OpenSSL 3.5.0 Released: Ditching the Three-Way Handshake for 0-RTT

OpenSSL 3.5.0 has been released, featuring support for various post-quantum cryptography methods and 0-RTT connections. The traditional three-way TCP handshake is considered too slow in today's always-on world. 0-RTT (Zero Round Trip Time), integrated into TLS 1.3, lets clients reconnect instantly without the handshake. A full handshake occurs on the initial connection, generating a session ticket used for subsequent connections, allowing the client to send data immediately without waiting for a server response. While security risks like replay attacks exist, 0-RTT's compatibility with the UDP-based QUIC protocol positions it as a key trend in future network connections.