Contact Learn C
Copy

Program 231: Decryption of Viginere Cipher using C

Program 231:
Click here to know Encryption of Viginere Cipher 
 
#include<stdio.h>
#include<string.h>
#include<ctype.h>
#include<stdlib.h>
main()
{
 int i,j,k,numstr[100],numkey[100],numcipher[100];
 char str[100],key[100];
 printf("Enter a string to Decrypt\n");
 gets(str);
 //converting entered string to Capital letters
 for(i=0,j=0;i<strlen(str);i++)
 {
  if(str[i]!=' ')
  {
   str[j]=toupper(str[i]);   
   j++;
  }
 }
 str[j]='\0';
 printf("Entered string is : %s \n",str);
 //Storing string in terms of ascii
 for(i=0;i<strlen(str);i++)
 {
  numstr[i]=str[i]-'A';
 }
 printf("Enter a key\n");
 gets(key);
    //converting entered key to Capital letters
 for(i=0,j=0;i<strlen(key);i++)
 {
  if(key[i]!=' ')
  {
   key[j]=toupper(key[i]);   
   j++;
  }
 }
 key[j]='\0';
     //Assigning key to the string
    for(i=0;i<strlen(str);)
    {
     for(j=0;(j<strlen(key))&&(i<strlen(str));j++)
     {
      numkey[i]=key[j]-'A';
      i++;
     }
     
    }
    
    for(i=0;i<strlen(str);i++)
    {
     numcipher[i]=numstr[i]-numkey[i];//changed from + to - for decryption 
     if(numcipher[i]<0)
     {
      numcipher[i]+=26;
     }
    }

    printf("Decrypted Vigenere Cipher text is\n");   
    for(i=0;i<strlen(str);i++)
    {
      printf("%c",(numcipher[i]+'A')); 
    }
    
 printf("\n");
}
Explanation:

//Coming Soon 
    Output:

    Decryption of Viginere Cipher using C

    Decryption of Viginere Cipher using C


    1 comment:

    1. factorial hundred In the last few days, the “factorial of 100” is one of the top subjects and a lot of maths geeks compute it using voice assistants such as Alexa, Shiri, etc.

      factorial hundred In the last few days, the “factorial of 100” is one of the top subjects and a lot of maths geeks compute it using voice assistants such as Alexa, Shiri, etc.

      factorial hundred In the last few days, the “factorial of 100” is one of the top subjects and a lot of maths geeks compute it using voice assistants such as Alexa, Shiri, etc.

      vegamovies Earlier people were not so much means to watch movies and to watch movies, we had to go to the movies hall where we were not allowed to go without tickets, but now people can watch movies online since the internet became cheaper.

      ReplyDelete

    Donate

    Download App and Learn when ever you want

    Get it on PlayStore
    Get it on Amazon App Store
    Get it on Aptoide