Original subtitles

It's one of the most astonishing stories

of the second World War.

As Nazi forces crushed all who opposed them,

a small group of geniuses based in a British country house

fought back.

And the codebreakers won.

The most famous of all was Alan Turing, whose story,

told in Oscar-winning movie "The Imitation Game,"

has gripped the world.

But there's one name that was left out of the film

and largely forgotten.

A codebreaker who should be as famous as Turing himself.

His name is Gordon Welchman.

Without him, the Nazi codes might never have been broken.

The war could have lasted two more years

and tens of thousands would have died.

When I was a child

there was always in the family the sense that dad had done,

done something quite important during the war,

but of course we didn't really know the details,

and it couldn't really be talked about.

His achievements didn't end with World War II.

He would move to the united states,

where he'd play a critical role in the cold war

and change the face of the modern battlefield.

With Edward Snowden's revelations

of total global surveillance,

we have now discovered Welchman's legacy

continues to this day.

But when Gordon Welchman chose

to come out of the shadows and reveal his secrets,

the dark world of espionage to which he had given so much

ruined him.

September 1939.

As Britain declared war on Nazi Germany,

an extraordinary motley army

was being assembled at Bletchley Park,

in the English countryside near London,

to fight a secret war.

Their mission was to crack

one of the hardest codes ever devised,

created on a machine called Enigma.

Enigma lay at the heart

of Hitler's armed forces communications system.

Bletchley Park's staff consisted of chess masters,

crossword addicts and bridge fanatics.

If they could break into Enigma,

they might just save the world from the nazis.

The best and the brightest were being recruited

from Britain's top universities.

Two of this elite

were the renowned mathematician Alan Turing

and the dean of a Cambridge college, Gordon Welchman.

Gordon Welchman was actually quite glamorous,

he was good looking, and he knew he was good looking.

He had a way with the ladies.

He was fantastically bright,

very pugnacious,

obviously a very proud man.

He did mountain climbing,

he did sailing, he loved dancing.

Here was a man

who had clearly been watching Hollywood movies.

Here was a kind of Errol Flynn and Robert Donat.

It's very much that kind of dashing, young chap

kind of feel to him,

as opposed to the shambling absent-mindedness

of many of his colleagues.

Welchman was one of the original elite codebreakers,

given the Herculean task of decoding the Enigma machine.

Enigma used a combination of rotors, plugs and wiring

to put German messages into secret code.

There were 1 in 159 million, million, million

possible combinations.

Breaking it looked impossible.

While others sought to crack the codes,

Welchman took a different approach.

Instead, he focused on what would come to be known

as traffic analysis.

The body of the message was unreadable.

But the first few letters and numbers were not in code.

This was the call sign-- the address--

identifying who the message was to and from.

There was crucial information in the call signs,

and Welchman started to track it,

linking up who was sending and receiving the messages,

where they were, where they went.

It was a brilliantly simple observation,

yet it would prove crucial.

They call it chat that comes over the air,

and by this means

we can build up a picture of a German unit--

of the air force, for example--

the headquarters-- any out-stations it has,

and how they keep in touch with it and so,

and send messages.

We were dealing with an entire communications system

that would serve the needs of the German forces.

The call signs came alive as representing those forces,

whose commanders would have to send messages to each other.

Just using traffic analysis,

Welchman started to reveal

the precise enemy forces that faced the allies.

Modern codebreaking was born.

And they had a big wall map,

and you could visually see the whole setup

of the German communications system.

Traffic analysis

was Bletchley's first major breakthrough.

Without an analysis of traffic

you would never have been able to use cryptography

to win the war.

When you hear phrases like traffic analysis

or signals intelligence,

it doesn't immediately sound quite so glamorous, really.

And I think possibly that's one of the reasons

why Gordon Welchman hasn't been recognized so much,

but if people knew just how absolutely

he was the kind of spine

of the entire Bletchley Park operation,

then they would look at him in a completely new way.

