puzzle machine

OWEN: Welcome. I’d like to welcome toGoogle Ralph Simpson. Ralph is a 30-plus yearveteran of technology industry, recently retired. He volunteers atHistory San Jose and is an avid collectorof cipher machines, has probably a coupledozen cipher machines in his collection. And he’s agreedto come here today to tell us abouthis Enigma machine. And he’s going to be demoing itand also letting people come up and play it withafterwards, I guess. RALPH SIMPSON: Sure. OWEN: And so welcome, Ralph. [APPLAUSE] RALPH SIMPSON: Thankyou very much, Owen. It’s a real pleasure and anhonor for me to be here today. I really appreciate the timethat you are providing here for me. To be able to speak at a GoogleTech Talk is quite an honor. And I really look forward to it. This little machine here is notonly of great interest to me, I think it also reflectsa huge historical value, both in terms of what itmeant in World War II, as well as what itled to afterwards, because in breaking thecode during World War II, basically the Allies had tocome up with modern computing. And you could argue that thecomputer revolution, Silicon Valley, and even Googlehere has its roots back to this little humbletypewriter in a wooden box. And so what I’dlike to do today is go through that early history,the technology of the machine, and, let’s see–the early history, the technology the machine. I’ll do a demonstrationas Owen mentioned. And then I want to talk aboutthe significance of this to World War II and how theAllies actually broke the code and how that led tomodern computing. Now there’s at theend a calculation of the key lengthof the Enigma, which I will not havetime to go through. But it’s there. It doesn’t take a lot of math. And it is enlightening,so I’d encourage you to use that as anexercise with a reader. It’s really quite interesting. So if you take a look at whatdrove the need for something like an Enigmamachine, it actually started in World War I becauseof the proliferation of radios for the first time in warfare. And that was a huge advantage. But after the war,the Germans were horrified to find outthat all of their messages were being read. And it wasn’t just the Germans. Every single messagewas being read. And part of thereason is that if you look at the types of cipherdevices that were available, they were really made fora different environment. They were made in order to senda message, a written message,

Default puzzle machineThey were made in order to senda message, a written message, by courier or in someother fashion where it wasn’t on a radio. As soon as you’re talking abouthaving hundreds or thousands of messages on a radiowith the same code, that can easily be broken. Letter frequencyanalysis, you identify which letters are the mostfrequent in the first letter of each message, the secondletter, the third letter. And generally youcan break these codes in minutes, not hours. And I brought a few examples. You see on the left here,it’s called a Vigenere wheel. This one was used bythe Confederate Army. It was invented inthe 1400s, so this has been around a long time. Here is a life-sizereplica of that wheel. There’s only five in existence,so I had to get a replica. But it’s a very simple device. You can see there’s thealphabet in two wheels here. You just use a codeword and spin this and come up with a newalgorithm for each code word. Unfortunately, thisis easily broken. And in fact, the North brokethe Confederate Vigenere wheel regularly. I mean, it was– the South onlyused three different code words all during the war,so it was quite easy for them to break it. And that’s despite the fact that”Scientific American” magazine in 1917 said thisdevice was unbreakable. Shows you what they know. Here’s another example. Now, this one came outjust after World War I. But it was used by the Armyup through World War II. This was invented bythe US Army in 1922. And you can see each of theseare separate wheels that have the alphabet in adifferent configuration around the outside. And the way it’sused is you just write your message in25 lines across this. And then you spin this wheelaround and pick any other line to send as your gibberish. And then the receiverwould print out that gibberish and then wouldhave to search around the wheel to see something that lookslike normal English or German or whatever your language is. But it was alsofound in 1922, just by coincidence in ThomasJefferson’s papers, that actually he invented this. I’m talking aboutour second president. He invented this device. And his had 36wheels instead of 25. But he described it exactly. And they actuallyhave an example of it at the NSA Museum inFort Meade, Maryland, where you can take a look at it. By the way, if youhave any questions, feel free to ask meas I go through this. Another thing Iwanted to show you,

1 puzzle machineAnother thing Iwanted to show you, I talked about this Vigenerewheel and it’s from the 1400s. That doesn’t meanthat it ended there. Here is a US versionof that Vigenere wheel that was used inthe Vietnam War. Vietnam. And what you do is you takethis little thing down. You attach a littlecassette tape to it. And then the cassette tape,by spinning this around, will put a differentMorse code on the tape. You can take this off andthen connect it to a radio. And it would send it in ablast mode very quickly. But it’s using theVigenere wheel. Now you may ask,why in the world would we use this in Vietnamwhen obviously there’s much better technologies,this one can be broken? Well, in battlefieldconditions, this is very fast. It’s easy to do. And if you only need to confusethe enemy for an hour or two, this works. If it’s more thanthat, it’s not good. Now I wanted to show youone other, or a couple more. Another one is a simple book. This is a code book from 1988. It’s called “CommercialCryptograph.” There were military versionsof these types of code books. But it has wordsand phrases written on one side, other words andnumbers written on the other. And so you all you have to dois just make up your message, look up the words, and sendother words or other numbers. And that’s how you send a code. This has also been inuse since the 1400s. And this isrelatively effective. The problem is, as soon asit’s broken by losing a book, you’re dead in the water. And to then send out books tothousands of army locations is just untenable. So it was typically usedmore for diplomatic locations and high commandsand things like that. And the last one I’ll showyou is another US Army one, just to show you what was usedby the US Army in World War II to compare it tothe Enigma machine. The Enigma machineis a 26-pound device. It’s a typewriter. You press on a key,a light lights up. Somebody has to write it down. That somebody is usuallya second operator, so that they can go fast. This device is a littlebit different than that. You can see thereare six wheels. It uses a wholedifferent technology. There is no battery,no electricity. And actually it performs an XORexclusive or operation in this. And then it printsout the results. And it can cipher and decipherjust with the switch of a key here. So it’s very handy,smaller, easier to carry. No batteries needed. But not as effective, andnot as cryptologically strong

puzzle machine But not as effective, andnot as cryptologically strong

