Dr Enigma at Turing Fest 2018

Dr Enigma was back at Turing Fest in Edinburgh this year to deliver a talk, as well as host a stand displaying two original, war-time Enigma machines.

It was great to be back at the festival, speaking with so many interesting people, and once again to be bringing a piece of history which is still relevant to the IT world today (see: War Hackers: Why Breaking Enigma is still relevant to cybersecurity today).

As Scotland’s premier IT event, the Enigma machine story, the hands-on demos of the original Enigma machines, and their links to Alan Turing, provide an interesting contrast to the high-tech world of blockchain, growth hacking and bootstrapping, as well as something you can actually touch and feel – something of a rarity in this digital age.

A big thanks to Brian Corcoran and the rest of the Turing Fest organisers for the invite and to everybody who came to the talk and to play with an Enigma machine.

If you’d like to book an Enigma machine talk or demo for your own event, see our Enigma machine events page or email:

Here are a few pictures of Turing Fest 2018:

Did the Nazis know the British were breaking the Enigma codes?

I am often asked whether the Germans had any idea that the British were successfully breaking Enigma during the war.

Surely, they say, there were German spies in Britain who would have been able to pick up some clues, and to report their findings back to Germany? It often comes as a surprise to them when I tell them that, firstly, all the German spies in Britain were directly controlled by the British, and that, secondly, British achievements were not known of in Germany until the 1970s.

Masterman was the Chair of the ‘Twenty Committee’, and his 1972 book revealed how the whole German spy network in UK was controlled by the British.

It seems that the Enigma machine – or, rather, its ciphers – were seen in Germany as unbreakable. After all, there were theoretically 3 x 10114 possible cipher patterns which the basic three-rotor machine could create, and testing all these possibilities one after the other is beyond modern computing power even now, and so was well beyond anyone’s wildest dreams during WW2.

The three-rotor Enigma had 3 x 10114 possible cipher patterns. Pic: James Martin/CNET and

With this exaggerated belief in the inviolability of the Enigma system, its users never stopped to think – or even to test – whether it could really withstand an organised attack using mathematics rather than the ‘brute force’ approach of attempting to test all those possibilities in succession. (See: War Hackers: Why Breaking Enigma is Still Relevant to Cybersecurity Today).

There were occasions when Allied successes in combat were such that questions were raised on the German side – investigations were set up to identify what had gone wrong, had valuable information been leaked?

Inevitably, when all the possible explanations were examined, unfounded faith in Enigma steered the investigators away from realising that Enigma might actually have succumbed to a sustained mathematical attack.

With hindsight, we can now identify occasions when more rigorous analysis might have revealed to the Germans that Enigma was, at least, breakable, even if not broken. Such a conclusion might have prompted tightening up or changing the way in which Enigma was used, or perhaps changing the wiring patterns of the rotors. The latter never happened, and such changes as were made to the operating procedures were never sweeping enough to shut out Bletchley for long.

Of course, great care had to be taken over Allied use of Intelligence derived from breaking Enigma. Over-hasty or injudicious use of such Intelligence could well have suggested to the Germans that Enigma-encrypted messages were being read. No-one on the Allied side, therefore, was permitted to base any action on a decrypt, unless there was also another way in which the relevant Intelligence might have been acquired.

The care with which Enigma-derived Intelligence was handled prevented its source from being discovered, and this, together with Germany’s unjustified faith in the machine’s power, meant that knowledge of Allied breaking of Enigma remained a secret not just throughout the war, but until 1974, when The Ultra Secret, a book written by RAF Intelligence officer Frederick Winterbotham, revealed the truth.

Ultra Secret 1e Dw
Winterbotham’s book, published in 1974, was the first to reveal the scale and importance of Enigma-breaking at Bletchley Park.

Even so, there was a perilous moment when Schellenberg’s handbook for the planned invasion of Britain (produced in 1940) reported that MI6 had moved its Communication Section from Broadway to Bletchley Park, and that its duties included Wireless/Radio communications.

The implications of this accurate observation, correctly linking MI6, Bletchley, and wireless communications, were never followed up. The evidence lay upon the printed page – but was never spotted.

