Cracking Enigma: A Chronology of Cryptographic Breakthroughs

The talk opens with the Enigma's design and its origins as a commercial cipher device before military adoption. The speaker explains how three rotors, a reflector and a plugboard scrambled each keystroke, and why operating habits such as repeated message indicators and routine daily settings gave cryptanalysts footholds.

The middle follows the chronology. Polish mathematicians deduced internal rotor and reflector wirings from intercepted traffic and a commercial unit, then built cyclometers and bombas to recover settings, until German changes in 1937 and 1938 ended that approach. Their work was handed to British and French intelligence in 1939. At Bletchley Park, Turing's team tackled the naval M3 with statistical methods such as Banburismus, worked through bigram tables, and used a crib-driven Bombe that eliminated plugboard candidates through logical contradictions.

The closing audience questions covered German security responses, the limited role of linguists, and how rotor wirings were chosen. The practical takeaway is that the breaks came from procedural weaknesses and statistical reasoning layered over mechanical computation, rather than from one single flaw in the machine.