The Enigma Machine Explained

cryptography is about mathematics it's about science it's about politics it's about privacy it's about human rights it's about technology it's a whole mess of different things and what you have is something suddenly the development the Telegraph you send messages around the world instantaneously and encryptions important because if you're going to send messages you need to make sure those messages aren't necessarily going to be intercepted and stolen with with radio communication you have that same situation and when we get to the second world war prior to the Second World War the Germans realize that that radios around you can send messages across battlefields in an instant but if I can send a radio message across a battlefield in an instant then the other side can also tap into those radio channels so if we're going to have high-tech radio communication we need to have high-tech encryption pencil and paper encryption isn't going to be good enough and so the Germans as the other country started working on it as well but but it was abandoned in Scandinavia and in America as well the Germans were the only ones that really took it to its logical conclusion and invented something it looks a bit like a typewriter a big cranky typewriter with the keyboard and you type in your message and out comes gibberish you send the gibberish over the radio at the other end somebody's got one of these enigma machines when these clanky typewriters they type in the gibberish and the real original message comes out and the complexity of the machine guarantees you your privacy show us the complexity of the machine right now I believe that you have a machine an actual Enigma machine from and is this an actual this was actually used during the Second World War this this machine yeah this one I don't know a huge amount about I've got one in London I'm very fortunate have one which was used in the Second World War and this one would have been used in the Second World War it's an Army machine no people in the audience don't worry you're not gonna have to Crane you're next we're actually going to have a shot of it up here on the UM on yeah on the stage for you so you can see that a bit better hang around this this nice wooden box it's pretty heavy and when you open it up you can see it does look just like a big old-fashioned typewriter it's got a keyboard here and the lamp board is here so that's where the gibberish appears is at the top and if we zoom in a little bit up to about here if I type in the letter P let's see what happens the letter e lights up so P is encrypted as an E but what's really clever about the enigma is if I type in an E again a P again a V lights up if I type in P again a Y lights up so we have a random letter generator the encryption doesn't seem to follow any kind of pattern and if you want a good form of encryption that's what you need a kind of random letter generator so where is this this randomness coming from well we can open up this machine here one thing we can tell is it's probably built prewar because this enamel plate was was only used pre-war during the war they were churning out these machines so quickly they just had a peak paper stuck there which would have come undone so here's the lamp board here's the keyboard there are 26 wires coming out of the keyboard into the lamps but before they go into the lamps they go round the side through these three rotors here and I can take these rotors out whoops it's not my machine I'm very very what about breaking it up so we can see here it's got 26 contact so the 26 wires and the keyboard going to the 26 contacts and they come out these contacts here and into those 26 contacts but in the middle of this object it's like spaghetti so an a will go in at 12 o'clock but it might come out as an F it will go in here as an F it might come out as a G and so on so the scrambled wiring inside these rotors is what leads to the encryption but on its own that's not enough scrambling is okay scrambling is simple we can we can scramble without needing a machine what the Enigma allows us to do let me just set it up in a certain way I've got it set up here 21 16 there we go and 11 so if I do that same process again if I hit P three times I hit the P first time the lamp lights up but also you're seeing that that rotor moved if that rotor moves then the key that the wiring goes in at a different Junction if it goes in a different Junction it follows a different electrical path if I type P again you'll see the lamp light up different lamp but also the rotor will move there we go and it's it's this dynamism for the rotors that gives you the the complicated encryption and when that wrote has done a full revolution it kicks the middle one when that's done a full revolution it kicks the end one so it's like a Milo meter on a car so that's all very well in terms of creating the the message what happens at the other end how do you transfer how do they decode it okay well first of all you've got to have a machine so you can have an enigma machine that'll help but but but with all forms of encryption this is called the algorithm this box of tricks is the algorithm it does the scrambling but you have to assume that the other side know the algorithm they know that they've got the Machine and the the Brits the Allies we'd have had one of these machines and so the real security relies in how you set up the machine so and your machine has to be set up in the same way as mine so for example I've got three rotors here those three rotors could be swapped around three rotors about six permutations this rotor before I send the message can be adjusted to one of 26 positions that can be done to one of 26 positions that to one of 26 positions 26 cubed from memory I think is around 20,000 I could be wrong multiplying it by the six permutations gets us to about 100,000 I can also change where this rotor kicks that rotor that's another factor of 26 then I went up to like two and a half million that one I can vary where that one kicks out that's another 26 R up to the hundreds of millions and and it's a bit down here if we pan down a bit it's what's called a plugboard here now all this does is it pull it swaps letters so if I plug a word Q with W when I type Q the path follows w's path and when I type W it follows Q's path now that there are 20 20 cables here in 26 holes and my memory is and it may be wrong but I think they're a hundred million million different ways to wire up that simple bit of kit x the 100 million or so we had before and your machine has to be set up exactly the same way as this so how do we communicate about how do you tell me what the configuration of my machine needs to be in a way that doesn't suffer the same you know lack of encryption that we could have had just by communicating freely in the first place it's it's kind of crude what you have is every month you have a bit of paper and that bit of paper has the settings of the machine and we might print we may be in the North African Network Rommel in his troops and everyone everyone in Ronald's Network would have one of these bits of paper and we wake up in the morning we'd say right it's the third or fourth of June and we'd set up our machine according to that fourth of June recipe and you've got the same piece of paper then we can communicate but that bit of paper has to be biked across the desert yeah we you know that the guy delivering it may be incompetent he may be a double agent he may lose it and this is known as a key distribution problem and it's expensive time-consuming and risky

Channel: World Science Festival

Views: 732,267

Rating: 4.852293 out of 5

Keywords: The Enigma Machine Explained, methods of encryption, code machine, Simon Singh, German enigma machine, how does Enigma Machine work, encrypt communications, rotor cipher machines, The Imitation Game, Alan Turing, decipher enigma, Joan Clarke, New York, world, science, festival, NYC, New York City, short, 2011

Id: ASfAPOiq_eQ

Length: 7min 59sec (479 seconds)

Published: Tue May 14 2013