September 5, 2012 • 45 mins
In this special episode co-hosted by TechStuff's Jonathan Strickland, the focus is on the codes, cipher machines, and cryptologists of World War II. Tune in to learn more about the Enigma Machine, Alan Turing, Code Talkers and more.
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Episode Transcript
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Speaker 1 (00:00):
Welcome to Stuff you missed in History Class from how
Stuff Works dot com. Hello, and welcome to the podcast.
I'm Sarah Dowdy and today I am joined by a
very special guest, Jonathan Strickland. Hey there, So you guys
(00:21):
probably remember Jonathan Strickland. He joined um. He joined both
of us a few months ago as the Admiral for
our Renaissance Festival episode. But this time he is here
in his real life version, presenting on technology, which is
your your specialty, my forte. As they say, there will
be no hazas this particular episode. Maybe we could squeeze
(00:45):
one and at the end or something. But Jonathan is
the co host of tech Stuff is probably a lot
of y'all know, and he also is a staff writer
who specializes in technology articles and Deplina and I often
talk about how you would like somebody like Jonathan and
Chris to join us for technology related episodes sometimes when
(01:06):
we really want something better explained than we're able to do.
And we've actually covered a lot of the same topics
as you and Chris too, Yes, that's true. We've We've
covered several things, including Ada Lovelace, who I think got
an enormous amount of praise on both of our podcast
she was phenomenal, absolutely holomonal to be able to reach
(01:27):
a point where not only was she able to write
programs for a machine that did not yet exist, but
recognize that numbers can substitute in for things and actually
represent other forms of media like music or pictures at
a time where there was no device to do that.
On is beyond my imagination to do all that while
being the daughter of Lord Byron. Of course, well you know,
(01:50):
I would say that helps probably had a little dose
of the crazy in there too, but no, absolutely phenomenal
and other topics as well, But yes, and this is
one that that I know that stuff you missed in
history classes touched on related topics, and we at Tech
Stuff have talked about some related topics, but we wanted
to sort of look at the overall picture of what
(02:11):
cryptography was like during World War Two. And this will
be sort of the kickoff of a little series that
I'm going to do with a few other How Stuff
Works podcast co host who all focusing on something that's
history related but also focused on their specialty. So that's
why Jonathan has picked Codes Today, something that is tech
(02:32):
related but has a really fascinating history behind it too, Yes,
and that history stretches way back before World War two,
of course. Uh. And I even had a little crash
course in cryptography I wrote up so that we could
kind of have a common language to work from. And
it does come from a pair of Greek words. Essentially
means hidden writing is what cryptography really boils down to,
(02:55):
and it is the idea of hiding a message by
encoding it and so way, and very common way is
using a cipher where you are replacing letters within a
message with some other letter or symbol or number, and
you're using a very specific key so that someone who
receives that message, the intended recipient, can take the encoded message,
(03:18):
they take the key, and then using the key, they
decode the message. But ideally anyone else who intercepts said
message would just have a bunch of gibberish that they
could not understand. Now, in reality, a lot of these
ciphers don't remain secure forever, and we will see, right
and there we have some very good examples of that.
(03:38):
But there are a lot of different types of ciphers,
and one of those, the most basic is the mono
alphabetic cipher. That's where you use one symbol to replace
each letter, and probably everybody is familiar with that one.
It's what I used in my spy club as a kid.
It's pretty straightforward. Maybe when you're eight it seems like
(03:59):
it would be a breakable, but in reality it's pretty
easy to crack right right. This would be when you
might say, all right, let's shift all the letters over
four letters, and no one will ever figure it out, right,
So A becomes D and B becomes E and uh.
It seems at first, when you are unaware of how
to analyze cryptography that that would be be fairly secure.
(04:22):
But just using something simple as a frequency analysis, which
is typically the frequency that certain letter combinations appear in
any given language. So if you know that the message
was written in English, you know it's ciphered, but it's
an English based language, you could start looking for letter
combinations that would give away what the coded letters are.
So look for double letters for example. Those could be
(04:44):
ta s or l's, things like that, things word very
short words exactly if you haven't. If you if you
have your text actually broken up in the same grouping
of of letters as your plain text, words are that's
a dead giveaway, which is why a lot of ciphers
are written in five letter blocks, so that you might
even have two short words combined together or a very
(05:06):
long word broken across a couple of blocks, and it
makes it harder to detect, but even then pretty easy
to figure out exactly the analysis. So another version of
this one that's a little bit more complicated, is the
polyalphabetic ciphers, and those substitute each letter with a different
symbol based upon where the letter appeared in the message.
(05:26):
So instead of a direct substitution, just it's the first letter,
it's the second letter, and so on, it can be
like that. Yeah, and there's there's a couple different methods
of doing this where, for example, the first time the
letter if the letter A appears in your message, it
maybe in ciphered. I'm just grabbing the letter at random
with L. And the second time the letter A appears,
(05:47):
it may be the letter D. And it all depends
upon the specific set of rules you have set down
for that key the algorithm, if you like, that's the
specific protocol the you follow, and that does make it
much more difficult to break because you can't guarantee that
every time you see a certain cipher that it's going
(06:07):
to translate to the same letter. Moving on from there,
we get a little bit more complicated and have polygraphic ciphers.
Those use a combination of letters, numbers, or symbols for
each quoted letters, so we don't have this direct translation anymore.
It's not going to be something that you can just
break out into the original words in the plane text
(06:30):
to the cipher text. That's right. You. It's very confusing
when you first get one of these messages because you
can't be sure how many characters represent one single letter,
and by doing that you really make it more difficult
to break the code. And then I think the last
one we have here is the transposition ciphers, which it's
kind of like a word jumble, where you've taken the
(06:50):
letters of the of the message, the plane text message,
and you just mixed up the letters. So you're not
replacing any letters here, you're mixing them up according to
a in a prearranged code. So you might say, all, right,
letter of this message should appear first, then the fifth
letter of the message apers second, and you just follow
(07:11):
that key and as long as the other person has
the same key, they can unscramble it, but of course
that's not terribly safe either. People with a lot of
imagination can piece us together, sort of like Sunday Morning.
Not for your top secret message. Yeah, a hobbyist could
could crack that with enough ingenuity and time. So another
element in here, and one that we're going to be
talking about quite a bit in our second episode on
(07:33):
this uh this subject is codebook. So code books, of
course contain a list of phrases that linked to specific
code words. So if you were just reading them, they
might be familiar words, but they don't have any meaning
to you. You can't you can't decipher it. You can't
into it what the word might represent in any way
unless you have the book right. So you could possibly
(07:54):
break a cipher and you know that this next word
is hawk, but you don't know what hawk means. It
could it could mean a bird, but it might actually
stand for something else, probably does in the case of wartime,
And you know, you might be able to make some guesses,
but you're not necessarily going to know. So codebooks were
also very very important on both sides during the World
(08:17):
War Two, And if you combine that with ciphers, you
are getting a pretty tough code. Finally, and then a
related technique to cryptography is called steganography, which is hiding
a message within an image or some other kind of medium. Right,
this is really super cool stuff. This is where let's say,
Sarah that I met you on the street and I
(08:38):
handed you a postcard and the postcard just said hey,
how are you doing? And it has nothing else on
there's no other message there, and you think, oh, well,
that's just completely innocent. But on the flip side of
the the postcard, where the picture is, which looks like
this nice little landscape, you could maybe actually noticed that
along the edge of a lake, there's really a message
that's in there. And you look more carefully and you
(09:00):
see that there's something hidden and it's hidden from plain
sighte uh. And it can get a lot more complicated,
especially with today's technology, where you can hide things in
u R L, you can hide things within a QR code.
It's it's lots of different ways of hiding a message,
but it's done in such a way that from the
casual observer's perspective, no message even existed. I like this one,
(09:22):
although it doesn't sound quite as practical as the others,
especially for wartime communications. You're not really thinking romantic spy
sort of stuff. Yes, exactly, all right, So now that
we've gotten a background on cryptography, we can start talking
about how it was used in World War Two, which
(09:43):
is sort of the heyday almost it seems, of cryptography.
It's it's really I would say World War Two is
probably the foundation for modern cryptography. The developments that were
made during that era leading up to World War Two,
but really uh intensely built upon during the years of
World War Two that has led to to the way
(10:04):
we use cryptography today. So it's it's an important time
in history as far as this whole development of science
is concerned. It is. And we're going to start by
talking about the axis powers use of cryptography, partly because
we want to start this whole thing off by talking
about the Enigma machine. It's probably the most famous example
of cryptography in World War Two, I would say, and
(10:27):
something that we have both talked about on our podcast.
Deplena and I talked about it in our Alan Touring episode.
You and Chris talked about it in your Alan Touring episode.
