The Enigma Machine - Bletchley Park takes a closer look at how it works

I'm Erica Munroe I'm the exhibition's manager at Bletchley Park and I'm Andrew fryer and I'm the outreach Learning Officer at Bletchley Park we're here in Bletchley parks historic mansion in the library and Andrews got something to show us I do I have a box here and this box is actually an Enigma machine [Music] this box this in the box is a new enigma machine yes very few of them left when you say very few 1020 maybe 350 Wow but very few of them are in good working order like that's complete say can we take a look we can't so I open the box okay there we are okay what is an enigma machine first of all it's a polyalphabetic cipher machine okay what does that mean well it substitutes one letter for another letter so you can encrypt a message all right so you type your message in this and does it come out somewhere or is it like a typewriter or well let me show you its electromechanical mm-hm so I turn it on because it has a power supply it has an internal power supply or you can run it from the vehicle that it's being carried on and then I can press a key and when I do that one of the lights lights out and if I press that key again a different light lights up so you've got your message on a bit of paper and you know you've got this letter and you press the key and you've got a light that lights up and that tells you your equipted letter yes that's absolutely right I don't so it's a different light each time is there is there older can you tell what less is gonna light up well that was something for the crypto analysts to work out here at Bletchley Park what happens of course that when I press the key not only does the light come on but the rotor moves around so every time I press the key this first wrote please and as it moves what it's doing is changing the substitution so a letter coming in will come into the rotor and will come out the other end of the rotor has a different letter okay so the person using this they simply use this machine to get a different set of letters that they then send to whoever they were sending a message to yes and the clever thing about it is there's so many way to set up the machine but it's very hard to break that code you know how many different ways there are I do 103 sextillion ways to set up this machine and of course we're not seeing part all of the machine because there is a part here that was added later when the German army took over the production of this machine and that's the plugboard at the front so you've got rotors here you've got plug board here and the person that says it up can can change how that is set up in different ways to make it encrypt differently yes so every month the setting sheet was sent around to all the enigma operators about common dance and the Enigma operator would look on the setting sheet and see the day's settings and then 12 o'clock midnight Berlin time all those settings would change to the next setting on the sheet okay so you had to have that sheet to know how you set up your machine yes and the person I guess you're sending the message to also has to not have exactly the same setting they do yes so if I open up the machine I'll show you what the operator would have to do so here we can see the rotors and I can actually move these rotors and this spindle comes out the rotors can all be taken off the spindle and this particular machine which would have been manufactured from 1938 onwards came with five rotors so it has three slots for the rotors but actually there would be a box with another two rotors that's just one here so I can show you and these rotors are then fitted into the machine in the correct order each rotor has a Roman numeral on it and that designates one two three four or five these five wrote three of the five rows you know said gophers right and you put them in any order oh no no the orders prescribed as well okay so on the setting sheet would be columns when the first column would be the rotors in the correct order right okay so before you even want to send your message you have to set up your machine you've got to get your rotors in the right order pick the right rotors put them in the right order so if this has been set up now and you've put in your your rotors what do you do next well around the ring of each rotor are series of numbers or letters on some these are numbers on this one and I have a clip on the rotor which I can undo and if I undo this clip I can actually turn these this ring around why would you not that well because that then changes the relationship between the wiring inside the rotor and the letter or number so it makes it even more complicated yeah so that's the second column on the setting sheet is the ring setting so each of these rotors would have a number and that would be the way you'd have to place the number on the rotor okay did they do this at the beginning of every single message that they sent change the ring settings and change the way the rotors know this was the daily setting right so daily setting would be the rotors and which order they're in then the ring setting but then the plugboard pairings right so the next part of the setting up would be to take one of the 10 cables and place it into one of the 26 sockets on the front what does that do well that substitutes one letter for another but it's fixed so that once that set up that's the same for the whole of that day right and you say substitutes one letter for another so if you didn't have a cable you push your button your light comes on saying that P becomes e but your cable then changes e to another yes letter again yes so so when you press the key the rotor will turn mm-hmm then the current will flow through the plugboard through the first router through the second router through the third rotor into a reflector at the end which is a fixed rotor where the substitution takes place as well the fixed wiring and then it reflects it back into this router into the second router into the first router and back through the plug board and then lights up the lamp Wow so can you show us now that we know that how we set it up can you show us again presses a button and light us up a letter and just see how that rotor turns round because just that one rating you're spinning yes you'll see that when when I close this up you'll see that this is able to turn you say that it goes through one rotor through the next rater and through the next rotor but I only saw one of those rotors turning I'm pressing the button yes so what happens sorry so what happens when I press the key is this first rotor will turn and this rotor will turn every time I press a key right now when I've set up the ring setting on here by moving the ring undoing the clip and moving the ring what happens is that a notch also moves and that notch is connected to one of these letters and that notch dictates whether the rotor moves or not so when this