tpage-alfresco / custom-enigma

This project implements the Wehrmacht Enigma M3 for educational purposes

Custom Enigma

This project implements the Wehrmacht Enigma M3 for educational purposes.

Rotor set is different from the one used in Enigma M3, this implementation uses following rotors:

• ROTOR_I
  • Ring FKQHTLXOCBJSPDZRAMEWNIUYGV
  • Notch H
• ROTOR_II
  • Ring SLVGBTFXJQOHEWIRZYAMKPCNDU
  • Notch M
• ROTOR_III
  • Ring EHRVXGAOBQUSIMZFLYNWKTPDJC
  • Notch V
• ROTOR_IV
  • Ring NTZPSFBOKMWRCJDIVLAEYUXHGQ
  • Notch M
• ROTOR_V
  • Ring BDFHJLCPRTXVZNYEIWGAKMUSQO
  • Notch D

Reflector is also different from the default UKW-B used by Enigma M3:

• LE:YJ:VC:NI:XW:PB:QM:DR:TA:KZ:GF:UH:OS

Plugboard is accepting default 10 plug cables configuration.

Complexity

Since there are changes in Enigma configuration, complexity is still in the same range:

• Combinations of 3 rotors out of 5 = (5 x 4 x 3) = 60
• Each ring can be set in any of 26 positions initially = (26 x 26 x 26) = 17,576
• Notch combinations (most-left rotor is excluded) = (26 x 26) = 676
• Plugboard combinations for 10 cables = 26! / (26 - 2 · 10)! · 10! · 2 · 10 = 150,738,274,937,250

Complexity is equals to 60 x 17,576 x 676 x 150,738,274,937,250 = 107,458,687,327,250,619,360,000

That can be expressed as 1.07 x 1023, and it's comparable with a 77 bit key

Additional details on Enigma classical configuration available in https://www.ciphermachinesandcryptology.com/en/enigmatech.htm

The goal of this project is to provide a cipher algorithm with the same complexity of Enigma M3 but with different initial settings. Hence, traditional cryptanalysis attacks can be performed on it but no standard program can be used as is.

Building the source code

Requirements

• Maven
• Java 17

Type following command from the root folder of the project:

$ mvn clean package

Executable JAR Application custom-enigma-0.8.0.jar will be produced in target folder.

Running the application

Create a text file including the plain text to be ciphered.

$ vi plaintext.txt
Every secret creates a potential failure point

Run the program create a plugboard, the rotor configuration and providing the name of the output file.

$ java -jar target/custom-enigma-0.8.0.jar \
    --input-file=plaintext.txt \
    --plugboard=IR:HQ:NT:WZ:VC:OY:GP:LF:BX:AK \
    --left-rotor=1   --left-rotor-position=0 \
    --middle-rotor=2 --middle-rotor-position=0 \
    --right-rotor=3  --right-rotor-position=0 \
    --output-file=cipher.txt

The program will produce the file cipher.txt including the ciphered text from the plain text.

$ cat cipher.txt
SFFDH WVUTYS UDZPHNW E TUOSMBPOT IMQZDLZ IKVEP

License

Copyright 2022 Angel Borroy

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.