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

// defines
#define NUMBER_OF_ROUNDS 4

// function prototypes
void printBits(int plaintext, int len);
int sboxLeft(int x);
int sboxRight(int x);
int atoh(char *x, int len);
int genSubKey(int key, int encryptSubKey[], int decryptSubKey[], int numberOfRounds);
int SDES(int data, int subKey[], int encrypt, int numberOfRounds);
int expand(int right);