But, beware of the Replay AttackAnd, so, today, OpenSSL 3.5.0 was released, and which supports a range of PQC methods and 0-RTT [here]:Overall, we have stuck with the 3-way handshake for many decades, and it is now seen as too slow in a modern “always-on, always-connected” world. In a normal Web connection, the client sends a SYN TCP request, the server then replies with a TCP SYN/ACK, and then the client sends back an ACK. This obviously slows down the connection, and where we might close a con...