The Enigma codes had still not been broken,

but Welchman now knew the exact position and strength

of thousands of German troops and hundreds of aircraft.

It made him realize that Bletchley Park

could become as forceful a part of Britain's defenses

as the army, navy and air force.

Their weapon would be intelligence.

No one else seemed to be doing anything

about this potential gold mine,

so I drew up a comprehensive plan,

which called for the close coordination

of radio interception,

analysis of the intercepted traffic,

breaking Enigma keys,

decoding messages on the broken keys,

and extracting intelligence from the decodes.

It was the end of 1939,

before open warfare between Britain and Germany had begun.

Welchman was pushing for a total reorganization

of Bletchley Park--

a radical plan that would require

far more people and resources

than a collection of crossword fanatics

and professors solving puzzles.

Welchman went to his boss.

He won high-level approval for my plan,

and we were able to start recruiting

the high-quality staff that would be needed.

Welchman created what was called Hut 6,

a modest name that belied the magnitude

of just what was achieved within its walls.

We had two or three or four little lights

hanging on wires from the ceiling,

and we had collapsible chairs and tables.

It really wasn't for a high-powered government machine.

I was a bit of a romantic,

and I thought, well, you know,

I might get involved in some clandestine operations.

Here, brilliant people made breakthroughs

that helped change the course of the war.

All were sworn to the utmost secrecy.

Welchman would remain head of Hut 6 until 1943.

In may 1940, Hitler's panzers invaded France.

And Bletchley Park at last

found a way to read some Enigma messages.

The intelligence they contained was code-named ultra.

And it made for horrifying reading.

The nazis were driving allied forces

back towards the English channel.

British, french and Belgian troops

were fighting desperately.

30 years after the war,

in the only filmed interview Welchman ever gave,

he revealed how ultra had saved thousands of British lives.

In the battle of France

probably the most important thing which came out of ultra

was that it was realized so early

that we were in a hopeless position.

Hut 6 had been established just in time.

Bletchley Park had revealed

the troops in France were surrounded.

They needed to escape now.

The evacuation of Dunkirk began.

It was decided to get out as quick as we could.

And this meant that there was time to organize.

Hut 6 had saved nearly 340,000 lives

and prevented the annihilation of the British army.

Its success was a testament to Welchman's steely-eyed vision.

Well, I think he was the right person

at the right time.

I think he probably had a lot of personal characteristics

that were really vital for his work here.

For Bletchley Park and Gordon Welchman,

it was just the beginning.

By the end of 1940, Hut 6, under Gordon Welchman,

was at the heart of the whole Bletchley Park operation.

Here, they used traffic analysis to select and target

particular German radio networks and operators.

Their traffic was then intercepted and decoded

thanks to a remarkable new electromechanical device

designed by Alan Turing.

It was helping to break key Enigma signals

on a daily basis.

It was called "The bombe."

It simulated all the possible configurations

of the Enigma machine.

The bombe could check them hundreds of times faster

than the smartest human.

But it was very limited.

To run a test, known as a bombe run,

it needed to compare a short phrase from the code

with what the codebreakers guessed

might be the original message.

For example, many German messages might begin

with the words "Heil Hitler's."

This guessed text was known as a crib.

If they were right in their guess,

the bombe could start cracking the code.

But they needed accurate cribs.

Welchman realized the German operators were only human.

Like anyone else they would fall into bad habits--

and if they could target these habits,

Bletchley might have a shortcut to break the codes.

What Welchman discovered

was that by understanding

the way that the Germans used their communications

you could start to predict more easily

where particular types of message would come.

There was a German commander

in Brittany somewhere, who, during the war,

regularly sent in every morning a message,

saying "Alles in ordnung," "everything okay here."

It was the same phrase he used every morning,

which was a godsend to the decryptors in Hut 6.

Armed with a crib, the Bletchley team

could now start a bombe run

and hope to find the Enigma settings.

But it was a race against time.

German codes were changed at midnight,

and the bombe might take days to find an answer.

Even if they cracked the code,

it could be too late to help the allies.

