Enigma Machine Simulator
Simulate the WWII electromechanical rotor cipher with real-time electrical signal flow, configurable rotors, plugboard, and step animation mode.
Updated May 2026
Click two letters to connect them (10 pairs remaining)
How to Use the Enigma Machine
Select M3 (standard 3-rotor) or M4 (4-rotor Naval). M4 auto-switches to thin reflectors.
Pick which rotor goes in each slot (I–V), set the starting position (letter in the window), and optionally adjust the ring setting.
Choose reflector B or C (B-Thin / C-Thin for M4). Both parties must use the same reflector to communicate.
Click two letters to connect them. Up to 10 pairs. Each pair swaps those letters before and after the rotor pass.
Press the keyboard buttons one by one to see the lampboard light up, or paste a full message in the Input area. Non-letter characters pass through unchanged.
Use the exact same settings (model, rotors, positions, ring, plugboard) and enter the ciphertext. The Enigma is self-inverse — encryption and decryption are identical operations.
How to use the Enigma machine simulator
The same procedure WWII operators followed
1. Choose the model
Pick Enigma M3 or M4 and the reflector (B/C for M3; B-Thin/C-Thin for M4).
2. Set the rotors and plugboard
Choose each rotor's type and starting position, the ring settings, and up to 10 plugboard pairs.
3. Type or paste your text
Use the on-screen keyboard for letter-by-letter encryption, or paste text for bulk encryption.
When you'd use this
The most common scenarios among simulator users
History or cryptography lessons
Show the electrical path visually — key → plugboard → rotors → reflector → lamp — instead of just describing it.
Studying classical cryptanalysis
See the structural flaw Bletchley Park exploited: no letter can ever encrypt to itself.
Verifying a custom Enigma implementation
Compare your own rotor and reflector code against a historically accurate reference engine, letter by letter.
Reproducing historical messages
Enter rotor and plugboard settings from documented examples and check whether your output matches.
Curiosity and hands-on history
Try out history's most famous cipher device without needing the original hardware.
What this Enigma simulator does
True to the original electromechanical behavior
M3 and M4 models
Wehrmacht/Luftwaffe army Enigma (3 rotors) and Kriegsmarine naval Enigma (4 rotors).
Real-time electrical signal flow
Watch the signal travel through the plugboard, rotors, and reflector on every keystroke.
Ring settings and double-stepping
Ringstellung (01–26) and the rotor turnover mechanism implemented with historical accuracy.
10-pair plugboard
Full Steckerbrett configuration, with color-coded labels for each connected pair.
Authentic rotor wiring
Historical wiring specifications from the Wehrmacht, Luftwaffe, and Kriegsmarine rotor sets.
Runs 100% in your browser
No download, no sign-up — everything runs locally on your device.
Why there are 158 quintillion possible settings
Common configuration mistakes
Using different settings to decrypt
To decrypt a message, you need the exact same settings used to encrypt it — rotors, positions, ring settings, and plugboard.
Mixing up M3 and M4 configurations
M4 (Kriegsmarine) adds a fixed fourth rotor and uses thinner reflectors — its settings aren't compatible with M3.
Expecting a letter to encrypt to itself
That's mathematically impossible given how the reflector works — if you ever see it happen, it's a bug in the simulator, not a mistake in your setup.
Alan Turing and Bletchley Park
Alan Turing (1912–1954) led the codebreaking effort at Bletchley Park. Polish mathematicians Marian Rejewski, Jerzy Różycki, and Henryk Zygalski were the first to break Enigma, back in 1932, and shared their methods with Britain in 1939.
The British Bombe, which Turing refined from the earlier Polish Bomba, exploited the fact that no letter could ever encrypt to itself. It went operational in 1941 — the resulting intelligence, codenamed Ultra, proved decisive ahead of D-Day.
Frequently asked questions
It was an electromechanical cipher device that encrypted each letter by routing an electrical signal through a plugboard, three or four rotors, a reflector, and back through the rotors in reverse. Every keystroke advanced at least one rotor, making it a polyalphabetic cipher with billions of possible configurations.
References
Technical and historical documentation, including original manuals and photographs.
Technical overview with rotor wiring tables and historical background.
The official Bletchley Park account of how Enigma was used and broken.
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