It's something that I think most people out there are
they've at least heard of it. Yes, And if you
were to look at one of these things, it would
look like it was a typewriter and a whole bunch
of lightbulbs and some plugs going every which way, and
(10:50):
you might wonder what was the purpose. Looks like a
mad inventor thought. It really doesn't. And the person who
actually thought it up was not a mad inventor. He
was he was quite He was ingenious in his own way,
as Dr Arthur Sherbius, And that was in nineteen twenty three,
and he was inventing this not as a means for
the government to pass along secret messages to various branches
of the military or intermilitary messages. It wasn't meant for
(11:14):
that at all. It was meant for corporations to try
and send secret messages so they could keep corporate secrets,
so that other competitors wouldn't steal corporate information, private information private.
But of course the German government quickly realized that this
could be a useful tool for very secret communications, and
so in nineteen the German Navy started using a modified
(11:39):
version of the Enigma machine and and from there it
sort of picked out the German Army followed in nineteen
The Air Force started using one in nineteen thirty three.
We should say, though they were all modified, they were
all a complicated version of this commercial machine, right, and
they even evolved during the course of World War Two somewhat. Now,
if you want to know what the basic sheen is,
(12:00):
you have to imagine imagine a disk around wheel, all right,
and it's thick, It's about maybe half an inch thick,
and on either side of the wheel are contacts electrical
context that an electrical UH current can pass through. Along
the outer edge of the wheel, where if it were
a tire, this is the part that we make contact
(12:22):
with the ground. Along that outer edge are letters that
represent positions. Now you have three of these in a
basic Enigma machine, all right, and you the way you
set these, how you set them determines the pathway the
electricity takes when it comes in on one side and
goes out the other. Now, uh, you can change the
(12:44):
orientation of these reels in multiple ways, so that makes
it very complex. So this pathway could take lots of
little criss cross the ways. And what it boils down
to is the typewriter part with all the keys. When
you press a letter, it sends an electric signal into
the rotors. It goes through this complicated pathway that's determined
(13:06):
by the orientation of those rotors. When it comes out
the other side, it lights up a light bulb representing
a different letter when you So when you press the
letter A, perhaps the letter Q yes. And so it
takes two people to do this. Someone has the normal message,
the message that is supposed to be encoded, and they
press a key. There's a second person who watches the
(13:27):
light bulbs and writes down which letter lights up. And
after you press that A, the rotor, the first rotor
on the left rotates one position. So that means the
pathways for the that electric current to follow through have
changed from the first letter to the second. That's right.
So if the first two letters were A A for
some reason, and you pressed A and the Q lit up,
(13:50):
the second time you press A, perhaps the M lights up,
and every time after that's gonna light up differently. So
you already have so many possibilities just from that simple
disc option. But there's a way to make it even
more complicated, right there. There are two things that make
this even more complex. One is that once you go
through a certain number of of moves with that first rotor,
(14:11):
the second rotor can rotate, which means you've just added
a whole new set of variables. And with the German
Navy they had four rotors in their Enigma machines, which
means that once the third one would rotate, it just
made it even more complex. And this allows you to
have a key that does not repeat. It does mean
that whoever has the recipient, whoever the recipient is, they
(14:31):
have to have a machine set up the exact same
way that your machine was set up. Now, the other
thing that made this complicated was they had plug boards,
so unfair really, the plug boards, and what the plug
boards did was you were you would attach a cable
that would swap the input of a certain key with
(14:52):
another key. So let's stick with A. Let's say that
you have a plug in the A and a plug
in the H, which means every time you press A,
it's as if you had pressed H on an unaltered machine.
So that makes it even more complex. And the plugboards
were added a little later. That was an evolution of
the Enigma machine. And the Germans were so confident that
(15:15):
this machine was uncrackable that they never ever worried about
anyone intercepting their messages because those ciphered messages would be
impossible to decipher. They were a little too confident, though,
because there were a few problems with the whole thing,
one being that the machine couldn't encode a letter as itself.
So you've been using the example A A could never
(15:38):
be A no matter what combination of rotors you were using,
no matter how many cables were involved, A just couldn't
be A. That's a pretty big clue. I mean, it
doesn't sound like it reduces your your options that much,
but it really does if you're thinking about it in
terms of probability. Right, Yes, that's that was one of
the things Touring jumped on right away was he said, well,
(15:58):
if this machine cannot in code a letter as itself,
that removes one option out, and by removing one option
you have given us a foothold. That was definitely a weakness.
Another was that in order to make this work again,
you had to have two machines and you had to
have them both set up the same way, which meant
if someone were able to get hold of a machine
(16:20):
and the codebook so they you could see which which
set up was needed for any particular day. You know,
everyone had to know how to set their machine up
once they received the message, then they could intercept a
message and then interpret how to decipher it. Um, you
just had to know the day the message had been sent.
(16:40):
You had to know the day the message was sent,
so and you had to have a corresponding codebook that
would tell you the right setting for that day. But
even without that, once they started learning how the actual
machine worked, they were able to start thinking, how can
we simulate this by building something of our own that
can take this information and perhaps decide of it. So
(17:00):
if we intercept a message, we can if if even
if we don't know what the original settings were, perhaps
we'll be able to create something that can run enough
simulations through where we can crack the code. And Polish
mathematicians got a toe hold in this by intercepting an
Enigma machine, so they could see a little bit what
(17:20):
what they were dealing with and what kind of machine
would need to be created to possibly break this code. Yes,
and they ended up sharing that information with Bletchley Park,
which a famous famous institution there during World War Two.
That was that was codebreaker central for the British a
manor house, and I should take this opportunity to I
think one time we said it was in London. It's
(17:42):
outside of London. That was the whole point, because it
was more secure being away from the city. But yeah,
with this information that the Polish mathematicians had with their
intercepted Enigma, the teams at Bletchley Park started working on
building these early computers called bombs to a eventually simulate
the Enigma machine and figure out how it worked and
(18:05):
figure out how to break it. But what I think
is interesting is that this was I was talking to
you about this earlier, and it's kind of hard for
me to wrap my mind around. But they're working by
process of elimination. Rather than like, Okay, what was it
set on? It's more what was it? How was it
not set? Yes? Yeah, By eliminating all the potential factors,
they narrow it down to the one that it actually was. Uh.
(18:28):
It really reminds me of quantum computing. Actually, I'm not
going to go into it, don't get there. But but
I'm just saying a similar thing. You're eliminating all the
all of the possibilities to get down to the one reality.
And it is pretty amazing. The bombas that the Polish
mathematicians had created ended up informing the British when they
(18:48):
started creating the the bumba b O m b E.
I always like to say the bum and uh and
yeah that was that was a huge, huge jump in
of crypto cryptanalysis and just the British war effort in general.
And one thing about all of these these codes and
decoding them is there's so many different names. There's the
(19:10):
name of the machine, there's the name that the opposing
force usually calls the code, and then the name of
the machine that is able to decode it. But in
this case, the Allied efforts to decode the German messages
was known as Ultra. Yeah, it was known as Ultra,
but you never said it ever, Ultra. I just didn't
(19:32):
say anything at Fletchley Park, like it's all done through
semaphoreign mime. Uh No. Ultra was such a secret term
that you were not supposed to utter it to other people.
Ultra was just a general term that referred to intercepted
and deciphered messages. And because it was such secret information,
(19:52):
you could not you could not reveal that to anyone
who was not already classified to know it so much
so that there were people who lost their jobs, who
were court martialed because they refused to deliver sources of
information because it fell under the umbrella of ultra. And
so there are people who are discredited during the war
(20:12):
because they were maintaining this level of secrecy, which is
pretty phenomenal, and they had a huge burden, which is
the flip side to cryptography. If you've intercepted a message
and you've successfully deciphered it, and you now know what
that information is, how do you act on that? Because
if you act on it in a way that reveals
(20:34):
to the enemy that you have understood what their messages are,
they are going to take efforts to change the way
that they are encoding things, thus putting you back to
square one. As long as your enemy feels that their
code is unbreakable, you're in a great position because they're
not going to take any more precautions with it. Otherwise
they can just develop a new machine, developed a more
(20:56):
difficult code. And yeah, like you said, you're back at
square one, then yes, and it is. I mean, it's
just it's it's hard to think about because you know
that a lot of these messages had life or death
consequences exactly, and they had to take very careful consideration
of how to act on it so that they could
preserve as many lives as possible without tipping their hand.
