handshake

RU: рукопожатие

An initial exchange of messages between two parties that establishes a shared context before data transfer begins. In TLS 1.3 the handshake negotiates cipher suites, authenticates the server (and optionally the client), and derives session keys in one round trip (1-RTT), or zero for resumed sessions (0-RTT). The handshake cost is why connection reuse and session tickets matter for latency.