Enigma (22 page)

Someone asked what would happen next.

“If one of the U-boats finds the convoy? It’ll shadow it. Send a
contact signal every two hours—position, speed, direction. That’ll
be picked up by the other hearses and they’ll start to converge on
the same location. Same procedure, to try to draw in as many
hunters as possible. Usually, they try to get right inside the
convoy, in among our ships. They’ll wait until nightfall. They
prefer to attack in the dark. Fires from the ships that have been
hit illuminate other targets. There’s more panic. Also, night-time
makes it harder for our destroyers to catch them.”

“Of course, the weather’s appalling,” added Cave, his sharp
voice cutting in to the silence, “even for the time of year. Snow.
Freezing fog. Green water breaking over the bows. That’s actually
in our favour.”

Kramer said: “How long do we have?”

“Less time than we originally thought, that’s for certain. The
U-boat is faster than any convoy, but it’s still a slow beast. On
the surface it moves at the speed of a man on a bicycle, underwater
it’s only as fast as a man on foot. But if Donitz knows about the
convoys? Perhaps a day and a half. The bad weather will give them
visibility problems. Even so—yes—I’d guess a day and a half at the
outside.”

Cave excused himself to go and telephone the bad news to the
Admiralty. The cryptanalysts were left alone. At the far end of the
hut a faint clacking noise began as the Type-X machines started
their day’s work.

“That’ll be D-D-Dolphin,” said Pinker. “Will you excuse me,
G-G-Guy?”

Logie raised a hand in benediction and Pinker hurried out of the
room.

“If only we had a four-wheel bombe,” moaned Proudfoot.

“Well, we ain’t got one, old love, so don’t let’s waste time on
that.”

Kramer had been leaning against one of the trestle tables. Now
he pushed himself on to his feet. There wasn’t room for him to
pace, so he performed a kind of restless shuffle, smacking his fist
into the palm of his left hand.

“Goddamn it, I feel so helpless. A day and a half. A measly,
goddamn day and a half jesus! There must be something. I mean, you
guys did break this thing once, didn’t you, during the last
blackout?”

Several people spoke at once.

“Oh, yes.”

“D’you remember that?”

“That was Tom.”

Jericho wasn’t listening. Something was stirring in his mind,
some tiny shift in the depths of his subconscious, beyond the reach
of any power analysis. What was it? A memory? A connection? The
more he tried to concentrate on it, the more elusive it became.

“Tom?”

He jerked his head up in surprise.

“Lieutenant Kramer was asking you, Tom” said Logie, with weary
patience, “about how we broke Shark during the blackout.”

“What?” He was irritated at having his thoughts interrupted. His
hands fluttered. “Oh, Donitz was promoted to admiral. We took a
guess that U-boat headquarters would be pleased as Punch. So
pleased, they’d transmit Hitler’s proclamation verbatim to all
boats.”

“And did they?”

“Yes. It was a good crib. We put six bombes onto it. Even then
it still took us nearly three weeks to read one day’s traffic.”

“With a good crib?” said Kramer. “Six bombes. Three weeks?”

“That’s the effect of a four-wheel Enigma.”

Kingcome said: “It’s a pity Donitz doesn’t get a promotion every
day.”

This immediately brought Atwood to life. “The way things are
going, he probably will.”

Laughter momentarily lightened the gloom. Atwood looked pleased
with himself.

“Very good, Frank,” said Kingcome. “A daily promotion. Very
good.”

Only Kramer refused to laugh. He folded his arms and stared down
at his gleaming shoes.

They began to talk about some theory of de Brooke’s which had
been running on a pair of bombes for the past nine hours, but the
methodology was hopelessly skewed, as Puck pointed out.

“Well, at least I’ve had an idea,” said de Brooke, “which is
more than you have.”

“That is because, my dear Arthur, if I have a terrible idea, I
keep it to myself.”

Logie clapped his hands. “Boys, boys. Let’s keep the criticism
constructive, shall we?”

The conversation dragged on but Jericho had stopped listening a
long time ago. He was chasing the phantom in his mind again,
searching back through his mental record of the past ten minutes to
find the word, the phrase, that could have stirred it into life.
Diana, Hubertus, Magdeburg, picket line, radio silence, contact
signal…

Contact signal.

