Cryptonomicon

The most interesting thing about this is that ten of the possible symbols (viz. 1, 2, 4, 5, 7, 9, 10, 13, 24, and 26) are not even used. Only sixteen different numbers appear in the message. Assuming each of those sixteen represents one and only one letter of the alphabet, this message has (Lawrence reckons in his head) 111136315345735680000 possible meanings. This is a funny number because it begins with four ones and ends with four zeroes; Lawrence snickers, wipes his nose, and gets on with it.

The most common number is 18. It probably represents the letter E. If he substitutes E into the message everywhere he sees an 18, then--Well, to be honest, then he'll have to write out the whole message again, substituting Es for 18s, and it will take a long time, and it might be time wasted because he might have guessed wrong. On the other hand, if he just retrainshis mind to construe18s as Es--an operation that he thinks of as being loosely analogous to changing the presets on a pipe organ's console--then what he sees in his mind's eye when he looks at the blackboard is

19 17 17 19 14 20 23 E 19 8 12 16 19 8 3

21 8 25 E 14 E 6 3 E 8 15 E 22 E 11

which only has 10103301395066880000 possible meanings. This is a funny number too because of all those ones and zeroes--but it is an absolutely meaningless coincidence.

"The science of making secret codes is called cryptography," Commander Schoen says, "and the science of breaking them is cryptanalysis." Then he sighs, grapples visibly with some more widely divergent emotional states, and resignedly plods into the mandatory exercise of breaking these words down into their roots, which are either Latin or Greek (Lawrence isn't paying attention, doesn't care, only glimpses the stark word CRYPTO written in handsized capitals).

The opening sequence "19 17 17 19" is peculiar. 19, along with 8, is the second most common number in the list. 17 is only half as common. You can't have four vowels or four consonants in a row (unless the words are German) so either 17 is a vowel and 19 a consonant or the other way round. Since 19 appears more frequently (four times) in the message, it is more likely to be the vowel than 17 (which only appears twice). A is the most common vowel after E, so if he assumes that 19 is A, he gets

A 17 17 A 14 20 23 E A 8 12 16 A 8 3

21 8 25 E 14 E 6 3 E 8 15 E 22 E 11

This narrows it down quite a bit, to a mere 841941782922240000 possible answers. He's already reduced the solution space by a couple of orders of magnitude!

Schoen has talked himself up into a disturbingly heavy sweat, now, and is almost bodily flinging himself into a historical overview of the science of CRYPTOLOGY, as the union of cryptography and cryptanalysis is called. There's some talk about an English fellow name of Wilkins, and book called Cryptonomiconthat he wrote hundreds of years ago, but (perhaps because he doesn't rate the intelligence of his audience too highly) he goes very easy on the historical background, and jumps directly from Wilkins to Paul Revere's "one if by land, two if by sea" code. He even makes a mathematics in-joke about this being one of the earliest practical applications of binary notation. Lawrence dutifully brays and snorts, drawing an appalled look from the saxophonist seated in front of him.

Earlier in his talk, the Schoen mentioned that this message was (in what's obviously a fictional scenario ginned up to make this mathematical exercise more interesting to a bunch of musicians who are assumed not to give a shit about math) addressed to a Nip naval officer. Given that context, Lawrence cannot but guess that the first word of the message is ATTACK. This would mean that 17 represented T, 14 C, and 20 K. When he fills these in, he gets

A T T A C K 23 E A 8 12 16 A 8 3

21 8 25 E C E 6 3 E 8 15 E 22 E 11

and then the rest is so obvious he doesn't bother to write it out. He cannot restrain himself from jumping to his feet. He's so excited he forgets about the weak legs and topples over across a couple of his neighbors' desks, which makes a lot of noise.

"Do you have a problem, sailor?" says one of the officers in the corner, one who actually bothered to wear a uniform.

"Sir! The message is, 'Attack Pearl Harbor December Seven!' Sir!" Lawrence shouts, and then sits down. His whole body is quivering with excitement. Adrenaline has taken over his body and mind. He could strangle twenty sumo wrestlers on the spot.

Commander Schoen is completely impassive except that he blinks once, very slowly. He turns to one of his subordinates, who is standing against the wall with his hands clasped behind his back, and says, "Get this one a copy of the Cryptonomicon.And a desk--as close to the coffee machine as possible. And why don't you promote the son of a bitch as long as you're at it."

***