Tcpcrypt is a protocol that attempts to encrypt (almost) all of your network traffic. Unlike other security mechanisms, Tcpcrypt works out of the box: it requires no configuration, no changes to applications, and your network connections will continue to work even if the remote end does not support Tcpcrypt, in which case connections will gracefully fall back to standard clear-text TCP. Install Tcpcrypt and you'll feel no difference in your every day user experience, but yet your traffic will be more secure and you'll have made life much harder for hackers.
Tcpcrypt has very high performance (up to 25x faster than SSL), making it feasible for high volume servers to enable encryption on all connections. While weaker by default, Tcpcrypt is more realistic for universal deployment.
hoot: https://twitter.com/dmazieres/status/1131700438795935744
[1] http://tcpcrypt.org/index.php
[2] https://github.com/scslab/tcpcrypt
[3] https://tools.ietf.org/html/rfc8547
[4] https://tools.ietf.org/html/rfc8548