The Enigma turned typing into ciphertext by sending each keystroke on a journey through a maze of rotating wired wheels. Press a key and current flows through the plugboard, across three rotors, into a reflector, and back out through the rotors by a different path — lighting a single lamp with the enciphered letter. Because at least one rotor steps with every keypress, the wiring is never the same twice: press A five times on the standard setup and you get B, D, Z, G, O.
This exhibit is a cryptographically exact Wehrmacht Enigma I. The five historical rotors carry their real wirings and turnover notches, the reflectors are the genuine UKW-B and UKW-C, and the stepping reproduces the famous double-step anomaly that made the machine subtler than its own operators knew. Set the rotor order, ring settings, and plugboard, and it enciphers identically to the steel original — including the property that made it usable in the field: encipher the ciphertext on the same settings and the plaintext falls straight back out.
Its fatal weakness hid in plain sight. A letter can never encipher to itself — the reflector guarantees it — and that single constraint, together with predictable message formats, gave Bletchley Park the wedge it needed. Watching the current refuse to ever return to the key you pressed is watching the flaw that helped end a war.
Specifications
- Model
- Wehrmacht Enigma I — 3 rotors + reflector
- Rotors
- Five wheels (I–V); choose three, any order
- Settings
- Rotor order, Ringstellung, plugboard, start position
- Simulated
- Exact wiring, double-step, live electrical path
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