gen-define-tls-handshake-basics-and-give-one-short-worked-exampl-b0f0

Define TLS handshake basics and give one short worked example.

# TLS Handshake Basics The **TLS (Transport Layer Security) handshake** is a process that establishes a secure, encrypted connection between a client and server before any application data is transmitted. ## Key Steps: 1. **ClientHello** - Client initiates connection, proposes TLS version and cipher suites 2. **ServerHello** - Server selects TLS version and cipher suite, sends its certificate 3. **Key Exchange** - Both parties establish shared encryption keys 4. **Finished** - Both confirm the handshake; encrypted communication begins ## Worked Example (TLS 1.2) **Scenario:** Browser connecting to `https://example.com` ``` 1. CLIENT → SERVER: ClientHello - "I support TLS 1.2, 1.3" - "I can use AES-256, AES-128..." - Random number: 0x3f2a8b... 2. SERVER → CLIENT: ServerHello - "Let's use TLS 1.2" - "Let's use AES-256-GCM" - Random number: 0x9c4d1e... - Certificate (contains server's public key) 3. CLIENT: - Verifies certificate is valid and trusted - Generates "pre-master secret" - Encrypts it with server's public key → sends to server 4. BOTH SIDES: - Derive session keys from pre-master secret + random numbers 5. CLIENT → SERVER: Finished (encrypted with new keys) 6. SERVER → CLIENT: Finished (encrypted with new keys) ✅ Secure connection established - Application data can now flow encrypted ``` **Result:** All subsequent HTTP requests/responses are encrypted using the agreed-upon cipher and session keys.