TLS

Motivation

TLS solves the problem of communicating securely over an untrusted network. Without it, intermediaries can read or modify traffic.

Where it fits

TLS connects networking, cryptography, HTTPS, certificates, public-key cryptography, and security operations.

Mental model

TLS establishes an encrypted channel between client and server. Certificates help prove identity, and key exchange establishes shared secrets for efficient symmetric encryption.

SSL vs TLS

SSL is the older predecessor. In modern systems, people often say SSL casually, but they usually mean TLS.

Subconcepts

SSL

SSL is the older protocol family that preceded TLS. In everyday conversation people still say “SSL certificate,” but modern secure web traffic uses TLS.

Common mistakes

• Thinking TLS only encrypts, when authentication also matters.
• Forgetting certificate expiration and trust chains.
• Using “SSL” to refer to modern TLS without understanding the distinction.