(21:19):
Was it information that could have been procured from some
other sources aside from breaking the code or how important
was it? Fortunately for the Allies, the Germans were extremely
confident that the Enigma code was unbreakable. And I think
the only way that they would have I think, I
think what their normal routine was the Germans this is
(21:42):
would be that if they felt that the code was endangered,
they would issue new codebooks and they would have a
new set of codebooks go out to the field rather
than scrap the system and start with something new, so
they'd stick with the system. They would just say, oh, well,
what's what is at risk? Here are the physical codebooks
that tell people what settings they need to have the
(22:03):
Enigma machine on. And I didn't really talk about but
the recipient of the message. To to de cipher a
message from the the coded one, you would give the
the ciphered message to a typist who would have their
own Enigma machines set up just like the first one,
they pressed the first letter, so if that A was
a QUE, they would press Q and the the A
(22:24):
light bulb lights up and so then you would have
a second person taking down the flat text message exactly. UM.
And I kind of was interested that the secrecy for
all of this really extended beyond the war to the
the BOMBA machines were all destroyed on Churchill's orders. After
the war. I read one account of one of the
women who had worked on the machines at Bletchley Park
(22:47):
and talking about how her crew just happily destroyed them
because they were so temperamental. They were just glad to
see them go. That's an unusual story either. There are
a lot of stories about destroy void cryptography machines because
it was just considered to be too dangerous to let
that information out further technology that could still be useful.
(23:10):
Although today, of course, most of these machines have been rebuilt.
You can see a lot of them if you visit
Bletchley Park, which I think is cool that they've They've
gone to the trouble of illustrating these because if you
watch a video of one, it's a little easier too
to comprehend than if you're just trying to read about
it or hearing about it too, to see exactly how
they were right. And there's some software out there as
(23:32):
well that simulates a lot of these different machines so
that you could type in a message and it would
come out as a ciphered message. And again you have
a friend who has that same software running, and you
tell them, all right, set your software to this setting
and run this message through and see what you get.
And it might say, you know, you are a poopy head.
(23:53):
It's all the messages I get from Chris all the time.
It's really worth worth coding. Yeah, it takes a lot
of effort to get that across. Another thing, though, is
Enigma kind of gets all the glory. I'd say, you know,
it's the only with if we were saying earlier that
it's probably when most people are familiar with, and it
might also be the only German code that people are
(24:15):
familiar with. Sure, and it's not the only German code
by a long shot. You wanted to speak specifically to
the Lawrenz machines, which the Lawrence machine was interesting. It
was a steam powered machine, so a little bit different
and also the kind of old school little steam punky,
little steam punky. Uh. It actually would send a message
over telephone wire, over a telegraph wire, um, and you
(24:39):
would have two machines set up where you would type
in a message onto one machine. It encodes it using
an ex or algorithm. And I to to explain that
would probably take an entire podcast on its own, but
just just to say that each letter is a symbol
assigned a certain binary value, and then there's a key
(25:03):
that also has a binary value. You add those two
values together, it creates a third value that becomes the
ciphered text. So as long as the other machine again
has the right key, uh, then you can decipher it.
And again the Germans were very confident about this. They thought, well,
we've got this. The key is is this this role
of tape. Essentially that both sides, both the sender and
(25:27):
the recipient, they have identical strips of tape that have
these values in it. The h the coded message gets
sent across the wire, they run the tape through the
receiving machine and then they get the plain text information.
Thinking that no one in between would ever be able
to crack that code, so there wasn't a whole lot
(25:47):
of fear about intercepting those messages either on the side
of the Germans, but there should have been. There should
have been, I mean Lorenz who have used for just
the most important information. It was reserved for high command
for Hitler. Kind of ironic if you think about how
they were so confident with Enigma that they wanted this
extra code, but it was eventually broken by the machine.
(26:10):
Colossus and um Letzley Park had a quote, and I
kind of wanted to get your opinion on this. They
called it the world's first practical electronic digital information processing machine,
a forerunner of today's computers. Yes, it was the first
of that nature. Uh, you can look at any act
which was not yet built. It was not finished until
(26:32):
um and all the other preceding computers were electro mechanical,
meaning that there were actually gears in parts that moved,
not just electronic circuits created by either wires you know
today we think of microchips. Back in the day, we're
talking about actual physical wires running to and fro and everywhere.
That's why these machines tended to be the size of
(26:54):
fairly sized room. Colossus is an apt term. Yeah, there
were there were ten of them and they were huge. Um, yeah,
that's perfectly accurate. It is definitely a predecessor to today's computer.
And of course, just as you would imagine today's computer,
the computer that's on your desktop, perhaps the computer that
you have in a pocket or in a bag near
(27:15):
you right now, far more powerful than Colossus. And I
watched the video of Colossus, you know, recommending these two
folks to to check them out and kind of get
a better feel for how these things look and how
they work. It reminded me almost of a workout machine,
partly because of the tapes all wrapped around the little reels,
and that combined with a wall of electronics, it really
(27:35):
does take up an entire room. So that's amazing to
to think that that is a computer predecessor. Yep, yep.
And again it was there to simulate these Lorenz machines
and try and crack what those codes were, and it
was a phenomenal achievement as far as technology is concerned. Okay,
(27:57):
so we've probably discussed Germany pretty thorough lead by now,
so we're gonna move over to Japan. And one thing
that I found really fascinating was that Japanese communications had
been monitored by the United States long long before World
War Two began, right, more than a decade before, and
(28:17):
Japan was not aware of that for quite a long
time too, But that that tends to be the best way.
That's usually how it happens, if you're doing everything correctly,
if you're doing things how you should. So, yeah, the
American said started screening Japanese telegrams between diplomats in November
nineteen one. And these were really simple messages, so nothing
(28:38):
like what we've been talking about with the Enigma. They
were easy to break, and they gave the Cipher Bureau,
which was the name of this UM code breaking organization
in the US at the time and its director, Herbert Yardley,
access to a lot of useful information. So it's diplomatic information,
it's not military, but still gives you some helpful stuff
(29:00):
if you're negotiating treaties, you know, that sort of thing.
Definitely a little inside peak, some insider trading on a
grand scale, that's what this is. But by the late
nineteen twenties, this uh to do this, they relied on
domestic cable companies in information, which is something kind of
(29:22):
relevant to this. But by the late nineteen twenties, use
of that information and plus monitoring of airwaves started to
become kind of distasteful, frowned upon, and so eventually the
cipher Bureau dissolved and Yardley, out of work trying to
make some money during the Great Depression, decided to write
(29:42):
a book and write a series of articles for the
Saturday Evening Post on codes and code breaking. His experiences
experience monitoring the information coming out of Japan, and it
sets some shock waves going through the world that this
information was so easily available. This this kind of proves
(30:04):
why it's important to keep that secret parts secret because
once once it got out that this was very easy
for them to break the codes. The message that sends
is we need to look at how we are ciphering
our messages, how we're encoding things, and try to introduce
as much randomness as possible. And randomness is what makes
(30:26):
codes so difficult to break. You know, once you start
being able to detect patterns, it's game over because it's
just a matter of time before you can start, before
you have to before that code gets cracked. So you
want to avoid patterns as much as possible and have
as much randomness in there as possible. But here's the trick.
Random is hard. Computers are not truly good at producing
(30:49):
random numbers. They are pseudo random because they're still following
a set of rules in order to create random numbers.
And on top of that, there needs to be someone
else out there who has the same set of random
data so they can decode the message you send them.
So there's going to be at least one copy of
whatever random, quote unquote random message you create or random
(31:13):
key you create in order to cipher a message. But
that was what really got countries around the world thinking,
how can we create more of a random feel for
our encoding technology, the random Yeah, if we don't, then
our messages get cracked. We might as well just be
sending plain text. It would be a lot easier and
(31:34):
a lot faster. And so that did sort of lead
to a shift in adopting these more complex mechanical machines,
like we've talked about already with the Enigma, which was
from the twenties, adopting machines more like that rather than
these old style codes right right, And the Japanese chose
a slightly different approach. Their machines did not look like
(31:57):
the Enigma and did not. While they were able to
generate randomness in a very similar way that the Enigma
machine did, so the outcome was very similar, the actual
mechanics were different. To explain, you want to know how Okay,
So it's an electro magnetic device and it's called it's
a step switching device as opposed to rotors, but very
(32:21):
similar in that if you encode a character, there is
a step switch that moves the encoder one step further
so that the next key you press gets coded to
a different one than it would be if it had
been the first key. That sounds really complicated, but really again, well,
we'll stick with the a's and the a's right that
(32:41):
that you're coding two a's in a row. Obviously this
would not be the case with the Japanese typewriter. But
if you press the letter A, then the first step
would be to encode that to whatever the setting has it.