is in position in the turnover position then the next rotor along is able to move because there's three levers underneath here when you press the key the three levers try and push the rotors around and three leaders are actually in between the rotors and there's nothing to stop the lever engaging so attending this time on this on this row TSO this rotor turns every time right but the ring stops this rotor from engaging and only when the lever is able to push into the knotch of this rotor will this rotor then turn around how often does that happen is that well that will happen at some point during the the 26 rotations of this okay or 26 positions for one rotation of this rotor this will turn around when this one reaches its rotor turn over position but then it will turn around 26 times after that 26 key presses after that and once this has turned it'll turn again 26 rotations of this one and this one will turn after 26 more rotations of that one right so when people say it's a bit like say the mileage reading on your car is the right hand we all goes round and then you'll see the next one go round and then yes but it isn't because because of this turnover position because it's you can select it right so it's not one it's not it's not but once it's in there it will turn 26 times after that but the fact is it will turn at a particular point for each of these two rotors okay and when you want and what that means is that if this rotor is in its turnover position this one moves all the time this one's in its turnover position then all three rotors will move at the same time right so it's not just a question of one or the other mm-hmm it has this feature called double stepping which means that if this rotor is turned into its turnover position it will then step twice in a row so it's not like a car I don t see I see that's really interesting cuz I think that a lot of people who who haven't heard the explanation that you've just given kind of think that that's standard how it works it's just one then the next and the next but there is there's a system there's a reason why yes ID as part of the design but of course the problem is if you can know the wiring for each rotor mm which the Allies did know then you can work out which rotor is in position by when the sequence turns in other words when the rotor turns over that's going to give you a clue - which rotor is in which position right because because you're once you know the rotor you know the turnover position of the rotor is fixed with our rotor right and that gives you the settings for the message but also indicates the settings for the whole day's messages once you've been able yeah get that yes so the plugboard at the front which was added later by the vert marked who are the German High Command who realized that they needed the better way of encrypting messages it wasn't quite secure enough for their purposes so they added this 26 hole plug board and eventually came to use ten cables why ten why why not 11 or three or well eleven would actually give you a better result in terms of security but for some reason they stopped at ten so we have on the on the setting sheet that sent round once a month there is a column which shows the plugboard pairings so it will have perhaps a B might be the first pairing in which case the operator would take a cable and plug it into a at one end and then plug the other end into B that would mean that it's a reciprocal connection so the current would flow from A to B on the way through and then on the way back would flow from B to a now in terms of how many ways there are to do that you'll be amazed to realize that how many ways there are to plug ten cables into 26 know your I can't cut it how many is there well approximately 150 trillion ways to do that one letter into another by plugging in 10k Wow goodness and that alone just doing that makes this so much more complicated than if the plug board wasn't there yes in fact at the very beginning the spy who took photos of the Enigma machine from the factory when that was passed to the French and then to the British the British didn't know what the plug board was had the British ever seen an Enigma machine before well they did exist some commercial nygma's so the Enigma machine was actually designed in 1918 and actually manufactured from 1923 onwards so it didn't come as a surprise to the mistress this was a known quantity know the government code and cypher school had bought two enigma machines okay before the war so what was different between their Enigma machines and these ones because it didn't have the plugboard on right so it was own it was only when the High Command close down the factory and then took it over and opened it to manufacture their version with the plugboard on it so the military version the Germans developed was basically uncrackable even though they had these two Enigma machines from the earliest days of the war yes it made it much harder to break even though the Polish had broken a version of it Wow so you've put your rotors in three of them from the five that you've got and you've closed the lid and you put your cables in as well that you've told us about what would the operator do then in order to send the message is that is that set up that it's set up for the day but for each message the operator had to think of a three-letter password right and that's just yes so and those three letters would be the three letters that would appear in these windows here and if some of these machines have numbers instead of letters like this one then there is a translating operators to 26 that was the prototype right but the operators didn't follow the protocol because they had to think of a password very quickly [Music] of course the fact they didn't helped codebreakers to break in so would they just leave the rotors as they were and then start the next message there was some of that and all they would use things like German swear words or their girlfriend's name right things that could be easily guessed yes I did I guess that helped Bletchley Park who did as a way into to solving that particular riddle of a particular message yes and also if someone's using the same password operators operating machine obviously you can identify individual you know three of their bad use of the machine [Music] so if you have any comments about a liquid any questions you want to answer please put them in the comments box brilliant and there's so much more imagine that we could find out there is if you've enjoyed it do you like us please subscribe and if you got any question 500 sets pop them in and let's check out the description box for other links that you can follow to find out a lot more about enigma [Music] you

Channel: Bletchley Park

Views: 43,351

Keywords: WW2, Enigma, Codebreakers, Enigma machine, Bletchley Park, Alan Turing, Encrypt, Decrypt

Id: 3Ux03qPgYVY

Length: 17min 29sec (1049 seconds)

Published: Fri Apr 10 2020