Note: This is going to be handed in tomorrow morning. For some inexplicable reason, I'm staying up late and noding this. This is not a cut and paste writeup, this is my personal essay for History 102 at the University of Waterloo that I nearly went insane from putting all those damned square brackets in. Vote as you may, just don't accuse me of plagarism. btw: this deals strictly with the European theatre, as it is a European history course. Feel free to msg me with corrections, I'm not an expert, and this was a bit hurried.
War has always relied on the advantage of knowledge. A cat and mouse game of obtaining information about your enemy’s troop volumes and positions, tactics and weapons while simultaneously minimizing the amount of information your foe can gather about you has always been a fundamental part of warfare. The need to obscure communications to prevent the information from falling into the wrong hands has been known since the days of Julius Caesar, who used primitive methods as early as 50 BC. The battle between the obscurers and those who sought to break the codes has therefore been a continual one, but it reached a new level of stature and importance during World War II with it’s decryption of Germany’s Enigma messages. This battle of wits fought by British mathematicians and statisticians shortened World War II and ushered in the age of information warfare.
The new face of warfare was first hinted at with the Zimmerman telegram, which after British interception and decryption revealed Germany’s proposed alliance with Mexico against the United States in World War I. This along with the sinking of the Lusitania helped propel the Americans into the first World War. While World War I is regarded as the war that caused the loss of innocence among the “old boys club” of military brass, some naive notions were still harbored among the political elite. This is best illustrated by US Secretary of State Henry Stimson’s famous quote that “Gentlemen do not read each other’s mail.” Stimson was shocked with a series of “highly unethical” decrypts from the Black Chamber, America’s earliest code breaking organization whose existence he had not previously known of. This was an attitude soon to change with the meteoric rise to power of Nazi Germany.
The main code of the Nazis before and during World War II was dubbed “Enigma”.
Initially designed to secure banking transactions in 1918, it lived up to its name with a staggering 150 million million million possible gear settings. It first underwent military trials in the early 1930’s, and this is where the first chink in Enigma’s armor appeared. Polish mathematicians were able to use careful analysis on the first Enigma messages and eventually managed to reconstruct a complete Enigma machine through pure mathematical inspection of the ciphered messages. Since the codes only changed once every few months in these pre-war periods, the decoding process was simplified greatly. In 1939, with the threat of war looming, the Poles decided they must pass the information on to the British and French to prevent its loss. This was the critical break Bletchley Park needed in its analysis of the German communications.
Bletchley Park began as a large piece of land with a jumbled mansion on it that so happened to coincide with a key intersection of roads, railways, and communication lines. The British “Government Code and Cipher School” was looking for a new, larger location to continue its work, and Bletchley appeared to have all the prerequisites. The first few employees arrived in the summer of 1939, and its numbers soon swelled so greatly that wooden huts had to be built outside the main house. These huts soon became legendary, specifically the purposely vaguely named Huts 3, 6, 4, and 8. These were the workplaces of the men and women who worked day in and out on cracking Enigma transmissions across Europe. Initial decrypts early in the war and even the prewar period tended to be nothing more than proof of concept breaks, and the keys broken tended to be fairly useless in the beginning of the war. Before 1941 Bletchley had broken only three German keys, one from the Norwegian campaign and two used by the Luftwaffe. This was soon to change however, as the mathematicians soon began to see patterns in German usage of Enigma.
Enigma decrypts soon started to confirm and then rise above and beyond field intelligence obtained by double agents and spies. In January of 1941 Bletchley Park began to receive information about the impending German attack on Greece. The decrypts seemed to indicate the large scale of this assault and that it seemed no British force transferred from the Middle East could prevent its advance. However, little tactical advantage was taken of these decryptions, and Germany invaded Greece in April 1941.
This seemingly inexplicable distrust of Enigma decrypts was prevalent in the early days of the war, perhaps from the commanders who could barely identify with a ragtag bunch of mathematicians who cared little for the war itself and more with a world of numbers. Churchill once said “I told you to leave no stone unturned to get staff, but I didn’t expect you to take me literally.” in response to the various cryptographers he had met during a tour of Bletchley Park. A misunderstanding of the mechanics of cryptography was also at fault. The presence of such “cheats” as code books, word cribs, and automated code breaking led one officer in the Naval Section to write “… in this war we have finally been able to call the bluff of cryptography.” They were “crossword puzzle solvers”, not trained intelligence analysts who understood the nuances of military strategy. This was an attitude shared by many of the top military brass of Britain in the early days of the war, which tended to lead to military blunders.
When Italy surrendered on the 3rd of September 1943, resistance to Allied movements was far from over. German reaction was immediate. intelligence had been able to report a complete picture of German units in Italy, and Enigma decrypts were able to update the commanders on recent troop movements. Specifically, before the Italian surrender, Allied commanders were aware that German units were having difficulties regrouping and reinforcements had not yet arrived. However, little was done in response to this seemingly quite valuable intelligence. Air support was lacking for a more aggressive attack; however those who knew of the Enigma decrypts were left somewhat baffled as to the lack of response to their work. In retrospect, many felt an initial attack farther north along the Italian coast would have prevented many deaths and possibly shortened the Italian campaign.