So we'll go with H and then the second that
that would then step up the code a step. You
(33:01):
press A again, it would then code to a different
letter so z and very much the same way as
the Enigma machine, but the actual parts didn't move the
same way. Whereas the Enigma had these rotors. The Japanese
typewriters used this this electromantic step system, and and they
(33:23):
had interesting code names they did. So. The first of
these electromagnetic code machines created by the Japanese was called
the cipher Machine Type A. It was known as red
to the U s, and the code it produced was
known as red um. That code was fully broken though
in nineteen seven, with a clue from one word the
(33:43):
Japanese word for and essentially was enough of a enough
of a hint for them to break code red. Yeah. Again,
it's one of those things where they're looking for repetition
and patterns, and if it's a word that's used a lot,
and if you're if you don't have enough steps there,
if you're key repeats fairly frequently, then you run the
(34:04):
danger of someone using frequency analysis on your message and
figuring out what it means. That was one of the
things that the Enigma was so good about was that
because there were so many possible combinations, that unless your
message was incredibly long and i'm talking novel length, then
you're not going to have to worry about the pattern
(34:24):
forming because you are not going to run out of
those variations. Well, and another problem too is that the
Japanese were sending several standard messages with their messages, so
well we should go back to So they did decipher
the code sent out by RED, and by that point,
though by night messages through RED announced that there was
(34:46):
another machine. That's probably a mistake too, to announce your
new machine through your old one that has been compromised.
And that new announcement was for the alphabetical typewriter, which
was codenamed Purple. That's probably the more famous of the two. Yes,
Purple is definitely more famous. And I read although from
a source that I consider questionable, so this could be apocryphal.
(35:11):
I want to proceed my my message with that that
the reason why I was called purple is because that was,
in fact the color of the binders that the United
States used to hold all the intercepted and deciphered messages.
A good story, yeah, I mean it seems legit. As
they say on the interwebs. I do have to say, well,
researching this though code read code Purple, I just kept
(35:33):
on getting a lot of information on air quality. Yeah,
but also very fitting for Atlanta. It is uh and
they the the United States was able to crack these
codes too. Um. The purple codes were not as sophisticated
as the Enigma machines were. Uh. And the United States
(35:55):
cracked them. And again, these are mostly diplomatic messages, they're
not military messages. But the United States is keeping tabs
on what's going on in the in the Pacific, and
they called their interception and deciphered messages. Uh. Magic, because
that's what it seems like when you're able to decode something.
I guess very tinker tailor soldier spy. Yes it is. Yes,
(36:18):
Gary Oldman would have had a lot of work during
this time, and it took him a while to decode it.
That we shouldn't make it sound like it was just
an easy tak No, it took quite some time. It
took more than a year a year and a half
of hard work to crack the code. But they were
able to figure that out. Um. And Uh, it's interesting
(36:41):
the person who discovered the correlation was someone that you
might not consider it first considering the time period. Right,
so we're in the middle of it was in September
n So World War two is is going on. The
Americans are not really they're just really monitoring at the moment.
The person who who discovered the correlation in a in
(37:04):
a couple of messages which was enough to allow us
to break the code, was Genevieve Grossian. So a woman
was the one who discovered the correlation. And again, it's
one of those things where we often overlook the people
who first make these these uh discoveries, because you know,
the big story about breaking the code is interesting, but
(37:25):
sometimes we lose sight of the people. And I thought, well,
that's someone that we should know about clearly, because this
is someone who was able to find the first stepping
stone that allowed us to crack the code. Alan Turing's
getting his moment. There's plenty to go around. Um, so
you know the timeline. By this point, you're probably thinking, well,
if Purple was cracked in ninety, um, what about Pearl Harbor?
(37:50):
How much was known? They were diplomatic messages, so there's
no evidence that they were receiving information about Pearl Harbor.
That doesn't mean though, there wasn't some pretty important information
that was gained from understanding Purple. Yeah, there was. There's
still some confusion and there are plenty of conspiracy theories
(38:11):
about how much information was gleaned from Purple that could
have prevented, could have at least prevented or at least
prepared everyone in Hawaii for this attack. And uh, there
was no specific message ever intercepted and decipher that had
anything to do with a specific attack on Pearl Harbor,
(38:32):
according to all official records. And again, conspiracy theorists might
disagree with that ben In here, maybe we have to
go with what history gives us, right, and what history
says is that there was no way of knowing directly
through the intercepted messages about the attack on Pearl Harbor.
History would have unfolded a very different way. I'm sure
had there been. What's ironic is that some of the
(38:55):
most important information that was gleaned from these messages was
about Germany rather than Japan. Ironic because of how how
proud they were of the Enigma. All this information was
really getting out through Purple anyway, that probably would have
made the Germans a little kind of upset. Yeah. The
Japanese ambassador to Berlin, a man named hiroshi Oshima. He
(39:17):
was pretty descriptive while talking about what was going on
in Germany and what the Nazi defenses were like and
all that information was being picked up through through magic um,
so a lot of information that ultimately helped prepare for
the D Day invasion. So Pearl Harbor is off the table,
possibly unless we're going to go conspiracy theory on it.
(39:38):
But d JA so still an important code to have broken. Yeah,
it's uh, it's amazing to me when you look at
some of the mistakes that were made, because often mistakes
are the only reason why certain codes were ever broken
in the first place. Either there were mistakes and procedure
where someone has set up a really secure system, but
(40:01):
the people part of the system isn't so secure. My
favorite example of that is somebody making a mistake in
the typing of the message and instead of resetting everything
so that the code is secure again, just typing out
a corrected message on the same setting, right, which makes
for just very slight differences between the two messages, right,
(40:23):
And that that was huge. That was an enormous help.
I mean, the protocol for that was if you were
to send a message and you made a mistake while
in ciphering it, that you were supposed to set it
to a new whatever machine was involved, you were supposed
to set to the next start over, start from scratch,
Start from scratch with a new setting, so that all
the message is going to be completely different because that
(40:45):
way the Allies don't know that it's the same message.
But by setting it back to the setting that was
for the first time you try to transmit it, that
means two copies of this message go out and that's
enough for the Allies to say, wait a minute, this
was in coomat. We can figure this out and we
can start working on what has gone wrong for them
(41:08):
and right for us. So human error is a is
a big part of these codes ultimately being cracked. It
seems ultimately yes, I would say that things everything from
using common salutations or a common prefix to whatever the
message is, that would often give the the analysts enough
(41:28):
information to work on to start cracking a code. Even
a weather report. The standards between a weather report the
numbers or directions of wind might be different, but it's
going to have a lot of the same vocabulary and
that weather report information. That's also a good point because
one thing that the British thought of while they were
trying to capture Enigma machines so they could get Enigma
(41:50):
machines and codebooks so that they be you know, the
Enigma machine was was fairly portable, fairly in the sense
that you could put one on a ship with much
The Lorens not portable. Uh, And the Purple machines were
not terribly portable either. In fact, uh, they just it
was once you once you built one, that's pretty much
(42:11):
where it stayed. But the Enigma machine was different. You
could actually move those around with effort. They were not
It wasn't a laptop, but it The British figured out
that the Germans were probably using Enigma codes not just
on official military craft, but also on things like ships
that were taking weather measurements, so weather research ships that
(42:34):
are not military ships. And they thought, well, why are
we focusing on capturing a German navy vessel when we
could capture one of these weather ships and get hold
of the code books that way. And in fact, that's
what a lot that's how a lot of the codes
were broken. They found code books that were accurate for
that that time period and we're able to start cracking codes.
(42:57):
So that's another instance of a mistake where you know,
you have to balance out who gets access to your
secret message at different levels of codes. Yeah, yeah, it
was because, again, if the machines had worked exactly correctly,
and that all the people had done what they were
supposed to do perfectly, and if the codebooks had remained
(43:19):
perfectly secure, the Enigma code was uncrackable. Next time, though,
we are going to be talking about some truly uncrackable codes.
We'll be talking about the Allies use of cryptography during
World War Two, So it'll it'll take us full circle
from this discussion of Enigma and Purple and Lawrens and
(43:40):
get into some codes that aren't based on machines, which
is a pretty huge difference. Indeed more portable for sure,
So that'll be next time. I don't know, do you
have any other comments were for the use of codes
by the Axis. I think I think we've really covered
it pretty well. What central thing to me is something
(44:00):
that I'll talk about more in our next episode about
how this sort of technology has evolved in how we
use it today. But that will be a good bookend.
I think that it will be how we wrap things up.
So if you want to let us know your ideas
about the access use of codes or just codes and
spies and all sorts of things during World War two.
(44:22):
You can email us. We're at history podcast at how
stuff works dot com. We're also on Twitter at Misston History,
and we are on Facebook and gosh, I'm sure we
have articles on codes, don't we. Oh yeah, I wrote one.
Did you write one? Well, then you go ahead and
find us off. Oh yeah. So go to how stuff
works dot com and look up code breaking because that
(44:42):
was one of my earliest articles. And I've been here
for nearly six years and started the same week. Yeah
and uh, And to this day it remains one of
my favorites because it was just such a fascinating world.
And I even include in that article a code that
you can break, so fun, get out your your um
cereal box sort of decoders and go for it. All right,
(45:05):
pretty much all you need. So How Code Breaking Works
by Jonathan Strickland at www dot how stuff works dot com.
