Cloaking redirect

I need a redirect that will cloak affiliate links to make it extremely hard to trace but not drop the affiliate cookie. I've found some that will cloak the link well but they lose the cookie.. Iframes keep the cookie but they're too easy to trace so that will not work. This needs to keep the cookie on every browser type every time but still be cloaked.. can be javascript or php or anything really aslong as it's readable by all browsers.