Safeguarding against ransomware and data loss
The way to avoid data loss is to have backup copies.

Improve your online security with a Password Manager
What is a password manager, and which one should you use, if any?

Protecting yourself from a targeted attack
What to do when you're at high risk to be the target of an attack.

How to recover an Ethereum wallet
You only know it works when you've tested it.

Is that email genuine?
Protect yourself from fake emails.

Anonymity and Privacy on the Internet — Part I
Hiding your IP address.

Anonymity and Privacy on the Internet — Part II
Avoid to leave your fingerprint.

Anonymity and Privacy on the Internet — Part III
Obtaining an anonymous email account.

Apparmor - How to use it
Where to start when building an apparmor profile for an application.

The Linux Audit System, or Who Changed That File?
How to properly set up and use the Linux Audit System to find out who modified some file.

Exploring processes
Some simple ways of getting information about a running process.

GCC compiler benchmarks
Performance comparison of GCC versions ranging from 3.3.6 to 4.6.0. Also includes results for LLVM (upto 3.0).

Running firefox (on Linux) as a different (unprivileged) user
This article is intended to give a short but concise howto for running firefox (or any other graphical application) under a different (nonprivileged) user.

Securing a VPS or dedicated server
Everybody writes about proactive security, thus this article focuses on something different: "intrusion resistance", i.e. the ability to confine an intrusion and limit the potential damage.

Intrusion detection: unprivileged intruders
Suggestions for detecting intruders hiding under the identity of legitimate shell users.

Defending against brute force ssh attacks
An overview of different methods (and their respective trade-offs)for dealing with the problem.

A comparison of file integrity checkers (scanners)
This comparison focuses on technical performance — in particular in corner cases which are likely to reveal problems —, rather than simply listing and comparing features.

Linux kernel rootkits
A paper describing different ways of subverting the Linux kernel, and methods for detection of kernel rootkits.

Detecting a sniffer on an IPV6-enabled Linux system
What works, and what doesn't.

PGP signatures on open source software, and why you should check them

List of PGP Keyservers
(with response times)

Passwords and password generators

Internet services on Linux
How to determine what internet services are running on your machine, and how to switch them off

Email Address/Text Encoder
Helps you to hide your email address from spambots that harvest addresses from websites.

Beginners tutorial / howto / guide on compiling applications from source.