Welchman's genius was to come up with a modification

of Alan Turing's brilliant design

and make it work many times faster.

It was Gordon Welchman

who spots the one thing that the machines need

that could give them an almost uncanny elegance and beauty

in the way that they worked.

Welchman came up

with an inspired, improvised solution.

It was called the diagonal board.

A simple electrical circuit enabled the bombe

to cross-check hundreds of possible combinations

at the same time.

It reduced bombe runs from days down to hours or even minutes.

Hut 6 could now read German messages,

sometimes before they were even read

by the intended enemy recipient.

So here we see an example

of Gordon Welchman's fantastic mathematical intelligence

coming through,

easily a match for that of Alan Turing.

By 1941, Bletchley's decodes

were starting to change the course of the war.

A German battleship, the Bismarck,

was scouring the Atlantic, destroying British shipping,

and threatening the nation's survival.

The main part of our fleet

was out pursuing the Bismarck.

She was the latest German ship

and the best thing they'd got in the navy

and very important.

On may 24, 1941,

the Bismarck sank the pride of the British navy, hms hood,

Britain's most modern and biggest battlecruiser.

1,400 British sailors lost their lives.

Only three of its crew survived.

Winston Churchill ordered the royal navy

to find and destroy the Bismarck.

But they had no way of knowing where it was.

At Bletchley, Welchman's team believed

they might be able to use intelligence to find it.

Sifting through the entirety of German naval communications

for any reference to the Bismarck

was a daunting challenge.

What I had to do was to take the Enigma telegrams

as they arrived in Hut 6,

and I had to put them into the machine.

Then I had to look at them and see whether--

they were all in German, of course--

see whether they appeared to be of any interest.

Then the breakthrough they had been hoping for.

We discovered this message from a German commander

to the commander of the Bismarck

saying, "Where are you going?

I'm worried about my son who's on board."

And the message came back,

which I got, which said "Brest."

At last they had a location.

The Bismarck was heading for the port of brest in northern France

being used by the German navy.

A powerful royal navy battle group of 13 vessels

was ordered to hunt down the Bismarck.

In this, perhaps the most dramatic naval film ever taken,

you will see salvos from the Bismarck

failing to hit one of our battleships.

This was during the chase right across the Atlantic

while the Nazi ship was running from the guns of our squadron.

A torpedo dropped from a British biplane

disabled the Bismarck.

The British warships closed in.

We were all absolutely on our toes

wondering what was going to come through next,

because we knew it was one of the major battles of the war.

When these pictures were taken during the action,

the Bismarck was nearing her end.

Hut 6 had the satisfaction

of decoding the very last message

sent from the stricken Bismarck.

"Ship unmanageable.

We shall fight to the last shell.

Long live the fuhrer."

And eventually they sank her.

This flagship of Hitler's navy went down

with over 2,000 of its crew.

I mean, that was a day to remember.

We were constructing a jigsaw,

but half the pieces were missing.

Now it all made a picture, and all the jigsaw came together.

We were invigorated immediately.

It was Britain's first significant victory

in the darkest days of World War II.

Bletchley Park had proved that intelligence could sink ships.

It was a weapon the allies were determined to use to the limit.

Under Welchman's supervision,

a ramshackle collection of wooden Huts

became the world's first intelligence factory,

rebuilt in brick on a whole new scale.

A handful of codebreakers

became thousands working around the clock.

Two bombes became 200.

Bletchley Park was breaking Enigma daily,

revealing the inner secrets of the German war machine.

And it was changing the course of the war.

They tapped into field marshal Erwin Rommel's battle plans,

and his forces were driven out of north Africa.

They located the u-boat wolf packs

lurking in the Atlantic,

and they were hunted down.

And thanks to Bletchley,

the allies knew their d-day deception had worked.

Hitler believed the real invasion was yet to come

and held back the panzers

that might have driven the allies into the sea.

For the very first time,

codebreaking had made a significant difference

to a war:

Bletchley is credited

with hastening the Nazi defeat by two years.

