This was really just a toy project since I was (and still am) fascinated by cellular automata and cryptography. Reversible block cellular automata can be used for symmetric encryption which to me was a really unexpected connection. So I implemented an encryption scheme in Julia using the block cellular automata rules Critters and Tron. Encryption and decryption do work, although I certainly doubt that my library constitutes a secure encryption algorithm. If you find it interesting though, trying to break this encryption and decrypt a message encrypted with this scheme could be a fun learning project. The library provides a hacky tool to animate the BCAs as well, so playing around with that could also be fun. The code is on GitHub.