“Guy, where d’you keep the keys to the Black Museum?”

“What, old thing? Oh, in my desk. Top right-hand drawer. Hey,
where’re you going? Just a minute, I haven’t finished talking to
you yet…”

♦

It was a relief to get out of the claustrophobic atmosphere of
the hut and into the cold, fresh air. He trotted up the slope
towards the mansion.

He seldom went into the big house these days but whenever he did
it reminded him of a stately home in a twenties murder mystery. (“
You will recall, inspector, that the colonel was in the library
when the fatal shots were fired…”) The exterior was a nightmare, as
if a giant handcart full of the discarded bits of other buildings
had been tipped out in a heap. Swiss gables, Gothic battlements,
Greek pillars, suburban bay windows, municipal red brick, stone
lions, the entrance porch of a cathedral—the styles sulked and
raged against one another, capped by a bell-shaped roof of beaten
green copper. The interior was pure Gothic horror, all stone arches
and stained glass windows. The polished floors rang hollow beneath
Jericho’s feet and the walls were decorated with dark wooden
panelling of the sort that springs open in the final chapter to
reveal a secret labyrinth. He was hazy about what went on here now.
Commander Travis had the big office at the front looking out over
the lake while upstairs in the bedrooms all sorts of mysterious
things were done: he’d heard rumours they were breaking the ciphers
of the German Secret Service.

He walked quickly across the hall. An Army captain loitering
outside Travis’s office was pretending to read that morning’s
Observer, listening to a middle-aged man in tweeds trying to chat
up a young RAF woman. Nobody paid any attention to Jericho. At the
foot of the elaborately carved oak staircase, a corridor led off to
the right and wound around the back of the house. Midway along it
was a door which opened to reveal steps down to a secondary
passage. It was here, in a locked room in the cellar, that the
cryptanalysts from huts 6 and 8 stored their stolen treasures.

Jericho felt along the wall for the light switch.

The larger of the two keys unlocked the door to the museum.
Stacked on metal shelves along one wall were a dozen or more
captured Enigma machines. The smaller key fitted one of a pair of
big iron safes. Jericho knelt and opened it and began to rummage
through the contents. Here they all were, their precious pinches:
each one a victory in the long war against the Enigma. There was a
cigar box with a label dated February 1941, containing the haul
from the armed German trawler Krebs: two spare rotors, the
Kriegsmarine grid map of the North Atlantic and the naval Enigma
settings for February 1941. Behind these was a bulging envelope
marked Munchen—a weather ship whose capture three months after the
Krebs had enabled them to break the meterological code—and another
labelled “U-110”. He pulled out armfuls of papers and charts.

Finally, from the bottom shelf at the back, he withdrew a small
package wrapped in brown oilcloth. This was the haul for which
Fasson and Grazier had died, still in its original covering, as it
had been passed out of the sinking U-boat. He never saw it without
thanking God that they’d found something waterproof to wrap it in.
The smallest exposure to water would have dissolved the ink. To
have plucked it from a drowning submarine, at night, in a high
sea…It was enough to make even a mathematician believe in miracles.
Jericho removed the oilcloth tenderly, as a scholar might unwrap
the papyri of an ancient civilisation, or a priest uncover holy
relics. Two little pamphlets, printed in Gothic lettering on pink
blotting paper. The second edition of the U-boats’ Short Weather
Cipher, now useless, thanks to the code book change. And—exactly as
he had remembered—the Short Signal Book. He flicked through it.
Columns of letters and numbers.

A typed notice was stuck on the back of the safe door: “It is
strictly forbidden to remove any item without my express
permission. (Signed) L.F.N. Skynner, Head of Naval Section.”

Jericho took particular pleasure in slipping the Short Signal
Book into his inside pocket and running with it back to the
hut.

♦

Jericho tossed the keys to Logie who fumbled and then just
caught them.

“Contact signal.”

“What?”

“Contact signal,” repeated Jericho.

“Praise the Lord!” said Atwood, throwing up his hands like a
revivalist preacher. “The Oracle has spoken.”

“All right, Frank. Just a minute. What about it, old love?”