That's enough to have saved thousands

or hundreds of thousands of lives.

By the time the war ended in 1945,

Bletchley Park had transformed military intelligence.

The brains at Bletchley

had taken on the brawn of the teutonic army

and won.

And Welchman was at the heart of it.

To think of him

as the Henry Ford of cryptography

is not a bad metaphor.

The industrialization of cryptography.

That's an astonishing achievement.

His legacy is in what Bletchley Park achieved,

what Bletchley Park contributed

to the success and the allied victory

in, in 1945.

It's hard to have a bigger legacy than that.

One war was over, but another was about to start.

It would see a remarkable contribution

from Gordon Welchman,

but at a devastating personal cost.

After the end of the second world war,

the legacy of the work of Bletchley Park and Hut 6

would endure.

Gordon Welchman's creation would find itself the model

for the National Security Agency, the NSA,

and its British equivalent, GCHQ.

The future lay in computers,

and while Bletchley had once led the world,

Welchman now believed bankrupt Britain

was squandering its technological lead.

You also have a sense of a man who understands

very, very well about the computer revolution,

the computer age that was about to come into being,

because this is a computer age

this is brought into being at Bletchley Park.

Welchman was determined to stay

at the forefront of the computer revolution.

That meant America.

The Massachusetts institute of technology

was asked by the three military services

to establish a new research center.

This new center, called Mitre,

was created to develop top secret defense technologies.

And they were recruiting the finest brains.

I imagine that the powers that be in England

got in touch with the powers that be in the united states

and said they had this wonderful guy

and he would like a job.

Working here put Gordon Welchman

right back at the heart of another intelligence war--

the cold war.

Film One of the most dangerous threats

to our nation's security

is the possibility of attack

by high-speed enemy bombers armed with nuclear weapons.

This was secret conflict on a global scale.

Huge strides in technology were needed

to hold the so-called red menace at bay.

During that period

was the Cuban missile crisis.

Okay, I mean, that was, that was really a tough period, okay?

I built a bomb shelter in my basement

in Bedford, Massachusetts.

A large-scale nuclear attack on the united states

could produce a patchwork pattern of fallout

covering two thirds of the nation.

We cannot afford to take that chance.

Welchman was given

the highest civilian security clearance.

It meant becoming a U.S. Citizen.

The job did require

a very high security clearance.

In fact it was high enough so that it--

the fact that I had it was classified.

With the frightening prospect

of a nuclear confrontation,

Welchman was given the vital task

of ensuring U.S. Military communications

were capable of withstanding attack.

All he had learned at Bletchley Park

was now applied to help achieve American supremacy

on a scale that would dwarf Hut 6.

Traffic analysis in World War II

led Welchman to understand

the way information flowed in battle

and how many different ways it flowed.

Welchman realized military communications

hadn't really moved on since his days at Bletchley.

Headquarters issued an order, units made reports.

But in modern warfare

instant access to battlefield information was essential.

Repeat, this is a yellow alert.

And computer technology

was advancing fast enough to make this possible.

He said, hey, with this digital communications

we can do some things that we've never been able to do before.

Welchman used all his experience

to develop a completely new kind of network.

Information on the battlefield was constantly updated,

immediately shared and totally secure.

Everybody periodically broadcast bits of information

about where they were, what they were doing.

Welchman called his idea a horseshoe,

but we would all recognize it today as the cloud.

Welchman's system instantly connected planes, submarines,

ground forces, battleships--

all the elements of the command structure--

all at the same time.

And that went out into the sky,

and anybody who was interested in knowing

what friendly aircraft are in this area

could immediately get those reports--

sort of like an instant Goggle,

and this was three, four decades before Goggle.

Gordon came up with this radical idea,

and people looked at it and said hey, that's pretty good,

and, uh, so, you know, my boss called me in

and said okay, make it work.

His ideas were really a game changer.

They changed the way people thought

about command and control,

and they changed the way battles were managed

and warfare was fought.

