Toolkit.
Guide · interactive

The TLS handshake

CLIENT Browser 198.51.100.24 SERVER example.com 93.184.216.34 01ClientHello 02 ServerHello · Certificate · Finished 03 Finished 04 Application data 1-RTT · TLS 1.3
Step 01 of 04

The client announces what it can speak and pre-ships a key share — so the server can derive the shared secret on receipt, saving a round trip.