Unravelling an Enigma

What a blazingly good fun day at Bletchley! A ‘few’ pictures of the day are shown below (hi-res versions are available on request).

Well… Some of us were ‘keen’ and so we were there in the queue for when the gates opened at 9:30am. Various en-route txts from the rest of our group coordinated our meet up over coffee and tea ready for the first tour at 11am.

There is easily more there than can be seen in one day. Did Chris ever make it out before the gates closed? Or is he still lost somewhere in the basement of Block B?…

Meanwhile, I was nearly locked in the RSGB amateur (Ham) radio station GB3RS as it was being shut down for the end of the day… Apparently, the station and displays have only recently been relocated from central London to Bletchley in July this year. They have a very good setup with some good hands-on equipment, some old historical stuff, and the latest state-of-the-art transceivers as witnessed by the various terrestrial and satellite aerials festooned around “Station X“.

… And then the more mundane mobile smartphone digital transceiver came to life to coordinate regrouping in the car park to make our timely escape…

We also enjoyed some good summertime weather that made for a very pleasant wander around the grounds and the various huts and stables. There’s various vintage vehicles and paraphernalia on show around the site to give a feel for the war period.

The wartime effort at Bletchley was certainly impressive with a cypher disassembly line spanning up towards 9000 staff with yet more staff in various outposts. Further expansion was limited by concerns to not overrun the available local services and for keeping the operation clandestine! Also impressive is the volunteer effort today that has brought Bletchley Park back to life. The ‘ultra’ secrecy surrounding the site meant that it was nearly bulldozed to disappear forever unknown under housing. The site was only rescued due to a conservation order placed on a number of trees on the site! Only some years later was the significance of the site ultimately revealed.

The rebuilding of a working Bombe and Colossus, each taking over a decade of re-engineering, are must-see pioneering marvels from the time. They are similarly epic to the Science Museum’s Babbage’s Difference Engine No 2, but also the Bletchley machines go somewhat beyond with their added complexity of electric/electronic circuitry and myriad connections… Elecro-Electronic-Mechanical marvels! And you get to see them working. With all the heat generated, and multiple machines crammed in, plus operators, plus the operators likely chain-smoking and always working under the pressure of time, and no windows, no wonder one of the huts was nick-named “Hell”.

Just a very few of the surrounding wartime stories are included on various display panels, but that still gives good context for the driving war effort.

All quite a feat all round.

Poor Eva in our group was put on the spot for translating the same repeating daily message for some lonesome Africa German outpost that the Allies very deliberately kept undisturbed… That one location must have been the safest but most boring place to be posted to for the entire war. It also helped Bletchley Park decrypt other messages that day…

Another deliberate curiosity was the Czech in-the-middle-of-nowhere posting that was of no strategic interest whatsoever that ‘happened’ to have one bomb dropped nearby. It also happened to uniquely have a few “z”s in its name…

Not to be missed are the stories of various hero pigeons that carried critical messages when all other ‘modern’ technology had failed!

And lots more. Too much to cover all in just one day.


Thanks to Jason for organizing a very good day. And thanks for the txt-ing coordinating from him to sheep-dog the rest of us all together!

And thanks are due to the volunteers we met at Bletchley who make it all enthusiastically and very knowledgeably work very well.


Further notes:

This seems timely: Alan Turing Monopoly

OK… A bit cheesy but a good idea. Hopefully not lost amongst all the other branded re-spins of that game… I like the use of “‘Auntie Flo is not so well’ (which was the secret phrase for…)”.

