Enigma Machine

I still sort of remember being a kid and discovering that you could make a map of letters and from that have a simple encoding mechanism.

For example (in the table shown below), the letter A would be encoded as M, B as N, C as O, and so on.

Letter	Encoding
A	M
B	N
C	O
...	...
Z	L

This is a substitution cipher and is pretty simplistic by modern standards, but as a kid I thought it was cool AF.

One evening I was watching a video on YouTube about the Enigma Machine. It piqued my interest and I decided to make something in Python to recreate the functionality.

History

The Enigma machine is a cipher device developed and used in the early- to mid-20th century to protect commercial, diplomatic, and military communication. It was employed extensively by Nazi Germany during World War II, in all branches of the German military. The Enigma machine was considered so secure that it was used to encipher the most top-secret messages.

The Enigma has an electromechanical rotor mechanism that scrambles the 26 letters of the alphabet. In typical use, one person enters text on the Enigma's keyboard and another person writes down which of the 26 lights above the keyboard illuminated at each key press. If plaintext is entered, the illuminated letters are the ciphertext. Entering ciphertext transforms it back into readable plaintext. The rotor mechanism changes the electrical connections between the keys and the lights with each keypress.

-- Wikipedia

Usage

uv run main.py "[message]" e|d [int]

Where:

"[message]" is the message to be encrypted/decrypted. Should be in quotes.
e|d is the direction of the message (encrypt or decrypt).
int is the number of iterations to be made.

Seed Values

When encrypting a message, a file will be written to the current directory. This file contains the seed values used to generate the encryption/decryption keys.

The seed values are integers between 0 and 58. In the file, each seed value is on a new line.

The number of iterations should match the number of seed values used.

Examples

Encode

Encode the message "You are here." with three iterations.

uv run main.py "You are here." e 3

The command above will create a file called "seed_values.txt" with the generated seed values.

Decode

Decode the message "NTb!QDbGDQDa" with three iterations.

uv run main.py '.NTb!QDbGDQDa' d 3

The command above expects a file called "seed_values.txt" with the seed values used to encode the message from the preceding example.

TODO

Add a param to tell the encode function to use an existing seed file.

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