Computer Science · Security Unit

Computer security, taught through one very exposed robotics club.

Eighty members, one shared password, and a laptop that goes home in a backpack. Over four sessions and a homework week, then four more, you'll fix that arrangement piece by piece — and pick up the CIA triad, authentication, encryption, layered defence, backups and a real security plan along the way.

Format: 4 sessions + homework, twice·Total: 8 hours class, 4 hours homework·No programming experience required

Executive summary

Start here. Read the sessions in order. Keep a separate answer document, attempt each activity before checking the answers, and correct mistakes in a different colour. Every session includes explanations, a diagram, a worked example, practice and feedback.

Week	Student notes	Class time	Homework
1	1. Security goals and risk	60 min	—
1	2. Malware and social engineering	60 min	—
1	3. Accounts and access control	60 min	—
1	4. Encryption and hashing	60 min	120 min
2	5. Networks and layered protection	60 min	—
2	6. Backups and incident response	60 min	—
2	7. Design a security plan	60 min	—
2	8. Assessment and revision	60 min	120 min
	Total	8 hours	4 hours

Videos and diagrams

Each session links two or three YouTube videos with a question to guide viewing. The named core viewing window fits inside the lesson timetable — stop when it ends. Everything else is optional, not extra compulsory homework. Videos are supplements: the notes contain what you need for the activities even if YouTube is blocked at school.

Note

Video titles and links were checked against web-indexed video pages or publisher references on 8 September 2026; playback and regional/school availability were not tested. Some videos are older — use the written notes for current password and cryptography guidance, and don't memorise historical statistics from them. Review sessions deliberately reuse earlier videos with new questions.

Diagrams are included as editable Mermaid code blocks. A Markdown viewer with Mermaid support renders them as diagrams; each also has a plain-language explanation, so the notes still work in a basic text editor.

Our continuing case study

Case file

The Harbour School Robotics Club has 80 members, two student treasurers and a teacher supervisor. It stores contact details and payment records. Its laptop is sometimes taken home. Right now, members share one password, everyone can edit the records, and the only copy lives on that one laptop. Your job, across this unit, is to improve that arrangement — without making the club impossible to actually run.

Use fictional information and disposable files for practical work. Do not try attacks on real accounts or networks. Never put a real password into a course answer or an online password checker.

Assessment status

Timed assessment

The previously mentioned past papers were not accessible when these notes were prepared. This is therefore a general Year 12 course, not a verified match to a specific qualification or exam board. All practice questions and marking guides are original. The final assessment is a learning check, not an official grade predictor.

What to submit to yourself

• Completed activities and a glossary.
• Week 1 homework, including a harmless file-recovery exercise.
• A justified security plan from Session 7.
• The marked 30-mark assessment, corrections and Week 2 transfer task.

Move on when you can explain each session's exit question without copying. If you can't, revisit the worked example and rewrite your explanation.

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7. 7
8. 8

Start · Session 1: Security goals and risk →