Is there also a ‘Turing Machine‘ game board? That would make for a hellish twisted sort of snakes and ladders for jogging forwards and backwards until completion… 😉


A few links:

Three points to note:

  • The Germans were ‘ahead of the game’ at the outbreak of WWII and due to their code breaking, they knew in advance the location of all British warships and lots more
  • The Polish Intelligence Service set the scene for how to break Enigma
  • And the turning point in the war was perhaps at or soon after Arnhem when the British decryption effort became the more successful to turn the tide of strategic information to help Montgomery against Rommel and for throughout the entire theatre of war. Especially, decoding Enigma/Lorenz was essential to the successful D-Day landings

Perhaps (at least in part) the war really was won by which side knew the more of the other…


10 comments to Unravelling an Enigma

  • Martin L

    And the ‘game’ continues all the more so today. Except… Replace the Bombes and Heath Robinson and Colossus with instead, The Cloud:

    A death blow for PPTP – CloudCracker

    Moxie Marlinspike’s CloudCracker promises it can crack any PPTP connection – within a day…

    … VPN access was successfully cracked… … as a demo that puts the nail in PPTP and MSCHAPv2’s coffin, CloudCracker is a complete success. …

    Those who are still using PPTP should find an alternative as soon as possible; options include L2TP/IPSec, IPSec with IKEv2 and OpenVPN. The same holds true, by the way, for corporate WLANs with WPA2 and EAP via MSCHAPv2, which can be cracked using the same concept. PEAP, the encoded variant, puts everything through an SSL tunnel whose security depends on users never accepting a fake certificate – and that can’t be guaranteed for companies that use their own signed certificates.

    (Also note the volunteer distributed parallel cryptographic breaking attempts of distributed.net, which began in 1997.)

  • Martin L

    TNMOC and Bletchley Park are in the recent news with:

    The Register: World’s oldest digital computer successfully reboots

    Bletchley’s boffins help bring back WITCH

    After three years of restoration by the National Museum of Computing (TNMOC) and staff at Bletchley Park, the world’s oldest functioning digital computer has been successfully rebooted at a ceremony attended by two of its original developers.

    The 2.5 ton Harwell Dekatron, later renamed the Wolverhampton Instrument for Teaching Computation from Harwell (WITCH), was first constructed in 1949…

    Update: And there’s a slightly more semi-serious follow-on article:

    The Register: DEKATRON reborn: Full details on World’s Oldest Digital Computer

    … The restored Dekatron is not a replica: it has been rebuilt from original parts and its use by visitors is encouraged – unlike the ENIAC on display at the Computer History Museum in Mountain View, California: you can look but you can’t touch that monster – it’s for display purposes only.

    The WITCH is a simple beast. Rather than follow the architects of ENIAC and build a general-purpose computer, its creators kept it simple: they built a 2.5-ton calculator that ate numbers and spat out answers.

    Of the original Dekatron team, Ted Cooke-Yarborough designed the electronics; Dick Barnes made the relays, and control and timing electronics; and Gurney Thomas created the Dekatron memory.

    “This was purely a mathematics machine,” museum spokesperson Stephen Fleming told The Reg. “It’s the number cruncher of its time.”…

    … The Dekatron has 828 Dekatron tubes. Also, there are 480 relays, 7,073 contacts or relay switches, 26-high-speed relays, 199 lamps, 18 switches, a 1.5 kilowatt power supply, thousands of connectors, some sheet-metal casing and a metal frame measuring 6m across, 2m high and 1m deep. …

  • Martin L

    Bletchley Park are blazing into the past again!

    Bletchley Park boffins start trailblazer EDSAC computer rebuild

    Physical production of a replica of EDSAC, aka the Electronic Delay Storage Automatic Calculator, has at last begun at The National Museum of Computing, located at World War II crypto centre Bletchley Park. EDSAC is an early computer originally put together at Cambridge University in the late 1940s.

    The initial work on the replica focused on punching out 20 chassis units based on the three that survive from the original EDSAC’s 140, each home to a selection of the computer’s 3,000-odd thermionic valves. These helped it process up to 650 instructions per second, not many by today’s standards, but two orders of magnitude more than the electromechanical computers that preceded it. …

    Cambridge’s First Computer

    It was great to hear the news today that work has started on rebuilding the EDSAC at Bletchley Park.

