Track 5 of 12
Security fundamentals
Learn how to think about security before you touch a tool.
Beginner 7 lessons Prerequisite: Foundations and the shell-in-practice track.
The conceptual heart of the course. It opens with the security mindset and threat modelling, which are ways of reasoning rather than pieces of software, then moves to the practical work: hashing, passwords and keys, reading a log, and reducing what your phone exposes. Everything here is defensive and aimed at your own device.
By the end, you can say what security actually protects, reason about what could go wrong with a system, and harden your own.
Lessons in this track
- 01 The security mindset There is no perfectly secure system, only different degrees of exposure. The aim is a smaller blast radius, not zero risk.
- 02 Thinking in threats: modelling a system A threat model is four questions you can ask about anything. The output is a short list with a decision next to each item.
- 03 Encoding and hashes Encode, decode and verify files with base64, xxd, strings and sha256sum on your phone.
- 04 Passwords, keys and secrets How hashing, long passphrases and a protected SSH key keep your secrets yours, not someone else's.
- 05 Reading logs and spotting oddities Learn what normal looks like, then find the failed logins and odd bursts hiding in plain text.
- 06 Hardening your Termux setup Fewer open doors and tighter file permissions make a smaller target, and that is the whole game.
- 07 Safe habits and privacy Anything you type or paste into a terminal can be written down, so plan for it being read later.