Cryptonomicon

October 14th and I index them in various ways: what destinations they were transmitted to, how long they were, and, if we were able to decrypt them, what their subject matter was. Were they orders for troop movements? Supply shipments? Changes in tactics or procedures? Then, I take all of the messages that were sent out from Rabaul on October 16th-the day after the Azure message came in from Tokyo-and I run exactly the same statistical analysis on them.'

Waterhouse steps back from the chalkboard and turns into a blinding fusillade of strobe lights. 'You see, it is all about information flow. Information flows from Tokyo to Rabaul. We don't know what the information was. But it will, in some way, influence what Rabaul does afterwards. Rabaul is changed, irrevocably, by the arrival of that information, and by comparing Rabaul's observed behavior before and after that change, we can make inferences.'

'Such as?' Comstock says warily.

Waterhouse shrugs. 'The differences are very slight. They hardly stand out from the noise. Over the course of the war, thirty-one Azure messages have gone out from Tokyo, so I have that many data sets to work with. Any one data set by itself might not tell me anything. But when I combine all of the data sets together-giving me greater depth-then I can see some patterns. And one of the patterns that I most definitely see is that, on the day after an Azure message went out to, say, Rabaul, Rabaul was much more likely to transmit messages having to do with mining engineers. This has ramifications that can be traced all the way back until the loop is closed.'

'Loop is closed?'

'Okay. Let's take it from the top. Azure message goes from Tokyo to Rabaul,' Waterhouse says, drawing a heavy line down the chalkboard joining those two cities. 'The next day, a message in some other crypto system-one that we have broken-goes from Rabaul to a submarine operating out of a base here, in the Moluccas. The message states that the submarine is to proceed to an outpost on the north coast of New Guinea and pick up four passengers, who are identified by name. From our archives, we know who these men are: three aircraft mechanics and one mining engineer. A few days later, the submarine transmits from the Bismarck Sea stating that it has picked those men up. A few days after that, our waterfront spies in Manila inform us that the same submarine has showed up there. On the same day, another Azure message is transmitted from Manila back up to Tokyo,' Waterhouse concludes, adding a final line to the polygon, 'closing the loop.'

'But that could all be a series of random, unconnected events,' says one of Comstock's math whizzes, before Comstock can say it. 'The Nips are desperate for aircraft mechanics. There's nothing unusual about this kind of message traffic.'

'But there is something unusual about the patterns,' Waterhouse says. 'If, a few months later, another submarine is sent, in the same way, to pick up some mining engineers and some surveyors who have been trapped in Rabaul, and, upon its arrival in Manila, another Azure message is sent from Manila up to Tokyo, it begins to look very suspicious.'

'I don't know,' Comstock stays, shaking his head. 'I'm not sure if I can sell this to the General's staff. It's too much of a fishing expedition.'

'Correction, sir, it wasa fishing expedition. But now I'm backfrom the fishing expedition, and I've got the fish!' Waterhouse storms out of the room and down the hall toward his lab-half the fucking wing. Good thing Australia is a big continent, because Waterhouse is going to take all of it if he's not held sternly in check. Fifteen seconds later he's back with a stack of ETC cards a foot high, which he pounds down on the tabletop. 'It's all right here.'

Comstock has never fired a gun in his life, but he knows card-punching and -reading machinery like a jarhead knows his Springfield, and he's not impressed. 'Waterhouse, that stack of cards carries about as much information as a letter home to Mom. Are you trying to tell me-'

'No, this is just the summary. The result of the statistical analysis.'

'Why the hell did you punch it onto ETC cards? Why not just turn in a plain old typed report like everyone else?'

'I didn't punch it,' Waterhouse says. 'The machine punched it.'

'The machine punched it,' Comstock says very slowly.

'Yes. When it was done performing the analysis.' Waterhouse suddenly breaks into his braying laugh. 'You didn't think this was the raw inputs, did you?'

