Part 7/17:
Rejewski’s key insight was recognizing that German procedures—specifically the practice of encrypting the message key twice—left mathematical patterns. This double encryption allowed him to construct equations that could infer internal wiring, ultimately enabling the Polish team to build their own replica Enigma machines by 1933. These tools allowed them to read German military traffic months before the war.
The Poles’ acts of sharing their breakthroughs with Britain and France in 1939—unmatched in secrecy and urgency—laid the groundwork for what would become Bletchley Park. Their systematic approach showed that even the most complex machine’s behavior could be understood with algebra and logic—principles that underpin modern cryptanalysis.