Cryptonomicon

Within a couple of months he is actually writing new chapters of the Cryptonomicon. People speak of it as though it were a book, but it's not. It is basically a compilation of all of the papers and notes that have drifted up in a particular corner of Commander Schoen's office over the roughly two-year period that he's been situated at Station Hypo, as this place is called[3]. It is everything that Commander Schoen knows about breaking codes, which amounts to everything that the United States of America knows. At any moment it could have been annihilated if a janitor had stepped into the room for a few minutes and tidied the place up. Understanding this, Commander Schoen's colleagues in the officers' ranks of Station Hypo have devised strenuous measures to prevent any type of tidying or hygienic operations, of any description, in the entire wing of the building that contains Commander Schoen's office. They know enough, in other words, to understand that the Cryptonomicon is terribly important, and they have the wit to take the measures necessary to keep it safe. Some of them actually consult it from time to time, and use its wisdom to break Nipponese messages, or even solve whole cryptosystems. But Waterhouse is the first guy to come along who is good enough to (at first) point out errors in what Schoen has written, and (soon) assemble the contents of the pile into something like an orderly work, and (eventually) add original material onto it.

At some point Schoen takes him downstairs and leads him to the end of a long windowless corridor to a slab of a door guarded by hulking Myrmidons and lets him see the second coolest thing they've got at Pearl Harbor, a roomful of machinery from the Electrical Till Corporation that they use mainly for doing frequency counts on Nip intercepts.

The most remarkable machine[4] at Station Hypo, however-and the first coolest thing in Pearl Harbor-is even deeper in the cloaca of the building. It is contained in something that might be likened to a bank vault if it weren't all wired up with explosives so that its contents can be vaporized in the event of a total Nip invasion.

This is the machine that Commander Schoen made, more than a year ago, for breaking the Nipponese cipher called Indigo. Apparently, as of the beginning of 1940, Schoen was a well-adjusted and mentally healthy young man into whose lap was dumped some great big long lists of numbers compiled from intercept stations around the Pacific (perhaps, Waterhouse thinks, Alpha, Bravo, etc.). These numbers were Nipponese messages that had been encrypted somehow-circumstantial evidence suggested that it had been done by some kind of machine. But absolutely nothing was known aboutthe machine: whether it used gears or rotary switches or plugboards, or some combination thereof, or some other kind of mechanism that hadn't even been thought of by white people yet; how manysuch mechanisms it did or didn't use; specific details of how it used them. All that could be said was that these numbers, which seemed completely random, had been transmitted, perhaps even incorrectly. Other than that, Schoen had nothing-nothing-to work on.

As of the middle of 1941, then, this machine existed in this vault, here at Station Hypo. It existed because Schoen had built it. The machine perfectly decrypted every Indigo message that the intercept stations picked up, and was, therefore, necessarily an exact functional duplication of the Nipponese Indigo code machine, though neither Schoen nor any other American had ever laid eyes on one. Schoen had built the thing simply by looking at those great big long lists of essentially random numbers, and using some process of induction to figure it out. Somewhere along the line he had become totally debilitated psychologically, and begun to suffer nervous breakdowns at the rate of about one every week or two.

As of the actual outbreak of war with Nippon, Schoen is on disability, and taking lots of drugs. Waterhouse spends as much time with Schoen as he is allowed to, because he's pretty sure that whatever happened inside of Schoen's head, between when the lists of apparently random numbers were dumped into his lap and when he finished building his machine, is an example of a noncomputable process.

Waterhouse's security clearance is upgraded about once a month, until it reaches the highest conceivable level (or so he thinks) which is Ultra/Magic. Ultra is what the Brits call the intelligence they get from having broken the German Enigma machine. Magic is what the Yanks call the intelligence they get from Indigo. In any case, Lawrence now gets to see the Ultra/Magic summaries, which are bound documents with dramatic, alternating red and black paragraphs printed on the front cover. Paragraph number three states:

NO ACTION IS TO BE TAKEN ON INFORMATION HEREIN REPORTED, REGARDLESS OF TEMPORARY ADVANTAGE, IF SUCH ACTION MIGHT HAVE THE EFFECT OF REVEALING THE EXISTENCE OF THE SOURCE TO THE ENEMY.

Seems clear enough, right? But Lawrence Pritchard Waterhouse is not so damn sure.

IF SUCH ACTION MIGHT HAVE THE EFFECT OF REVEALING...

At about the same time, Waterhouse has made a realization about himself. He has found that he works best when he is not horny, which is to say in the day or so following ejaculation. So as a part of his duty to the United States he has begun to spend a lot of time in whorehouses. But he can't have that much actual sex on what is still a glockenspiel player's pay and so he limits himself to what are euphemistically called massages.

ACTION... EFFECT... REVEALING...

The words stay with him like the clap. He lies on his back during these massages, arms crossed over his eyes, mumbling the words to himself. Something bothers him. He has learned that when something bothers him in this particular way it usually leads to his writing a new paper. But first he has to do a lot of hard mental pick-and- shovel work.

It all comes to him, explosively, during the Battle of Midway, while he and his comrades are spending twenty-four hours a day down among those ETC machines, decrypting Yamamoto's messages, telling Nimitz exactly where to find the Nip fleet.

What are the chances of Nimitz finding that fleet by accident? That's what Yamamoto must be asking himself.

It is all a question (oddly enough!) of information theory.

...ACTION...

What is an action? It might be anything. It might be something obvious like bombing a Nipponese military installation. Everyone would agree that this would constitute an action. But it might also be something like changing the course of an aircraft carrier by five degrees-or notdoing so. Or having exactly the right package of forces off Midway to hammer the Nipponese invasion fleet. It could mean something much less dramatic, like canceling plans for an action. An action, in a certain sense, might even be the total absence of activity. Any of these might be rational responses, on the part of some commander, to INFORMATION HEREIN REPORTED. But any of them might be observable by the Nipponese-and hence any of them would impart information to the Nipponese. How good might those Nips be at abstracting information from a noisy channel? Do they have any Schoens?

...EFFECT...

So what if the Nips did observe it? What would the effectbe exactly? And under what circumstances might the effect be REVEALING THE EXISTENCE OF THE SOURCE TO THE ENEMY?

If the action is one that could never have happened unless the Americans were breaking Indigo, then it will constitute proof, to the Nipponese, that the Americans have broken it. The existence of the source-the machine that Commander Schoen built-will be revealed.

Waterhouse trusts that no Americans will be that stupid. But what if it isn't that clear-cut? What if the action is one that would merely be really improbableunless the Americans were breaking the code? What if the Americans, in the long run, are just too damn lucky?

And how closely can you play that game? A pair of loaded dice that comes up sevens every time is detected in a few throws. A pair that comes up sevens only one percent more frequently than a straight pair is harder to detect-you have to throw the dice many more times in order for your opponent to prove anything.

If the Nips keep getting ambushed-if they keep finding their own ambushes spoiled-if their merchant ships happen to cross paths with American subs more often than pure probability would suggest-how long until they figure it out?

Waterhouse writes papers on the subject, keeps pestering people with them. Then, one day, Waterhouse receives a new set of orders.

The orders arrive encrypted into groups of five random-looking letters, printed out on the blue tissue paper that is used for top-secret cablegrams. The message has been encrypted in Washington using a one-time pad, which is a slow and awkward but, in theory, perfectly unbreakable cipher used for the most important messages. Waterhouse knows this because he is one of the only two persons in Pearl Harbor who has clearance to decrypt it.