Applied Crypto Protocols

TLS 1.3 · Signal · Kerberos · PKI

1:00

How TLS 1.3, PKI, Kerberos, and Signal combine cryptographic primitives with carefully designed rules to build real-world secure channels.

By the end, you can

Explain how TLS 1.3 achieves confidentiality, integrity, and authentication in one round trip.
Describe what makes a TLS 1.3 session key ephemeral and why that provides forward secrecy.
Identify the security trade-off of TLS 1.3 0-RTT early data and the appropriate mitigation.
Trace the PKI chain of trust from root CA through intermediate to leaf certificate.
Distinguish CRL/OCSP, OCSP stapling, and Certificate Transparency logs by the role each plays.
Explain how Kerberos authenticates users without transmitting their passwords and how timestamps stop replays.
Describe the purpose of each of the four DH computations in X3DH (mutual auth, forward secrecy, one-time prekey).
Explain how the Double Ratchet's symmetric and DH ratchets together provide forward secrecy and post-compromise security.
Apply the four protocol design rules (authenticate, fresh randomness, stop replays, resist downgrade) to assess a protocol design.

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