50求个白痴问题~~很白菜哦！

$licdomain = $domain;
$tmpvar = base64_encode(md5($domain.$str[$val]."jnyzn090211"));
    $domain = base64_encode($domain);
    $module = base64_encode($str[$val]);
    $lic = $tmpvar."=@".$domain."=@".$module;
    $data= $lic;
 
  if (sizeof($_POST) == 0)
    {
     unset($data);
 
    }
这是我一个朋友给我的php算法 是算域名的key  谁能帮帮忙完善下？？上面贴的是核心算法。
实例：www.05308.com  key:OTczMGZlYjdiMWJlNmRjN2RlYTcxOTJiYzc1NzQ2Y2U==@MDUzMDguY29t=@c3lzdGVtPVBST0ZFU1NJT058Zm9ydW09UFJPRkVTU0lPTnxhcnRpY2xlPVBST0ZFU1NJT058b2Jvb2s9UFJPRkVTU0lPTnxwYXk9UFJPRkVTU0lPTnx3YXA9UFJPRkVTU0lPTnx3YXBhcnRpY2xlPVBST0ZFU1NJT058d2FwZm9ydW09UFJPRkVTU0lPTnxiYWRnZT1QUk9GRVNTSU9OfGdyb3VwPVBST0ZFU1NJT058c3BhY2U9UFJPRkVTU0lPTnxpbmZvPVBST0ZFU1NJT058Y2FydG9vbj1QUk9GRVNTSU9OfHF1aXo9UFJPRkVTU0lPTnxuZXdzPVBST0ZFU1NJT058cHJvZHVjdD1QUk9GRVNTSU9OfHRlYW09UFJPRkVTU0lPTnx2b3RlPVBST0ZFU1NJT058bm90ZT1QUk9GRVNTSU9OfGxpbms9UFJPRkVTU0lPTg小弟先谢谢大家了