The first step in solving a Playfair given a "tip" or "crib" is to try to determine where ... Note also that, like the Enigma cipher, no letter in Playfair can be encrypted to itself—this ...

Tricks of the Trade Letter frequency, contact analysis, cribs: These are just some of the myriad weapons in the arsenal of Bletchley Park codebreakers. The first step in breaking any cipher is to ...