M for more on this and thousands of other topics.
Is it how stuff works dot com.
Welcome to Stuff you missed in History Class from how
Stuff Works dot com. Hello, and welcome to the podcast.
I'm Sarah Dowdy and today I am joined by a
very special guest, Jonathan Strickland. Hey there, So you guys
(00:21):
probably remember Jonathan Strickland. He joined um. He joined both
of us a few months ago as the Admiral for
our Renaissance Festival episode. But this time he is here
in his real life version, presenting on technology, which is
your your specialty, my forte. As they say, there will
be no hazas this particular episode. Maybe we could squeeze
(00:45):
one and at the end or something. But Jonathan is
the co host of tech Stuff is probably a lot
of y'all know, and he also is a staff writer
who specializes in technology articles and Deplina and I often
talk about how you would like somebody like Jonathan and
Chris to join us for technology related episodes sometimes when
(01:06):
we really want something better explained than we're able to do.
And we've actually covered a lot of the same topics
as you and Chris too, Yes, that's true. We've We've
covered several things, including Ada Lovelace, who I think got
an enormous amount of praise on both of our podcast
she was phenomenal, absolutely holomonal to be able to reach
(01:27):
a point where not only was she able to write
programs for a machine that did not yet exist, but
recognize that numbers can substitute in for things and actually
represent other forms of media like music or pictures at
a time where there was no device to do that.
On is beyond my imagination to do all that while
being the daughter of Lord Byron. Of course, well you know,
(01:50):
I would say that helps probably had a little dose
of the crazy in there too, but no, absolutely phenomenal
and other topics as well, But yes, and this is
one that that I know that stuff you missed in
history classes touched on related topics, and we at Tech
Stuff have talked about some related topics, but we wanted
to sort of look at the overall picture of what
(02:11):
cryptography was like during World War Two. And this will
be sort of the kickoff of a little series that
I'm going to do with a few other How Stuff
Works podcast co host who all focusing on something that's
history related but also focused on their specialty. So that's
why Jonathan has picked Codes Today, something that is tech
(02:32):
related but has a really fascinating history behind it too, Yes,
and that history stretches way back before World War two,
of course. Uh. And I even had a little crash
course in cryptography I wrote up so that we could
kind of have a common language to work from. And
it does come from a pair of Greek words. Essentially
means hidden writing is what cryptography really boils down to,
(02:55):
and it is the idea of hiding a message by
encoding it and so way, and very common way is
using a cipher where you are replacing letters within a
message with some other letter or symbol or number, and
you're using a very specific key so that someone who
receives that message, the intended recipient, can take the encoded message,
(03:18):
they take the key, and then using the key, they
decode the message. But ideally anyone else who intercepts said
message would just have a bunch of gibberish that they
could not understand. Now, in reality, a lot of these
ciphers don't remain secure forever, and we will see, right
and there we have some very good examples of that.
(03:38):
But there are a lot of different types of ciphers,
and one of those, the most basic is the mono
alphabetic cipher. That's where you use one symbol to replace
each letter, and probably everybody is familiar with that one.
It's what I used in my spy club as a kid.
It's pretty straightforward. Maybe when you're eight it seems like
(03:59):
it would be a breakable, but in reality it's pretty
easy to crack right right. This would be when you
might say, all right, let's shift all the letters over
four letters, and no one will ever figure it out, right,
So A becomes D and B becomes E and uh.
It seems at first, when you are unaware of how
to analyze cryptography that that would be be fairly secure.
(04:22):
But just using something simple as a frequency analysis, which
is typically the frequency that certain letter combinations appear in
any given language. So if you know that the message
was written in English, you know it's ciphered, but it's
an English based language, you could start looking for letter
combinations that would give away what the coded letters are.
So look for double letters for example. Those could be
(04:44):
ta s or l's, things like that, things word very
short words exactly if you haven't. If you if you
have your text actually broken up in the same grouping
of of letters as your plain text, words are that's
a dead giveaway, which is why a lot of ciphers
are written in five letter blocks, so that you might
even have two short words combined together or a very
(05:06):
long word broken across a couple of blocks, and it
makes it harder to detect, but even then pretty easy
to figure out exactly the analysis. So another version of
this one that's a little bit more complicated, is the
polyalphabetic ciphers, and those substitute each letter with a different
symbol based upon where the letter appeared in the message.
(05:26):
So instead of a direct substitution, just it's the first letter,
it's the second letter, and so on, it can be
like that. Yeah, and there's there's a couple different methods
of doing this where, for example, the first time the
letter if the letter A appears in your message, it
maybe in ciphered. I'm just grabbing the letter at random
with L. And the second time the letter A appears,
(05:47):
it may be the letter D. And it all depends
upon the specific set of rules you have set down
for that key the algorithm, if you like, that's the
specific protocol the you follow, and that does make it
much more difficult to break because you can't guarantee that
every time you see a certain cipher that it's going
(06:07):
to translate to the same letter. Moving on from there,
we get a little bit more complicated and have polygraphic ciphers.
Those use a combination of letters, numbers, or symbols for
each quoted letters, so we don't have this direct translation anymore.
It's not going to be something that you can just
break out into the original words in the plane text
(06:30):
to the cipher text. That's right. You. It's very confusing
when you first get one of these messages because you
can't be sure how many characters represent one single letter,
and by doing that you really make it more difficult
to break the code. And then I think the last
one we have here is the transposition ciphers, which it's
kind of like a word jumble, where you've taken the
(06:50):
letters of the of the message, the plane text message,
and you just mixed up the letters. So you're not
replacing any letters here, you're mixing them up according to
a in a prearranged code. So you might say, all, right,
letter of this message should appear first, then the fifth
letter of the message apers second, and you just follow
(07:11):
that key and as long as the other person has
the same key, they can unscramble it, but of course
that's not terribly safe either. People with a lot of
imagination can piece us together, sort of like Sunday Morning.
Not for your top secret message. Yeah, a hobbyist could
could crack that with enough ingenuity and time. So another
element in here, and one that we're going to be
talking about quite a bit in our second episode on
(07:33):
this uh this subject is codebook. So code books, of
course contain a list of phrases that linked to specific
code words. So if you were just reading them, they
might be familiar words, but they don't have any meaning
to you. You can't you can't decipher it. You can't
into it what the word might represent in any way
unless you have the book right. So you could possibly
(07:54):
break a cipher and you know that this next word
is hawk, but you don't know what hawk means. It
could it could mean a bird, but it might actually
stand for something else, probably does in the case of wartime,
And you know, you might be able to make some guesses,
but you're not necessarily going to know. So codebooks were
also very very important on both sides during the World
(08:17):
War Two, And if you combine that with ciphers, you
are getting a pretty tough code. Finally, and then a
related technique to cryptography is called steganography, which is hiding
a message within an image or some other kind of medium. Right,
this is really super cool stuff. This is where let's say,
Sarah that I met you on the street and I
(08:38):
handed you a postcard and the postcard just said hey,
how are you doing? And it has nothing else on
there's no other message there, and you think, oh, well,
that's just completely innocent. But on the flip side of
the the postcard, where the picture is, which looks like
this nice little landscape, you could maybe actually noticed that
along the edge of a lake, there's really a message
that's in there. And you look more carefully and you
(09:00):
see that there's something hidden and it's hidden from plain
sighte uh. And it can get a lot more complicated,
especially with today's technology, where you can hide things in
u R L, you can hide things within a QR code.
It's it's lots of different ways of hiding a message,
but it's done in such a way that from the
casual observer's perspective, no message even existed. I like this one,
(09:22):
although it doesn't sound quite as practical as the others,
especially for wartime communications. You're not really thinking romantic spy
sort of stuff. Yes, exactly, all right, So now that
we've gotten a background on cryptography, we can start talking
about how it was used in World War Two, which
(09:43):
is sort of the heyday almost it seems, of cryptography.
It's it's really I would say World War Two is
probably the foundation for modern cryptography. The developments that were
made during that era leading up to World War Two,
but really uh intensely built upon during the years of
World War Two that has led to to the way
(10:04):
we use cryptography today. So it's it's an important time
in history as far as this whole development of science
is concerned. It is. And we're going to start by
talking about the axis powers use of cryptography, partly because
we want to start this whole thing off by talking
about the Enigma machine. It's probably the most famous example
of cryptography in World War Two, I would say, and
(10:27):
something that we have both talked about on our podcast.
Deplena and I talked about it in our Alan Touring episode.
You and Chris talked about it in your Alan Touring episode.