It's still in use today, and it will be for a long time.

The legacy of the two giants of Bletchley Park

endures to the present day.

Alan Turing had made a decisive contribution

to the computer revolution.

Gordon Welchman's work

anticipated how the Internet and the cloud would later develop,

and how technology would enable a surveillance society.

in 1971 Welchman moved to the new England town of Newburyport

and married his third wife, teeny.

He was now 65 and still at the peak of his powers.

He had made a decisive impact on both the second world war

and now the cold war.

Yet everything he had achieved

was known only within his clandestine world.

Fighting an intelligence war against the Soviet Union,

the U.S. And British governments

had kept the success of Bletchley Park secret

for two decades.

Everyone who worked there had been sworn to silence.

But then, in 1974, came an event

that had unexpectedly far-reaching consequences.

"The ultra secret,"

a government-approved book by an ex-MI6 officer,

revealed for the first time the role of codebreaking

in winning the second world war.

Suddenly daylight was being let in

on a hitherto secret world.

It was a shocking moment for all those like Welchman,

who had taken their oath of secrecy so seriously.

For years and years

I didn't even read the histories of the war

because I was afraid that somehow or other

I might reveal something that I'd learned from ultra.

I think it was an enormous relief.

He could tell these stories, and could talk to us,

and could share memories that

he'd kept tamped down for so long.

An idea began to form in Welchman's mind--

that he should write his story.

I seemed to have

a very special responsibility

in that I was the only person alive

with inside knowledge

of a very telling episode in cryptologic history.

In 1977 he also took the deliberate decision

to appear on the BBC series "The Secret War,"

which dared to reveal the still-classified story

of ultra intelligence.

I don't know whether I should say this,

but it seems to me

that some of the things really

have been kept secret too long,

that there is a point

at which you do more damage by deceiving your own people

about the true history of World War II

than you could possibly do

by telling now the story as it actually happened.

Determined to set the record straight,

as well as to give public recognition

to those whose work had been war-winning,

Welchman had to write from his own prodigious memory

and discreet research from former colleagues.

He had no access to official papers,

which were still classified.

It was seven years' work.

I think my father felt

that he had a very important insight

on a particular piece of history which very few other people had,

and he just kept reading the obituaries

and realizing that there were fewer and fewer people left.

But Gordon Welchman,

after a life spent in the secret world,

didn't realize that world was about to turn on him.

Gordon Welchman's book, "The Hut Six Story,"

was published in the united states

in February 1982

and in the UK the following may.

For the first time in print,

an insider's account of the full secret history

of codebreaking's role in World War II

was laid bare.

Importantly, it incorporated Welchman's use

of traffic analysis.

The book also included a warning.

Welchman believed lessons from the war were being ignored.

The Americans were making the very same mistakes

with their security that the Germans had once made.

He thought he could talk about this

in a way that would reach the general public,

that would not disclose any secrets,

it would not tell tales you shouldn't.

He hoped it would make some money,

but he really hoped it would generate a conversation.

The secret world didn't wait long to hit back.

I was on my way to work,

and this car speeded up and stopped

right smack in the, almost in the middle of the road.

Nobody stops there, so I had to see what was going on.

Um...

There's Gordon's house, right there,

and the two men jumped out wearing black suit,

black tie and black sunglasses.

They looked like the men in black,

and they raced across the street.

Gordon answered the door, and you could see them, you know,

busily discussing something,

and all of a sudden Gordon took the door and he slammed it,

almost in their faces.

Later I found out that it was the national security agency.

There had been books about the ultra secret

prior to his publication.

There was no putting the toothpaste back in the tube--

the secret was out--

but Welchman's book was the first about cryptanalysis

by an actual insider who had done it.

It was still the height of the cold war.

If our continent were attacked,

this red telephone would be lifted from its cradle,

and instantly the united states would launch

the greatest counter-attack in history.

Signals intelligence remained, at that time,

at the very heart of the intelligence conflict

that was being conducted during the cold war.