2 puzzle machineBut not as effective, andnot as cryptologically strong as the Enigma machine. So this one was used, again,as a battlefield cipher. It was typically broken by theGermans in a couple of hours. OK. So let me go on. What I wanted to show you waskind of the background of what environment was in placewhen the Enigma machine was invented, and why there wasa need for something that was stronger, thatcould work better than what was inexistence at the time. And it turns out thatthe Enigma machine wasn’t the onlyrotor-based cipher machine. Now, what was uniqueabout the Enigma machine and these otherrotor-based cipher machines is the rotor itself. This is the Enigma rotor. And as you can see, it hasthese little pin connectors. There’s 26 of them,representing all the letters of the alphabet. On the other sideis the connectors. And what it hasin the middle are wires that will connect oneletter to a different letter. So an A may be connectedto a G in this rotor, but the A may be connectedto a B in one of the others. They’re all wired differently. And so this is thekey innovation, which maybe doesn’tsound all that great. But at the time this was huge,because when you put three in a row, that means that theletter is changed three times. And actually in the Enigma,there’s a reflector. So it goes through. And then it goesthrough a reflector. It’s changed again and thengets changed three more times. So this was quite an effectiveway to encipher messages. The other thing was thatit made it very easy. If you notice onsome of the others, it’s a very manualprocess, error-prone, a lot of fiddling around. Here, you just typeon a typewriter. Much less room for error. So that was the innovation. Now, it turns out that theEnigma wasn’t the only one that was invented in thissame time frame. Like I said, WorldWar I showed the need. And so this was inventedaround the world. There are fourdifferent countries, four different inventorsall within a few years came up with thissame rotor concept. And the first inventor washere in the US, Edward Hebern. He was actually in jail forstealing a horse in 1915. And he said he came up withthe idea while he was in jail. And when he got out, he cameup with a really nifty-looking device. He didn’t make a lotof those, although he did get a million dollarsworth of investment money. He built a huge manufacturingplant in Oakland that was going tohouse 1,500 workers. And after making acouple of dozen machines,

3 puzzle machineAnd after making acouple of dozen machines, he went bankrupt. And then he got thrown in jailagain for stock manipulation, so that one went by the wayside. Then we have the Enigma machine. Now, that Enigmamachine you can see is different than the onethat’s sitting before you. That was the first version. It weighed 110 pounds. And not a lot of those sold. It was very cumbersome to use. And then by the mid’20s, he came up with this version, whichis a 26-pound device. And it got accepted bythe German military. Hugo Koch in Hollandcame up with a design. He actually developed someprototypes in the lab. But they didn’t work verywell, so he never really was able to sellthese commercially. And Arvid Damm isan interesting guy. He came up with adevice and sold some. And in fact, the guy that boughthim out was named Hagelin. Hagelin formed a companycalled Crypto AG. And the first big sale he hadwas this device right here. He sold 140,000 of theseto the US government, which allowed himthen after the War to sell these around the world,or a follow-on version of that. And he ended up sellingto 130 countries, their military, diplomats. It was used everywhere. What wasn’t knownwas that the NSA had a sweetheart deal withthem and had a back door. So this story of the NSAgoes way back, right? This is from the ’50s. And that back doorexisted for about 40 years before it was unearthedby Iran in 1999. So there’s a whole history here. I could do a whole notherTech Talk on Hagelin. But I have to go on. And as you can see onthe next slide, what I want to talk about nowis the Enigma machine. Now, the Enigma wasinvented, as you can see, by Arthur Scherbius. w And HugoKoch was the other inventor that I said nevergot off the ground. His device was too intermittentand didn’t work well. But in 1927, Scherbiusdid a strange thing. He bought the rightsto Koch’s patent. Now, the reason Isay that’s strange is Scherbius hadthe earlier patent. And it turns out theywere identical patents. So why would he buy this right? It was never really understood. It was kind of amystery, until 2003. So here again in the storyof ciphering, a lot of times we find things out after thefact, sometimes decades or even hundreds of yearsafter the fact. And here what we found out wasthat the rotor-based cipher machine was not inventedby these four gentleman that I showed you earlier. We have to rewrite history. It was actually invented bytwo Dutch Naval officers. They built a machine in 1915. And that machine worked. They showed it tothe Dutch Navy. And this was atWorld War I time. They decided to squelch it. And they would notallow these two Naval officers to patent that device. And it just so happensthat the patent attorney that these DutchNaval officers hired was the brother-in-lawof Hugo Koch. What a coincidence. And it turns out alsothat Hugo Koch and Arthur Scherbius were collaborators. So they worked togetherin stealing the patent and coming up with the Enigma. And I think that Scherbiusfelt a little bit like he owedsomething to Hugo Koch and gave him a little bit ofmoney to buy out his patent. So that’s the storybehind Hugo Koch. So after all of thisand all the stories you’re going to readabout Hugo Koch, it turns out it’sthese two Dutch Naval officers that inventedthe Enigma machine. Yes? AUDIENCE: Do you have anyidea who the two Dutch Naval officers are? RALPH SIMPSON: Yeah. Yeah. The question is, who are thetwo Dutch Naval officers? I don’t know a lot about them. I do know their names. It’s Theo van Hengel. And the other oneis RPC Stengler. Those are the twoDutch Naval officers. There’s not a lot ofinformation about them. But they were theones that invented it. They were tasked to invent it,basically, by the Dutch Navy. And when they did,the Dutch Navy didn’t want it outfor some reason. It’s also interestingthat they happened to release thatrequirement that they not publish this orget a patent on it. But Hugo Koch cameout with his patent just two weeksbefore that release. And so it was too late. So here is a picture of it. And you can see itin front of you here. This is a typewritertype device. The innovation is these rotorsthat messes up the alphabet. And the other thingthat I should mention is that the waythis works is when you press a key– andthis key does two things. It advances the rotorsmechanically, not electrically. And it sets up anelectrical signal that goes throughfirst the plug board– and I’ll discuss each of thesepieces more in just a minute. But it first goesthrough the plug board. Then it goes througheach of the three rotors. It goes through areflector, reflecting back through the three rotors,back to the plug board. And then it lights up a light. So it does create quitea different algorithm, because that rotor will advanceevery time you push a key. And it advances odometer style,with the right one advancing once each time you press, thenext one advancing every 26 times, and so forth. So that’s the waythis thing works. I’ll go througheach of the pieces here, just so you have a goodsense for what this is all about. I really like the way thatthey put this together. It’s 26 pounds. It’s very heavy. But this thing is definiteGerman engineering. It’s heavy duty, very well made. You can see the keys aremade of stainless steel. This is over a70-year-old device. I’ve done nothing to it. And it works rightout of the box. And I haven’t hadto do anything to it other than put a littlebit of oil on it. And it works to this day. And you can tell it’s verystrongly made, because it does have to advance somepretty heavy rotors. So in other words, youcan’t touch-type on this. You have to push downone letter at a time. And it takes a bit of effort. The other thing Ishould mention is, you’ll notice thatthere’s only 26 keys. There’s no special characters,no