Encryption class

[neel_basu]

Hi! all if you dont have mCrypt you can use this Encryption class as an alternative

(based on XOR Encryption)

Plese post if you find any bugs.

<?php
class crytpo{
/*
Encryptor Class without mcrypt
Author Neel basu
This is a Pre release beta of Zogmoyd's next version's Level 1 Encryption Class
Made on july 15 2007. Its Under GPL Licence
Please see GNU GPL before using it. 
you can Use it Untill the above message is intact.
*/
private $val;
public function __construct(){
if(!defined('BLOCK_SIZE')){define('BLOCK_SIZE', 4);}
if(!defined('BLOCK_JUNK')){define('BLOCK_JUNK', 5);}
if(!defined('ENC_BIN')){define('ENC_BIN', true);}
if(!defined('ENC_DEC')){define('ENC_DEC', false);}
$this->val = array(' ', '+', '_', '*', '&', ':', '-', '@', '=', '%');
}
private function blockise($str){
if(strlen($str) >= BLOCK_SIZE*2){return $str;}
while(strlen($str) < BLOCK_SIZE*2){
	$str .= chr(BLOCK_JUNK);
}
return $str;
}
private function dblockise($str){
for($i=strlen($str)-1;$i>=strlen($str)-1-8;$i--){
	if($str[$i] != chr(BLOCK_JUNK)){break;}
	$str = substr($str, 0, $i);
}
return $str;
}
private function psubstr($str, $start, $len){
if($start < 0){$tmp = "";return $tmp;};
return substr($str, $start, $len);
}
private function get_block($str, $i){return $this->psubstr($str, $i, BLOCK_SIZE);}
private function x_enc($string, $key){
  for($i=0; $i<=strlen($string)-1; $i++){
    for($j=0; $j<=strlen($key)-1; $j++){
      $string[$i] = $string[$i]^$key[$j];
    }
	if($i != 0 && $i != strlen($string)-1){
		$string[$i] = $string[$i]^$string[$i-1]^$string[$i+1];
	}
  }
return $string;
}
private function x_dcd($string, $key){
  for($i=strlen($string)-1; $i>=0; $i--){
	  if($i == 0 || $i == strlen($string)-1){
	    for($j=0; $j<=strlen($key)-1; $j++){
	      $string[$i] = $string[$i]^$key[$j];
	    }
	  }else{
	  	$string[$i] = $this->x_enc($string[$i], $key)^$string[$i-1]^$string[$i+1];
	  }
 }
return $string;
}
private function enc($str, $key){
$str = base64_encode($this->blockise($str));
for($i=0;$i<=strlen($str)-1;$i+=BLOCK_SIZE){
	if($i == 0 || $i == (strlen($str)-BLOCK_SIZE)){
		$repl = $this->x_enc($this->psubstr($str, $i, BLOCK_SIZE), $key);
		$str = substr_replace($str, $repl, $i, BLOCK_SIZE);
	}else{
		if($i == BLOCK_SIZE){
			$b = $this->x_enc($this->get_block($str, $i), $key);
		}
		$repl = $this->x_enc($this->get_block($str, $i+BLOCK_SIZE), $this->get_block($str, $i-BLOCK_SIZE));
		$str = substr_replace($str, $repl, $i, BLOCK_SIZE);
	}
}
$str .= $b;
return $str;
}
private function dcd($str, $key){
$b = $this->x_dcd($this->get_block($str, strlen($str)-BLOCK_SIZE), $key);
$str = substr($str, 0, strlen($str)-BLOCK_SIZE);
for($i=strlen($str)-BLOCK_SIZE;$i>=0;$i-=BLOCK_SIZE){
	if($i == 0 || $i == (strlen($str)-BLOCK_SIZE)){
		$repl = $this->x_dcd($this->psubstr($str, $i, BLOCK_SIZE), $key);
		$str = substr_replace($str, $repl, $i, BLOCK_SIZE);
	}else{
		if($i == BLOCK_SIZE){
			$str = substr_replace($str, $b, $i, BLOCK_SIZE);
		}else{
			$repl = $this->x_dcd($this->psubstr($str, $i-BLOCK_SIZE, BLOCK_SIZE), $this->psubstr($str, $i-(BLOCK_SIZE*2), BLOCK_SIZE));
			$str = substr_replace($str, $repl, $i, BLOCK_SIZE);
		}
	}
}
return $this->dblockise(base64_decode($str));
}
public function encode($str, $key, $mode = ENC_BIN){
if($mode == ENC_BIN){
	return $this->enc($this->enc($str, $key), md5($key));
}elseif($mode == ENC_DEC){
	return $this->dec_encode($this->enc($this->enc($str, $key), md5($key)));
}
trigger_error("Invalid MODE SPecified", E_ERROR);
return false;
}
public function decode($str, $key, $mode = ENC_BIN){
if($mode == ENC_BIN){
	return $this->dcd($this->dcd($str, md5($key)), $key);
}elseif($mode == ENC_DEC){
	return $this->dcd($this->dcd($this->dec_decode($str), md5($key)),$key);
}
trigger_error("Invalid MODE SPecified", E_ERROR);
return false;
}
private function dec_decode($salted){
	$key = array(0,1,2,3,4,5,6,7,8,9);$ret = '';
    $val = $this->val;
    $str = str_replace($val, $key, $salted);
    for($i=0;$i<=strlen($str)-1;$i+=3){
  		$current_group = $str[$i].$str[$i+1].$str[$i+2];
  		$tmp_int = (int)($current_group);
  		$ret .= chr($tmp_int);
  	}
    return base64_decode($ret);
}
private function dec_encode($salt){
	$str = base64_encode($salt);$tmp = '';
  for($i=0;$i<=strlen($str)-1;$i++){
      if(ord($str[$i]) < 100){
        if(ord($str[$i]) > 0 && ord($str[$i]) < 10){
          $num = "00".ord($str[$i]);
        }
        elseif(ord($str[$i]) >= 10 && ord($str[$i]) < 100){
          $num = "0".ord($str[$i]);
        }
      }
      else{
        $num = ord($str[$i]);
      }
      $tmp .= $num;
    }
   $key = array(0,1,2,3,4,5,6,7,8,9);
   $val = $this->val;
   $ret = str_replace($key, $val, $tmp);
   return $ret;
}
}
?>

