Ring settings multiply Enigma’s keyspace by 17,576. We add them to our C64 emulator, see why brute force alone can’t keep up, and set the stage for smarter attacks.

The Commodore 64 searches nearly six million Enigma M3 configurations to find the one that matches a known plaintext crib. First the concept, then BASIC, then 6502 assembly fast enough to crack it in about 22 minutes.

A working Enigma M3 emulator on the Commodore 64. First in BASIC for clarity, then in 6502 assembly for speed. Eight rotors with dual notches, plugboard, and the double-step anomaly, all on a 1 MHz machine.

Why German cryptographers believed Enigma was unbreakable, and why Allied codebreakers ultimately proved them wrong.