Enigma Machine Simulator (M3)
The WWII cipher machine, with rotors, rings, and plugboard.
About this tool
The Enigma machine encrypted German military communications in World War II, and breaking it at Bletchley Park shortened the war. This simulator faithfully reproduces the 3-rotor Wehrmacht (M3) Enigma: choose from rotors I–V, set the ring settings (Ringstellung) and starting positions, pick reflector B or C, and wire up plugboard (Steckerbrett) pairs.
The rotor stepping, including the famous double-step anomaly, matches the real machine. Because Enigma is reciprocal, the same settings both encrypt and decrypt — set the machine to a message's starting position and type the ciphertext to recover the plaintext. Everything runs in your browser.
Like everything on encrypt.tools, this runs entirely in your browser — nothing you enter is transmitted or stored.
Frequently asked questions about Enigma Machine
How do I decrypt an Enigma message?+
Set the machine to the exact settings used to encrypt it — same rotors, ring settings, plugboard, and starting positions — then type the ciphertext. Because Enigma is reciprocal, typing ciphertext with the original settings produces the plaintext.
What was Enigma's fatal weakness?+
Enigma never encrypts a letter to itself, and its reciprocal wiring plus predictable message formatting gave codebreakers 'cribs' — guessed plaintext. Combined with captured key sheets and Alan Turing's bombe machines, this let Bletchley Park break it.
What is the plugboard for?+
The plugboard (Steckerbrett) swaps pairs of letters before and after the rotors, massively increasing the number of possible settings. Enter pairs like 'AB CD EF' to connect A↔B, C↔D, and E↔F.
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