Htaccess Redirect To Captcha Site Before File Download

Hi, Short: ______________________________ => Download Link (<a href) ... then => Captcha Page => PHP Variable With Download Link => Enter Captcha => Start Download => Successful Start? Redirect To Thank You Page Long description: I have a very simple project for you. After clicking on a download link I want to be redirected to a captcha page, but I don't want to change any links at all. Then after I enter the captcha the download should finally start. So let's say I want to download [login to view URL] then you need to write a htaccess code to redirect me, then you need to get the last request (the download link) and give it to me via a simple PHP variable. I also want a simple solution to redirect the user to a thank you page after a success file download. There are probably several ways to solve this, so I don't care how you solve this as long as I don't have to change any links and I can access the download link via PHP. Requirements: - No Links Should Be Changed - Need Download Link As PHP Variable This should be a piece of cake for every programmer. I'd do it myself, but I still need to learn more about modrewrite and I want an elegant solution. Budget: The cheaper the better Thanks! Oliver