[music]
Today, we're at Bletchley Park in
honor of Alan Turing's 100th birthday.
Bletchley Park, just north of London, in
between Cambridge and Oxford, was
considered by many as the birthplace of
modern computer science.
In 1938, again in anticipation of war, the
Government Code and Cypher School through,
in, in the main, their operational
director a gentleman called Alastair
Denniston, had drawn up a list. He had
sent two people out to troll through the,
people at Oxford and primarily Cambridge
and to some extent Oxford and drew up a
list of people who they approached who
agreed in the event of war would report
immediately to Bletchley park [inaudible]
declared war on September third 1939. The
following day, September fourth during and
several others reported to Bletchley Park.
As the requirement for more people was
needed some, predominately a gentleman
called Gordon Welchman, who had been on
the initial list, he'd arrived the same
day as Turing, he want back to Cambridge
and he started recruiting all his best
students and in effect what they created
here was the world's first [inaudible], a
secretive organization where there were no
rules, eventually their main benefactor
became the prime minister Winston
Churchill and they persuaded Churchill
that this place needed more resources.
Churchill agreed, and he wrote a famous, a
letter was written by Welchman, Turing and
the two deputies to Churchill.
And one of their number, a gentleman called
[inaudible] actually delivered it in
person to Downing Street. Churchill
amazingly read the letter the same day it
was delivered. He put a famous action to
stay stamp on it, with a handwritten note
to his chief of staff, a chief called
General Ismay, which said expedite with
extreme priority, and report to me when it
is done. And really, from that point,
September 1941 Bletchley Park got all the
resources they needed. They threw, in
effect, the smartest people together in
Britain and said, here's a budget, this is
the endgame and that's why they invented
some of these technologies which probably
wouldn't have been invented for years.
≫> In many ways, Bletchley Park was
an early version of a multidisciplinary
science center, much like CERN or NCSA is
today. Many brilliant people, with
different skills and backgrounds were
brought together to solve difficult
problems. The combination of the skills
and collaborative environment, resulted
not in just solving the problems of
cryptography that they were facing. But in
addition solved broader problems for all
of computing and all of society. ≫>
When the people arrived here, they knew
when they arrived the Germans had taken a
machine a machine which we tend to call
Enigma. Enigma was a particularly a very
[inaudible] encryption machine. That
machine was modified from the commercial
version. And it allowed them to encrypt
messages. This was going to become a
machine to be used for operational
communications. Very short 200, 250
character messages. Hitler had conceived
and his generals a type of warfare never
seen before which became known as
Blitzkrieg. Very fast movement 50 miles a
day. Particularly when they invaded France
and, and the latter stages of their
invasion of Poland. You couldn't use
fixed line communication. You needed to use
wireless communications. Here was a device
which was portable. Weight 25 pounds. Ran
of a battery. You could encrypt messages
and then in a separate process they could
be sent using the fairly new technology of
wireless radio. It was the Poles who were
the first to recognize that the age of
machine cryptography had arrived, and the
sort of people who would be good at
dealing with it were mathematicians. In
fact, they even went so far as to put on a
course on cryptography at the University
of Poznan invited twenty or 30 young
German-speaking mathematicians to enroll.
It was a very difficult course and by the
time the course was finished, there were
really only three graduates who they
recruited, their names were Marian
Rajewski, Henry Zygalski and Jerzy
Rozycki. And these three were the core
of this team, and, they are the ones who
really made the early breakthroughs. They
convened a conference. At their secret
headquarters. This was actually July 39.
And at that conference, they gave the
British everything, they revealed what
they had done, they gave them a replica of
the Enigma machine and all of their work.
That information came back to Bletchley Park
and once they were established in
Bletchley Park, they then used the Polish
method to break the Enigma machine. The
Poles had actually built some machines
themselves. One of which was called a
Bomba. Now, that machine, the name
apparently comes from a Polish ice cream
dessert of the same name. So in effect,
vanilla ice cream with chocolate sauces.
Around it >> This machine was called
in honor of what the Poles did. But the
Poles' technique was based on a particular
way that at that time the Germans
enciphered their messages. They, at that
point, were repeating the message header,
and that was the attack which the Poles
developed on it. They believed correctly
that when, when the war would start, that
the Germans would change the way, the way
they were doing that and they called for
help. They told Turing and the people here
everything they have done, which we are
and should be very grateful. But they also
proved that it was possible. And that, I
think was the spur that kicked the Brits
into actually doing something about it.