So this was as important and as secret as it could get.

I think that people who saw what he wrote

felt he was imperiling current operations.

Welchman's World War II work

in traffic analysis

might have been 40 years earlier,

but what he had discovered

was still so vital to the secret world

that revealing it, even now, was considered dangerous.

On February 22, 1982, the men in dark glasses returned.

These two young gentlemen came in;

one from NSA and one from,

I believe it was air force intelligence.

And they said, well, this information

has never been declassified,

and therefore is still in violation

of the wartime secrets laws.

Gordon was taken aback.

He said, "This is, this is absurd."

They were delivering a message to him,

and it was an ominous message.

I believe they had conversations with Mr. Welchman.

Beyond that, I'm not sure that I can talk

about anything meaningful.

And it became clear

the American authorities were not going to back off.

It was really quite devastating;

he was quite unprepared for that.

Welchman enlisted the help of another writer

who had fallen afoul of the NSA.

We lived in the same area,

so we could actually get together physically

and as far--the kind of things

that you don't want to talk over the telephone--

especially when you're dealing with NSA.

He couldn't do any publicity,

he couldn't answer questions from reporters,

he couldn't appear on television shows and so forth,

and that was a really big problem.

The NSA threatened Welchman

with an obscure legal clause

dealing with the sharing of cryptology.

This same law is now being used

on NSA whistleblower Edward Snowden's.

The part of the espionage act.

I think it's ten years in prison and a heavy fine.

So these were very, very serious charges.

I could see he was nervous,

I could see the physical effects

that the NSA was having on him.

That devastates somebody that's spent their entire life

trying to protect U.S. And British governments,

and now they're told that they're going to be charged

with a crime possibly of giving secrets to the enemy.

He'll be prosecuted as maybe being a spy or a--

not a spy, but a leaker.

There was one final act

with devastating consequences.

On the April 29, 1982,

Welchman's security clearance was withdrawn.

All of a sudden he disappeared.

"Dear Mr. Welchman,

the Mitre corporation believes it would be mutually beneficial

to temporarily suspend your access to classified materials.

This suspension is effective this date.

Please acknowledge receipt of this letter

by signing in the space provided below."

And he signed below.

Rather than stay silent,

Welchman went on the offensive, writing letters and articles,

which he hoped would exonerate him,

including a recently discovered unpublished paper:

"Ultra revisited-- a tale of two contributors."

The stories of Alan Turing's life and mine

have two things in common.

First, we were regarded by our boss

as the two greatest contributors

to the wartime success of Bletchley Park.

Second, we have been branded as security risks.

What has happened to me

can be compared with what happened to Turing.

For many in the intelligence community,

Welchman was being naive

to imagine he could reveal the secrets of Hut 6

with impunity.

But he never lost his belief

that this was information the public needed to know.

With Welchman gagged by the security services,

his book flopped.

He sold only 900 copies.

The rest were pulped.

He suffered a lot,

he went through a great deal to put "Hut Six Story" out.

The strain was, was also coming

at a very difficult time.

He'd had some more medical problems.

It was a cruel irony that Gordon Welchman,

a master of the clandestine world,

who helped win World War II by breaking enemy codes

and also helped the west win the cold war

by keeping their communications secret,

would himself fall afoul of the secret state.

I believe that the rules at the time

about secrecy were really inflexible.

The people who administered inflexible rules

themselves had spent a full career

being indoctrinated with the idea that secrecy was the base.

I am today glad that the book is out.

By now Welchman was seriously ill with cancer.

I'm not saying that he was blameless,

but he had broken the procedures,

and the law was never invoked,

but he lost his job and his livelihood

without ever appearing in court

or ever facing any criminal charge.

And finally, you know, I think he realized

that it, it wasn't going to go away.

They probably couldn't successfully prosecute him,

but they would break him financially.

Gordon Welchman never redeemed himself.

On October 8, 1985, he died.

It made two of the last three years of his life

really quite hellish.

But his legacy would continue.