numbers, anything else, no space bar. So they don’t allow thatin the cipher message. You have to writeout the numbers. They did allow an Xfor a sentence stop. And basically, they ranall the words together, because you don’twant to give hints on where the spaces or thespacing of words could be. So that’s the way that works. If you go to the nextelement here– so I’m going to go through the waythat the electrical signal will go. So next is the plug board. Now, as you cansee, the plug board is in the same formatas the typewriter keys. And the bulbs will bein the same format. It’s a QWERTZ format,not a QWERTY format. And basically what this doesis you attach one letter to another. So if you were topress– for instance, here you can seethat I’ve got a Q and it’s attached to something. Let’s call it the O. Soif you press a Q here, it’s going totransfer that to an O before it goes to the rotors. OK? That’s all it does. And coming back, ifit comes back as an O, it’ll change it to aQ. That’s all it does. This was something thatScherbius did not design. So Scherbius designed all ofthis sans this plug board. And it turns out that the plugboard added more cryptological strength than all the rest ofthe machine combined, which is very interesting. So the military added that. And they only usedit for the military. They continued to sell acommercial version of this to other countries that didnot include the plug board. OK. And here is a pictureof the rotors. And I think I showedyou these already. One thing I don’tthink I mentioned was there’s a little notch here. This notch can be moved toany of the 26 characters. And what that notch does is,when it’s in the machine, it sets the point for whenthe next rotor to the left will advance. Yes? AUDIENCE: I noticed thatnot all the plug board connections had connections. What happens when you don’thave the letter connected? RALPH SIMPSON: Yeah. When it’s not connected,it basically bypasses. Oh. The question is thatnot all the plug board connections had a cable in it. And that was done on purpose. And so if a letter was notplugged, let’s say a B, the B just went straightthrough without any change. OK. And so this is the rotors. You can see a coupleof facts about these. I have three of them here. But in a general ArmyEnigma situation, they would havefive to select from. And each day they wouldhave to change them. And therefore, you can have fivein one position, any of five, four, three, 60 differentcombinations of rotors in this. You can also set thison any of 26 letters. And there’s three of them. So it’s 26 cubed. And the notch can be seton any of 26 positions. But only the righttwo rotors matter. The left rotor isn’tgoing to move anything. So that gives you a sensefor the key strength of just the rotors. It’s actually not a big number. In the Naval version of theEnigma, they had four rotors. So that gave thema little bit more. And they also could selectfrom eight, instead of five, so that also gave thema greater strength. Next that I want to talkabout is the reflector itself. The reflector is thisitem here that you see with the bigred B on it, just to the left of the three rotors. And what that does isit takes the signal from the leftmost rotor and itswaps it for another letter. And so it works muchlike the plug board, but with all theletters plugged. So if for instanceyou come in as an A and it was enciphered to a G,if you came in to this reflector with a G, it would comeout enciphered as an A. And the reason forthat is this allows you to encipher and decipherwith the same code settings. Very handy. Ease of use was all-importanton a battlefield, so this made it very easy. Also, this becamea very big home in the design of theEnigma, because what it meant was no lettercould encipher to itself. And so keep that in mindas I go through this, because that was a big hole. But I think theGermans felt that this was important to be ableto encipher and decipher without having to changekeys or change settings. And so they left it that way. All right. So the last section Iwanted to show you on this is the lamp board. The lamp board actuallyhas a small little light underneath each of theletters, so when you press down on a key, a light lights up. It seems very simple. But it goes through thistremendous calculation of changing letters. And the other thingI should mention is that there isa battery in this. It’s a square, fairly large 41/2 volt battery that was used in World War II. I’ve replaced it withtwo AA batteries, which is only 3 volts. But it seems to work fine. And also you can attachthis to a 220 volt plug, which was aEuropean power supply. And so it works– withjust a flip of the switch you can attach it to that. Or you can attach it to atransformer they also had. So there was multipleways to do this. Within the lid here, you seea couple of other things. There are some spare plugcables for the plug board. There are somespare light bulbs, in case you have aburned-out light. Interestingly, I’ve had thismachine for about 12 years. And I’ve never had alight burn out yet. Yes? AUDIENCE: [INAUDIBLE]? RALPH SIMPSON: To test what? AUDIENCE: To testall the lights. RALPH SIMPSON: Yes. Yes. That’s a good question. So the question is, is therea way to the test lights, rather than just tryingit, because how do you know if the light’s out, right? Well, they thought ofthat, believe it or not. So if you lookinside here, there’s a little empty plug herethat’s written in German. But it’s basically a test plug. You just put the light in there. And if it lights up it works. If it doesn’t, it’s deadand you throw it away. And so they thoughtof those things too. OK. Oh, and also I have inhere a little light filter. It’s really justa tinted plastic. And what this is used for iswhen you’re in direct sunlight, it’s sometimes hard tosee the light light up. And so when you put this inhere and cover the lights, it actually shows upa little bit better. And you can read these. Now, I’m going to leave thisin place, because when we film, it turns out you can seethe letters light up better even on video this way. And then here is adescription of how to take care of the machine. It tells you abouthow to oil it, how to sand thelittle rotor fingers, and what you need to doto keep it operational. So here’s the wiring diagram. I’ve already really gonethrough all of this. But this will justshow you an example if you hit the H keywhat it goes through. And each of thesenumbers represents a change of characters. So if you hit the Hkey and the H cable is plugged over to the O,as you see, it changes. That’s the firstchange of letters. And then it goes throughthe three rotors, where it’s changed. It goes through the reflector,back through the three rotors, and back through the plug board. So it could be changed ninetimes, seven times, or eight times, but at least seventimes for every hit of the key. And every time youpush a key, you’re going to get a differenttransformation. So that is the strengthof the Enigma machine. So I said I wasn’t going togo through the calculation of the key length of the Enigma. But I want tomention what it is. The Enigma has atheoretical maximum number of settings of 3times 10 to the 114th. The math is at the back. You can read it. But that’s far morethan the number of atoms in the universe. And for this crowd,I have to say it’s also 300 trilliontimes more than a google. So it’s quite a large number. Now, the Germans weren’t ableto achieve that, actually, because it would’ve takenrooms full of rotors and other inconveniences. So the way they used itwith just five rotors, the way they used the plug boardand so forth, what they saw was 10 to the 23rd, whichbefore the days of computers is nothing to sneezeat, let me tell you. 10 to the 23rd is stillequivalent to a 