Cyber Security
From first principles of trust and cryptography to attacking and defending real systems.
In this track · 10 lessons
Foundations
3 lessons- 1What security actually protects~11 minBefore any tool or attack, security is about three goals — confidentiality, integrity, availability — and a habit of thinking like an attacker.
- 2Hashing — a fingerprint for data~12 minInteractiveA hash turns any data into a short, fixed fingerprint that changes completely if the data changes at all — and can't be run backwards. It underpins integrity checks and password storage.
- 3Keys, and how strangers share a secret~13 minInteractiveEncryption needs a shared key — but how do two strangers agree on one over a channel everyone can see? Public-key ideas make the impossible routine.
Core
3 lessons- 4TLS — how the padlock works~14 minInteractiveEvery https:// page runs on TLS, which combines the Foundations primitives — key exchange, certificates and symmetric encryption — into a secure channel. Here's the whole handshake.
- 5Authentication — proving who you are~14 minInteractivePasswords, hashing at scale, multi-factor auth and session tokens — how systems verify identity, and the many ways that goes wrong.
- 6Web vulnerabilities — how attackers get in~15 minMost breaches don't break the cryptography — they exploit the application. Injection, XSS and broken access control, and the one habit that defends against them.
Advanced
2 lessons- 7Thinking like an attacker~14 minReal attacks aren't a single magic exploit — they're a campaign with stages. Learn the attack lifecycle and you learn where defenders get to intervene.
- 8Network security — attack and defend~14 minThe network is the battlefield attackers cross. Man-in-the-middle, denial of service and the defences — firewalls, segmentation and zero trust — that shape the fight.
Expert
2 lessons- 9Detection and incident response~14 minPrevention fails eventually, so mature security assumes breach: detect fast, respond calmly, recover cleanly. Meet logging, SIEM, the SOC and the incident lifecycle.
- 10The human layer — the real front line~13 minThe strongest cryptography is undone by a convincing email. Social engineering, security culture, and why the best defenders treat people as the primary attack surface.
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