Secure Program Data encryption

What would be the best way of storing data securely away from users. What I have is a stack of files that get downloaded by the program, at the moment they COME encrypted, and stored in a temp location. Now where would be the be place to store them, and how would I store them? The program reads normal unencrypted files but in order for me to open them at the moment I nee to decrypt them in the temp folder and open them from there. This is bad because anyone could find the temp folder and simply copy out all the unencrypted files. Opening the files and then decrypting the bytearray is out of the question because the program only takes a filename as a option. Please just point me in the right direction!

Thanks,

-Josh

If data needs encrypting then you shouldn't really be storing it anywhere in an unencrypted format. But that's your decision so I'll assume you've decided.

But - bear in mind that newer versions of windows restrict where an application can write. For example in Windows7 all applications run with restricted permissions so can't even write to the program's own folder in the programfiles folder. Hiding files 'somewhere' in the file system isn't really a good strategy anymore.

Consider maybe a virtual drive ?

Ok. thanks. The application only takes in unencrypted files as a option.

Hmmmmm.... How does windows protect access to the SAM and other system folders?

-Josh