It's something that I think most people out there are
they've at least heard of it. Yes, And if you
were to look at one of these things, it would
look like it was a typewriter and a whole bunch
of lightbulbs and some plugs going every which way, and
(10:50):
you might wonder what was the purpose. Looks like a
mad inventor thought. It really doesn't. And the person who
actually thought it up was not a mad inventor. He
was he was quite He was ingenious in his own way,
as Dr Arthur Sherbius, And that was in nineteen twenty three,
and he was inventing this not as a means for
the government to pass along secret messages to various branches
of the military or intermilitary messages. It wasn't meant for
(11:14):
that at all. It was meant for corporations to try
and send secret messages so they could keep corporate secrets,
so that other competitors wouldn't steal corporate information, private information private.
But of course the German government quickly realized that this
could be a useful tool for very secret communications, and
so in nineteen the German Navy started using a modified
(11:39):
version of the Enigma machine and and from there it
sort of picked out the German Army followed in nineteen
The Air Force started using one in nineteen thirty three.
We should say, though they were all modified, they were
all a complicated version of this commercial machine, right, and
they even evolved during the course of World War Two somewhat. Now,
if you want to know what the basic sheen is,
(12:00):
you have to imagine imagine a disk around wheel, all right,
and it's thick, It's about maybe half an inch thick,
and on either side of the wheel are contacts electrical
context that an electrical UH current can pass through. Along
the outer edge of the wheel, where if it were
a tire, this is the part that we make contact
(12:22):
with the ground. Along that outer edge are letters that
represent positions. Now you have three of these in a
basic Enigma machine, all right, and you the way you
set these, how you set them determines the pathway the
electricity takes when it comes in on one side and
goes out the other. Now, uh, you can change the
(12:44):
orientation of these reels in multiple ways, so that makes
it very complex. So this pathway could take lots of
little criss cross the ways. And what it boils down
to is the typewriter part with all the keys. When
you press a letter, it sends an electric signal into
the rotors. It goes through this complicated pathway that's determined
(13:06):
by the orientation of those rotors. When it comes out
the other side, it lights up a light bulb representing
a different letter when you So when you press the
letter A, perhaps the letter Q yes. And so it
takes two people to do this. Someone has the normal message,
the message that is supposed to be encoded, and they
press a key. There's a second person who watches the
(13:27):
light bulbs and writes down which letter lights up. And
after you press that A, the rotor, the first rotor
on the left rotates one position. So that means the
pathways for the that electric current to follow through have
changed from the first letter to the second. That's right.
So if the first two letters were A A for
some reason, and you pressed A and the Q lit up,
(13:50):
the second time you press A, perhaps the M lights up,
and every time after that's gonna light up differently. So
you already have so many possibilities just from that simple
disc option. But there's a way to make it even
more complicated, right there. There are two things that make
this even more complex. One is that once you go
through a certain number of of moves with that first rotor,
(14:11):
the second rotor can rotate, which means you've just added
a whole new set of variables. And with the German
Navy they had four rotors in their Enigma machines, which
means that once the third one would rotate, it just
made it even more complex. And this allows you to
have a key that does not repeat. It does mean
that whoever has the recipient, whoever the recipient is, they
(14:31):
have to have a machine set up the exact same
way that your machine was set up. Now, the other
thing that made this complicated was they had plug boards,
so unfair really, the plug boards, and what the plug
boards did was you were you would attach a cable
that would swap the input of a certain key with
(14:52):
another key. So let's stick with A. Let's say that
you have a plug in the A and a plug
in the H, which means every time you press A,
it's as if you had pressed H on an unaltered machine.
So that makes it even more complex. And the plugboards
were added a little later. That was an evolution of
the Enigma machine. And the Germans were so confident that
(15:15):
this machine was uncrackable that they never ever worried about
anyone intercepting their messages because those ciphered messages would be
impossible to decipher. They were a little too confident, though,
because there were a few problems with the whole thing,
one being that the machine couldn't encode a letter as itself.
So you've been using the example A A could never
(15:38):
be A no matter what combination of rotors you were using,
no matter how many cables were involved, A just couldn't
be A. That's a pretty big clue. I mean, it
doesn't sound like it reduces your your options that much,
but it really does if you're thinking about it in
terms of probability. Right, Yes, that's that was one of
the things Touring jumped on right away was he said, well,
(15:58):
if this machine cannot in code a letter as itself,
that removes one option out, and by removing one option
you have given us a foothold. That was definitely a weakness.
Another was that in order to make this work again,
you had to have two machines and you had to
have them both set up the same way, which meant
if someone were able to get hold of a machine
(16:20):
and the codebook so they you could see which which
set up was needed for any particular day. You know,
everyone had to know how to set their machine up
once they received the message, then they could intercept a
message and then interpret how to decipher it. Um, you
just had to know the day the message had been sent.
(16:40):
You had to know the day the message was sent,
so and you had to have a corresponding codebook that
would tell you the right setting for that day. But
even without that, once they started learning how the actual
machine worked, they were able to start thinking, how can
we simulate this by building something of our own that
can take this information and perhaps decide of it. So
(17:00):
if we intercept a message, we can if if even
if we don't know what the original settings were, perhaps
we'll be able to create something that can run enough
simulations through where we can crack the code. And Polish
mathematicians got a toe hold in this by intercepting an
Enigma machine, so they could see a little bit what
(17:20):
what they were dealing with and what kind of machine
would need to be created to possibly break this code. Yes,
and they ended up sharing that information with Bletchley Park,
which a famous famous institution there during World War Two.
That was that was codebreaker central for the British a
manor house, and I should take this opportunity to I
think one time we said it was in London. It's
(17:42):
outside of London. That was the whole point, because it
was more secure being away from the city. But yeah,
with this information that the Polish mathematicians had with their
intercepted Enigma, the teams at Bletchley Park started working on
building these early computers called bombs to a eventually simulate
the Enigma machine and figure out how it worked and
(18:05):
figure out how to break it. But what I think
is interesting is that this was I was talking to
you about this earlier, and it's kind of hard for
me to wrap my mind around. But they're working by
process of elimination. Rather than like, Okay, what was it
set on? It's more what was it? How was it
not set? Yes? Yeah, By eliminating all the potential factors,
they narrow it down to the one that it actually was. Uh.
(18:28):
It really reminds me of quantum computing. Actually, I'm not
going to go into it, don't get there. But but
I'm just saying a similar thing. You're eliminating all the
all of the possibilities to get down to the one reality.
And it is pretty amazing. The bombas that the Polish
mathematicians had created ended up informing the British when they
(18:48):
started creating the the bumba b O m b E.
I always like to say the bum and uh and
yeah that was that was a huge, huge jump in
of crypto cryptanalysis and just the British war effort in general.
And one thing about all of these these codes and
decoding them is there's so many different names. There's the
(19:10):
name of the machine, there's the name that the opposing
force usually calls the code, and then the name of
the machine that is able to decode it. But in
this case, the Allied efforts to decode the German messages
was known as Ultra. Yeah, it was known as Ultra,
but you never said it ever, Ultra. I just didn't
(19:32):
say anything at Fletchley Park, like it's all done through
semaphoreign mime. Uh No. Ultra was such a secret term
that you were not supposed to utter it to other people.
Ultra was just a general term that referred to intercepted
and deciphered messages. And because it was such secret information,
(19:52):
you could not you could not reveal that to anyone
who was not already classified to know it so much
so that there were people who lost their jobs, who
were court martialed because they refused to deliver sources of
information because it fell under the umbrella of ultra. And
so there are people who are discredited during the war
(20:12):
because they were maintaining this level of secrecy, which is
pretty phenomenal, and they had a huge burden, which is
the flip side to cryptography. If you've intercepted a message
and you've successfully deciphered it, and you now know what
that information is, how do you act on that? Because
if you act on it in a way that reveals
(20:34):
to the enemy that you have understood what their messages are,
they are going to take efforts to change the way
that they are encoding things, thus putting you back to
square one. As long as your enemy feels that their
code is unbreakable, you're in a great position because they're
not going to take any more precautions with it. Otherwise
they can just develop a new machine, developed a more
(20:56):
difficult code. And yeah, like you said, you're back at
square one, then yes, and it is. I mean, it's
just it's it's hard to think about because you know
that a lot of these messages had life or death
consequences exactly, and they had to take very careful consideration
of how to act on it so that they could
preserve as many lives as possible without tipping their hand.
(21:19):
Was it information that could have been procured from some
other sources aside from breaking the code or how important
was it? Fortunately for the Allies, the Germans were extremely
confident that the Enigma code was unbreakable. And I think
the only way that they would have I think, I
think what their normal routine was the Germans this is
(21:42):
would be that if they felt that the code was endangered,
they would issue new codebooks and they would have a
new set of codebooks go out to the field rather
than scrap the system and start with something new, so
they'd stick with the system. They would just say, oh, well,
what's what is at risk? Here are the physical codebooks
that tell people what settings they need to have the
(22:03):
Enigma machine on. And I didn't really talk about but
the recipient of the message. To to de cipher a
message from the the coded one, you would give the
the ciphered message to a typist who would have their
own Enigma machines set up just like the first one,
they pressed the first letter, so if that A was
a QUE, they would press Q and the the A
(22:24):
light bulb lights up and so then you would have
a second person taking down the flat text message exactly. UM.
