Restriction access aplications to folders + (un)crypt on fly

[filinjs]

Hello everybody.
Looking for soft:
+ OS WinXP
+ restrict access to folders(only trusted applications),as it do S'n'S
+ (de)crypt on the fly

Thats for trusted application access is easy always.
But for untrusted files(folders) hidden or crypted.

Anybody know such soft ?

For example Notepad can open this file and read,but IE don't see file or see crypted file.

It is desirable to autobackup cryptes archives too.

Thanks.