<?php
/**
 * AgileBill - Open Billing Software
 *
 * This body of work is free software; you can redistribute it and/or
 * modify it under the terms of the Open AgileBill License
 * License as published at http://www.agileco.com/agilebill/license1-4.txt
 *
 * Originally authored by Tony Landis, AgileBill LLC
 *
 * Recent modifications by Deon George
 *
 * @author Deon George <deonATleenooksDOTnet>
 * @copyright 2009 Deon George
 * @link http://osb.leenooks.net
 *
 * @link http://www.agileco.com/
 * @copyright 2004-2008 Agileco, LLC.
 * @license http://www.agileco.com/agilebill/license1-4.txt
 * @author Tony Landis <tony@agileco.com>
 * @package AgileBill
 * @subpackage Core
 */

if (! defined('LICENSE_KEY'))
	define('LICENSE_KEY','47012093-4943-32127707');

/**
 * The main AgileBill CORE RSA Class
 *
 * @package AgileBill
 * @subpackage Core
 * @todo This Class appears unused.
 */
class CORE_RSA {
	private $primes = array();
	private $maxprimes = 0;

	public function __construct() {
		mt_srand((double)microtime()*1000000);

		$this->primes = array(
		4507,4513,4517,4519,4523,4547,4549,4561,4567,4583,4591,4597,
		4603,4621,4637,4639,4643,4649,4651,4657,4663,4673,4679,4691,4703,4721,4723,4729,4733,4751,
		4759,4783,4787,4789,4793,4799,4801,4813,4817,4831,4861,4871,4877,4889,4903,4909,4919,4931,
		4933,4937,4943,4951,4957,4967,4969,4973,4987,4993,4999,5003,5009,5011,5021,5023,5039,5051,
		5059,5077,5081,5087,5099,5101,5107,5113,5119,5147,5153,5167,5171,5179,5189,5197,5209,5227,
		5231,5233,5237,5261,5273,5279,5281,5297,5303,5309,5323,5333,5347,5351,5381,5387,5393,5399,
		5407,5413,5417,5419,5431,5437,5441,5443,5449,5471,5477,5479,5483,5501,5503,5507,5519,5521,
		5527,5531,5557,5563,5569,5573,5581,5591,5623,5639,5641,5647,5651,5653,5657,5659,5669,5683,
		5689,5693,5701,5711,5717,5737,5741,5743,5749,5779,5783,5791,5801,5807,5813,5821,5827,5839,
		5843,5849,5851,5857,5861,5867,5869,5879,5881,5897,5903,5923,5927,5939,5953,5981,5987,6007,
		6011,6029,6037,6043,6047,6053,6067,6073,6079,6089,6091,6101,6113,6121,6131,6133,6143,6151,
		6163,6173,6197,6199,6203,6211,6217,6221,6229,6247,6257,6263,6269,6271,6277,6287,6299,6301,
		6311,6317,6323,6329,6337,6343,6353,6359,6361,6367,6373,6379,6389,6397,6421,6427,6449,6451,
		6469,6473,6481,6491,6521,6529,6547,6551,6553,6563,6569,6571,6577,6581,6599,6607,6619,6637,
		6653,6659,6661,6673,6679,6689,6691,6701,6703,6709,6719,6733,6737,6761,6763,6779,6781,6791,
		6793,6803,6823,6827,6829,6833,6841,6857,6863,6869,6871,6883,6899,6907,6911,6917,6947,6949,
		6959,6961,6967,6971,6977,6983,6991,6997,7001,7013,7019,7027,7039,7043,7057,7069,7079,7103,
		7109,7121,7127,7129,7151,7159,7177,7187,7193,7207,7211,7213,7219,7229,7237,7243,7247,7253,
		7283,7297,7307,7309,7321,7331,7333,7349,7351,7369,7393,7411,7417,7433,7451,7457,7459,7477,
		7481,7487,7489,7499,7507,7517,7523,7529,7537,7541,7547,7549,7559,7561,7573,7577,7583,7589,
		7591,7603,7607,7621,7639,7643,7649,7669,7673,7681,7687,7691,7699,7703,7717,7723,7727,7741,
		7753,7757,7759,7789,7793,7817,7823,7829,7841,7853,7867,7873,7877,7879,7883,7901,7907,7919,
		7927,7933,7937,7949,7951,7963,7993,8009,8011,8017,8039,8053,8059,8069,8081,8087,8089,8093,
		8101,8111,8117,8123,8147,8161,8167,8171,8179,8191,8209,8219,8221,8231,8233,8237,8243,8263,
		8269,8273,8287,8291,8293,8297,8311,8317,8329,8353,8363,8369,8377,8387,8389,8419,8423,8429,
		8431,8443,8447,8461,8467,8501,8513,8521,8527,8537,8539,8543,8563,8573,8581,8597,8599,8609,
		8623,8627,8629,8641,8647,8663,8669,8677,8681,8689,8693,8699,8707,8713,8719,8731,8737,8741,
		8747,8753,8761,8779,8783,8803,8807,8819,8821,8831,8837,8839,8849,8861,8863,8867,8887,8893,
		8923,8929,8933,8941,8951,8963,8969,8971,8999,9001,9007,9011,9013,9029,9041,9043,9049,9059,
		9067,9091,9103,9109,9127,9133,9137,9151,9157,9161,9173,9181,9187,9199,9203,9209,9221,9227,
		9239,9241,9257,9277,9281,9283,9293,9311,9319,9323,9337,9341,9343,9349,9371,9377,9391,9397,
		9403,9413,9419,9421,9431,9433,9437,9439,9461,9463,9467,9473,9479,9491,9497,9511,9521,9533);