And I kind of was interested that the secrecy for
all of this really extended beyond the war to the
the BOMBA machines were all destroyed on Churchill's orders. After
the war. I read one account of one of the
women who had worked on the machines at Bletchley Park
(22:47):
and talking about how her crew just happily destroyed them
because they were so temperamental. They were just glad to
see them go. That's an unusual story either. There are
a lot of stories about destroy void cryptography machines because
it was just considered to be too dangerous to let
that information out further technology that could still be useful.
(23:10):
Although today, of course, most of these machines have been rebuilt.
You can see a lot of them if you visit
Bletchley Park, which I think is cool that they've They've
gone to the trouble of illustrating these because if you
watch a video of one, it's a little easier too
to comprehend than if you're just trying to read about
it or hearing about it too, to see exactly how
they were right. And there's some software out there as
(23:32):
well that simulates a lot of these different machines so
that you could type in a message and it would
come out as a ciphered message. And again you have
a friend who has that same software running, and you
tell them, all right, set your software to this setting
and run this message through and see what you get.
And it might say, you know, you are a poopy head.
(23:53):
It's all the messages I get from Chris all the time.
It's really worth worth coding. Yeah, it takes a lot
of effort to get that across. Another thing, though, is
Enigma kind of gets all the glory. I'd say, you know,
it's the only with if we were saying earlier that
it's probably when most people are familiar with, and it
might also be the only German code that people are
(24:15):
familiar with. Sure, and it's not the only German code
by a long shot. You wanted to speak specifically to
the Lawrenz machines, which the Lawrence machine was interesting. It
was a steam powered machine, so a little bit different
and also the kind of old school little steam punky,
little steam punky. Uh. It actually would send a message
over telephone wire, over a telegraph wire, um, and you
(24:39):
would have two machines set up where you would type
in a message onto one machine. It encodes it using
an ex or algorithm. And I to to explain that
would probably take an entire podcast on its own, but
just just to say that each letter is a symbol
assigned a certain binary value, and then there's a key
(25:03):
that also has a binary value. You add those two
values together, it creates a third value that becomes the
ciphered text. So as long as the other machine again
has the right key, uh, then you can decipher it.
And again the Germans were very confident about this. They thought, well,
we've got this. The key is is this this role
of tape. Essentially that both sides, both the sender and
(25:27):
the recipient, they have identical strips of tape that have
these values in it. The h the coded message gets
sent across the wire, they run the tape through the
receiving machine and then they get the plain text information.
Thinking that no one in between would ever be able
to crack that code, so there wasn't a whole lot
(25:47):
of fear about intercepting those messages either on the side
of the Germans, but there should have been. There should
have been, I mean Lorenz who have used for just
the most important information. It was reserved for high command
for Hitler. Kind of ironic if you think about how
they were so confident with Enigma that they wanted this
extra code, but it was eventually broken by the machine.
(26:10):
Colossus and um Letzley Park had a quote, and I
kind of wanted to get your opinion on this. They
called it the world's first practical electronic digital information processing machine,
a forerunner of today's computers. Yes, it was the first
of that nature. Uh, you can look at any act
which was not yet built. It was not finished until
(26:32):
um and all the other preceding computers were electro mechanical,
meaning that there were actually gears in parts that moved,
not just electronic circuits created by either wires you know
today we think of microchips. Back in the day, we're
talking about actual physical wires running to and fro and everywhere.
That's why these machines tended to be the size of
(26:54):
fairly sized room. Colossus is an apt term. Yeah, there
were there were ten of them and they were huge. Um, yeah,
that's perfectly accurate. It is definitely a predecessor to today's computer.
And of course, just as you would imagine today's computer,
the computer that's on your desktop, perhaps the computer that
you have in a pocket or in a bag near
(27:15):
you right now, far more powerful than Colossus. And I
watched the video of Colossus, you know, recommending these two
folks to to check them out and kind of get
a better feel for how these things look and how
they work. It reminded me almost of a workout machine,
partly because of the tapes all wrapped around the little reels,
and that combined with a wall of electronics, it really
(27:35):
does take up an entire room. So that's amazing to
to think that that is a computer predecessor. Yep, yep.
And again it was there to simulate these Lorenz machines
and try and crack what those codes were, and it
was a phenomenal achievement as far as technology is concerned. Okay,
(27:57):
so we've probably discussed Germany pretty thorough lead by now,
so we're gonna move over to Japan. And one thing
that I found really fascinating was that Japanese communications had
been monitored by the United States long long before World
War Two began, right, more than a decade before, and
(28:17):
Japan was not aware of that for quite a long
time too, But that that tends to be the best way.
That's usually how it happens, if you're doing everything correctly,
if you're doing things how you should. So, yeah, the
American said started screening Japanese telegrams between diplomats in November
nineteen one. And these were really simple messages, so nothing
(28:38):
like what we've been talking about with the Enigma. They
were easy to break, and they gave the Cipher Bureau,
which was the name of this UM code breaking organization
in the US at the time and its director, Herbert Yardley,
access to a lot of useful information. So it's diplomatic information,
it's not military, but still gives you some helpful stuff
(29:00):
if you're negotiating treaties, you know, that sort of thing.
Definitely a little inside peak, some insider trading on a
grand scale, that's what this is. But by the late
nineteen twenties, this uh to do this, they relied on
domestic cable companies in information, which is something kind of
(29:22):
relevant to this. But by the late nineteen twenties, use
of that information and plus monitoring of airwaves started to
become kind of distasteful, frowned upon, and so eventually the
cipher Bureau dissolved and Yardley, out of work trying to
make some money during the Great Depression, decided to write
(29:42):
a book and write a series of articles for the
Saturday Evening Post on codes and code breaking. His experiences
experience monitoring the information coming out of Japan, and it
sets some shock waves going through the world that this
information was so easily available. This this kind of proves
(30:04):
why it's important to keep that secret parts secret because
once once it got out that this was very easy
for them to break the codes. The message that sends
is we need to look at how we are ciphering
our messages, how we're encoding things, and try to introduce
as much randomness as possible. And randomness is what makes
(30:26):
codes so difficult to break. You know, once you start
being able to detect patterns, it's game over because it's
just a matter of time before you can start, before
you have to before that code gets cracked. So you
want to avoid patterns as much as possible and have
as much randomness in there as possible. But here's the trick.
Random is hard. Computers are not truly good at producing
(30:49):
random numbers. They are pseudo random because they're still following
a set of rules in order to create random numbers.
And on top of that, there needs to be someone
else out there who has the same set of random
data so they can decode the message you send them.
So there's going to be at least one copy of
whatever random, quote unquote random message you create or random
(31:13):
key you create in order to cipher a message. But
that was what really got countries around the world thinking,
how can we create more of a random feel for
our encoding technology, the random Yeah, if we don't, then
our messages get cracked. We might as well just be
sending plain text. It would be a lot easier and
(31:34):
a lot faster. And so that did sort of lead
to a shift in adopting these more complex mechanical machines,
like we've talked about already with the Enigma, which was
from the twenties, adopting machines more like that rather than
these old style codes right right, And the Japanese chose
a slightly different approach. Their machines did not look like
(31:57):
the Enigma and did not. While they were able to
generate randomness in a very similar way that the Enigma
machine did, so the outcome was very similar, the actual
mechanics were different. To explain, you want to know how Okay,
So it's an electro magnetic device and it's called it's
a step switching device as opposed to rotors, but very
(32:21):
similar in that if you encode a character, there is
a step switch that moves the encoder one step further
so that the next key you press gets coded to
a different one than it would be if it had
been the first key. That sounds really complicated, but really again, well,
we'll stick with the a's and the a's right that
(32:41):
that you're coding two a's in a row. Obviously this
would not be the case with the Japanese typewriter. But
if you press the letter A, then the first step
would be to encode that to whatever the setting has it.
