Module 18 — Cryptography internals
Every chapter: first principles, What insiders know, a See it yourself lab, connections, and a quiz with worked answers.
Entropy: randomness from physical memory
Ring oscillators, DRAM jitter, TRNG vs DRBG, `/dev/random`'s pool — why deterministic machines must steal unpredictability from physics.
AES and modes: the symmetric state machine
The 16-byte block, the key schedule, ECB's leaks, CTR's nonce discipline, GCM's GF(2^128) multiply — and each mode's exact failure.
Public key: bignums are the attack surface
RSA and ECC from the arithmetic up; CRT reassembly; constant-time discipline — the layouts that leak and the blinding that hides them.
TLS 1.3: a state machine about memory hygiene
Transcript hash, key schedule, forward secrecy as key erasure, 0-RTT as the replay trade — the handshake as managed memory.
Implementation failures: the attack catalog
Heartbleed, Lucky 13, nonce reuse, side channels from Rowhammer to Spectre — every famous break as a memory story.