How many Enigma machines are there left?

How many Enigma machines are there left in the world? This is a question frequently asked at my Enigma presentations. It is impossible to answer this precisely, as nobody knows.

A 3-rotor Enigma machine

There is no obligation on the owner of an Enigma machine to register it in any way – it’s not, after all, a transmitter – but fortunately, the late David Hamer decided years ago to keep records of all the machines he heard about, both those owned privately, and those in museums and other public collections.

Obviously, such a list can’t be complete (I know of several Enigma machines which are not listed, and there are almost certainly many more) but it’s the nearest thing we have to a worldwide catalogue at present. As more Enigma machines are being discovered, and as it’s unlikely that a significant number of the machines listed have subsequently been destroyed, the list understates the number of survivors, rather than the reverse. Nevertheless, analysing the list produces some interesting results.

Numbers of known Enigma machines that still exist

  • 318 Enigma machines left TOTAL
  • 284 Enigma machines issued for use in or before WW2
  • 34 Enigma machines that played no part in WW2
  • 186 3-rotor Army/Air Force machines left
  • 63 4-rotor naval Enigma machines left

The most recently available version of the list shows 318 Enigma machines, of which 34 played no part in WW2, leaving 284 machines issued for use by Germany in or before the war.

These can be further subdivided into different types: for example 186 are standard 3-rotor Enigma machines of the sort used by the Germany Army and Air Force, and 63 are 4-rotor naval Enigma machines (adopted on 1 February 1942).

So the list enables us to answer the original question, by saying that, roundly, perhaps around 300 WW2 machines survive, of which about 1 in 5 is a 4-rotor naval machine.

Close-up of the scrambler unit of a 4-rotor machine, one of the rarer Enigma types

However, as well as identifying the type of each machine, the list also includes the serial numbers of each. Every Enigma machine carries an individual serial number, which is not only stamped into the metal base (inside, and only visible when the rotors are removed), but also engraved into the rotors (including the reflector rotor) and included in the data shown on a metal label mounted centrally in front of the keyboard.

The case itself may also carry a small metal or plastic number plate. The label in front of the keyboard may give additional information about which manufacturer made the machine and when. This data can be used to provide an estimate of how many machines were made, even though the serial numbers are not members of one continuous series of numbers.

Enigma x 2! Ralph Simpson of The Cypher History Museum (San Jose), with Dr Enigma – each with their personal Enigma machines

The numbers are prefaced by a single upper case letter (there are 6 of these), which can be correlated with the machine type or user. For example, all naval machine numbers, whatever the model, are prefaced by ‘M’, for ‘Kriegsmarine’. Examining the numbers, and making some realistic assumptions, suggests that about 37,000 machines might have been made, of which at least 284 (less than 1%) survive. As noted above, about one fifth of the survivors are 4-rotor naval machines.

These conclusions must necessarily be tentative, but in the absence of original German records, they are the best we can do. They also suggest that published (unsubstantiated) estimates that there were as few as 20,000, or as high as 120,000 machines, are wide of the mark.

Following David Hamer’s death last year, other experts have volunteered to maintain and update the list. I’ll revisit this subject if any amendments are necessary.

If you’d like to learn more about the fascinating Enigma machine story, and play with one of these iconic machines yourself, you can attend one of my Enigma machine events or book me for your own.

War Hackers: Why Breaking Enigma is still relevant to cybersecurity today

This year marks 100 years since the precursor of the Enigma machine was first patented by Arthur Scherbius.

Although known best as the enciphering machine used by the Nazis during World War Two, the Enigma machine in fact pre-dates the war and was available commercially until the late 1920s, after which the German government swallowed up the company, removed the machines from the open market and upgraded the hardware.

Cover of the original manual for an Enigma machine

So how could the cracking of coding technology that is a century old still have any relevance to today’s cybersecurity world, where ciphers, and the hacking of them, are infinitely more complex?

Well, the story of breaking the Enigma code is a fascinating tale of cat and mouse, which anyone in the cybersecurity space today will appreciate. Essentially, the Poles, Brits and Americans, who each broke Enigma ciphers at different points during the war, were hackers, constantly probing for weaknesses in the Enigma system.

