The Hidden History of Code Breaking: The Secret World of Cyphers, Uncrackable Codes, and Elusive Encryptions

Journalist and historian McKay (The Secret Lives of Codebreakers) offers a sweeping examination of codes, ciphers, and other types of encrypted communication from ancient Greece to today’s intelligence agencies. In brief sections, McKay catalogs “50 codes that changed the world,” delving into their origins, uses, and how to decipher them. Topics covered include an ancient Greek system of rods and strips of paper used for battlefield communication (the jumbled message on the strip of paper could only be deciphered when wound around a rod in a certain way); the ciphers used by the Venerable Bede in medieval England (religious correspondents dabbling in heretical affairs, fearful of interference from the authorities, would use ciphers to prove the authenticity of their letters); and Samuel Morse’s system of dots and dashes. A more extensive treatment is given to Bletchley Park, the top-secret British compound where computer scientist Alan Turing and his team cracked the Nazis’ Enigma coding machine. Presented in a breezy style, with each section capped by a historically based puzzle for the reader to solve, this delights and intrigues. (Aug.)