After his death his methods and insights

not only became part of the west's military thinking,

they also became the very heart

of the new intelligence networks,

as the world became more and more connected, via computer.

Only in 2013

would the significance of that legacy become clear.

It's been 30 years since Gordon Welchman died,

and yet the true legacy of his work is only now emerging.

In June 2013, Edward Snowden's

leaked tens of thousands of highly classified files.

Our intelligence agencies were harvesting metadata--

our phone numbers, our computers' IP addresses,

the websites we visit, those we message or call

and where we are at any given moment.

It suddenly occurred to me

that actually what we do, now do with metadata,

is in a sense a highly developed version

of what Welchman started with traffic analysis.

That's what it is, metadata and analytics now in a digital world

are essentially our way of doing traffic analysis,

and it can be very, very revealing.

Metadata analysis is today's version

of Welchman's own traffic analysis

during World War II.

One of the things that Gordon Welchman discovered

was how important it is

to not just to read what's in a message

but to derive intelligence by the activities of messages,

how many are being sent, where, message--

where they're being sent,

how many are being sent from one place to another.

These are what's called the externals--

not the content, but the externals--

and today that's extremely important.

Today we call it metadata, basically,

and the NSA uses this enormously.

For many, what Snowden's was revealing

was that we live in a surveillance state,

that the NSA have turned Welchman's legacy

against their own citizens, destroying our privacy.

But for others, traffic analysis is keeping us safe.

After 9/11, CIA analysts were on the hunt

for Osama Bin Laden,

the most wanted man on the planet.

They turned to a technique

Gordon Welchman had developed so powerfully in World War II.

Traffic analysis, now known as metadata analysis.

If I want to understand

how to destroy this terrorist organization,

if I want to take them down as an organization,

then I have to look for their vulnerabilities,

and to look for their vulnerabilities,

I have to understand their network.

I found a lot of similarities in Welchman's work.

I have this mass of information,

and it doesn't necessarily make a lot of sense,

and what I have to do is I have to look for patterns in that.

In an ever more connected world,

with more data, more patterns,

traffic analysis is only becoming more powerful

as an intelligence tool.

What we call link analysis or network analysis--

the more sophisticated version of that--

is the absolutely critical tool in finding covert networks,

whether it's terrorists or crime networks,

because they're trying to hide

their entire organizational structure.

With modern encryption,

today's codes seem genuinely unbreakable,

and so traffic analysis

is all security agencies have to work with.

We were able to find out a great deal

about what Al-Qaeda was doing and Bin Laden

by a looking at the metadata,

what the externals of the messages were--

where are they going?

How frequently are they being sent?

It was bin laden's courier

who unwittingly led navy seals to his compound--

and traffic analysis that found the courier.

Welchman's legacy in action.

Today, Edward Snowden's is branded by many a traitor

for revealing the secrets of modern traffic analysis.

Gordon Welchman also went public

for something he truly believed in.

But after a glittering career,

he spent the last three years of his life fighting illness,

fighting for his reputation,

and feeling outcast

from the very world he had helped to build.

Alan Turing's brilliant work at Bletchley Park

has made him an iconic figure in our history.

His pioneering spirit sparked the computer revolution

and is now part of all our lives.

It was Gordon Welchman's misfortune

that his equally brilliantly work

has not earned him the public accolades it deserves.

His top secret work impacts on every one of us

as much as Turing's.

But this very secrecy

denies him his rightful place in our history.

99.9% of the people in the world

have never heard of Gordon Welchman,

and you say the name "Gordon Welchman"

and they just kind of stare back at you--

and yet he contributed so much.

Shortening the war by two years? Good heavens.

Saving thousands of lives?

And yet nobody knows who he is.

I have no qualms about saying he was a genius.

I'm enormously proud of my grandfather.

Still sometimes distressed about...

What happened after he published his book

and how much that meant to him.

He was certainly proud of what he'd done.

There's always an element

that it was a pity he didn't get recognized, but...

It's too bad he couldn't be here today.