It was a combination of mathematical genius along with exploiting said weaknesses in the hardware, prescribed protocol and just plain user error, that helped Allied forces break Enigma ciphers and allowed them to read many of the messages (though not all by a very long way) and gain advantages which eventually led to Allied victory and the shortening of the war.

Dropbox, San Francisco, Feb 2018

As part of our recent Silicon Valley Tech Tour, Dr Enigma presented at the Dropbox HQ in San Francisco, and during this visit I spoke to Scott Joaquim of Dropbox’s Security Team. He perfectly sums up why the Enigma story is still so relevant to IT security and what they are trying to achieve at Dropbox today:

“At Dropbox, one of our core company values is being worthy of trust. With over half a billion users and 300,000 companies using our platform, security and privacy are our top priority.

So for us, one of the most riveting elements of the history of the Enigma machine is that, in spite of the machine’s technical sophistication, it was human error, procedural flaws, and leaks of key information that helped enable the Bletchley Park team and others to crack the codes.

It’s a dramatic testament to the fact that a system or organization can only be as secure as the people who are operating or taking care of it. At Dropbox this is why we cultivate a culture of security where every employee, regardless of their role, takes personal responsibility for keeping Dropbox and our users secure.”

Speaking at Dropbox HQ, San Francisco, Feb 2018

Indeed, with more ways to set up an Enigma machine than there are atoms in the observable universe, the Nazis were convinced that Enigma ciphers were unbreakable. And indeed they were correct in believing that they were safe from a brute force attack; it would have taken a lifetime to run through each setting at that point in history.

However, clever people approached the problem differently, discovering and exploiting weaknesses with both the machine’s hardware, the user protocols set from above, as well as just every day user laziness, to attack and break the ciphers.

As Scott from Dropbox noted, it’s a stark reminder that systems are only as secure as their weakest link. It’s not just holes in the code which need to be patched; social engineering attacks are nothing new, and the lessons that Alan Turing and the Enigma hackers learned back then, still have much to teach us today.

To learn more about the fascinating Enigma story and its relevance today, book Dr Enigma for an Enigma Machine presentation and hands-on demo with his original Enigma machine.

Enigma Machine visits Silicon Valley Tech Companies

In late February, I flew to California with my Enigma Machine to deliver presentations on ‘The Greatest Hack in History’ at the request of a number of major tech companies including FaceBook, PayPal and Dropbox.

I was also invited to speak at the major tech news network CNET, who then wrote an article about my visit (which you can read here: Enigma: Up close with a Nazi cipher machine) and also did a photo shoot.

Interest in the talk and Enigma Machine demo was extremely high and it was a pleasure to be able to speak infront of such enthusiastic audiences at such sucessful and interesting companies. Visit the Gallery to see some pictures of my Silicon Valley Tech Tour, and keep an eye on the events page if you want to come and play with a real Enigma machine.

The Stolen Enigma machine

Bletchley Park – war station for Britain’s codebreakers – is nearly 100 miles from where I live, so I don’t go there at the drop of a hat. However, I do go quite often, my first visit being over 20 years ago but, because of the distance, I try to combine calling in at Bletchley with some other mission. This often means that I have my Enigma machine with me because I’m en route for a speaking engagement. Do I leave the machine in my car while I call at the shop, visit an exhibition, or meet up with a contact? I do not! When I’m asked why I lug the machine with me, I respond with another question: where is the only place from which an Enigma machine has been stolen recently? Answer: Bletchley Park.


1 April 2000 was a Saturday, and Bletchley was open (it was only open two days per fortnight back in those days). That night, the national news programmes reported that a ‘unique code machine had been stolen from Bletchley Park’. I found this both worrying and puzzling, because I didn’t think that the Bletchley Park Trust owned a unique Enigma machine. The basic facts soon surfaced: what had been stolen, from a display case in the mansion during opening hours, was an Abwehr Enigma, a rare type with no plugboard, and with four rotors. A much quoted value was £110,000, which I felt to be something of an overestimate at that time. Was the Trust embarrassed? – you bet, because this machine wasn’t theirs, it belonged to GCHQ.

