like (nearly) every other addon: just unpack the folder Enigma to ..\interface\addons
/enigma channelnumber <1-10>: the channel you want to use
/enigma key <string>: the key you want to use (case sensitive)
when you send a message to the selected channel it will be encrypted, see the screenshots for example.
a word about the encryption algorithm:
just a substitution with length(key) alphabets, therefore it's a rather weak encryptiopn, but strong enough to fulfill it's purpose: hide the messages from unwanted people.
TODO: fix those funny chars (umlauts et al)
support multiple channels with different keys