7y-bit key, which if you compare that withthe original DES standard which was used up until this century,it’s much better than that. But let’s compare it towhat they were expecting. There were no computers. They were expectingbrute force, manual type of breaking of the key. And to break a key that has 10to the 23rd as its key length, it would take 100,000 operatorseach checking a different key every second 24 by 7 fortwice the age of universe to break this machine. So I think they feltpretty safe that this was a safe machine for them. And by all rights,it should have been. But let’s talk abouthow the Germans actually used this Enigma. First of all, theyhad a daily key. And the daily key, I thinkI’ve already hinted at, there were five rotors. They had to select three andput them in a specific order. That was the first set of keys. Then they had to change thenotch setting for two of them. That is another key. They had to change theplug board settings. Then they had toplace the rotors in a particular configuration. Once they set that, they’reable to send a message. But they didn’t justcode in a message. And the reason is, if youhave hundreds or thousands of messages all going with thesame key, that could easily be broken. Letter frequency analysisagain will tell you what’s the most frequentletter of the first of each of these messages, the secondletter in each message, and so forth. It would be quickly broken. So what they hadthem do was they had them send anew rotor setting. And they were toldspecifically to make it random. And unfortunately,what would happen with the German operatorsis they got lazy. And they would justuse three letters in a row, or threecolumns in a row, or sometimes theirgirlfriend’s initials. In fact, one operator hada girlfriend named Cil. And the British called thistype of breaking of code cillies because it was so frequent. I mean, he typicallyused that every day. And so we could count onhim to help break codes. Now, another thingthat they did was they sent that three-letternew code twice. And the reason forthat was they’re sending this byMorse code, by radio. And sometimes thatwould get garbled. And they would wantto send it twice to make sure that itwas received correctly. So that’s what they did. They would send that twice. And it turns out that thatslight problem that they created, or thatslight shortcoming was exploited by the Polish. And they were ableto break the code. So now what I’d liketo do is give you a demonstrationof this if I can. I hope you can see enough thatI can explain this to you. OK. So like I said, the firstthing you have to do is set up these rotorsin a particular format. And so I’ve set it up. I’ve got it writtendown here, in fact. and I will put this inthe message clip holder, just as the Germans would have. OK. So this is my cheat sheet. So the rotor order is goingto be 3, 1, 2 in my example. Here’s Rotor 1– I mean 3. And here’s 1, so that’s next. And then 2. And so that’s goingleft to right. That’s the order. You put this on the spindle. And you kind ofpress it together. And you put it in this– youput it in the machine like this. And it’s in there. Now the other thing we hadto do that I will assume I’ve already done this is set thenotches in the right locations. OK. Now this is in. And I can screw this down. The next thing I have todo is put these rotors on a particular setting. And the setting thatthey sent me for today– and this is a daily setting, soI have to do this every day– is EJ zero, EJO. So I will set this toEJO, which by the way all these are in numbers here. And EJO is 5, 10 and 20. And if I didn’t know that,there’s a little cheat sheet right here on the lid thattells me that’s 5, 10, and 20. So it makes iteasy and foolproof. The next thing I have todo is set the plug boards. Now the Germans,interestingly, always used 10 cables for the plug board. And you may ask, well,why don’t they use all 13 and swap all the letters? Well, it turns out 10 isbetter than 13 cryptologically. And in fact, thecryptologic strength goes up as you go fromzero cables up to 11. 11 gives the most. And then it dropsoff significantly when you go to 12 and 13. So then the questionis, well, why didn’t they use 11 then,if that was stronger? Or why didn’t they varythe number of cables? Here’s my theory. OK. This is just my own theory. My own theory is they wanted touse the same number of cables so that the cables weren’tlaying around extra and could get lost. And the other is,why 10 instead of 11? They felt 10 was strong enough. And it kind of matched theirsensibilities of order. It’s a good roundnumber, you know? And so why not use 10? They could send that 10. It’s nice and neatin their code books. And that’s what they did. And so that’s what theyused, is 10 every time. So let’s assume I’vegot that all set up. And now I’m an operator. I’m a German operator. I want to send a message. So the first thingI have to do is I’ve got it all set upto the right settings. And the first thingI do is I make up a three-letter new setting. And being kind ofa bad operator, I’m going to set it up tomy wife’s initials, TES. So T gives me aC. Is that right? Wait a minute. I’ve got this– oh, I’m sorry. I had this on the wrong thing. 5, 10, and 15. So I’m going to typein T. And that gives me a Y. E, which gives me an H. Andthen S. It gives me a Y again. OK. Now I have to writethese down, right? Now, I’ve got to dothat again, because as I said I’m typing in TES twice. So again T. Thistime it gives me a Z. E gives me a C. AndS this time gives me an E. So those six letters, I have towrite down and send them along with the message. But before I encode the message,I have to set this to the TES, right? So T, if I look on mycheat sheet here, is 20. E is 5. And S is 19. So now I’ve set mymachine to 20, 5, 19. That’s TES. And now I can send my message. And I’m just going to senda simple hello message. So I’ll type in H. Thatgives me an X. E, which gives me an O. L gives me a D. I’m typing in L again. This time I get a Q.Notice it’s different, because it’s a different code. And then O, which gives me an H. Now I’ve got my message tosend, the six letters which is sending thenew setting twice, and then the letters of hello. The way I would send thisis in groups of five. I would send the message byMorse code across a radio usually. And then the receiverwould get this message. And the message hewould get would just be that string of lettersthat I just mentioned. And what he woulddo is first set this to the originalcode setting, which is as I said EJzero, 5, 10, and 15. And he would then decodethe first six letters. And I don’t know ifyou were keeping track. But I have it writtendown just in case. It starts with YHY. So if I type in Y I geta T. H gives me an E. And Y again givesme an X. That’s TES. That’s what I should set it to. But I’ll type inthe next three just to verify that I didn’tget some garbled message. And the next three were ZCE. So I’ll type in aZ. And I get at T. And I’m sorry. I’m looking at thiskeyboard backwards. And it’s a little bit different. C is an E. And thelast letter was– CZE. And E is an S. So it verifies. I got TES again. So now I know I need toset my settings to TES. And when I do that, that’sagain I said 20, 5, and 19. Now I can type in therest of the message that was sent to me. And that starts with XODQH. So X gives me an H. O– oops. Let me back up a minute. I didn’t see it. Well, that shouldbe a– trust me. It’s an E. It’s just notshining up through this thing very well. XOD– I think it’s, let’s see. D. After telling you that thishas worked flawlessly for me, it seems to be disconnecting. OK. There it goes. Back up. 19. So it started with X.That’s the H. O. Now there’s something wrong here. But it worked this morning. Believe me. Anyways, you typein