// Copyright (c) The University of Cincinnati. All rights reserved.
// UC MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
// THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
// TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
// PARTICULAR PURPOSE, OR NON-INFRINGEMENT.  UC SHALL NOT BE LIABLE
// FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING,
// RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
// DERIVATIVES.
// By using or copying this Software, Licensee agrees to abide by the
// intellectual property laws, and all other applicable laws of the
// U.S., and the terms of this license.

// Author : Antarpreet Singh
//

#include <iostream>
#include <vector>
#include <math.h>

using namespace std;

void binary(int,vector<bool>&,int);
int decimal(bool*, int);

void DES10(vector <bool> *ptext, vector <bool> *key, vector <bool> *ctext) {

  int i;
  int right_index = 6; 
  bool l[4];
  for(i=0; i<4; i++) {
    l[i] = (*ptext).at(right_index+i);
  }

  bool t[6];

  for(i=0; i<6; i++) {
    t[i] = (*ptext).at(i)^(*key).at(5-i);    
  }
  
  bool temp[4] = {t[5], t[4], t[3], t[2]};
  bool temp2[2] = {t[1], t[0]};
  int sboxout;

  switch(decimal(temp,4)) {
    case 0:
          switch(decimal(temp2,2)) {
            case 0: sboxout = 13; break ;
            case 1: sboxout = 1; break ;
            case 2: sboxout = 7; break ;
            case 3: sboxout = 2; break ;
          }
          break;
    case 1:
          switch(decimal(temp2,2)) {
            case 0: sboxout = 2; break ;
            case 1: sboxout = 15; break ;
            case 2: sboxout = 11; break ;
            case 3: sboxout = 1; break ;
          }
          break;
    case 2:
          switch(decimal(temp2,2)) {
            case 0: sboxout = 8; break ;
            case 1: sboxout = 13; break ;
            case 2: sboxout = 4; break ;
            case 3: sboxout = 14; break ;
          }
          break;
    case 3:
          switch(decimal(temp2,2)) {
            case 0: sboxout = 4; break ;
            case 1: sboxout = 8; break ;
            case 2: sboxout = 1; break ;
            case 3: sboxout = 7; break ;
          }
          break;
    case 4:
          switch(decimal(temp2,2)) {
            case 0: sboxout = 6; break ;
            case 1: sboxout = 10; break ;
            case 2: sboxout = 9; break ;
            case 3: sboxout = 4; break ;
          }
          break;
    case 5:
          switch(decimal(temp2,2)) {
            case 0: sboxout = 15; break ;
            case 1: sboxout = 3; break ;
            case 2: sboxout = 12; break ;
            case 3: sboxout = 10; break ;
          }
          break;
    case 6:
          switch(decimal(temp2,2)) {
            case 0: sboxout = 11; break ;
            case 1: sboxout = 7; break ;
            case 2: sboxout = 14; break ;
            case 3: sboxout = 8; break ;
          }
          break;
    case 7:
          switch(decimal(temp2,2)) {
            case 0: sboxout = 1; break ;
            case 1: sboxout = 4; break ;
            case 2: sboxout = 2; break ; 
            case 3: sboxout = 13; break ;
          }
          break;
    case 8:
          switch(decimal(temp2,2)) {
            case 0: sboxout = 10; break ;
            case 1: sboxout = 12; break ;
            case 2: sboxout = 0; break ;
            case 3: sboxout = 15; break ;
          }
          break;
    case 9:
          switch(decimal(temp2,2)) {
            case 0: sboxout = 9; break ;
            case 1: sboxout = 5; break ;
            case 2: sboxout = 6; break ;
            case 3: sboxout = 12; break ;
          }
          break;
    case 10:
          switch(decimal(temp2,2)) {
            case 0: sboxout = 3; break ;
            case 1: sboxout = 6; break ;
            case 2: sboxout = 10; break ;
            case 3: sboxout = 9; break ;
          }
          break;
    case 11:
          switch(decimal(temp2,2)) {
            case 0: sboxout = 14; break ;
            case 1: sboxout = 11; break ;
            case 2: sboxout = 13; break ;
            case 3: sboxout = 0; break ;
          }
          break;
    case 12:
          switch(decimal(temp2,2)) {
            case 0: sboxout = 5; break ;
            case 1: sboxout = 0; break ;
            case 2: sboxout = 15; break ;
            case 3: sboxout = 3; break ;
          }
          break;
    case 13:
          switch(decimal(temp2,2)) {
            case 0: sboxout = 0; break ;
            case 1: sboxout = 14; break ;
            case 2: sboxout = 3; break ;
            case 3: sboxout = 5; break ;
          }
          break;
    case 14:
          switch(decimal(temp2,2)) {
            case 0: sboxout = 12; break ;
            case 1: sboxout = 9; break ;
            case 2: sboxout = 5; break ;
            case 3: sboxout = 6; break ;
          }
          break;
    case 15:
          switch(decimal(temp2,2)) {
            case 0: sboxout = 7; break ;
            case 1: sboxout = 2; break ;
            case 2: sboxout = 8; break ;
            case 3: sboxout = 11; break ;
          }
          break;
  }
  
  vector<bool> sboxout_bool(4,0);

  binary(sboxout,sboxout_bool,0);
 
  for(i=3; i>=0; i--) {
    (*ctext).push_back(sboxout_bool[i]^l[3-i]);    
  }
}

/******************************************************************/

int decimal(bool* bin, int no_bits)
{
  int i,dec=0;
  
  for(i=0;i<no_bits;i++)
  {
    dec = dec + bin[i]*pow(2,i);
  }
  return(dec);
} 
/******************************************************************/
void binary(int number, vector<bool> &bin, int index) {
	int remainder;

	if(number <= 1) {
		bin[index] =number;
	}
  else {
	remainder = number%2;
	bin[index] =remainder;
	binary(number>>1,bin,index+1);
  }    
}
/******************************************************************/