ultra is a Rust implementation of the Enigma machine that includes the ability to decrypt ciphertext. Installation ultra can be installed from crates.io using Cargo: Usage Encrypt a message with rotors 1-4-2, key setting D-O-G, and ring setting C-A-T: $ ultra --rotor=142 --key=DOG --ring=CAT "The quick brown fox jumps over the lazy dog." Ntz ntqlz jmwll art bbnow wzqk keq ievk lzo. Encrypt a message using random Enigma settings: $ ultra --randomize "The quick brown fox jumps over the lazy dog." ...