Enigma Machine Simulator
Explore historical rotors, ring settings and the Enigma lamp board.
Try before you buy.
- Free preview: the machine settings and completion checks, with the message output, lamp sequence and electrical trace hidden.
- Locked until you unlock it: download and copy.
- Unlock: Pro pass, ₹179 for 30 days or ₹79 for 1 week, a one-time payment that never renews. Unlock: Pro pass, $5.99 for 30 days or $2.99 for 1 week, a one-time payment that never renews.
Ways to unlock shows how to get the full result.
Printing this result is locked in the free preview.
Keyboard
Press a key to append it to the message and run from the chosen starting settings.
Result and lamp board
| Setting or result | Value |
|---|
Locked in the free preview. Opens the ways to unlock this result.
Locked in the free preview. Batch runs unlock with a pass.
Locked in the free preview. Query results unlock with a pass.
About the Enigma Machine Simulator
Simulate the letter path through an Enigma I, naval M3 or four-rotor M4. Choose rotor order, individual ring settings, starting windows, reflector and plugboard cables. Each key press advances the moving rotors before the signal goes through them and returns from the reflector.
The free preview shows your setup and completion checks. A pass opens the full transformed message, lamp replay, signal path, copy and downloads. Machine settings can be carried in a local URL fragment without including your message.
How to use it
- Choose the machine and three different moving rotors from left to right; M4 adds Beta or Gamma at the far left.
- Set each ring from 1–26 or A–Z, then set the three or four starting window letters and up to ten plugboard pairs.
- Enter letters or ciphertext, choose how non-letters are handled, and run Encrypt / decrypt.
- With a pass, select a key press or play the lamp board; copy or download the full message and settings report.
- To decrypt, use the same initial setup and starting windows; begin a fresh run with the ciphertext.
Examples
Enigma I · I II III · B · rings 1 1 1 · AAA · no plugboard · AAAAA
BDZGO
The first key press steps the right rotor from A to B before encryption.
III II I · rings 1 1 1 · KDO · six key presses
KDP → KDQ → KER → LFS → LFT → LFU
The middle rotor advances on two consecutive presses at the notch transition.
Common uses
- Study the stepping mechanism and electrical return path.
- Reproduce a historical key sheet with ring and plugboard settings.
- Compare three-rotor and four-rotor configurations in classroom puzzles.
Rotor order and rings
Rotors are entered in the operator’s left-to-right order. Enigma I selects I–V; M3 and M4 select I–VIII. M4 adds the stationary Beta/Gamma rotor and a thin B/C reflector. Ring settings offset the wiring relative to the window labels; the turnover notch is on the alphabet ring, so its window letter remains the same.
Why the middle rotor double-steps
Before each key press, the right rotor advances. The middle advances when the right is at its turnover notch or the middle is at its own notch. The left moving rotor advances when the middle is at its notch. In M4 the extra Greek rotor stays stationary.
References
Enigma technical description and Py-Enigma rotor and machine reference.
Limitations
- This models the military I/M3/M4 letter machines with straight entry wheel, ordinary B/C or thin B/C reflectors and at most ten plugboard cables. Other commercial variants and accessories are outside this simulator.
- Only ASCII A–Z goes through the machine. Lowercase is accepted as uppercase. Other characters are preserved without stepping, removed, or rejected according to your choice.
- A local run accepts up to 100,000 characters. Every letter has a replay step; larger input should be split while carrying the previous final windows into the next part.
- Historical Enigma is not suitable for protecting present-day secrets. The result does not authenticate a message.
Privacy
On this device; its files download once
Messages and machine settings are processed locally. No upload, stored message, server lookup or automatic settings transmission is performed. A settings URL fragment is prepared only when you choose the settings-link control.
Frequently asked questions
What do I get without a pass?
Without a pass, Enigma Machine Simulator shows the machine settings and completion checks, with the message output, lamp sequence and electrical trace hidden. Until you unlock it, the result can’t be downloaded or copied. A Pro, Premium or Ultimate pass, a one-time payment that never renews, unlocks the full result. The pricing page lists the passes and their prices.
Are rings and starting windows the same?
No. The ring setting changes the wiring’s offset relative to the alphabet labels; starting windows set where the rotors begin for a message. Both affect the result.
Does the M4 Greek rotor turn?
No. Beta or Gamma stays at the selected position. The other three rotors use the naval stepping mechanism, including double stepping.
What is in a settings link?
Only the machine, rotor order, rings, start windows, reflector, plugboard and non-letter rule. The message and result are excluded. Anyone with the link can read the settings.
Why does decrypting with the final windows fail?
Encryption and decryption need the same initial setup and starting windows. A fresh run starts at the windows in the form; the displayed final windows describe where that run ended.