CRYPTCAT

Cryptcat is exactly what it sounds like: Netcat with encryption . Now you can encrypt that datapipe, proxy, or relay. Hackers can keep their Netcat traffic hidden so that nosey admins would have to do more than just sniff the network to find out what they were up to.

Cryptcat uses an enhanced version of Twofish encryption. The command-line arguments are the same. Obviously Cryptcat isn't terribly useful for port scanning and communicating with other services that don't use the same encryption used by Cryptcat. But if your Netcat usage includes an instance of Netcat running somewhere in listen mode and a separate instance of Netcat being used to connect to it, Cryptcat gives you the added benefit of securing that connection.

You can download Cryptcat from http://farm9.org/Cryptcat/.