pyenigma command-line application

Py-Enigma includes a simple application,, to let you perform Enigma text transformations on the command-line. This allows for quick experimentation and scripting of operations.

Getting help

To get help and see all the available options, invoke with the --help option:

$ python --help

usage: [-h] [-k KEY_FILE] [-d DAY] [-r ROTOR [ROTOR ...]]
                   [-i RING_SETTING [RING_SETTING ...]]
                   [-p PLUGBOARD [PLUGBOARD ...]] [-u REFLECTOR] [-s START]
                   [-t TEXT] [-f FILE] [-x REPLACE_CHAR] [-z] [-v]

Encrypt/decrypt text according to Enigma machine key settings

optional arguments:
  -h, --help            show this help message and exit
  -k KEY_FILE, --key-file KEY_FILE
                        path to key file for daily settings
  -d DAY, --day DAY     use the settings for day DAY when reading key file
  -r ROTOR [ROTOR ...], --rotors ROTOR [ROTOR ...]
                        rotor list ordered from left to right; e.g III IV I
                        ring setting list from left to right; e.g. A A J
                        plugboard settings
  -u REFLECTOR, --reflector REFLECTOR
                        reflector name
  -s START, --start START
                        starting position
  -t TEXT, --text TEXT  text to process
  -f FILE, --file FILE  input file to process
  -x REPLACE_CHAR, --replace-char REPLACE_CHAR
                        if the input text contains chars not found on the
                        enigma keyboard, replace with this char [default: X]
  -z, --delete-chars    if the input text contains chars not found on the
                        enigma keyboard, delete them from the input
  -v, --verbose         provide verbose output; include final rotor positions

Key settings can either be specified by command-line arguments, or read
from a key file. If reading from a key file, the line labeled with the
current day number is used unless the --day argument is provided.

Text to process can be supplied 3 ways:

   if --text=TEXT is present TEXT is processed
   if --file=FILE is present the contents of FILE are processed
   otherwise the text is read from standard input


    $ --key-file=enigma.keys -s XYZ -t HELLOXWORLDX
    $ -r III IV V -i 1 2 3 -p AB CD EF GH IJ KL MN -u B -s XYZ
    $ -r Beta III IV V -i A B C D -p 1/2 3/4 5/6 -u B-Thin -s WXYZ

There are numerous options, but most are hopefully self-explanatory. There are two ways to invoke

  1. Explicitly specifying all initial key settings
  2. Using a key file to initialize the Enigma machine

Specifying all key settings

Here are some examples of specifying all the key settings on the command-line:

$ python --rotors I IV V --ring-settings 5 17 8 \
  --plugboard AV BS CG DL FU HZ IN KM OW RX --reflector C \

$ python -r I IV V -i 5 17 8 \

These two invocations create the same settings, the first uses long form option names, while the second uses short form.

If no --text or --file options are provided, will prompt for input:

$ python -r I IV V -i 5 17 8 -p AV BS CG DL FU HZ IN KM OW RX -u C -s DRX

Using a key file for settings

It is often unwieldy to type so many options on the command-line, so provides a way to store key settings in a simulated key sheet file:

$ python --key-file keyfile --start='AAB' --day=29 --text='HERE IS MY MESSAGE'

If the --day option is omitted, the day is determined from the current date.

The format of the key sheet file is described in Key file format.

Verbose output

The --verbose or -v option is useful if you wish to view the final rotor positions and view how many times the rotors stepped while processing your text:

$ python --key-file keyfile --start='XHC' --day=29 --file msg.txt --verbose
Final rotor positions: YXY
Rotor rotation counts: [1, 16, 412]