those letters. And you get H-E-L-L-O. Andthat’s how you would decipher the message. Now this seemsrather convoluted. In a way, it is. But comparing this toprevious cipher methods, this was more foolproof. It was a much stronger cipher. And therefore the GermanNavy and German Army definitely relied on this. They used this extensively. Yes? AUDIENCE: When theysent out the daily code, did they send it encodedwith the previous day’s code? RALPH SIMPSON: No. No. The question is, when theysent out the daily code, did they send it encodedwith the previous code? That would be one way to do it. But what they did was theysent out a book that had 30 days’ worth ofcodes written in it. If you were in thesubmarine service, though, you got three months’worth of these codes. And so there again,keep that in mind, because that was one ofthe shortcomings of this. And by stealing the codebooks, you sometimes were able to decipher this. And I think ifthey sent it daily, it might have been abetter way to do it. AUDIENCE: If yousent it daily, you would have been able to decipherall the codes any time you had one day’s code. RALPH SIMPSON: Yes. That’s true. That’s true. If you ever got one day’s code,yeah, that’s the other fallacy, yeah. But the books were sent outwidely to all of the Army units that had these. And there were tensof thousands of them. So that was also dangerous. And sometimes the Alliesdid steal those code books. Yes. Can I go back? AUDIENCE: Was there aprotocol for stolen code books or [INAUDIBLE]? RALPH SIMPSON: I don’t know ifthere was a protocol, because I think this was somethingthat they did everything they could to prevent. So for instance on a submarine,if a submarine was lost at sea or they were sinking, theywere told to blow it up. Cipher machines, if theenemy were approaching and they weregoing to lose, they were ordered to destroy thecipher machines, the code books, everything. The code books for theboats and the submarines were made of a water-dissolvabletype of material. So if it got in theocean, it would dissolve. So there were a lot ofprecautions that were taken. And in fact, I think thatled to some of the reasons why there are so few Enigmamachines in existence today. A lot of those weredestroyed by the Nazis as the Allies advancedon their positions. OK. So that’s the demonstration. I now want to talk about someof the shortcomings, which I’ve already been hinting at. You see here a picture ofPanzer General Heinz Guderian. And in the bottom left,you’ll see an Enigma machine. And it’s interesting thatthere’s an Enigma operator there. And beside him is theperson that would typically be telling him the message todecipher and writing it down. And then the third person is theperson that operates the radio and sends the Morsecode back and forth. So this is quite anelaborate operation. There’s three operatorsthere to send a message. And in fact, Iwould say that one of the shortcomings of thismachine is that it’s so strong. And so let me elaborate. The cryptologic strengthof this was so good that the Germans neverbelieved that it was broken, all throughout the warand afterwards, even when they were presented withpretty strong evidence that it was brokenand they were told it was broken by theirallies, the Japanese. They didn’t believe it. They didn’t believethat it could be broken. So that was one ofthe shortcomings. Another is thisreflector design. I mentioned that itallows for ease of use by deciphering andenciphering with the same key. But what it alsodid was it made sure that no letter gotencoded to itself. And one of the ways that theAllies liked to break codes is come up with a crib. And a crib is what they thinkcould be included in a message. And the Germans being veryprecise in their language and especially inthe military, we could count on them to usecertain words over and over in messages. And one of them wasa weather report that went out to the minuteevery day in the morning. And the front of itsaid weather report. And by using those words,you can pretty well tell. You can eliminate alot of rotor positions, because you can’t haveone letter coming back to the same letter. So it wouldn’t necessarilytell you the code. But it would tell youwhich ones to eliminate. So you don’t have the 10 to the23rd key settings to try out. The other is that the rotorshad a regular odometer motion to them. Now, it turns out that the US,besides these 140,000 machines which were used inthe battlefield, had another machinethat was more similar to this called a SIGABA. And the difference betweenthe SIGABA and this is that it had 10 rotorsto change the letters. And it had five otherrotors to change the motion of those 10 rotors. And it was irregular. And so by having anirregular motion, you’ve just added immenselyto the cryptologic strength. And in fact, that machine wasnever broken by the Germans. But anyways, theodometer movement is a problem becausewhat that means is you’re only changingone rotor for 26 times. And then when this one flips,you go in another 26 times only changing that samefast-moving rotor. And so the third rotoractually never moves in the entire message. And the reason is that theGermans were told never to send a message morethan 250 characters. When you do, you go all overagain and send a new setting. And 250 wouldn’t allowthat third rotor to move. So that was one of the problems. And another isthe lax operations by some of theoperators, especially in the Army and theAir Force, for instance using girlfriend’s initialsand things like that. Sometimes theyeven went so far as to send a message twicewith different keys, like they accidentally didn’treset the keys from yesterday and then they sent the samemessage with today’s key. That’s a huge, hugeproblem for anybody that understandscryptography that you can break into a code that way. So let me ask you, see thatEnigma machine in the corner? I’ve blown it up here. Is there anythingunusual that you can tell about thatEnigma machine? Can anybody spot it? It’s not real obvious. Yes? AUDIENCE: [INAUDIBLE]? RALPH SIMPSON: What’s that? AUDIENCE: [INAUDIBLE]? RALPH SIMPSON: Yes. Exactly. It’s missing a plug board. So, if you look atthis machine, it’s actually not missingthe plug board. They put some white paperor cardboard or something over the plug board. Now this was a picturetaken at World War II. Why would they cover overthe plug board, you may ask. AUDIENCE: [INAUDIBLE]? RALPH SIMPSON: What’s that? AUDIENCE: [INAUDIBLE]? RALPH SIMPSON: Yeah. Those changed every day. They changed every day. So it’s not a matter ofgiving away a secret, or not a secretof the plug board. But I have anotherpicture of a plug board. And you can see thatalso has that covered. I went back and looked at a lotof different Enigma pictures from World War II thatcame from the Germans. And they all areeither covered over or they show it at an angle thatyou can’t see the plug board. And I think it’s becausethis was a military edition. They felt it wasa secret edition. And all the otherEnigma machines went out without a plug board. In fact, they also soldthese Enigma machines to the Italians and theJapanese sans the plug board. Yes? Question? AUDIENCE: You sure itwasn’t just a wrist strap? RALPH SIMPSON: Thequestion is, am I sure it’s not a wrist strap. Well, if you put thisup, it doesn’t really provide much of awrist rest there, because you’ve got thewooden board here anyways. And on top of that,you’re not touch-typing. You have to push downpretty hard on these things. So I though thatwas interesting, that they felt that this plugboard was important enough that they kept itcovered in the pictures. Yes? AUDIENCE: So a machinewithout a plug board would not be ableto decode a message from a machinewith a plug board? RALPH SIMPSON: That’s right. Exactly. So