The idea with protocol was always to keep the handshake/authentication part open, but don't commit to the details of the application client-server messaging. To

The idea with protocol was always to keep the handshake/authentication part open, but don't commit to the details of the application client-server messaging. To that end the protocol spec for the original version was available from the moment the system went live and it was detailed enough so that some people made a sniffer and started reversing the application layer (which was fine with me). After the LogMeIn acquisition we revised the handshake protocol a bit to allow for security parameter negotiation and re-negotiation, and the spec again was published. It should still be there on the website, but I don't have a URL at hand. Also, I wasn't involved with Hamachi for few years now, but I think they had a plan to switch to TLS altogether, so that must've been done by now.