    Many regard the EDSAC as the first computer because it was the first machine to store its instructions in electronic memory. This is only one definition, as Babbage, Turing or those chaps at Manchester University who built an electronic calculator would argue that they also had made a computer. What is undisputed is that the EDSAC was Cambridge’s first computer, established the first computer science department and course, and is a very important milestone in British computing. …

    There’s an EDSAC emulator that can be tried, but best read around a little first to get to see what it was all about!

  • Martin L

    Recently in the news:

    The road to uncovering a wartime Colossus

    The story of how the Colossus computer at Bletchley Park aided the allied code-cracking effort during World War II is becoming well known. Its claim to be a forerunner of modern-day computers is also well established.

    What is much less well known is the tale of how Colossus’s story came to be told in the first place. It is a tale of how one man’s dogged efforts overcame official secrets and official indifference to rewrite computer history…

    … All those codebreakers signed the Official Secrets Act which demanded that they kept quiet about their wartime career.

    Almost all the machines were broken up once they ceased to be useful and design documents were burnt or destroyed at the same time.

    “I got to know more about it than they did,” Prof Randell told the BBC. “They were so compartmentalised that those who worked in one hut would not dream of talking to people in another hut.”

    Prof Randell tripped over the story of Colossus in 1970…

    … Prof Randell’s lecture and Coombs’s comments meant the computer history books would have to be rewritten.

    ENIAC was not the first computer, it was the 11th,” he said…

    … “They were so modest and so bloody brilliant,” he said. “It was one of the best experiences of my life.”

  • Martin L

    For another essential part of the jigsaw that included Bletchley Park, there was also the derring-do beyond the front lines of the war effort:

    When Ian Fleming picked my grandfather to steal Nazi secrets

    … Overseeing them from the adjoining office was the formidable Admiral John Godfrey, their boss and the inspiration for M in the James Bond novels.

    And back at the start of the war, the main preoccupation of his team was how to address a key British weakness – the fact that the Germans led the Allies in all sorts of technologies – encryption, rockets, submarines, torpedoes, mines and much more.

    In 1942, Fleming proposed a simple solution…

    … Here Fleming’s Red Indians, as he once called them, were more successful. They were deployed again during the offensives in Malta, Sicily and the Italian mainland during 1943. This rag-tag collection of marines and intelligence experts seized codes, secret documents and all sorts of novel German kit including an Enigma machine. They even bagged an Italian admiral.

    So when the Allies were planning the greatest offensive of them all…

    That story was uncovered by chance accident of an unusual name and a chance meeting. What other such stories remain Top Secret still?

  • Martin L

    Bletchley Park continues to be in the news with the hard work being done by hugely dedicated volunteers to continue the ever expanding TNMOC and their resurrection of the dawn of electronic computing:


    ‘Flash-Gordon’ tech: How Sir Maurice Wilkes made practical computers possible

    ENIAC – a time before integrated circuits

    26th June 2013 – Born this day 100 years ago in Cambridge, Sir Maurice Vincent Wilkes was a pivotal figure in the world of digital computing.

    Few would dispute the critical role played by Wilkes in developing practical computing that would ultimately lead to the accessible machines we rely upon today. Certainly for the British computing scene, his contributions were vital. …

    … in 1946 he began the work for which he is still best known – the development of the Electronic Delay Storage Automatic Calculator (EDSAC). EDSAC was a general purpose, electronic digital stored-program computer inspired by John von Neumann’s Electronic Discrete Variable Automatic Computer (EDVAC) binary architecture.

    Operational in 1949, EDSAC used vacuum tubes for logic, mercury delay lines for memory, punch tape for input and a teleprinter for output.

    EDSAC stands out…

    … Until EDSAC, machines were limited in the jobs they could perform by their hardware – gears, levers, relays – or the program. But an electron is an electron is an electron, no matter what the program, and the valves worked by controlling the flow of the current in a sealed container.

