Half Lost, Half Bored – Companion Videos for Getting Started in Security

Security courses assume a lot: computer architecture, some maths, the terminal, Linux, networks, the web. In my course “Introduction to Security and Privacy”, students who have never opened a terminal sit next to students who run Linux at home. In the first tutorial, one half is lost and the other half is bored.

This semester our chair made 19 short companion videos in three series, which anyone may use under CC BY-SA 4.0. The teaser explains the idea in under two minutes.

The first series, Terminal basics, has six videos. It shows how to work in a terminal, log in to a university machine with ssh, copy files back and forth, use a key instead of a password, and keep a program running with tmux while the laptop is closed.

The eight videos of The network follow data on its way from your own laptop to a machine at the university: addresses, routing, NAT, ports, VPN and ssh tunnels. In five videos, Software Security explains what happens in the processor and in memory while a program runs, how a buffer overflow exploits that, and what helps against it.

Each video has a companion page that goes beyond the video. It explains the material again step by step for reading, with the commands to copy and the output you should see on your own machine. Notes for Windows and macOS and a section on common problems help when something does not work as shown. At the end come exercises to try yourself and questions to check your understanding: answer first, then open the model answer and compare.

The narration is in plain English, with captions in English and German.

Students who already know something skip it, and those who start from zero begin at the beginning. The aim is that everyone starts the tutorials from roughly the same place.

Video is most useful where something changes over time, and in security that is often the case. A login with a key takes several steps, a data packet passes through twenty stations, and a program writes past the end of a block of memory and overwrites what lies behind it. On the blackboard you draw the state before and the state after. In a video you see what happens in between.

I am sceptical of videos that simply film a lecture. They are rarely better than the lecture itself.

We built the series with Claude Code, an AI tool that writes program code on its own, runs it and checks the result. Each scene is programmed as a small web page, and a browser takes a picture of it frame by frame. Narration, music and captions are generated from code as well. When we change a sentence in the script, only that one scene is recorded again, and a single command rebuilds the whole chapter.

All 19 videos together took about two days to make, and polishing took a few days more. The limit was not the machine but how fast we could review.

We decided what each chapter teaches and in which order. We read and cut the scripts before anything was animated. Every command shown in a video ran on a test system first, and the output on screen is the real one. We watched every finished video before it went online.

The colophon of the website describes the instructions the tool received, what the individual steps looked like, and which parts are under which licences.

We cannot yet say whether the videos actually narrow the gap in the first tutorial, because the semester has only just started. Nor do we know who watches them: the students who need them, or those who know most of it already.

If you teach security, networks or systems basics yourself, you may use, link and adapt the videos and companion pages, as long as you name the source and share your changes under the same licence.

Which topics would help bring everyone up to the same level quickly? I would be glad to hear your suggestions.