G312 theft

The machine, serial number G312, made the front cover of the very next issue of Invaluable, a trade periodical devoted to exploring security measures designed to protect art collections, and to tracking down stolen objects when security has failed. BT, then still co-owner of the site offered a £5,000 reward for information leading to its recovery. The grounds around the mansion were searched, the lake was dragged, but to no avail. Machine and thief had vanished. Speculation was rife; many declared it was an ‘inside job’, arising out of rivalries between board members of the Bletchley Park Trust, others argued that it must have been stolen to order for a wealthy client.


It was more than five months later that the Trust received a strange letter, from someone purporting to be in possession of the machine, but wishing it to be returned to its rightful owners. The catch? The writer claimed that an (unidentified) person had bought the machine for £10,000, and would like to be re-imbursed for what he had innocently paid out. Words like ‘ransom’ and ‘blackmail’ would come into most people’s minds at this point.


The Trust and the police worked closely on the case. The ransom wasn’t paid, but the blackmailer wasn’t traced. He grew more demanding, leaving threatening voice mails for the CEO of Bletchley Park, and raising his price to £25,000. This the Trust finally agreed to pay – but before any payment was made, the blackmailer posted the machine to Jeremy Paxman, who was the presenter of the BBC 2 programme ‘Newsnight’. The machine itself was unharmed, but three of its four rotors had been removed. The blackmailer threatened to destroy these if the ransom were not paid in full.


By this time communications with the blackmailer had broadened to include messages published in the personal columns of The Times, and a Times journalist, Nick Fielding, became a go-between, relaying messages of various sorts to police and blackmailer. Finally, in October, an antique dealer, Dennis Yates, was arrested in a telephone box making an incriminating call to Fielding. The rotors were recovered later, undamaged.


Yates was charged with handling stolen goods, and blackmail. His case came to court in September 2001, and he pleaded guilty so readily to the first charge that the second was not proceeded with. He was subsequently sentenced to ten months’ imprisonment, but released within three months. The thief has never been identified, but security at Bletchley Park has been stepped up.

Yates Oct 2001

On a number of occasions, I have had a trade stand at the National Vintage Communication Fair, and was intrigued to find that Yates was often there as well. We passed the time of day, but I never felt able to raise with him the subject of G312. However, the last time I saw him at one of these fairs, on his stand he had – an Enigma machine!

Yates 5.13

What a story – theft, blackmail, coded messages, anonymous letters and parcels, and a mysterious buyer – but the complete story has never been told, and now may well be lost for ever, as a Vintage Radio website recently reported that Yates had been found dead in his car earlier this year.

Enigma Machine Visits Skyscanner

Earlier this year, I was invited to one of the UK’s most successful tech companies, Skyscanner, to give a demonstration of my Enigma machine to some of their software engineers. I have found there’s a real interest from ‘techies’ about the Enigma machine story and the Alan Turing connection, and it was a pleasure to be able to share a little about the story, with such lovely people. (BTW if you’re a software engineer and live in California then take a look at my forthcoming Enigma Machine Silicon Valley Tech Tour, and get in touch if you’d like me to visit your company or tech-meet up).

As part of my visit, they made a short video of me explaining a few things about the Enigma machine which you can watch below. Thanks to Skyscanner for having me, and especially to Lisa Venter and Łukasz Suliga for creating the video.



Alan Turing’s Out-tray: cache of letters found

A collection of nearly 150 letters to and by Alan Turing has been found in a neglected filing cabinet in a storeroom at Manchester University. Turing worked at the university from May 1948, when he was appointed Deputy Director of the university’s Computing Machine Laboratory. There was no Director as such, but the Head of the Mathematics Department was Professor Max Newman, a distinguished mathematician who had been a Bletchley Park codebreaker during the war. Newman’s influence on Turing went back to the 1930s, when his lectures at Cambridge had inspired Turing to work on the Entscheidungsproblem, and this led to Turing’s seminal 1936 paper ‘On Computable Numbers’.