So we'll go with H and then the second that
that would then step up the code a step. You
(33:01):
press A again, it would then code to a different
letter so z and very much the same way as
the Enigma machine, but the actual parts didn't move the
same way. Whereas the Enigma had these rotors. The Japanese
typewriters used this this electromantic step system, and and they
(33:23):
had interesting code names they did. So. The first of
these electromagnetic code machines created by the Japanese was called
the cipher Machine Type A. It was known as red
to the U s, and the code it produced was
known as red um. That code was fully broken though
in nineteen seven, with a clue from one word the
(33:43):
Japanese word for and essentially was enough of a enough
of a hint for them to break code red. Yeah. Again,
it's one of those things where they're looking for repetition
and patterns, and if it's a word that's used a lot,
and if you're if you don't have enough steps there,
if you're key repeats fairly frequently, then you run the
(34:04):
danger of someone using frequency analysis on your message and
figuring out what it means. That was one of the
things that the Enigma was so good about was that
because there were so many possible combinations, that unless your
message was incredibly long and i'm talking novel length, then
you're not going to have to worry about the pattern
(34:24):
forming because you are not going to run out of
those variations. Well, and another problem too is that the
Japanese were sending several standard messages with their messages, so
well we should go back to So they did decipher
the code sent out by RED, and by that point,
though by night messages through RED announced that there was
(34:46):
another machine. That's probably a mistake too, to announce your
new machine through your old one that has been compromised.
And that new announcement was for the alphabetical typewriter, which
was codenamed Purple. That's probably the more famous of the two. Yes,
Purple is definitely more famous. And I read although from
a source that I consider questionable, so this could be apocryphal.
(35:11):
I want to proceed my my message with that that
the reason why I was called purple is because that was,
in fact the color of the binders that the United
States used to hold all the intercepted and deciphered messages.
A good story, yeah, I mean it seems legit. As
they say on the interwebs. I do have to say, well,
researching this though code read code Purple, I just kept
(35:33):
on getting a lot of information on air quality. Yeah,
but also very fitting for Atlanta. It is uh and
they the the United States was able to crack these
codes too. Um. The purple codes were not as sophisticated
as the Enigma machines were. Uh. And the United States
(35:55):
cracked them. And again, these are mostly diplomatic messages, they're
not military messages. But the United States is keeping tabs
on what's going on in the in the Pacific, and
they called their interception and deciphered messages. Uh. Magic, because
that's what it seems like when you're able to decode something.
I guess very tinker tailor soldier spy. Yes it is. Yes,
(36:18):
Gary Oldman would have had a lot of work during
this time, and it took him a while to decode it.
That we shouldn't make it sound like it was just
an easy tak No, it took quite some time. It
took more than a year a year and a half
of hard work to crack the code. But they were
able to figure that out. Um. And Uh, it's interesting
(36:41):
the person who discovered the correlation was someone that you
might not consider it first considering the time period. Right,
so we're in the middle of it was in September
n So World War two is is going on. The
Americans are not really they're just really monitoring at the moment.
The person who who discovered the correlation in a in
(37:04):
a couple of messages which was enough to allow us
to break the code, was Genevieve Grossian. So a woman
was the one who discovered the correlation. And again, it's
one of those things where we often overlook the people
who first make these these uh discoveries, because you know,
the big story about breaking the code is interesting, but
(37:25):
sometimes we lose sight of the people. And I thought, well,
that's someone that we should know about clearly, because this
is someone who was able to find the first stepping
stone that allowed us to crack the code. Alan Turing's
getting his moment. There's plenty to go around. Um, so
you know the timeline. By this point, you're probably thinking, well,
if Purple was cracked in ninety, um, what about Pearl Harbor?
(37:50):
How much was known? They were diplomatic messages, so there's
no evidence that they were receiving information about Pearl Harbor.
That doesn't mean though, there wasn't some pretty important information
that was gained from understanding Purple. Yeah, there was. There's
still some confusion and there are plenty of conspiracy theories
(38:11):
about how much information was gleaned from Purple that could
have prevented, could have at least prevented or at least
prepared everyone in Hawaii for this attack. And uh, there
was no specific message ever intercepted and decipher that had
anything to do with a specific attack on Pearl Harbor,
(38:32):
according to all official records. And again, conspiracy theorists might
disagree with that ben In here, maybe we have to
go with what history gives us, right, and what history
says is that there was no way of knowing directly
through the intercepted messages about the attack on Pearl Harbor.
History would have unfolded a very different way. I'm sure
had there been. What's ironic is that some of the
(38:55):
most important information that was gleaned from these messages was
about Germany rather than Japan. Ironic because of how how
proud they were of the Enigma. All this information was
really getting out through Purple anyway, that probably would have
made the Germans a little kind of upset. Yeah. The
Japanese ambassador to Berlin, a man named hiroshi Oshima. He
(39:17):
was pretty descriptive while talking about what was going on
in Germany and what the Nazi defenses were like and
all that information was being picked up through through magic um,
so a lot of information that ultimately helped prepare for
the D Day invasion. So Pearl Harbor is off the table,
possibly unless we're going to go conspiracy theory on it.
(39:38):
But d JA so still an important code to have broken. Yeah,
it's uh, it's amazing to me when you look at
some of the mistakes that were made, because often mistakes
are the only reason why certain codes were ever broken
in the first place. Either there were mistakes and procedure
where someone has set up a really secure system, but
(40:01):
the people part of the system isn't so secure. My
favorite example of that is somebody making a mistake in
the typing of the message and instead of resetting everything
so that the code is secure again, just typing out
a corrected message on the same setting, right, which makes
for just very slight differences between the two messages, right,
(40:23):
And that that was huge. That was an enormous help.
I mean, the protocol for that was if you were
to send a message and you made a mistake while
in ciphering it, that you were supposed to set it
to a new whatever machine was involved, you were supposed
to set to the next start over, start from scratch,
Start from scratch with a new setting, so that all
the message is going to be completely different because that
(40:45):
way the Allies don't know that it's the same message.
But by setting it back to the setting that was
for the first time you try to transmit it, that
means two copies of this message go out and that's
enough for the Allies to say, wait a minute, this
was in coomat. We can figure this out and we
can start working on what has gone wrong for them
(41:08):
and right for us. So human error is a is
a big part of these codes ultimately being cracked. It
seems ultimately yes, I would say that things everything from
using common salutations or a common prefix to whatever the
message is, that would often give the the analysts enough
(41:28):
information to work on to start cracking a code. Even
a weather report. The standards between a weather report the
numbers or directions of wind might be different, but it's
going to have a lot of the same vocabulary and
that weather report information. That's also a good point because
one thing that the British thought of while they were
trying to capture Enigma machines so they could get Enigma
(41:50):
machines and codebooks so that they be you know, the
Enigma machine was was fairly portable, fairly in the sense
that you could put one on a ship with much
The Lorens not portable. Uh, And the Purple machines were
not terribly portable either. In fact, uh, they just it
was once you once you built one, that's pretty much
(42:11):
where it stayed. But the Enigma machine was different. You
could actually move those around with effort. They were not
It wasn't a laptop, but it The British figured out
that the Germans were probably using Enigma codes not just
on official military craft, but also on things like ships
that were taking weather measurements, so weather research ships that
(42:34):
are not military ships. And they thought, well, why are
we focusing on capturing a German navy vessel when we
could capture one of these weather ships and get hold
of the code books that way. And in fact, that's
what a lot that's how a lot of the codes
were broken. They found code books that were accurate for
that that time period and we're able to start cracking codes.
(42:57):
So that's another instance of a mistake where you know,
you have to balance out who gets access to your
secret message at different levels of codes. Yeah, yeah, it
was because, again, if the machines had worked exactly correctly,
and that all the people had done what they were
supposed to do perfectly, and if the codebooks had remained
(43:19):
perfectly secure, the Enigma code was uncrackable. Next time, though,
we are going to be talking about some truly uncrackable codes.
We'll be talking about the Allies use of cryptography during
World War Two, So it'll it'll take us full circle
from this discussion of Enigma and Purple and Lawrens and
(43:40):
get into some codes that aren't based on machines, which
is a pretty huge difference. Indeed more portable for sure,
So that'll be next time. I don't know, do you
have any other comments were for the use of codes
by the Axis. I think I think we've really covered
it pretty well. What central thing to me is something
(44:00):
that I'll talk about more in our next episode about
how this sort of technology has evolved in how we
use it today. But that will be a good bookend.
I think that it will be how we wrap things up.
So if you want to let us know your ideas
about the access use of codes or just codes and
spies and all sorts of things during World War two.
(44:22):
You can email us. We're at history podcast at how
stuff works dot com. We're also on Twitter at Misston History,
and we are on Facebook and gosh, I'm sure we
have articles on codes, don't we. Oh yeah, I wrote one.
Did you write one? Well, then you go ahead and
find us off. Oh yeah. So go to how stuff
works dot com and look up code breaking because that
(44:42):
was one of my earliest articles. And I've been here
for nearly six years and started the same week. Yeah
and uh, And to this day it remains one of
my favorites because it was just such a fascinating world.
And I even include in that article a code that
you can break, so fun, get out your your um
cereal box sort of decoders and go for it. All right,
(45:05):
pretty much all you need. So How Code Breaking Works
by Jonathan Strickland at www dot how stuff works dot com.
M for more on this and thousands of other topics.
Is it how stuff works dot com.
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