Just "discovered" Cipher Saber and wrote an Arduino implementation that's used through the Serial Monitor.
For more information on what CipherSaber:
http://ciphersaber.gurus.org/
http://ciphersaber.gurus.org/faq.html
Hackaday.IO project:
https://hackaday.io/project/168713-ciphersaber-a-simple-rc4-cipher-for-arduino
Source code at Gitlab:
https://gitlab.com/arduinoenigma/ciphersaber