Enigma M3: Naval Cipher

The Navy did not trust the Army's machine, and it was right not to. The Enigma M3 takes the same three-rotor frame and hands its operators a larger box: rotors VI, VII and VIII, which the Army never carried. Three slots, eight wheels to choose from, and rotors VI–VIII carry two turnover notches each rather than one — a small change that multiplies the number of possible keys and made the naval traffic markedly harder to read than the Army's. M3 is a working reconstruction. Press a key and the rotors step, the current runs out through the plugboard, through the wheels, into the reflector and back by a different path, and a lamp lights. Historical wiring, historical notches, historical stepping. Encipher a signal, wind back to the same ground setting, type the ciphertext, and the original returns — the machine is its own inverse, exactly as it was. TYPE STRAIGHT INTO ANY APP The Enigma keyboard is how a signal actually leaves this app. Switch to it in Messages, Mail, Notes or anywhere else you can type, and every letter is enciphered as you press it — the app you are in receives ciphertext, never the plaintext. A strip above the keys shows what you actually wrote, because the field itself never sees it. The rotors step as you go, and a reset key winds them back to the day's ground setting when you start a fresh signal. SET IT LIKE A SIGNALS OFFICER The key sheet carries a month of daily keys: which wheels in which order, ring and ground settings, and the plugboard pairs. Tap the day and the machine is set, the way it was done from a printed sheet on a plotting table. WHAT'S HERE • Rotors I–VIII, reflectors B and C, and a thirteen-cable plugboard • The Enigma keyboard, for enciphering inside any other app • A month of daily keys, generated from a seed you can share • Share sheet support to encipher text you have already written • Home Screen and Lock Screen widgets carrying the day's key • Shortcuts and Siri actions for enciphering and deciphering A NETWORK OF YOUR OWN Two people reading each other need the same key sheet, exactly as two ships needed the same printed one. Share yours by AirDrop, or hand it straight to a nearby device — it never touches a server, because there is no server. Whoever holds it can read you; nobody else can. Nothing you type leaves your phone.