Cryptography

Applied

TLS, PGP, Signal, real systems.

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220 XP
TLS 1.3 Handshake
One RTT, key shares, encrypted extensions, Finished.
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230 XP
Certificate Chains
X.509 trust paths, hostname matching, revocation.
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250 XP
Signal Double Ratchet
X3DH, symmetric chain, DH step, forward secrecy.
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210 XP
PGP & Web of Trust
Hybrid encryption, trust paths, why PGP lost.
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240 XP
Noise & HPKE
Patterns, handshake tokens, hybrid public-key encryption.
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220 XP
TLS 1.3 vs 1.2
1-RTT, 0-RTT, no CBC, no RSA, ECH — what changed and why.
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200 XP
Certificate Transparency
Append-only Merkle logs of every issued cert. SCTs. Why Chrome enforces it.
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200 XP
ACME & Let's Encrypt
Free, automated TLS — http-01 vs dns-01 vs tls-alpn-01.
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240 XP
Zero-Knowledge & MPC
ZK-SNARKs/STARKs, multi-party computation, and where they show up in the wild.
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