HTTPS and TLS Encryption

Explain how HTTPS protects data in transit.

Problem with HTTP

Plaintext transmission — any intermediary can eavesdrop or tamper.

TLS Handshake

1. Client Hello: Client sends supported TLS versions and cipher suites.
2. Server Hello: Server selects version and cipher suite, returns digital certificate.
3. Certificate Validation: Client verifies the certificate is signed by a trusted CA.
4. Key Exchange: Both sides negotiate a symmetric Session Key.
5. Encrypted Communication: All subsequent data is encrypted with the Session Key.

Certificate Authority (CA)

A trusted third-party that issues and validates digital certificates, establishing a chain of trust.

TLS 1.3 Improvements

Simplified handshake (1-RTT), deprecated weak cipher suites, Forward Secrecy enforced by default.