From Knoppix Documentation Wiki
Security for HD-Installed Knoppix
The following are the basic steps to keeping your computer secure through software updates.
- Make sure you have the debian security update APT source in your /etc/sources.list
deb http://security.debian.org stable/updates main contrib non-free deb http://security.debian.org testing/updates main contrib non-free deb http://security.debian.org unstable/updates main contrib non-free
Keep an eye on http://www.debian.org/security/ , when there are updates you can download the .deb files individually then install them by running
dpkg -i PACKAGE_NAME.deb
You can subscribe to the debian-security-announce mailing list to be sent an email when there is a new security update.
Security is not a simple thing, the best reference is The Securing Debian Howto : http://www.debian.org/doc/manuals/securing-debian-howto/
Q: how to make a encrypted filesystem and also swap Q: how to encrypt all network and internet traffics