Aage Johansen wrote:

> Geoff Worboys wrote:
> > ...
> > . TrueCrypt
> > http://www.truecrypt.org/
> > this is what I use now.
> > ...
>
> Could you say something about "performance penalty", if any?
> How do the sizes of encrypted and unencrypted files compare?

TrueCrypt is a whole-volume disk encryption facility. Performance is
felt mostly when disk sectors are first read and unencrypted. After that
the system's disk cache works its magic and you probably will not notice
any slow down.

Size of encrypted and unencrypted data is the same (insignificant
additional overhead to encrypted volumes).