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The Bletchley Park experience

Tuesday, July 28, 2009

On the 18th July 2009 a rag-tag army of geeks invaded Bletchley Park. Thanks to the genius of Neil Crosby's unorganising Big Geek Day Out. However, the geeks were spotted well in advance by the Bletchley Park organisation, and soundly routed and disarmed and subject to a wonderful show of hospitality and an abundant knowledge.

Britain's best-kept secret

Bletchley Park is one of Britain's best-kept secrets of World War II, it was instrumental in shortening the duration of the War, being positively involved in every major conflict. It was a collection of talent and genius; staffed with mathematicians, engineers, linguists, chess players and demon crossword puzzle solvers. They quietly carried out their duty, careful never to break the seal of secrecy. And even twenty-five years after the end of World War II, the public still had no idea what happened at Bletchley Park. When the official secrecy expired and those records were made public for the first time in the mid 1970s we started to see the marvelous and ingenious work successfully executed by the collaboration of brains at Bletchley Park.

I think Bletchley Park exemplifies the quiet British determination and grit, its quirky inventiveness and eccentricities even at the most desperate of times. It's also a fascinating story of modesty, and so many of the people of Bletchley Park never received the recognition they so richly deserved - even today.

In war we glorify the conquerors - Eisenhower, Montgomery, Rommel, Doernitz - the people who made their names on the field of battle. We worship the political leaders Roosevelt and Churchill. Sometimes we remember the operatives working well behind enemy lines always in danger of being caught every moment of their lives. But for a few geeks sitting in wooden huts safely ensconced hours north of London, they are so easy to overlook, and yet their contribution to the defence of Europe is absolutely massive.

Bletchley Park was the center of Britain's intelligence war against the Axis powers. It principally was devoted to cracking and translating messages between the enemy military units, but it also ran counter-intelligence and special operations.

The main story of Bletchley Park is the story of Enigma and Bombe, and the codebreakers. Enigma, the machine that encrypted German military communications, and Bombe, the British machine that sought to break that encryption.

Cracking Enigma with Social Engineering

The breaking of Enigma wasn't all brute force. The codebreakers had a number of cribs - or techniques to reduce the possibilities - and many of them, as is thematic even in modern day codebreaking are down to social engineering. But in Bletchley Park's case it was reverse social engineering. Understanding habits of Enigma operators or message senders, and exploit it to reduce the possibilities.

One particular brilliant piece of social engineering was finding duplicate messages. If you have the entire encrypted message and you can with reasonably certainty guess the start of the message then we immediately narrow the possibilities of setup because we know how the first few letters are translated. That crib is then handwired into Bombe, and it spouts out possible starting settings that result in the matched combinations of letters.

There were a number of sources of these messages, the first was weather messages sent to U-Boats in the Atlantic, the German navy used standard weather reporting. So if the codebreakers could guess the weather pattern they could be reasonably certain of the decrypted message, so had a menu for the Bombe to process.

Why crack a message you already know? Well, the German military made one gigantic mistake - mainly out of confidence that Enigma was unbreakable. The Enigma start settings were the same for everyone in the same branch of the military, so breaking that one known message meant that they had the Enigma settings for all messages sent by the same branch of the military of that day.

The second piece of social engineering was a small German army unit in the middle of the North African desert. They sent virtually the identical message everyday reporting through their chain of command. Every day the message was "Nothing to report". That's enough of a menu for Bombe to brute force it's way to a solution. Now, what was utterly brilliant was Bletchley Park's request that the British Army in North Africa not send any of their units into the area this German unit was based. And so, the codebreakers virtually guaranteed that everyday they had the same message arriving ready for them to break the current day's settings.

Another source of repetitive messages were commands issues from near the top of the military hierarchy. They often started with the formal "Special Orders/Instructions" (out of habit essentially). So frequently the codebreakers guessed certain messages would start with the German word "Besonder".

I was amazed that social engineering was a critical part of breaking Enigma. Kevin Mitnick infamously demonstrated the power of social engineering in cracking computer systems, but the Bletchley Park codebreakers had already proved how effective it can be.

Chess and Bletchley Park

The 1939 Chess Olympiad in Buenos Aires was interrupted by the outbreak of World War 2. On the English team were Stuart Milner-Barry (later knighted), Conel Hugh O'Donel Alexander (or just Hugh Alexander) and Harry Golombek. All three left immediately and made their way back to Britain. Milner-Barry was the first to be recruited into Bletchley Park, and he in turn recruited both Alexander and Golombek.

So three of the best chess players in England were part of the Bletchley Park intelligence war. Each contributed substantially in their own way.

Milner-Barry headed up Hut 6 under Gordon Welchman, was later the person chosen to hand-deliver that petition to Winston Churchill begging for funding to keep the Bletchley Park operation going, which in turn Churchill became a staunch supporter of Bletchley Park's efforts. (Sir Stuart reprised that role by hand delivering a letter to John Major pleading for the preservation of Bletchley Park in 1992).

Hugh Alexander became the head of Hut 8 (the Enigma code-breaking effort), taking over from Alan Turing, becoming an instrumental part of the code breaking efforts. In Building B they recognise 4 individuals in particular for their efforts during the War. Turing was one of them, so was Gordon Welchman and Alexander was another.

After the war Alexander was recruited into GCHQ, and that basically killed off his chess ambitions. In a radio-match he beat the Russian champion Mikhail Botvinnik (who was regarded as the strongest player in the post-war world, and two years later becoming World Chess Champion). Unfortunately Alexander's commitments to the British intelligence community mean that playing international tournaments in the Soviet Block was far too risky to national security. So the British chess community were deprived of a potential World Championship candidate and potential grandmaster. His chess contributions were limited to local tournaments and writing chess books - including a memorable book about the legendary Boris Spassky - Bobby Fischer World Championship Match.

Alexander showed so much promise in the pre-war years, establishing himself in International tournaments like Nottingham 1936 where he placed respectfully despite having to face 5 World Champions. That promise and intellect was refocused into intelligence work through his experiences in Bletchley Park, so what was robbed from the chess world played a part in keeping Britain safe during the War and the subsequent cold war.

Harry Golombek continued being a chess correspondent, and a well recognised one. His book covering the 1948 World Championship Match Tournament is one of many splendid example of chess journalism.

Something to be proud of

I'm immensely proud of all the people who worked in and with Bletchley Park during the War. Every single one of them. I am still aggrieved however that Britain, or Churchill in particular, gave up its leading role in the computer revolution. I understand the political circumstances of the imminent threat of Communist Europe and Cold War threat provoked Churchill into hiding all evidence of the superiority of British Intelligence Services; but each time I see Silicon Valley herald itself as being the dog's bollocks, I wistfully remember that we handed that advantage over to them on a silver plate. And that is the nature of the British Spirit and stoicism.

I loved our big geek day out in Bletchley Park. I learnt far more than I imagined. Geekwise I'm satiated. But I know I want to go back and learn more. Thank you to the Bletchley Park staff for making us feel very welcome. Thank you for fighting hard to keep the story of Bletchley Park alive - the story of the British geeks and their phenomenal contribution to protecting our freedoms.

Bletchley Park - no movie can do it justice. Not even a blog post can convey just how instrumental they were. And I didn't even mention the working Colossus, the counter-intelligence operations, the pigeons, the D-Day involvement, the unheeded warnings, the Lorenz cipher, the Harrier Jumpjet, the amazing private tour we had, Alan Turing, the Computer History museum, the Churchill museum, the cipher museum... so much.

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