1. Logistics:
   Feedback on assignment 5.

2. Network security (next 3 lectures): TLS, surveillance+censorship, DoS attacks

3. Three properties guaranteed by TLS:
   * Authentication
   * Confidentiality
   * Integrity
   * Guaranteeing this in the physical and cyber world
     --> Hard computational problems

4. Cryptographic primitives:
   * PubEncrypt
   * PubDecrypt
   * SymEncrypt
   * SymDecrypt
   * Sign
   * Verify
   * Message integrity

5. How TLS achives auth, confidentiality, and integrity using these primitives
   * Authentatication: Certificate authorities and signatures
   * Confidentiality: Pub keys for handshake followed by symmetric keys for data
   * Integrity: Sign and verify primitives

6. Aside: IPSec

7. What could go wrong? (If time permits)
   * Root CA is compromised
   * Private key is stolen
   * Problem is no longer hard.
   * Insufficient validation
   * Every detail matters.