Now, Turing understood the weaknesses of
the way they'd done it and developed a
trip-based mechanism based on the fact
that every military organization in the
world cannot stop itself sending
stereotyped messages. He even talked to a
brilliant team of engineers led by Dr.
Keene who told him roughly the speed that
it would be possible to examine potential
stops for. Between, between them, they
then designed the, the machine called bomb
which would look for that and do so in
sensible time. Here is an , example where
we have intercepted this message S N M K
G. We're pretty sure that, that is,
because this particular operator always
did this, this is his morning weather
forecast. So here we have the guessed
German plain text [foreign] weather
forecast and the two are lined up. At that
point the Enigma's ability, or inability
to encode a letter as itself is useful
because you can make sure you've got no
clashes here. And from these guest
letters, we, the trip makers would derive
a picture like this called a menu where,
you'll notice that, that position starts
at E here. G is encoded as E. So we have G
going to E. It starts at P at the end
here. E goes to V. This is reversible of
course. We can describe this other way
around. So here's E to V that's ZZG here.
S is going to A. So, S is going to V,
excuse me. So, here's another link. And
eventually we can go all the way around,
and we can close this loop. Like that. It
was the closed loops that they were
looking for. The operation of the bomb was
simply that if there is a letter which you
can feed in at this point. And which comes
around though a string of one, two, three,
four, five, six enigmas and comes back as
that same letter, then it's possible the
position of these wheels match the
position of the wheels when Gunter started
encoding his message on his enigma. It
turned out to be a bit more picky about
loops and menus than, perhaps they had
hoped, although it worked. And at that
point, Welchman added a completely left
field master stroke called the diagonal
board which I think is fair to say made,
the difference between success and failure
to Turing's original idea. And here lies
three diagonal boards. That's one, that's
the other. This is the third one, hiding
in place where you can't see it. But can,
can you see Z down to A? Okay? There's
nothing connecting that to the machine.
It's just bolted there for convenience.
The only connections to the machine are
when you connect x into one of the
enigmas. So, what'll happen is, when we
turn the machine on, you'll see it , it
will run up to speed, okay? The, the, the
motor will be running, and the clutch will
drop in. Then, we'll see the various carry
mechanisms happening. Then when we stop
the machine, you'll see it slow down. And
then the clap shot's up. So, Tony, if
you'd run it up for us please. That's
going. It's going. Could you turn on
[inaudible] hose please? Okay. Thank
you.So, what you saw there was the middle
carry, then we switched on carry home to
make the slow carry work all the time. So,
these bars are just pushing around all the
drums. And you can see that all the 36
Enigmas are just in step. They're all just
turning and they are a resource. These are
the very fast relays, the three banks or
actually four for the chains due to the
detection. Yeah. This is the control
logic. Okay. And then these this is the 26
bit register that notes a stop and then
allows the machine to slow down before it
stops the [inaudible]. That, our favorite
statistic is the sheer amount of wire in
the thing. We've lost count but it's
somewhere between ten and twelve miles of
wire in each one of these. ≫>
Germans really, there was two main systems
they were using. Enigma was their
operational system. That was being used
for all specific operational
communications. Again, very short, maximum
of 250 characters. Instructions, orders
for Panzer division to move from one
location to another or for a submarine to
attack a convoy, an aircraft, to, during
the Battle of Britain to attack specific
targets. The Germans started to introduce,
through probably 1941, a different system.
The intercept service which Britain had
put into place, to intercept these
messages started hearing traffic which was
clearly not Enigma traffic. Enigma traffic
was Morse Code, easily identifiable.
People can be trained fairly simply to
transcribe, to listen to Morse Code and
transcribe the letters. This was a totally
different signal, it was not discernible,
it was not transcribable, this was Adolf
Hitler's communication channel, betw een
his army generals. So, very long winded,
communications, top secret, and so this
was, an even more daunting task, arguably,
then in England, because this encryption
machine that was used with this system
there were various ones of them Hitler
referred to these as Geheimschreiber, his
secret writers, several companies, Seimens
that exists today, making, were making
machine Hagland, but there was also the
Lorenz company. And that was a primary
machine particularly Lorenz Desk Set 42.
