Hi im looking for some code which can hide url from address bar after redirect

Here is current look

http://www.my-site.com/download/?http://www.target-url.com

I have a DOWNLOAD button in custom redirect page which appear after 5 sec. But user can get link from address bar before appear DOWNLOAD button.

so i want some code which can encode or hide target url from address bar so user only get link from DOWNLOAD button which appear after 5 sec.

http://www.my-site.com/download/?xxxxxxxx

Im using WP link cloaking with custom redirect page. If you have any other better idea please share that too.

Thanks