'Well, I-'

'The inputs filled several rooms. I had to run almost every message we have intercepted through the whole war through this analysis. Re member all those trucks I requisitioned a few weeks ago? Those trucks were just to carry the cards back and forth from storage.'

'Jesus Christ!' Comstock says. He remembers the trucks now, their incessant comings and goings, fender-benders in the motor pool, exhaust fumes coming through his window, the enlisted men shoving heavy carts up and down the hallways, laden with boxes. Running over people's feet. Scaring the secretaries.

And the noise. The noise, the noise, from Waterhouse's goddamned machine. Flowerpots vibrating their way off file cabinets, standing waves in coffee cups.

'Wait a sec,' says one of the ETC men, with the nasal skepticism of a man who has just realized he's being bullshitted. 'I saw those trucks. I saw those cards. Are you trying to get us to believe that you were actually running a statistical analysis on each and every single one of those message decrypts?'

Waterhouse looks a little defensive. 'Well, that was the only way to do it!'

Comstock's math whiz is homing in for the kill now. 'I agree that the only way to accomplish the analysis that is implied by that'-he waves at the mandala of intersecting polygons on Waterhouse's map-'is to go through all of those truckloads of old decrypts one by one. That is clear. That is not what we are objecting to.'

'What are you objecting to, then?'

The whiz laughs angrily. 'I'm just worried about the inconvenient factthat there is no machine in the whole world that is capable of processing all of that data, that fast.'

'Didn't you hear the noise?' Waterhouse asks.

'We all heard the goddamn noise,' Comstock says. 'What does that have to do with anything?'

'Oh,' Waterhouse says, and rolls his eyes at his own stupidity. 'That's right. Sorry. Maybe I should have explained that part first.'

'What part?' Comstock asks.

'Dr. Turing, of Cambridge University, has pointed out that bobbadah bobbadah hoe daddy yanga langa furjeezama bing jingle oh yeah,' Waterhouse says, or words to that effect. He pauses for breath, and turns fatefully towards the blackboard. 'Do you mind if I erase this?' A private lunges forward with an eraser. Comstock sinks into a chair and grips its arms. A stenographer reaches for a benzedrine tablet. An ETC man chomps down on a number two lead pencil like a dog on a drumstick. Strobes flash. Waterhouse grabs a fresh stick of chalk, reaches up, and presses its tip to the immaculate slate. The crisp edge of the stick fractures with a slight pop, and a tiny spray of chalk particles drifts to the floor spreading into a narrow parabolic cloud. Waterhouse bows his head for a minute, like a priest getting ready to stride up the aisle, and then draws a deep breath.

The benzedrine wears off five hours later and Comstock finds himself sprawled across a table in a room filled with haggard, exhausted men. Waterhouse and the privates are pasty with chalk dust, giving them a ghoulish appearance. The stenographers are surrounded with used pads, and frequently stop writing to flap their limp hands in the air like white flags. The wire recorders are spinning uselessly, one reel full and one empty. Only the photographer is still going strong, hitting that strobe every time Waterhouse manages to fill the chalkboard.

Everything smells like underarm sweat. Comstock realizes that Waterhouse is looking at him expectantly. 'See?' Waterhouse asks.

Comstock sits up and glances furtively at his own legal pad, where he hoped to draw up an agenda. He sees Waterhouse's four assertions, which he copied down during the first five minutes of the meeting, and then nothing except a tangled field of spiky doodles surrounding the words BURY and DISINTER.

It behooves Comstock to say something.'This thing, the, uh, the burying procedure, that's the, uh-'

'The key feature!' Waterhouse says brightly. 'See, these ETC card machines are great for input and output. We've got that covered. The logic elements are straightforward enough. What was needed was a way to give the machine memory, so that it could, to use Turing's terminology, bury data quickly, and just as quickly disinter it. So I made one of those. It is an electrical device, but its underlying principles would be familiar to any