ultra is a Rust implementation of the [Enigma machine] that includes the
ability to decrypt ciphertext.
ultra can be installed from [crates.io] using Cargo:
$ cargo install ultra
Encrypt a message with rotors 1-4-2, key setting D-O-G, and ring setting C-A-T:
bash
$ 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:
```bash $ ultra --randomize "The quick brown fox jumps over the lazy dog." Kxj mcwzf oqgmz pwr vnfqq iwhv wcr qqgt lgd.
Rotors: 5-2-3 / Key: A-A-G / Ring: N-W-Q / Plugs: CG EZ HW IJ MP TY ```
Attempt to decrypt a piece of ciphertext:
bash
$ ultra --decrypt "$(cat ciphertext.txt)"
...
Decryption relies on a combination of [index of coincidence], bigram, and quadgram frequencies to infer the original Enigma machine settings, and as a result, it is quite likely that messages shorter than 500 characters will not come anywhere close to being decrypted correctly.
The original version of this project was based on [James Lyons'] articles about the Enigma machine (see [this blog post] for a brief overview). As of version 0.6.0, the decryption algorithm was updated, inspired by [this Computerphile video].
ultra is licensed under the MIT License.