TLS extension

C25115 concept

A TLS extension is an optional, standardized addition to the TLS protocol that allows clients and servers to negotiate extra capabilities or parameters (such as supported protocols, server names, or security features) during the handshake.

Observed surface forms (3)

TLS protocol extension ×1
TLS protocol mechanism ×1
Transport Layer Security feature ×1

Instances (10)

NPN (Next Protocol Negotiation)
ALPN (Application-Layer Protocol Negotiation)
surface form: ALPN
Server Name Indication extension
SNI
Max Fragment Length extension
Client Certificate URL extension
TLS heartbeat extension (later deprecated) via concept surface "TLS protocol extension"
surface form: TLS heartbeat extension
Encrypted Client Hello
TLS extensions via concept surface "TLS protocol mechanism"
Trusted CA Indication extension