Cryptonomicon

Chapter 19 ULTRA

Lawrence Pritchard Waterhouse goes into battle armed with one-third of a sheet of British typing paper on which has been typed some words that identify it as a pass to Bletchley Park. His name and some other things have been scribbled on it in some upper-class officer's Mont Blanc blue-black, the words ALL SECTIONS circled, and a stamp smashed across it, blurred into a red whore's kiss, with sheer carelessness conveying greater Authority and Power than the specious clarity of a forger.

He finds his way round the mansion to the narrow lane that runs between it and its row of red-brick garages (or stables, as his grandparents would be likely to peg them). He finds it a very pleasant place for a cigarette. The lane is lined with trees, a densely planted hedge of them. The sun is just setting now. It is still high enough to snipe through any small defects that it finds in the defensive perimeter of the horizon, so narrow red beams strike him surprisingly in the eye as he ambles back and forth. He knows one is shining invisibly through the clear air several feet above him, because it is betraying an aerial: a strand of copper wire stretched from the wall of the mansion to a nearby cypress. It catches the light in precisely the same way as the strand of the spiderweb that Waterhouse was playing with earlier.

The sun will be down soon; it is already down in Berlin, as in most of the hellish empire that Hitler has built from Calais to the Volga. Time for the radio operators to begin their work. Radio does not, in general, go around corners. This can be a real pain when you are conquering the world, which is inconveniently round, placing all of your most active military units over the horizon. But if you use shortwave, then you can bounce the information off the ionosphere. This works a good deal better when the sun is not in the sky, sluicing the atmosphere with wideband noise. So radio telegraphers, and the people who eavesdrop on them (what the Brits call the Y Service) are, alike, nocturnal beings.

As Waterhouse has just observed, the mansion has an aerial or two. But Bletchley Park is a huge and ravenous spider that requires a web the size of a nation to feed it. He has seen enough evidence, from the black cables climbing the mansion's walls and the smell and hiss of the massed teletypes, to know that the web is at least partly made of copper wires. Another piece of the web is made of rude stuff like concrete and asphalt.

The gate swings open and a man on a green motorcycle banks steeply into the lane, the two cylinders of his machine blatting away, the noise stinging Waterhouse's nose as he rides by. Waterhouse strides after him for some distance, but loses his trail after a hundred yards or so. That is acceptable; more of them will be along soon, as the Wehrmacht's nervous system awakens and its signals are picked up by the Y Service.

The motorcyclist went through a quaint little gate that joins two old buildings. The gate is topped by a tiny cupola with a weathervane and a clock. Waterhouse goes through it and finds himself in a little square that evidently dates back to when Bletchley Park was a precious Buckinghamshire farmstead. To the left, the line of stables continues. Small gables have been set into the roof, which is stained with bird shit. The building is quivering with pigeons. Directly in front of him is a nice little red brick Tudor farmhouse, the only thing he has seen so far that is not architecturally offensive. Off to his right is a one-story building. Strange information is coming out of this building: the hot-oil smell of teletypes, but no typing noises, just a high mechanical whine.

A door opens on the stable building and a man emerges carrying a large but evidently lightweight box with a handle on the top. Cooing noises come from the box and Waterhouse realizes that it contains pigeons. Those birds living up in the gables are not feral; they are homing pigeons. Carriers of information, strands of Bletchley Park's web.

He homes in on the building that smells of hot oil and gazes into a window. As evening falls, light has begun to leak out of it, betraying information to black German reconnaissance planes, so a porter is strutting about the courtyard slamming the black shutters closed.

Some information comes into Waterhouse's eyes at least: on the other side of that window, men are gathered around a machine. Most of them are wearing civilian clothes, and they have been too busy, for too long, to trifle much with combs and razors and shoe polish. The men are intensely focused upon their work, which all has to do with this large machine. The machine consists of a large framework of square steel tubing, like a bedstead set up on one end. Metal drums with the diameter of dinner plates, an inch or so thick, are mounted at several locations on this framework. Paper tape has been threaded in a bewilderingly loopy trajectory from drum to drum. It looks as if a dozen yards of tape are required to thread the machine.

One of the men has been working on a rubber drive belt that goes around one of the drums. He steps back from it and makes a gesture with his hand. Another man flips a switch and the drums all begin to spin at once. The tape begins to fly through the system. Holes punched in the tape carry data; it all blurs into a grey streak now, the speed creating an illusion in which the tape appears to dissolve into a ribbon of smoke.