Jericho could see it all much faster than he could convey it.
Indeed, it was quite hard to formulate it in words at all. He spoke
slowly, as if translating from a foreign language, reordering it in
his mind, turning it into a narrative.

“Do you remember, in November, when we got the Short Weather
Cipher Book off the U-459? When we also got the Short Signal Book?
Only we decided not to concentrate on the Short Signal Book at the
time, because it never yielded anything long enough to make a
worthwhile crib? I mean, a convoy contact signal on its own, it
isn’t worth a damn, is it? It’s just five letters once in a blue
moon.” Jericho withdrew the little pink pamphlet carefully from his
pocket. “One letter for the speed of the convoy, a couple for its
course, a couple more for the grid reference.”

Baxter stared at the code book as if hypnotised. “You’ve removed
that from the safe without permission? But if Lieutenant Cave is
correct, and whichever U-boat finds the convoy is going to send a
contact signal every two hours, and if it’s going to shadow it till
nightfall, then it’s possible—theoretically possible—it might send
as many as four, or even five signals, depending on what time of
day it makes its first sighting.” Jericho sought out the only
uniform in the room. “How long does daylight last in the North
Atlantic in March?”

“About twelve hours,” said Kramer.

“Twelve hours, you see? And if a number of other U-boats attach
themselves to the same convoy, on the same day, in response to the
original signal, and they all start sending contact signals every
two hours.”

Logie, at least, could see what he was driving at. He withdrew
his pipe slowly from his mouth. “Bloody hell!”

“Then again, theoretically, we could have, say, twenty letters
of crib off the first boat, fifteen off the second—I don’t know, if
it’s an attack by eight boats, let’s say, we could easily get to a
hundred letters. It’s just as good as the weather crib.” Jericho
felt as a proud as a father, offering the world a glimpse of his
newborn child. “It’s beautiful, don’t you see?” He gazed at each of
the crytanalysts in turn: Kingcome and Logie were begin-to look
excited, de Brooke and Proudfoot seemed thoughtful, Baxter, Atwood
and Puck appeared down-right hostile. “It was never possible till
this moment, because until now the Germans have never been able to
throw so many U-boats against such a mass of shipping. It’s the
whole story of Enigma in a nutshell. The very scale of the Germans’
achievement breeds such a mass of malrial for us, it’ll sow the
seeds of their eventual defeat.”

He paused.

“Aren’t there rather a lot of ifs there?” said Baxter drily. “If
the U-boat finds the convoy early enough in the day, if it reports
every two hours, if the others all do the same, manage to intercept
every transmission…”

“And if” said Atwood, “the Short Signal Book we pinched in
November wasn’t changed last week at the same time as the Weather
Cipher Book.”

That was a possibility Jericho hadn’t considered. He felt his
enthusiasm crumble slightly.

Now Puck joined in the attack. “I agree. The concept is quite
brilliant, Thomas. I applaud your—inspiration, I suppose. But your
strategy depends on failure, does it not We will only break Shark,
on your admission, if the U-Boats find the convoy, which is exactly
what we want to avoid. And suppose we do come up with that day’s
Shark settings—so what? Marvellous. We can read all the U-boats’
signals to Berlin, boasting to Donitz about how many Allied ships
they’ve sunk. And twenty-four hours later, we’re blacked out
again.”

Several of the cryptanalysts groaned in agreement.

“No, no,” Jericho shook his head emphatically. “Your logic is
flawed, Puck. What we hope, obviously, is that the U-boats don’t
find the convoys. Yes—that’s the whole point of the exercise. But
if they do, we can at least turn it to our advantage. And it won’t
just be one day, not if we’re lucky. If we break the Shark settings
for twenty-four hours, then we’ll pick up the encoded weather
messages for that entire period. And, remember, we’ll have our own
ships in the area, able to give us the precise weather data the
U-boats are encoding. We’ll have the plaintext, we’ll have the
Shark cipher settings, so we’ll be able to make a start on
reconstructing the new Weather Code Book. We could get our foot
back in the door again. Don’t you see?”

He ran his hands through his hair and tugged at it in
exasperation. Why were they all being so dim?

Kramer had been scribbling furiously in a notebook. “He’s on to
something, you know.” He tossed his pencil into the air and caught
it. “Come on. It’s worth a try. At least it puts us back in the
fight.”