the question is, if it didn’thave a plug board you couldn’t decode a message from amachine with a plug board. And that’s true, because thatadds a whole different levels. Unless you tookout all the plugs. Then it would be equivalent. OK. So let’s talk abouthow the Allies actually broke the Enigma code. It was broken by the Polish. And I’m sure all of youhave heard the story. This seemed to be a littlebit kept secret, not secret, but people thoughtthat the British are the ones that broke it. But actually the Polish did. And what happened was, in1932, being between Germany and Russia, theywere very nervous about the military buildupof these large countries on their borders. And so they were carefullylooking at the messages that the Germans were sending. And they noticed adifference in 1932. And that difference was itlooked like these were not being coded with the same ciphermachines that they were using, or the cipher devices theywere using in the past. And it was some kindof machine cipher. They eventually were able toreverse-engineer an Enigma machine. They figured that outthrough the commercial Enigma and saw that they also hadsome kind of other swap, like the plug board. And so theyreverse-engineered it. And also the Polishdid something else. For the first timein a cipher bureau, they hired mathematicians. And Marian Rejewski wasthe main mathematician that they hired who endedup breaking the code. And it turns outthat they actually could not break thecode even with this. First of all, theyonly had three people working on this in Poland. OK. Three mathematicians. But in 1933, it turns outthat the French approached an official in the cipherbureau by the name of Hans-Thilo Schmidt. He got that positionbecause he’s the brother of adecorated Panzer general. But this particularperson was in debt. He needed money. He spent a lot of moneyon wine, women, and song. And as they say,he wasted the rest. Since he was in need ofmoney, he went to the French and offered the Enigmacodes, the keys, and some diagrams of the Enigma. And so the French tookit, gave it to the Poles and to the English. And the French and Englishcould not break the code even with those keys. Now, they could breakthe codes for those days, but it didn’t help thembreak it afterward. The Poles took thatinformation, got the information about thedouble-coding of the day’s keys, the three-letter setting. They were able to figureout that if you typed TES twice, the T and the T, ifthe second rotor hasn’t moved gives you a hint,and the E and the E and the S and S. You don’tknow what letters they are, but you know thatthey’re the same. And so that givesyou a hint, if you had the rotor wiringand the reflector wiring to help figure this out. And they were ableto figure it out. It’s maybe not quite assimple as I described. It still took quite a while. But they were able to figurethat out in 1933, early ’33. They had broken the code andwere reading it until 1939 when they got invaded. And the day they gotinvaded, September 1, ’39, is the first dayof World War II. So they were successful in this. It turns out thatin July of ’39, they finally told their allies,the French, who had given them the way to breakit, and the English. And both the Frenchand English were astonished thatthey’d been breaking this code for 6 and 1/2 yearsand they had not themselves made any progress. And in fact,besides breaking it, the Poles made whatthey called a bombe. It was a device that strungtogether six Enigma machines and allowed them to breakthe code much faster. They were able to breakthe code typically in about 15 minutes every day. And then the restof the day, they would decode them inreal time, just as fast as the Germanswere decoding them. And so this wasquite a breakthrough. They passed this along. And unfortunatelyfor them, they passed along replica machines, allthe information they had. And then very quickly afterwardsthe Germans invaded Poland. And it was all over for them. And so the UK setup a major operation to help break this code. Here’s their park. They bought this homein Bletchley Park, north of London. They had up to 11,000people working on this. Remember, the Poles had three. But to their credit, they had amuch tougher problem to solve. When the Poles had tosolve this problem, there were only three rotors. And so the three rotorswere in different positions, of which there’s only six. That’s why theirsix-machine bombe worked. But now that there’sfive rotors to pick from, now all of a sudden you need 60. They didn’t have the ability tocreate a bombe with 60 rotors. And so they leftit to the English. Now, the English also couldhave done a 60 rotor bombe. But that would have beenquite an undertaking. They figured out theycould do a 36-Engima bombe and manually eliminatesome of the settings and still figure outthe code fast enough. So that’s what they did. They made a 36-machine bombe. And they were able to break thecode, typically in a few hours, because what it would do isit would allow the operator to know whichsettings could work. Then they’d haveto manually test that setting and then goon and test the next one. Also interestingly,throughout the war the British were very carefulwith this information. So if they got informationthat said, for instance, that a submarine was going tosurface at a certain location to be resuppliedby a mother ship, they wouldn’t just go and bombthat location, because then it would give away that theyhad read this message. So what they would do isthey would fly a spotter plane over it, makesure the German saw it. Then their boat thathappened to be nearby would come over andbomb it and blow it up. This almost backfiredon them once. They knew that there were goingto be two submarines being resupplied in this remotelocation in the Atlantic. So they sent outthis spotter plane. They bombed it. But in that sameexact message it said that there were going tobe these other submarines going through this straitin northern Europe. And they had to decide whichones they wanted to bomb. They decided to get theones in the mid-Atlantic. Well, it turns out thatlegitimately the Allies found these submarinesgoing through this strait. And they knockedone of them out. And so this caused a bigconcern by the British military. And in fact, Hitlercalled a meeting that included the Navy, theAir Force, and the Army. And all of the headsof these groups came in to discussthe possibility that the Allies hadbroken the code. But they alsobrought in the person that was in charge ofthe Enigma machine, who told them why it wasabsolutely impossible for them to have broken this code. And so they all wenton their merry way. And nothing was done. They could have easilystarted changing things. But they didn’t even do that. So let me set what was goingon in the North Atlantic with the U-boats. Before the US enteredthe war, the U-boats were having a field day. They were sinkingAllied boats in droves. In the few months beforethe US entered the war, it was 60 boats per month,at a tremendous loss of life and loss ofsupplies that were really needed for the wareffort for the Allies. The U-boats, the way theywould do this is they would form wolf packs. There would be anumber of U-boats all roaming around the Atlantic. They would spot a convoy,because they were all separated. But rather than attackit with one U-boat, they would send a messageback to headquarters. Headquarters would thensay, form a wolf pack. Here’s the location. Maybe up to a dozenU-boats would go there. And they’d all pickout a different boat. And they’d fire onthem simultaneously. And it was at a tremendousloss of life for the Allies. And this went onfor many months. So it turns out that this wasa major strategy of Hitler’s. He was expecting that the UKwould capitulate and surrender because