Please see the discussion of this code on: https://forum.processing.org/two/discussion/15156/simple-aes-encryption-example This project is an example which was adapted into the following: https://github.com/CalPlug/ESP8266_Load_Controller
This project also contains a Base-64 encoder / decoder and a Kansas City Standard file to audio converter. This was used in the project as a test of the Base64 encryption and added to the project.