File encryption

[Mork <mortfromork () videotron ca>]

Hi group!

Question on file encryption. We want to add a layer to our file security.
Our hard disks are encrypted and we would like to add single file
encryption.

We are using Utimaco Private Crypto for single file but we need to re-save
the file everytime we make a change.

What is the best product that would silently encrypt and decrypt on-the-fly
so it's transparent to the users?

Thanks!

Mork!