Security - Rail Fence (complex) Encryption using C program.

This C program demonstrate how to encrypt data using Rail fence (complex) technique.

Assumptions:

1. 5 X 5 matrix is used.
2. Key = 21345

Sample Output:

RAIL FENCE ENCRYPTION

Input Data: A B C D E F G H I J K L M N O P Q R S T U V W X Y

Input data arranged in 5 X 5 matrix:
A B C D E
F G H I J
K L M N O
P Q R S T
U V W X Y

Key Used = 2 1 3 4 5

Ciphertext: B G L Q V A F K P U C H M R W D I N S X E J O T Y

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/*

Definition: Write a C program to Encrypt given data using Rail fence (complex) technique.

Assumptions:

1. 5 X 5 matrix is used.
2. Key = 21345

*/

#include<stdio.h>
int main()
{
 char str[5][5];
 int i,j,k, key[5]={2,1,3,4,5}, cnt=65;

 printf("RAIL FENCE ENCRYPTION\n\n");
 printf("Input Data: A B C D E F G H I J K L M N O P Q R S T U V W X Y\n\n");

 //Input data A to Y is stored in str[][] matrix.
 printf("Input data arranged in 5 X 5 matrix:\n");
 for(i=0; i<5; i++)
 {
  for(j=0; j<5; j++)
str[i][j]=cnt++;
 }

 //To print full matrix..
 for(i=0; i<5; i++)
 {
  for(j=0; j<5; j++)
printf("%c ",str[i][j]);
printf(" \n");
 }
 printf(" \n");
 printf("Key Used = 2 1 3 4 5 \n\n");
 printf("Ciphertext: ");

 for(j=0; j<5; j++)
 {
k=key[j]-1;
for(i=0; i<5; i++)
printf("%c ",str[i][k]);
 }
 return 0;
}

//Data can be taken from input.txt data file.
//Ciphertext can be stored into output.txt using C file management.

Output of the program

RAIL FENCE ENCRYPTION

Input Data: A B C D E F G H I J K L M N O P Q R S T U V W X Y

Input data arranged in 5 X 5 matrix:
A B C D E
F G H I J
K L M N O
P Q R S T
U V W X Y

Key Used = 2 1 3 4 5

Ciphertext: B G L Q V A F K P U C H M R W D I N S X E J O T Y

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