The papers which have just surfaced cover the period from March 1949 to 2 June 1954, and thus run right up to Turing’s death on 7 June. I have not yet been to Manchester to see the originals, but I have read the archivist’s synopsis of every one. Despite there being numerous items written after Turing’s trial and conviction for ‘gross indecency’ in March 1952, no reference is made to any of the problems he faced at this time: his trial, the verdict, the hormone injections and psychiatric analysis, the loss of his Security Clearance, etc. In fact, they shed little light on Turing the man, although he does make some admissions as to his dislike of the USA, his lack of skill as a reviewer, and the gap between his writing and speaking styles.


The subject matter of many of the letters testifies to his growing success and reputation as a mathematician. He receives many requests to write papers and books, to speak at conferences, to review papers, to advise other academics and students on research, to supply copies of his own papers (we’re talking here not just pre-internet days, but pre-photocopier, too), and to permit the Manchester University computer to be used to do work for others. Although none of the letters is outstandingly important, their sheer number and diversity demonstrate clearly that Turing was a highly respected mathematician, right at the forefront of the newly emerging computer revolution, whose views were sought by other eminent mathematicians across the world.


The first Manchester computer, the one Turing used, was called ‘The Baby’, but it was superseded by a series of ‘Atlas’ machines, which remained in use into the late 1960s. It is here that I can reveal a connection from my own past. In the 1960s, I was working for a firm of consulting civil engineers, and we wished to design some large asymmetrical suspended road slabs as part of Newcastle’s Central Motorway East. Computer analysis was the best way forward, so we commissioned Manchester University to run our analyses overnight (day-times were reserved for in-house use). Now comes the bit that anyone under 50 will find incredible. We sent our inputs to Manchester, as punched paper tapes, on the train – and the stacks of fanfold computer paper with the Atlas results came back by train the next day. This was the highest of high-tech in the 1960s!


Of course, in those days, I knew nothing of Turing. Having been researching his achievements during the last twenty years, I am now often asked to speak about Turing and his work. In August, it was the Turing Fest in Edinburgh, and in October I am contributing to a 2-day study tour about Alan Turing, organised by the New Scientist.

Hacking Enigma | US Tour 2018 | Dr Enigma is coming to America!

Due to increasing demand for the Enigma machine to appear in the USA, I’m putting on a special tour to the US so that more people get the chance to hear the fascinating Engima story, and play with a real Enigma machine.

The event: ‘Hacking Engima | How The Nazi Codes Were Cracked’ will be coming to US shores in February 2018. I am now taking bookings so contact me asap if you would like to host an event. More details below.

Hacking Engima | How The Nazi Codes Were Cracked

Learn about perhaps the world’s greatest ever hack, how some of the greatest minds in history broke the Enigma codes, something Nazi Germany never believed possible.


In this unique event, British Enigma Machine expert, owner and speaker, Dr Mark Baldwin, will present the incredible Enigma Machine story and perform a live demo where the audience get to play with an original, iconic Enigma Machine.


The Enigma Machine Story (45m + 15m for Q&A)
One hour talk on the Enigma Machine and how World War 2 Codebreakers broke German ciphers; the fascinating history, technical explanation and human story behind one of the world’s most important hacks.


Live Demo of an original Enigma Machine (30m)
Live demonstration of Dr Baldwin’s personal Enigma Machine, where the audience can not only get up close but actually touch, photograph and play with a real, genuine Enigma Machine, and ask further questions.

Dr Baldwin’s talk and live demo is hugely popular with the audience, read the Enigma machine talk testimonials to hear what people are saying about the experience.

Note: Length and content of the event can be adjusted to suit audience.



Image based on photo taken by Si Barber

Is The Imitation Game a true story?

What a spell-binding film but what a travesty! To make the story even more dramatic than real life, director Morten Tyldum introduced numerous distortions. The website Information is Beautiful analyses 17 films which claim to be based on true stories, scoring each scene according to how true it actually is.

Of the 17, ‘The Imitation Game’ comes a miserable bottom, with a truth rating of only 41.4%, way below any of the others.

One part that was accurate however, was the depiction of the Engima machine that was shown in the short U-boat scene. I know this because it was my 4-rotor Enigma machine that was used in the film!

4 Rotor Engima Machine
Dr Baldwin’s 4-rotor Enigma machine, as seen in The Imitation Game