Pillar 3 · Security

Security

How systems get attacked and defended. Eight guides in the full TechForge style — diagrams, quizzes, interview questions — from threat modeling to incident response.

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What is security, really?

Security is not a feature you bolt on — it’s a property you design for. Every control defends one of three things: that data stays secret, stays unaltered, and stays available. Attackers look for the one place you forgot.

The goal isn’t perfection — it’s raising the cost of attack above its reward and shrinking the blast radius when a control fails. Threat modeling, least privilege, and defense in depth are the three ideas everything else hangs off.

These guides are strictly defensive and educational: understand how attacks work so you can stop them. Practice only on systems you own or are explicitly authorized to test — your own lab, CTFs, or a signed engagement.

Learning path

Eight guides, in order — diagrams, real examples, interview questions and a quiz in each.

1
Security Fundamentals
The CIA triad, threat modeling with STRIDE, defense in depth and least privilege.
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2
Cryptography Basics
Symmetric vs asymmetric, hashing, signatures, key exchange — and the golden rules.
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3
AuthN & AuthZ
Password hashing done right, sessions vs JWT, OAuth 2.0 and OIDC without hand-waving.
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4
Web Attacks (OWASP)
SQL injection, XSS, CSRF, SSRF and IDOR — how each works and its one correct fix.
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5
TLS & PKI
The padlock explained — certificates, the chain of trust, the handshake and forward secrecy.
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6
Network Security
Firewalls, segmentation, DMZs, DDoS defense and the zero-trust model.
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7
Secure Development
Secrets management, dependency and supply-chain risk, and shifting security left.
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8
Attacks & Incident Response
The kill chain, why phishing wins, the PICERL playbook and blameless postmortems.
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