No, it is not an illusion. Real smoke is curling up from the spinning drums. The tape is running through the machine so fast that it is catching fire before the eyes of Waterhouse and the men inside, who watch it calmly, as if it were smoking in an entirely new and interesting way.

If there is a machine in the world capable of reading data from a tape that fast, Waterhouse has never heard of it.

The black shutter slams home. Just as it does, Waterhouse gets one fragmentary glimpse of another object standing in the corner of the room: a steel rack in which a large number of grey cylindrical objects are stored in neat rows.

Two motorcyclists come through the courtyard at once, running in the darkness with their headlights off. Waterhouse jogs after them for a bit, leaving the picturesque old courtyard behind and entering into the world of the huts, the new structures thrown up in the last year or two. “Hut” makes him think of a tiny thing, but these huts, taken together, are more like that new Pentagon thing that the War Department has been putting up across the river from D.C. They embody a blunt need for space unfiltered through any aesthetic or even human considerations.

Waterhouse walks to an intersection of roads where he thought he heard the motorcycles making a turn, and stops, hemmed in by blast walls. On an impulse, he clambers to the top of a wall and takes a seat. The view from here is no better. He knows that thousands of people are at work all around him in these huts, but he sees none of them, there are no signposts.

He is still trying to work out that business that he saw through the window.

The tape was running so fast that it smoked. There is no point of driving it that fast unless the machine can read the information that fast—transforming the pattern of holes in the tape into electrical impulses.

But why bother, if those impulses had nowhere to go? No human mind could deal with a stream of characters coming in at that speed. No teletype that Waterhouse knew of could even print them out.

It only makes sense if they are constructing a machine. A mechanical calculator of some sort that can absorb the data and then do something with it—perform some calculation—presumably a cipher-breaking type of calculation.

Then he remembers the rack he glimpsed in the corner, its many rows of identical grey cylinders. Viewed end-on, they looked like some kind of ammunition. But they are too smooth and glossy for that. Those cylinders, Waterhouse realizes, are made of blown glass.

They are vacuum tubes. Hundreds of them. More tubes in one place than Waterhouse has ever seen.

Those men in that room are building a Turing machine!

It is no wonder, then, that the men in the room accept the burning of the tape so calmly. That strip of paper, a technology as old as the pyramids, is merely a vessel for a stream of information. When it passes through the machine, the information is abstracted from it, transfigured into a pattern of pure binary data. That the mere vessel burns is of no consequence. Ashes to ashes, dust to dust—the data has passed out of the physical plane and into the mathematical, a higher and purer universe where different laws apply. Laws, a few of which are dimly and imperfectly known to Dr. Alan Mathison Turing and Dr. John von Neumann and Dr. Rudolf von Hacklheber and a few other people Waterhouse used to hang around with in Princeton. Laws about which Waterhouse himself knows a thing or two.

Once you have transfigured the data into the realm of pure information, all that is required is a tool. Carpenters work with wood and carry a box of technology for measuring it, cutting it, smoothing it, joining it. Mathematicians work with information and need a tool of their own.

They have been building these tools, one at a time, for years. There is, just to name one example, a cash register and typewriter company called the Electrical Till Corporation that makes a dandy punched-card machine for tabulating large quantities of data. Waterhouse's professor in Iowa was tired of solving differential equations one at a time and invented a machine to solve them automatically by storing the information on a capacitor-covered drum and cranking through a certain algorithm. Given enough time and enough vacuum tubes, a tool might be invented to sum a column of numbers, and another one to keep track of inventories, and another one to alphabetize lists of words. A well-equipped business would have one of each: gleaming cast-iron monsters with heat waves rising out of their grilles, emblazoned with logos like ETC and Siemens and Hollerith, each carrying out its own specialized task. Just as a carpenter had a miter box and a dovetail jig and a clawhammer in his box.

Turing figured out something entirely different, something unspeakably strange and radical.

He figured out that mathematicians, unlike carpenters, only needed to have one tool in their toolbox, if it were the right sort of tool. Turing realized that it should be possible to build a meta-machine that could be reconfigured in such a way that it would do any task you could conceivably do with information. It would be a protean device that could turn into any tool you could ever need. Like a pipe organ changing into a different instrument every time you hit a preset button.

