Free THAT WAS THE MILLENIUM THAT WAS by John Scalzi Page B

on to something. The Nazis were not purchasing Korn CDs with their encrypted messages, you know.
    Cryptanalysis is the best use of the brain because cryptology (the science of encrypting information) is nearly as difficult. People have been coding information for as long as there's been a reason to hide news from someone, of course, though early methods were almost charmingly simplistic. The Greeks did it by writing messages on a piece of cloth spiraled down a stick of a certain thickness; unraveled , the cloth strip was gibberish (it was all Greek to them). The Romans used letter transposition, shifting all the letters by a certain amount, not unlike you would do for your Lucky Charms Secret Decoder Ring. Although in this case, it would be Julius Caesar and not some fey leprechaun telling you how many letters to click over, and the secret message would be to take Masada rather than to eat more sugary cereal.
    Serious coding had to wait until this millennium, and the 15th Century, when the Arabs (who had been caretaking and expanding on Western knowledge while Europe festered in that unfortunate dark age it had going) codified fundamentals of both cryptology and cryptanalysis. They were the first people to figure out that certain letters (such as vowels) appear with more frequency than others, and that you could crack a simple code based principally on frequency counts of certain letters. I know, you're thinking, " Duh , who doesn't know about letter frequency distributions and probable plaintext in cryptanalysis?" But remember, this was a simpler time.
    Cryptology in itself probably never won any wars, but cryptanalysis certainly helped to win them, and it was enough of a priority that combatants would often go to desperate measures to crack the enemy's codes. Take the Confederate army (please). The Confederate army had such a difficult time cracking the Union's codes that they actually published encoded Union messages in newspapers to encourage the folks at home to play along. Sort of like a Word Jumble, where the unjumbled message would be Sherman's request for torches, the better to burn his way from Atlanta to the sea. The Union had no problem cracking Confederate codes, incidentally; the Rebs were using a relatively unsophisticated cipher. Stupid Confederates.
    Probably the most famous example of the importance of cryptanalysis comes from the Second World War, and the vaunted British "Ultra" program to crack the German encryption code, known as "Enigma." Spearheaded by the famous mathematician Alan Turing, the Ultra project gave the Allies an immense advantage in terms of knowing what the Germans were up to -- even if they couldn't take advantage of all the information. If Allied forces just happened to show up where the Germans were, the Germans would figure out their code had been broken, you see. The Nazis were genocidal curs, but they weren't morons.
    This made for some torturous maneuverings: The Brits would decrypt the location of a German convoy, for example, and then send out a plane that would "discover" the convoy, after which they would blow it up right pretty. Be that as it may, sometimes sacrifices were made: The British once discovered that the town of Coventry was going to be bombed, and rather than evacuate the town -- and risk exposing their knowledge -- the bombing was allowed to happen.
    A little-known secret about the British Ultra project, however, is that much of the heavy lifting in that effort came not from the British but from the Poles. During the 1930s the Polish government, which had a justifiably dim view of the Germans, assigned Marian Rejewski, Jerzy Rózycki and Henryk Zygalski to crack the Enigma code. They did it the old-fashioned way: First they procured expired Enigma codes and a booklet that explained how to set up an Enigma ("So You Want To Send Secret Messages: A Beginner's Guide"). Then they built a replica of the Enigma machine. Then they whacked away at the codes and the rewired