As an alternative, you could winzip each of your files with a password so it would not matter if your files were uploaded by someone else because they could never user them.
An even more secure method would be to use PGP (Pretty Good Privacy) encryption on your files, here is the URL:
http://www.pgpi.org/
Either way should give you the protection you are after. Just remember that to get the kind of security you are after will take a bit of work on your part because, as 6_Pac hinted, there is no quick security fix.
UK Bob