The details were a bit hazy. This was not a blueprint for an actual machine, rather a thought experiment that Turing had dreamed up in order to resolve an abstract riddle from the completely impractical world of pure logic. Waterhouse knows this perfectly well. But he cannot get one thing out of his mind as he sits there atop the blast walls at the dark intersection in Bletchley Park: the Turing machine, if one really existed, would rely upon having a tape. The tape would pass through the machine. It would carry the information that the machine needed to do its work.

Waterhouse sits there staring off into the darkness and reconstructs Turing's machine in his mind. More of the details are coming back to him. The tape, he now recollects, would not move through the Turing machine in one direction; it would change direction frequently. And the Turing machine would not just read the tape; it would be able to erase marks or make new ones.

Clearly you cannot erase holes in a paper tape. And just as clearly the tape only moves through this Bletchley Park machine in one direction. So, much as Waterhouse hates to admit this fact to himself, the rack of tubes he just spied is not a Turing machine. It is some lesser device—a special-purpose tool like a punched-card reader or Atanasoffs differential equation solver.

It is still bigger and more fiendishly terrific than anything Waterhouse has ever seen.

A night train from Birmingham blows through, carrying bullets to the sea. As its sound dies away to the south, a motorcycle approaches the park's main gate. Its engine idles as the rider's papers are checked, then Waterhouse hears a Bronx cheer as it surges forward and cuts the sharp turn into the lane. Waterhouse climbs to his feet at the intersection of the walls, and watches carefully as the bike sputters past him and homes in on a “hut” a couple of blocks away. Light suddenly leaks from an open door as the cargo changes hands. Then the light is snuffed and the bike stretches a long loud raspberry down the road to the park's exit.

Waterhouse lets himself down to earth and gropes his way down the road through the moonless night. He stops before the entrance to the hut and listens to it teem for a minute. Then, working up his courage, he steps forward and pushes the wooden door open.

It is unpleasantly hot in here, and the atmosphere is a nauseating distillation of human and machine odors, held in and concentrated by the coffin doors slabbed down over all the windows. Many people are in here, mostly women working at gargantuan electrically powered typewriters. He can see even through his squint that the place is a running sluice for scraps of paper, maybe four by six inches each, evidently brought in by the motorcyclists. Near the door, they have been sorted and stacked up in wire baskets. Thence they go to the women at their giant typewriters.

One of the few men in the place has risen to his feet and is homing in on Waterhouse. He is about Waterhouse's age, that is, in his early twenties. He is wearing a British Army uniform. He has the air of a host at a wedding reception who wants to make sure that even the most long lost, far-flung members of the family are properly greeted. Obviously he is no more a real military man than is Waterhouse himself. No wonder this place is surrounded by so much barbed wire and RAF men with machine guns.

“Good evening, sir. Can I help you?”

“Evening. Lawrence Waterhouse.”

“Harry Packard. Pleased to meet you.” But he has no idea who Waterhouse is; he is privy to Ultra, but not to Ultra Mega.

“Pleasure's mine. I imagine you'll want to have a look at this.” Waterhouse hands him the magic pass. Packard's pale eyes travel over it carefully, then jump around to focus on a few sites of particular interest: the signature at the bottom, the smeared stamp. The war has turned Harry Packard into a machine for scanning and processing slips of paper and he goes about his work calmly and without fuss in this case. He excuses himself, works the crank on a telephone, and speaks to someone; his posture and facial expression suggest it is someone important. Waterhouse cannot hear the words above the clicking and thrumming of the massed typewriters, but he sees interest and bemusement on Packard's young, open, pink face. Packard gives Waterhouse a sidelong glance or two while he is listening to the person at the other end of the line. Then he says something respectful and reassuring into the phone and rings off.

“Right. Well, what would you like to see?”

“I'm trying to get an overall sense of how the information flows.”

“Well, we are close to the beginning of it here—these are the headwaters. Our wellsprings are the Y Service—military and amateur radio operators who listen in on Jerry's radio transmissions, and provide us with these.” Packard takes a slip from a motorcyclist's pannier and hands it to Waterhouse.

It is a form with various boxes at the top in which someone has written in a date (today's) and time (a couple of hours ago) and a few other data such as a radio frequency. The body of the form is mostly occupied by a large open space in which the following has been printed in hasty block letters:

the whole thing preceded by two groups of three letters each:

“This one came in from one of our stations in Kent,” Packard says. “It is a Chaffinch message.”

“So—one of Rommel's?”

“Yes. This intercept came in from Cairo. Chaffinch gets top priority, which is why this message is on the top of the pile.”