Situations where commanders ignored this new form of intelligence soon came to be the exception rather than the rule. A proving ground for Bletchley Park came in the situation of the North Atlantic, where German “wolf packs” of submarines roamed the sea in search of merchant vessels. The German navy used a slightly more complicated version of the Enigma cipher which was broken in the latter half of 1941. Britain now knew the location of U-boat patrols, and using Enigma decrypts convoys could now be routed away from the threat. From the beginning of the year until June, U-boats averaged 282,000 tons of shipping sunk each month. After the cracking of the naval codes, this dropped to an average of 120,000 tons a month and then soon to a mere 62,000 tons in November when the U-boats were temporarily withdrawn from the north Atlantic. This was invaluable for British supply levels and morale, but paled in comparison to the next victory over the U-boats, aided by British cryptanalysts.
When the U-boats returned to the north Atlantic in the fall of 1942 from their previous theatre off the coast of America, it was with a vengeance. They were using a new Enigma key, dubbed “Shark” by Bletchley Park, which was currently uncrackable. This resulted in a drastic spike in Allied shipping tonnage lost along convoy routes. Bletchley soon came through however, and the new key was broken in December of 1942. This allowed the convoys to use their previous techniques of routing convoys away from the known positions of enemy U-boats. A problem arose however, in the massive numbers of U-boats that were being directed onto these shipping lanes. Soon there was nowhere to route convoys to, due to the sheer amount of U-boats in the water. It was now no longer sufficient to merely avoid the submarines; an offensive would have to be made. Allied escort forces soon began a full scale attack against the U-boats to such effect that shipping losses were immediately reduced by two-thirds and the Germans suffered such extreme losses that the U-boats were removed from the north Atlantic theatre, never to return. The accuracy of Enigma decrypts was vital in this assault, as it pinpointed the location and strength of the “wolf packs” that once the hunter, had now become the hunted.
Bletchley Park not only had an impact upon the war itself, but an impact upon the world that reaches even to today. It began with the pure volume and speed in which Enigma encoded messages were received, ciphered texts quickly began to come too many and too fast for typical pencil and paper decryption methods of old. The first solution came in the “bombes”, mechanical devices named for the ticking noises they made as they rapidly checked all possible keys for the Enigma messages that needed to be decrypted that day against “cribs”, a series of letters or words the cryptanalyst believed was encrypted in the message. These were successors to the very similar “bombas” the Poles had in use even before 1939. Soon however, it was seen that even the bombes would come up short against the greatest challenge Bletchley had faced thus far. This challenge was “Lorenz”, the personal cipher of Hitler and his high command.
Lorenz was completely different than Enigma, and as such all the previous analysis techniques used had to be thrown out the window. Instead of substituting one letter for another based on a logical progression of gears, Lorenz instead used random data to obscure the text to be ciphered. If the data was truly random, there was no hope for Bletchley as it would be completely impossible to crack. However, through a series of operator errors and intensive analysis of messages, it was revealed that the “random” data was generated by a machine after all, and could therefore be predicted and reproduced. Initial attempts at decoding worked, but were so slow and labor intensive that it could be weeks or even months before the messages were deciphered, rendering them effectively useless. An automated solution for solving Lorenz equivalent to the Enigma bombes would be ideal.
The first solution came in the form of the “Robinson”, a machine that used two long loops of paper, one for the message to be decoded and the other for the “random” data that had been computed appropriately. By continuously changing the position of the loops, every single possible combination could be worked through to find the original message. Robinson had a critical problem however. It was inherently unreliable, as the extreme speed the paper loops needed to be fed at tended to jam and tear the paper, rendering the work done thus far useless.
The second solution that would influence us to this day came in the aptly named “Colossus”. Based on a pre-war thesis about the then theoretical programmable electronic computer by Alan Turing, it was colossal in both size and power. Its principal advantage was replacing the weak link of the Robinson, the paper tape, with electronic valves. Electronic valves instead of mechanical switches allowed the Colossus to operate at an incredible speed. The optical reader alone allowed the encrypted message to be read in at five times the speed of the Robinson, and processing time after that was mere hours as compared to the Robinson’s weeks and months. It was so well adapted to its task that the personal computer of ten years ago was still slower than the Colossus in decryption of Lorenz ciphers.
A total of 10 Colossi were built throughout the war, their design constantly updated and improved. They decoded thousands of messages and were regarded as invaluable to the war effort, a far cry from the relative obscurity that Bletchley languished in during the beginning of the war. At the end of the war, the Colossi were regarded as so crucial that their very existence must not be revealed. All ten were dismantled; all blueprints and technical references were destroyed as well. They remained a secret for over thirty years.
While the world did not know directly of the existence of Colossus, it felt its influence nonetheless. Alan Turing, the man who laid the theoretical framework for the machine is today regarded as the father of modern computing, and cryptanalysis techniques developed in Bletchley laid the framework for modern cryptography. Perhaps more importantly, Bletchley Park showed military leaders the true power of cryptography and information analysis. From its humble beginnings to its eventual domination of the British intelligence scene, Churchill described Bletchley Park in his own eloquent way as “the goose that laid the golden egg but never cackled.”