That machine, and unlike Enigma that had
three encryption wheels have twelve
encryption wheels. They approached the
post office research lab at Dulles Hill in
London, a young engineer called Tommy
Flowers went into the project he was in
effect told, well, go ahead, if you can
get approval. Flowers go back to the post
office, got approval, put a small card
team together, and in less than a year had
a working prototype, quite a remarkable
achievement. The first Colossus as this
machine became known to mark one had 1,500
valves or vacuum tubes in it. And it, it
brought in the Bletchley Park at work
almost straightaway. The people here were
convinced, they asked for a more powerful
computer. Flowers had already anticipated
this, he already had it in production.
2,500 valves in a era when no machine had
more, that used valves had more than about
fifteen, here was a machine with two and
one-half thousand. Flowers was told that
they needed the Mark too by June first
1944 because there was a certain date in
the diary. June 5,1944 was the schedule
date for Operation Overlord D-day. They
had actually ended up in June sixth
because of bad weather Flowers delivered
the mark, the first mark to the Bletchley
Park on June first. They switch it on, it
worked straightaway. They immediately
started decrypting messages between the
German high command, and much to their
delight, delight, they discovered that all
of the subterfuge about the D-Day landings
had worked. Hitler believed that the main
invasion was going to be at t he port in
Calais not at Normandy. That intelligence
was fed back to General Eisenhower at
Allied Screen Command Headquarters, and
there is reasonable evidence to conclude
that D-Day might have not gone ahead on
June sixth 1944 without the intelligence
from Bletchley Park. ≫> This is the,
Colossus computer at Bletchley Park. Now
we're in [inaudible] of Bletchley Park,
which was the, one of the first purpose
built computers centers and some ten of
these machines were installed here,
starting in January of 1944. Now, in the
years previously a new way of encrypting
messages was discovered and it was being
used in Germany and it was all high level
messages between Hitler and his generals.
And they were encrypted on a machine
called the Lorentz machine. And it used
teleprinter traffic teleprinter codes to
actually transmit those messages. Now, by
'43, it was taking some six hours sorry,
six weeks to actually decode those
messages, and decode those messages
laboriously by hand. The problem with that
is within six weeks the usefulness of the
intelligence that you'd gained from those
messages had obviously gone. So, that
process needed to be speeded up. Now, some
techniques had been tried from, some of
the electronic techniques had been tried
here at Bletchley Park. But this machine,
when it was put into use in early '44,
reduced that six week period to decode the
message down to six hours and that's
really just a phenomenal jump. The
machines, the messages themselves were
received at various intercept stations
around the country and were punched onto
paper tape. Now, there are two paper tapes
on the machine here at the moment, one
that we are running and one which is ready
for the next run. Now this tape, there are
two here, I'll take one. Each row across
the tape, are punched by poles, and each
of those is an alphanumeric character. And
that's the encrypted message that was
received, and being punched on the tape.
Now although Colossus has, all the
elements of a modern, electronic co
mputer, it doesn't have the memory that's,
we expect in a stored program computer.
Now what happens is that tape that
message, some 5,000 characters in that
message is actually formed in a loop and
is read over here is a series of
photoelectric sensors and lights and each
character is read and 5,000 characters per
second are read. Now each clunk of the
machine you can hear there is another
5,000 characters being read into the
machine. So we are reading that same 5,000
characters each time. This is the Control
panel of the Colossus computer, so its
this side of the machine that we are
actually we runs during wartime we are
actually using. Now I can set up the
particular algorithm I want to test, and
routines I want to test, using these
control panels. And each clunk of the
machine at the moment is another state
where we're actually trying a, a new
algorithm and repeating that algorithm on
that repeating 5000 characters. The
results that the machine detects are
presented here. Now, we're doing a
statistical analysis of that encrypted
tape. Now the machine would run for some
six hours. There are 2,500 valves in this
machine. You can't see that many from the
front, but once we go between the racks of
the machines, you get an idea of the
scale. 2,500 valves, each valve has a
heater, a hot wire heater in the center of
the valve, and operates at about 2-300
volts DC. Now five and a half 2500 valves,
plus the power supply is generates over
eight kilowatts of, uses over eight
kilowatts of electricity. And by this
point, when we're standing in between the
racks, you can feel the heat coming off of
these racks. Colossus is a combination of
electronics, and we can see the rack, the
electronics here, and these valves chassis
members, and also electro-mechanical,
switch gear. So there are banks of relay
panels here. These big single motion
detectors are a sort of motorized switch
that will actually spin around. There's
banks of those in the machine. The