Packard leads Waterhouse down the central aisle of the hut, between the rows of typists. He picks out one girl who is just finishing up with a message, and hands her the slip. She sets it up next to her machine and commences typing it in.

At first glance, Waterhouse had thought that the machines represented some British concept of how to build an electric typewriter—as big as a dinner table, wrapped up in two hundred pounds of cast-iron, a ten-horse motor turning over under the hood, surrounded by tall fences and armed guards. But now that he is closer he sees that it is something much more complicated. Instead of a platen, it has a large flat reel on it carrying a roll of narrow paper tape. This is not the same kind of tape he saw earlier, smoking through the big machine. This is narrower, and when it emerges from the machine, it does not have holes punched through it for a machine to read. Instead, every time the girl slams down one of the keys on the keyboard—copying the text printed on the slip—a new letter is printed on the tape. But not the same letter that she typed.

It does not take her long to type in all of the letters. Then she tears the tape from her machine. It has a sticky backing which she uses to paste it directly onto the original intercept slip. She hands it to Packard, giving him a demure smile. He responds with something between a nod and a smart little bow, the kind of thing no American male could ever get away with. He glances at it and hands it to Waterhouse.

The letters on the tape say

“In order to obtain those settings, you have to break the code—which changes every day?”

Packard smiles in agreement. “At midnight. If you stay here—” he checks his watch “—for another four hours, you will see fresh intercepts coming in from the Y Service that will produce utter gibberish when we run them through the Typex, because the Jerries will have changed all their codes on the stroke of midnight. Rather like Cinderella's magic carriage turning back into a pumpkin. We must then analyze the new intercepts using the bombes, and figure out the day's new codes.”

“How long does that take?”

“Sometimes we are lucky and have broken the day's codes by two or three o'clock in the morning. Typically it does not happen until after noon or evening. Sometimes we do not succeed at all.”

“Okay, this is a stupid question, but I want to be clear. These Typex machines—which merely do a mechanical deciphering operation—are a completely different thing from the bombes, which actually break the codes.”

“The bombes, compared to these, are of a completely different, enormously higher order of sophistication,” Packard agrees. “They are almost like mechanical thinking machines.”

“Where are they located?”

“Hut 11. But they won't be running just now.”

“Right,” Waterhouse says, “not until after midnight when the carriage turns back into a pumpkin, and you need to break tomorrow's Enigma settings.”

“Precisely.”

Packard steps over to a small wooden hatch set low into one of the hut's exterior walls. Next to it sits an office tray with a cup hook screwed into each end, and a string tied to each cup hook. One of the strings is piled up loose on the floor. The wall hatch has been slid shut on the other string. Packard puts the message slip on top of a pile of similar ones that has accumulated in the tray, then slides the hatch open, revealing a narrow tunnel leading away from the hut.

“Okay, your pull!” he shouts.

“Okay, my pull!” comes an answering voice a moment later. The string goes taught and the tray slides into the tunnel and disappears.

“On its way to Hut 3,” Packard explains.

“Then so am I,” Waterhouse says.

Hut 3 is only a few yards away, on the other side of the inevitable blast wall. GERMAN MILITARY SECTION has been scrawled on the door in cursive; Waterhouse presumes that this is as opposed to “NAVAL” which is in Hut 4. The ratio of men to women seems higher here. During wartime it is startling to see so many hale young men in one room together. Some are in Army or RAF uniforms, some in civvies, and there is even one Naval officer.

A large horseshoe-shaped table dominates the center of the building, with a rectangular table off to the side. Each chair at each table is occupied by intent workers. The intercept slips are pulled into the hut on the wooden tray and then move from chair to chair according to some highly organized scheme that Waterhouse can only vaguely grasp at this point. Someone explains to him that the bombes just broke the day's codes around sundown, and so the entire day's load of intercepts has just come down the tunnel from Hut 6 during the last couple of hours.

He decides to think of the hut as a mathematical black box for the time being—that is, he'll concentrate only on its inputs and outputs of information and ignore the internal details. Bletchley Park, taken in its entirety, is a black box of sorts: random letters stream into it, strategic intelligence streams out, and the internal particulars are of no interest to most of the people on the Ultra distribution list. The question that Waterhouse is here to figure out is: is there another vector of information coming out of this place, hidden subliminally in the teletype signals and the behaviors of the Allied commanders? And does it point to Rudolf von Hacklheber, Ph.D.?