The Book of the Week is “The Code, The Evolution of Secrecy From Mary, Queen of Scots to Quantum Cryptography” by Simon Singh, published in 1999. This book described a few different contexts in which communications needed to be deciphered or kept secret– in war, in determining whether to execute a queen, in learning about life in ancient Egypt and Greece, and in electronic exchanges to prevent theft of identity or assets, or maintain privacy.
The author related not only the details of how the WWII Allies were able to outwit the Germans by learning what they were doing, but also every last technical detail of the code-breaking, which is brain-breaking for most laypeople. But not for cryptography hobbyists.
Anyway, beginning in the early 1930’s for about eight years, a German intelligence agent sold information on his country’s secret communications operations, to a French intelligence agent. The French couldn’t have been bothered with such time-consuming, labor-intensive work that would allow them to intercept encoded military messages to and from Germans.
However, Poland was interested. The French turned it over to the Poles because the latter felt vulnerable to invasion from both sides, from the Soviets and Germans. Fortunately, Poland had a long standing-agreement with France to share such information.
Also, fortunately, the Poles’ lead cryptographer was a genius. But it took even him a year to compile a catalogue of alphabet-letter chain lengths in order to be able to decipher the Germans’ daily messages, whose code was different every day.
In 1938, the Germans added two more scramblers to their existing three, which made code-breaking by foreign intelligence agents, very nearly impossible. So in the summer of 1939, the Poles sent their deciphering equipment to Great Britain, which took over the spying operation.
In early September 1939, the Government Code and Cypher School in Britain hired its own genius, Alan Turing. He invented a setup of structures in which the completing of an electrical circuit would be indicated by a lit bulb when a code was broken. Construction of the contraptions of the top secret operation was completed by summer 1940, but the code-breaking was still agonizingly slow.
Different German contingents, such as the North Africa campaign, the army in Europe, the Luftwaffe, and the navy each had different codes. The navy’s was the hardest to break. But the work was worth doing because it significantly shortened the war by informing the British what the Germans were going to do next.
The Allies’ knowledge of German messages was especially helpful in the Battle of the Atlantic, and was instrumental in the Pacific Theater at Midway– in killing a powerful Japanese admiral in the Solomon Islands.
Eventually, 420 Native Americans of the Navajo tribe conveyed messages on behalf of, and to and from the Americans, because their language was indecipherable to the Japanese.
At this book’s writing, “Diffie, Hellman and Merkle [Americans] have become world famous cryptographers who [allegedly] invented the concept of public-key cryptography while Rivest, Shamir and Adelman [also Americans] have been credited with developing RSA [in 1977], the most beautiful implementation of public-key cryptography.”
However, three different British men conceived of the concept first– by early 1974. They were sworn to secrecy, as it was part of a classified military operation, and computing at the time wasn’t powerful enough to implement their concept. Being Americans, the aforementioned latter trio patented their method, and in 1996, sold their company for $200 million.
Interesting factoids: Cryptanalysts are in greater demand than ever before. The U.S. National Security Agency is still the world’s largest employer of mathematicians.
At this book’s writing, quantum cryptography was the wave of the future in cybersecurity, because it would be absolutely unbreakable. It would use either photon transmission or fiber-optics. The message sender and receiver could see whether there was an interloper because the messages would be altered. A card game– Hanabi– has since been invented, that uses the logic that allows communicators to decipher one another’s messages, while preventing third parties from doing so.
Read the book to learn about Philip Zimmermann (someone whom the National Security Agency viewed as a troublemaker), and the whole kit and caboodle on how codes were historically made and broken, and how messages can be kept secure. Six ways to Sunday.