technology is equipment that was well know
n for the British Post Office. This
machine was designed by a chap called
Tommy Flowers. And Tommy Flowers is an
engineer at the, research center in London
for the British post office. Tommy was
asked to look at the problem of how to
automate this task, this manual task. And
Tommy came up with the idea of using
electronics to do this. At the time, the
idea of using more than half a dozen
valves in any circuit. Which is
[inaudible] simply poo pooed. Valves had a
bad reputation. People had valves in their
radios at home. They failed when they
switched the radios on. So the idea of
using 2500 which is simply phenomenal. But
Tommy understood that it's probably, it's
almost certainly the thermal shock that
kills valves in the first place. So, if
you leave the machine on and don't subject
it to that shock, you won't have a
problem. Now all of the ten Colloseus
machines here at Bletchley Park were left
on permanently. The machines are operated
by Wrens in three shifts throughout
the day. We, have to be seen equally
careful. This is obviously, this is a
replica of the machine, itself. But the
same problems apply. We need to be,
careful in bringing the supply voltages up
gradually, so we don't suffer from thermal
shock, and in the same way in shutting the
machine down. Tommy had the idea of
generating the key, cuz it's a key that
we're comparing with that encrypted type,
generating that key electronically, and
these counters here, they're called the
souratron rings, souratron valves,
actually holds that, that count. Now we
describe Colossus' not having a memory,
we're saying not, not having a memory in
the sense that, modern computers have a,
have a memory that's common for data and
for programs. Well, the program here. Set
on those control panels at the front and
that's switch, switch and plug programmed,
much like say, its contemporary ENIAC
machine. But these machines, these valves
at the back do act as a store, in the
sense of counters, and they're actually
counting the score that we're actually
getting. Each pass through the algorithm.
We, we can see at the back here well,
certainly some of the modern technology. I
suspect the wartime guys that were
building and debugging these machines.
I've given anything for a little
[inaudible] and let alone a logic
analyzer. If I look into the machine down
here back, you can see the projected image
that's coming off the tape. And that's
shining onto five photo sensitive valves.
And it's those valves that are actually
reeling the 5,000 characters every second.
The paper tape was used well into the
1960's and 70's. At this speed it was
simply phenomenal and hadn't really been
thought of before. And our original museum
director Tony Sale wanted to rebuild the
Colossus and build a replica that was a
machine. This was some twenty years ago.
There is very little information out
there, there are a few pictures that are
attached, possibly illegally. A few scraps
of circuit diagrams, and just the memories
of some of the original pioneers who
worked on the machine. And when Tony
started the plant, Tommy Flowers was still
alive and remember he was able to draw
circuits. [inaudible] finding the parts as
well. But the important thing is the
machine was designed by a post office
engineer at the time. An engineer that was
used to designing systems for telephone
switching. So, a lot of the components
here, everything from the relay banks, to
the switches, to the power supplies, were
common to British post offices in the
pre-war period. So, when Tony then wants
to find the components to rebuild the
replica, he's lucky in the sense that the
last of those exchanges are being
decommissioned from post offices around
the country. Tony was therefore able to
really sort of back up a pickup truck. At
the back of the exchange and take away all
of those components and dismantle all
those components. And they are, they were
absolutely perfect. And it was just that
timing. It really couldn't have been
better. ≫> So, Allen Turing actually
left Bletchley Park after about three and
a half years. His involvement really
finished. He went to the United States.
Turing became, was not actually involved
in the development of Colossus. Some of
the statistical work that he did was used
by the people. Pri-, predominately Bill
[unknown], who was the guy who actually
constructed Lorentz machine quite
remarkably a remarkable feat indeed Jerry
even got into things like speech
scrambling systems and went to the United
States and was involved in other projects
so he wasn't really involved in Colossus.
At the end of the war Jerry went to work
for the National Physics Laboratory, again
pursuing these sort of ideas and then of
course he ended up in the University of
Manchester where March Newman, who had run
the department where the Colossus
computers had been located. But Newport
also ended up as the head of mathematics
and obviously then at that point Jerry
became involved in the very early computer
developments in Britain Gordon Weitzman
immigrated to the United States at the end
of the war. In 1948 he immigrated to the
United States and became involved in many
of the early American Community
Developments Project. World Wind Welchman
worked at MIT and he taught the first
course in computer science at MIT. So
Turing then was involved with things like
The Manchester Baby and the Frankie Mark
one and the nearly computing developments
I guess this is well known of course,
Touring tragically committed suicide in
1940, 1954. [music]