of this, because of thisblockade and lack of supplies. And you can see the quotehere from Winston Churchill. He said the only thing thatever really frightened me during the war wasthe U-boat peril. Now this is despite the V-2peril, the peril of D-Day and the landing there, all theproblems they had in Africa. The U-boat peril was the onlything that really frightened him, and I thinkfor good reason. I mean, this could havelost the war for him. So here’s what changed that. U-110. You’ve probably heard aboutthe movie or seen the movie “U-571.” That was an importantU-boat that was captured, code keys and all that. But this was thefirst one, the U-110. And here you see the captain. He was actually a hero in this. The U-boat was purposelycaptured in a way that they wanted to get thecode keys from the U-boat. And so when it was bombed and itsurfaced, rather than just let everybody surrender,if they did, they would havescuttled the U-boat. They would have setoff charges within it and it would have sank. So they purposely startedshooting at the tower to get everybody out of theboat quickly before they could set these depth charges. And they did. And by gettingeverybody out quickly, they then roundedthem up and put them on the Allies’ boat,this “HMS Bulldog.” And the captain sawwhat was happening. And he saw that thecharges were not set. So he jumped in thewater to swim back to set the chargesto sink his boat. And the Allies sawthat and killed him. And so the Allies went on board,got all the Enigma machines, all the code books. And this boat happened to havebeen out for about one month. As I said, they have threemonths’ worth of code settings. So the Allies now had the nexttwo months’ of code settings that they couldbreak very easily. And that’s exactlywhat they did. This single act is what changedthe Battle of the Atlantic. And the reason was, not onlydid they have the next two months’, it gave them insightsinto the kinds of messages the Germans were sending, thekinds of cribs they could look for, and how they could thenbreak future Enigma codes from the Navy. So here’s how this goes backto the beginning of computing. And the father of computingis considered Alan Turing. [SOUNDS FROM LOUDSPEAKER] RALPH SIMPSON: Hello? OK. OK. So here’s Alan Turing. He was the person thatled the effort in the UK in breaking the code. He was a mathematician,who came up with– he was the brainsbehind breaking the code. And he came up with theEnglish version of the bombe. By the way the bombewas named after they think an ice cream treat thatthe Polish code breakers were eating at the time theycame up with the idea. But others say it couldbe the ticking of a bomb. So we’re not really sure. In the UK, they built210 of these things. Now these, as you can see,they’re not insignificant. They’re quite large. The one you’re looking at hereis the US version of the bome. The English version had acolumn of three Enigma rotors. And it simulated 36 machines. These rotors onthe English version would spin about twice a second,so quite fast, but slow enough that when they got a possiblehit it could just stop. The operator would then writedown that setting for someone to manually testout to see if that could be a possible setting. Meanwhile, they wouldstart back the machine and it would spin again. Now, all of that would not haveworked for the Naval Enigma. And the reason isthere’s just not enough hours inthe day to do this. The Naval Enigma, having fourrotors selected from eight, it’s hugely moredifficult to break. They also had aselection of reflectors that I didn’t mentionthat were pluggable, so they could changethe reflector. So it was immenselymore complex. And so what the US did was theyinvented a new kind of bombe. Not only did it have fourrotors and it spun faster– it spun at a rate of 29revolutions per second. So the problem with that is–well, first of all, the problem is the brushes wore out quicklyand it was tough to manage. But the other problemwas you couldn’t stop it and then read the setting. It was spinningtoo fast to stop it on a dime like that when it’sgoing 29 times per second. So what they did was theycame up with a new invention. And that invention ismemory, believe it or not. So the top of thatmachine, that box that you see on top,that long box, that is memory for fourbytes of information. [LAUGHTER] And you can see thismachine at the NSA cipher museum in Maryland. That top box held radio tubes. Each radio tube representeda bit of information. And it held the four bytesthat represented the code here of the rotor code. And it would print it out. So this was a major advance. And I would almost say thisis– it’s memory, right? So it’s the beginningof modern computing. The British also cameup with another machine to break a different typeof cipher device, which was the cipher devicethey used for telegraphs. And that was called Colossus. And that also was another stepforward in modern computing, because it was programmable. So this is thebeginning of computing. This is what we’retalking about here as far as this homelylittle wooden box that looks like a typewriter set thestage for things like computing and Silicon Valley andGoogle and all of that. So by the end ofthe war, the US was able to break the NavalEnigma code in 12 hours. That’s quite a while. But from then on, theywere broken in real time. So that was quite anadvantage that they had. They were able to identifywhere these submarines were.They were able to blastthem out of the water. And it turned the tide. This turned the tide ofthe Battle of the Atlantic. It was unfortunate that byfinding out where they were, they had to select whichconvoys they were going to save. They could not save them all. That would just giveaway the entire secret. And then they would beout, that information. So they would haveto selectively pick which ones they wantedto take care of. Another way that they were ableto break these code that they found out was thatthe weather trawlers, these were almostunarmed small boats that they could easily capture. And they would have threemonths’ worth of Enigma codes on them. And they wouldpurposely, of course, sink them immediately and makesure that the Germans never suspected that theywere really after them to get the code books. So what happened bythe end of the war was that 82% of the sailors thatwent into service– including the Admiral’s son, AdmiralDonitz who was in charge of all these, his son was oneof them– died at sea. And 725 of 1,155U-boats were gone. And in fact, towardthe end of the war, even before the endof the war, they quit going out into theAtlantic altogether. It just was notfruitful for them. They were losing more submarinesthan they were sinking boats. One of the thingsthat you’ll read if you read up on theEnigma, a lot of people will claim thatbreaking the Enigma allowed the Allies to shortenthe war by about two years. That’s a made-up number. I don’t know if it’s true. But two years woulddefinitely have saved millions andmillions of lives. I think there is nodoubt that whether it’s two years, threeyears, one year, it made a change and ahuge difference in the war. But even I thinkgreater than that was breaking itallowed the invention of the modern computing, whichhas changed our lives forever. And I think that is thelegacy of this device. Now, after World War II,it’s also interesting that a couple things happened. One was nothing happened. So here we havethis huge success. There were 11,000 peopleworking on breaking this code in the UK. And there were severalthousand in the US. And nobody told this secret. I can’t imagine this happeningtoday in a day of Snowden and releases and allthat kind of stuff. But this was kept secretfor 30 years, until 1974. So in the meantime, there weresome of these Enigma machines