------------------------- USAGE ----------------------------------

<?php
$str = "1111111111111111111111111111111";
$key = "neel";
$crypto = new crytpo();
$e = $crypto->encode($str, $key);
echo "Encrypted \t[".$e."] Length \t".strlen($e)."\n\n";
$d = $crypto->decode($e, $key);
flush();//This is not needed at all.
echo "Decrypted \t[".$d."] Length ".strlen($d)."\n";
?>

Encrypted [

P5q#Qqn_<1gvOkqno4QrjztwFeQ

*T)

bQQvi:j2<] Length 68

 

Decrypted [1111111111111111111111111111111] Length 31

<?php
$str = "1111111111111111111111111111111";
$key = "neel";
$crypto = new crytpo();
$e = $crypto->encode($str, $key, ENC_DEC);
echo "Encrypted \t[".$e."] Length \t".strlen($e)."\n\n";
$d = $crypto->decode($e, $key, ENC_DEC);
flush();//This is not needed at all.
echo "Decrypted \t[".$d."] Length ".strlen($d)."\n";
?>

Encrypted [ -@+_  &% =+ @= =_ @* =% %% =* @@ -: =: == @ ++@ @_ --++-+ _ =  -: %%+_  -=++%+  ++  @++ &+_  :  =& : ++-+_  %=+ % :-+   @= @  @ +_+ %@++ ++_ &=+  +_ + * =: =_+ % =- =_ @  -:++- :* %=++  @& %  %%+ @ =%++* =- -: @@ @: @: =_++_+ : =: =_ @@ @@ -- &% @  :  %@ =&++_++* @@+ -++% -+] Length 276

 

Decrypted [1111111111111111111111111111111] Length 31

ENC_DEC is an optional argument that again encrypts the encrypted string with 10 characters

$this->val = array(' ', '+', '_', '*', '&', ':', '-', '@', '=', '%');

near line 15 . You can change these characters to customize it.

------------------------------ SECURITY --------------------------------------

See here we are encrypting 1111111111111111111111111111 a repetative character string

But see the encrypted String there is no repetation

If you use ENC_DEC the hacker will need to know 11 things

the keyword and that 10 Characters

Thats hardly possible.