)  
                    {  
                     p1=-1;  
                    }  
                    if(t1==4)  
                    {  
                      t1=-1;  
                    }  
                   printf("%c%c",matrix[t][t1+1],matrix[p][p1+1]);  
               }  
               else if(p1==t1)  
               {  
                    if(p==4)  
                    {  
                          p=-1;  
                    }  
                    if(t==4)  
                    {  
                      t=-1;  
                    }  
                    printf("%c%c",matrix[t+1][t1],matrix[p+1][p1]);  
               }  
               else  
               {  
                   printf("%c%c",matrix[t][p1],matrix[p][t1 ]);  
               }  
         }  
         getch();  
     }