around, some of themwithout the plug boards. And the US and the UK encouragedour allies to use these things. And our allies and enemiesalike used them for 30 years. And unbeknownst to them,they were being cracked. And this particular machine camefrom Norway, one of our allies. They were invaded earlyon in World War II. The Germans leftbehind these machines, because when they left,they didn’t have time to destroy all the thingsthey left behind in Norway. So Norway’s secret police,their equivalent of the CIA, used these machinesfor 30 years, with the US and Britain decodingevery one of those messages. So in 1974, whenthis was disclosed, they made these things surplus. And as a result, it wenton the surplus market and eventually into my hands. The other thing I shouldmention is kind of a rarity. Some people ask me, howmany of these were made? How much are they worth? Those kind of things. We think about 30,000 of thesemachines with the plug boards were made. We found serial numbersup into 28,000’s, so we’re assuming around30,000 were made. Today, we know ofabout 350 that exist. Half of those are in museums. Half are in private hands. And of those half that arein private hands, about half of them are in the US. So the US has half of them. The rest are scatteredaround the rest of the world. And these things havebeen quite collectible. Around the year 2000, youcould pick these things up for $20,000 or less. And they stayed that wayfor quite a few years. I picked this up in 2002for less than $20,000. But today, they seem to begoing for over $200,000. The highest that I know ofone selling for was $260,000. But oftentimes they’re goingon Sotheby’s or Christie’s or something like that andthey’re bringing $200,000, I think partially because ofthe added notoriety because of a couple of moviesthat have come out. One was called “Enigma.” One was called “U-571,” whichdepicts a US crew boarding a submarine andstealing the codes. It’s actually a Britishcrew that did this, so the British aren’ttoo happy with our movie. But that’s what’s happened. And I call this a collector’sitem for the uber-geek. So I considermyself an uber-geek for having such a thing. If you’re interested indownloading this presentation, I have it on my website. My website isciphermachines.com. You can just typethat in Enigma.ppt, and you can download thisentire presentation, including the follow-on addendum that hasthe mathematical calculation for the key, for thelength of the key. So are there anyother questions? Yes? AUDIENCE: What’s the actualorigin of the word Enigma? RALPH SIMPSON: I don’t know theactual– some people have asked me, because they think did theUS or the British use this word and the Germans did not. It turns out enigma meansthe same thing in German as it does in English. And it’s spelled the same way. Now, I don’t know ifthat’s part of the reason that Scherbius picked that name. But enigma means the same thing. It’s a puzzle, a tough puzzleto break or something like that. And it’s identicalin both languages and spelled the same way. So maybe that’s just fortunate. I don’t know. But I’m not sure of theoriginal origin of the name. Yes? Other questions? Comments? Yes? AUDIENCE: [INAUDIBLE]published the way that works. And other people havedesigned replicas [INAUDIBLE]? RALPH SIMPSON: Yes. AUDIENCE: Has anybody actuallypublished engineering diagrams of the actual mechanicsof the machine? RALPH SIMPSON: So thequestion is, has anybody published engineeringdiagrams of the mechanics of the machine? I believe they have. Now, I haven’t really looked forthat, so I can’t say for sure. But I believe they have. I think that– ifyou look online, I think you’ll find quite a bit. I know of a person in NorthCarolina who actually makes these replicas to be almostas precise as could be, other than they look new. So when he builds it, youcan’t tell the difference other than it looks new. And he uses thesame crinkle paint, the same exact materials. And I believe he goesto Germany to get the same trees to make the wood. So it’s quite precise. AUDIENCE: [INAUDIBLE]? RALPH SIMPSON: Yes. And actually, one ofthings that surprised me when I received thismachine was it’s in relatively good condition. If you take a look–afterwards you’re welcome to come up and take alook– the paint looks good. It’s hard to believethat it was made in 1941. It’s over 70 years old. It went through thewar and afterwards. And it still looks inrelatively good condition. I think that these were prettywell babied by their operators. I think they understoodthe value of it. They knew that they were tovalue this with their life, that if an enemy came along,they were to destroy it. And therefore, they tookvery good care of them. Although, on theoutside the box, you can see that thereis quite a bit of– I’ve got something blocking it here. There’s some scratchesand so forth. But for a 70-year-olddevice, I would say that’s inrelatively good shape for going through the war. I can imagine this thinggot quite a bit of use during that time. Yes? AUDIENCE: [INAUDIBLE]? RALPH SIMPSON: OK. The question is, why did theNavy switch to a better one and the Army andAir Force didn’t? I think it has to do–and this is my theory. I think it has to dowith Admiral Donitz. He was skepticalthat this had not been broken, becausehe was not– I mean, he trusted his submarineoperators and commanders to be able to do what wasneeded to fight the war. And they were losing. And there were enoughevidence that he thought that thiscould be broken. On the other hand, itcould’ve been spies. You know, it could have beenother technologies, like radio direction finders orsomething like that. But I think he wassuspicious all along. And so part of theway along the way he came up and had themdesign the four-rotor. The Army and Navydecided they didn’t want to go with that, becauseit would have been quite a bit more work for them to themswap out all these machines. And remember, there could’vebeen 30,000 of these. To swap those out inthat many locations versus a few submarinesand a few boats, it was easier forthe Navy to do that. I think it was a combinationof things like that. In fact, they interviewedAdmiral Donitz after the war and asked him if he thoughtthat the code was broken. And he said no way. And then in ’74 when it wasannounced that it was, just before his death, hewas quite surprised. So I think even thoughhe was suspicious, he still believedthat it was safe. Yes? AUDIENCE: So howmuch more complex would it have to be for itto be– for them to have not been able to take 12 hours,say 36 hours for them to break the code? RALPH SIMPSON: Yeah. AUDIENCE: How muchmore complicated would they have had to makeit so that [INAUDIBLE]? RALPH SIMPSON: OK. So the question is,how much more complex would the devicehave to be that it couldn’t be broken in 12 hours? And just adding– noteven adding another rotor to the design, but adding acouple more rotors to what can be selected from wouldprobably do that and more. That adds a lotof complexity when you have these extra rotors. And if you only supplyinga few to some boats and some submarines, youcan probably do that. I don’t think theyfelt it was necessary. And so why didn’t they do it? They had no suspicion thatthis was broken, because of the care that wastaken to make sure that they didn’tmisuse the information. The British didn’t eventell their commanders many times wherethis was coming from. They would tell them thiscame from a trusted spy. And so they would acton the information, but not even know that it camefrom breaking the Enigma code. Yes? I think we’re out of time? OK. We’re out of time. Feel free to come and takea look at the machine. I thank you very much foryour time and attention. [APPLAUSE]

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