		$this->maxprimes = count($this->primes)-1;
	}

	public function generate_keys(){
		$e = false;
		$d = false;
		$q = false;

		while (! $e || ! $d) {
			$p = $this->primes[mt_rand(0,$this->maxprimes)];

			while (! $q || ($p==$q))
				$q = $this->primes[mt_rand(0,$this->maxprimes)];

			$n = $p*$q;
			$pi = ($p-1)*($q-1);
			$e = $this->tofindE($pi,$p,$q);
			$d = $this->extend($e,$pi);
			$keys = array($n,$e,$d);
		}

		return $keys;
	}

	private function mo($g,$l) {
		return $g-($l*floor($g/$l));
	}

	private function extend($Ee,$Epi) {
		$u1 = 1;
		$u2 = 0;
		$u3 = $Epi;
		$v1 = 0;
		$v2 = 1;
		$v3 = $Ee;

		while ($v3 != 0) {
			$qq = floor($u3/$v3);
			$t1 = $u1-$qq*$v1;
			$t2 = $u2-$qq*$v2;
			$t3 = $u3-$qq*$v3;
			$u1 = $v1;
			$u2 = $v2;
			$u3 = $v3;
			$v1 = $t1;
			$v2 = $t2;
			$v3 = $t3;
			$z = 1;
		}

		$uu = $u1;
		$vv = $u2;

		if ($vv < 0)
			$inverse = $vv+$Epi;
		else
			$inverse = $vv;

		return $inverse;
	}

	private function GCD($e,$pi) {
		$y = $e;
		$x = $pi;

		while ($y != 0) {
			$w = $this->mo($x,$y);
			$x = $y;
			$y = $w;
		}

		return $x;
	}

	private function tofindE($pi) {
		$great = 0;
		$cc = mt_rand(0,$this->maxprimes);
		$startcc = $cc;

		while ($cc >= 0) {
			$se = $this->primes[$cc];
			$great = $this->GCD($se,$pi);
			$cc--;

			if ($great == 1)
				break;
		}

		if ($great == 0) {
			$cc = $startcc + 1;

			while ($cc <= $this->maxprimes) {
				$se = $this->primes[$cc];
				$great = $this->GCD($se,$pi);
				$cc++;

				if ($great == 1)
					break;
			}
		}

		return $se;
	}

	public function rsa_encrypt($m,$e,$n) {
		$asci = array();
		$coded = '';

		for ($i=0; $i<strlen($m); $i+=3) {
			$tmpasci = '1';

			for ($h=0; $h<3; $h++) {
				if ($i+$h <strlen($m)) {
					$tmpstr = ord(substr($m,$i+$h,1))-30;

					if (strlen($tmpstr) < 2)
						$tmpstr = '0'.$tmpstr;

