A safe way to offer a paid downloadable product on wp?

Hi,

Is there any way to offer “safely” a paid downloadable product on wp to a client who has purchased it, without the search engines finding the download page? (So that no one can access the page without making the payment first)Is there some code that you can put into this page that would prevent the search engines from finding it? Or is some third party download service the only choice..? But at least those thirdparty downloading services I have used myself to be able to download some product have required signing up first. So I’d rather offer this downloadable product on my website so that the buyers can get it instantly after payment without some extra hassle. Is the password protected page the only way to secure the download page or are there some other ways, like some codes that would “hide” it or some plugins? Thanks!