PSK

RU: PSK

Pre-Shared Key: a symmetric key distributed to communicating parties out of band before the session begins. In TLS 1.3, PSKs also serve as the session resumption mechanism — the server issues a ticket after the initial handshake, and the client redeems it in the next connection's ClientHello to skip a full handshake. PSK-only mode lacks forward secrecy; PSK with DHE mode (psk_dhe_ke) restores it.