				} else {
					break;
				}

				$tmpasci .= $tmpstr;
			}

			array_push($asci,$tmpasci.'1');
		}

		for ($k=0; $k< count($asci); $k++) {
			$resultmod = $this->powmod($asci[$k],$e,$n);
			$coded .= $resultmod.' ';
		}

		return trim($coded);
	}

	private function powmod($base,$exp,$modulus) {
		$accum = 1;
		$i = 0;
		$basepow2 = $base;

		while (($exp >> $i)>0) {
			if ((($exp >> $i) & 1) == 1)
				$accum = $this->mo(($accum*$basepow2),$modulus);

			$basepow2 = $this->mo(($basepow2*$basepow2),$modulus);

			$i++;
		}

		return $accum;
	}

	public function rsa_decrypt($c,$d,$n) {
		$decryptarray = explode(' ',$c);
		$resultd = '';
		$deencrypt = '';

		for ($u=0; $u<count ($decryptarray); $u++)
			if ($decryptarray[$u] == '')
				array_splice($decryptarray,$u,1);

		for ($u=0; $u< count($decryptarray); $u++) {
			$resultmod = $this->powmod($decryptarray[$u],$d,$n);
			$deencrypt .= substr($resultmod,1,strlen($resultmod)-2);
		}

		for ($u=0; $u<strlen($deencrypt); $u+=2)
			$resultd .= chr(substr($deencrypt,$u,2)+30);

		return $resultd;
	}
}

/**
 * Encrypt some data
 */
function CORE_encrypt($data) {
	$rsa = new CORE_RSA;

	$keys = explode('-',LICENSE_KEY);
	$rc4_key = do_rc4(LICENSE_KEY,'en',false);

	$rsa_data = $rsa->rsa_encrypt($data,$keys[1],$keys[0]);
	$rc4_data = do_rc4($rsa_data,'en',$rc4_key);

	return $rc4_data;
}

/**
 * Decrypt the data
 */
function CORE_decrypt($data) {
	$rsa = new CORE_RSA;

	$keys = explode('-',LICENSE_KEY);
	$rc4_key = do_rc4(LICENSE_KEY,'en',false);

	$rc4_data = do_rc4($data,'de',$rc4_key);
	$rsa_data = $rsa->rsa_decrypt($rc4_data,$keys[2],$keys[0]);

	return $rsa_data;
}

/**
 * Do the encryption/decryption
 */
function do_rc4($data,$case,$pwd) {
	if (! $pwd)
		$pwd = '21e0*kO-(uV9B0@jFk-er';

	if ($case == 'de')
		$data = urldecode($data);

	$key = array();
	$box = array();
	$temp_swap = '';
	$pwd_length = strlen($pwd);

	for ($i = 0; $i <= 255; $i++) {
		$key[$i] = ord(substr($pwd,($i%$pwd_length),1));
		$box[$i] = $i;
	}

	$x = 0;
	for ($i=0; $i<=255; $i++) {
		$x = ($x+$box[$i]+$key[$i])%256;
		$temp_swap = $box[$i];
		$box[$i] = $box[$x];
		$box[$x] = $temp_swap;
	}

	$temp = '';
	$k = '';
	$cipherby = '';
	$cipher = '';
	$a = 0;
	$j = 0;

	for ($i=0; $i<strlen($data); $i++) {
		$a = ($a+1)%256;
		$j = ($j+$box[$a])%256;
		$temp = $box[$a];
		$box[$a] = $box[$j];
		$box[$j] = $temp;
		$k = $box[(($box[$a]+$box[$j])%256)];
		$cipherby = ord(substr($data,$i,1))^$k;
		$cipher .= chr($cipherby);
	}

	if ($case == 'de')
		$cipher = urldecode(urlencode($cipher));
	else
		$cipher = urlencode($cipher);

	return $cipher;
}
?>