    In a world of integrated circuits and compact design, it’s hard to comprehend how a device that at best resembles a lightbulb and at worst something from a Flash Gordon rocket ship could make a real-life computer run. …

    … One of the first computers credited with using vacuum tubes was the Atanasoff-Berry Computer (ABC). It was built in 1937 but was not programmable and was designed primarily to solve linear equations. The Colossus computers, in working order from 1943 and used from early the next year onwards to crack the German military commands during World War II, also used tubes and were programmable. This was also the case with Electronic Numerical Integrator and Computer (ENIAC), which began work for the US Ballistic Research Laboratory in 1948. ENIAC forged the way for a generation of programmable vacuum tube computers from 1949, spearheaded by Wilkes’ EDSAC. …

    … Fortunately, brilliant Colossus designer and General Post Office engineer Thomas “Tommy” Flowers decided that thousands of vacuum tubes could and should be used reliably in an electronic computer as long as the environment was stable and the circuits were kept on constantly. …


    Demo shows off first parts of Edsac rebuild

    A project to recreate a pioneering UK 1940s computer has hit a significant milestone as the first working parts of the restored machine are demonstrated.

    Key elements of the restored Electronic Delay Storage Automatic Calculator (Edsac) were unveiled on Wednesday. They were shown off at a Bletchley Park event marking the 100th anniversary of the birth of Edsac’s designer, Sir Maurice Wilkes, who died in 2010. The Edsac restoration project began in 2011 and should be completed by 2015.

    Edsac, widely accepted to be the world’s first practical general purpose computer, first ran in May 1949. …

    Clocking in the digital age

    First working parts of the EDSAC reconstruction are demonstrated at a celebration of the centenary Sir Maurice Wilkes, father of British computing

    … At the Wilkes’ centenary celebrations, the first components of the EDSAC reconstruction including its internal clock were demonstrated to an audience that included Wilkes’ family members and an operator of the original EDSAC. The recreation of EDSAC, when completed by a team of volunteers in two years’ time, will be used to inform the public about Britain’s rich computer heritage and to inspire young people to learn about engineering and computer science…


    Rise of the machines, south of Milton Keynes

    Computers make a noise at TNMOC

    …It’s the sounds that get you: wheels spinning, processors squeaking, the furious hammering of teleprinters, and some 1980s synth.

    Yes, computers really were this noisy – something you forget in an era when even the benign tap of the keyboard is giving away to the silent swoosh of finger on glass.

    I’m at The National Museum of Computing History (TNMOC) in Bletchley Park, near Milton Keynes, home to some of the oldest and rarest computers in the world…

    The two The Register articles are surprisingly serious and interesting compared to their usual editorial frivolity. Some spectacular history is being rebuilt at TNMOC that has just got to be a must-see!

  • Martin L

    For a bit of a Colossus of a lego cutie in true The Register irreverence, see:

    Behold, replica Nazi-code-cracking Colossus computer IN LEGO FORM

  • Martin L

    The Register visits Bletchley Park! And gives rather a good writeup. But how in Milton Keynes did the writer manage to get around the place in under two hours?!!… Must be a pleb journo… 🙁 So, a surprisingly good writeup considering. 😉 There’s a rather interesting snippet that it was Bletchley that sank the Bismarck. The film portrayal of a lucky chance find by a spotter plane flying to the ends of its range was all a Churchillian ruse to keep “Ultra” a secret:

    Bletchley rebooted: The crypto factory time remembered

    High commands and dirty words in German – the story retold

    … the bit about the radar is not the whole story. The RAF command actually already knew the Luftwaffe’s plans before their pilots took off from France during those long days of summer and autumn.

    That’s because the encrypted communications used by the Luftwaffe – thousands of messages about flight operations and targets – had been hacked by code-breakers of Bletchley Park, just outside Milton Keynes…

    … Bletchley also saw the first computers ever used to hack crypto, called the Tunny and Colossus. The Colossus machines read 5,000 characters a second; with 10 Colossus operated by 500 staff they broke 63 million characters of “high-grade” German communications.

    This story has been hidden from history. That’s thanks to WWII…

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