Question about encoding a String.

[deathemperor]

I want to encode a String of a media URL so that when I embed it to play in HTML page the users can only listen or watch it in the player but they cannot copy the link.

Is it possible to do so with md5() function ?

I want to do that because I don't want other sites leech my media.

by the way is it possible to prevent hot linking with media files using .htaccess (when someone embed link from my site to a HTML page in their site) ?

Thanks in advance, I do need a solution.