Hiding a file structure

If I place sensitive but not critical info on a CD, how can I protect against directory browsing? Use CrytoAPI? What kind of a performance bite does this take in memory? Is there any other function in the API that would disable directory browsing???

[KENNNY]

i don't thing you can just *hide* your files from users in explorer - you can give them the hidden attribute, but people can still show hidden files.
encrypting won't help - it'll just make the files unreadable..not invisible.

Kennny thanks for the post thought that there might be something somewhere in the API that could make this file structure invisible to the user. Thanks.