Bledsoe waved a dismissive hand. “Hell, sure there’d be losses. A lot of them, no doubt. So what? They’d be South Korean losses, not Americans. Well,” he corrected himself, grimacing at the annoyance, “all right, there are quite a few American troops right up there, sure. But you can’t make an omelette without breaking eggs, can you?”
It seemed to Ranjit that the party was getting unpleasant, and then as Bledsoe tossed a crumpled napkin into a wastebasket, he thought he saw a reason. The napkin bounced off an empty whiskey bottle. Apparently his was not the first conference Bledsoe had convened that day.
Ranjit cleared his throat. “Well, Mr. Bledsoe, I come from a small country with problems of its own. I don’t want to criticize American policy.”
Bledsoe bobbed his head in agreement. “And that’s another thing,” he said, and interrupted himself to offer a refill with the bottle. Ranjit shook his head. Bledsoe shrugged and recharged his own glass. “Your little island,” he said. “Shree—Shree—”
“Sri Lanka,” Ranjit politely corrected.
“That’s the one. D’you know what you’ve got there?”
Ranjit considered. “Well, I think it’s probably the most beautiful island in the—”
“I’m not talking about the whole damn island, for Christ’s sake! My God, there’s a million beautiful islands around all over the world and I wouldn’t give you a nickel for any of them. I’m just talking about one little harbor you’ve got there, Trinkum—Trinco—”
Ranjit took pity. “I think you mean Trincomalee. I was born there.”
“Really?” Bledsoe considered that datum, found no use for it, and continued. “Anyway, I don’t give a damn about the town. It’s the harbor that’s a world-beater! Do you know what that could be? It could be the world’s best base for a nuclear submarine navy, Mr. Sub—Subra—”
He had refilled his glass once again, and the sippin’ whiskey was beginning to show its effects. Ranjit sighed and rescued him again. “It’s Subramanian, Mr. Bledsoe, and, yes, we know what a base it could be. In World War II it was headquarters for the Allied fleet, and before that Lord Nelson himself said it was one of the world’s greatest harbors.”
“Oh, crap, what does Lord Nelson have to do with it? He was talking about a place for sailing ships, for God’s sake. I’m talking nukes! That harbor’s deep enough that submarines can dive well below what any enemy could find, much less attack! Dozens of them! Maybe hundreds. And what did we do about it? We let goddamn India snap up treaty rights for the whole damn port. India, for God’s sake! And what the hell India needs a navy for in the first place, I can’t—”
Ranjit was getting tired of this opinionated drunk. Gamini was Gamini, but Ranjit couldn’t be expected to put up with much more of this. He stood up. “Thanks for the drink, Mr. Bledsoe, but I’m afraid I have to be getting along.”
He held out a hand to be shaken in farewell, but Bledsoe didn’t reciprocate. He glared up at Ranjit, then deliberately put the top back on the whiskey bottle. “Excuse me one second,” he said. “We have some unfinished business.”
He disappeared into one of the suite’s bathrooms. Ranjit heard running water, thought it over, shrugged, and sat down. It was more than one second, though. It was close to five minutes before T. Orion Bledsoe appeared again, and he hardly seemed the same man. His face was scrubbed, his hair was brushed, and he was carrying a partial cup of steaming black coffee—no doubt from the coffee machine that seemed to be standard equipment in any American hotel bathroom.
He didn’t offer Ranjit any of the coffee. He didn’t offer any explanations, either, just sat down, glanced at the whiskey bottle as though astonished to find it there, and said briskly, “Mr. Subramanian, if I should mention the names Whitfield Diffie and Martin Hellman, what would they mean to you?”
Slightly confused by the abrupt change in both subject and demeanor—but a little encouraged by the fact that the conversation had suddenly entered into an area he knew something about—Ranjit said, “Public-key cryptography, of course. The Diffie-Hellman-Merkle procedures.”
“Exactly,” Bledsoe said. “I don’t think I need tell you that Diffie-Hellman is in serious trouble, because of the quantum computers.”
He didn’t. Although Ranjit had never taken any particular interest in codes or code-cracking himself—not counting his exploits in learning one professor’s computer password—every mathematician in the world had a pretty good idea of what had gone on.
Diffie-Hellman was based on a very simple idea, but one that had been so difficult to execute that the idea had been useless until the age of really powerful computers. The first step in encoding any message that one wished to keep private was to represent it as a series of numbers. The simplest way to do that, of course, would be to replace the letter A with a one, the B with a two, and so on through Z equals twenty-six. (Naturally, no cryptographer in the world, or at least none over the age of ten, would take seriously such a trivial system of substitutions.) Then these numbers could be combined with an enormous number—call it “N”—in such a way that the original simple substitution was concealed. Simply adding the substituted numbers to giant N might do the trick by itself.
But N had a secret of its own. The way it was generated by cryptographers was by multiplying two large prime numbers together. Any decent computer could do that kind of multiplication in a fraction of a second, but once the two large primes were multiplied together, trying to discover what the primes themselves had been was a brutal job that, even with the best computers, could take many years. Hence the description “trapdoor cipher”—easy to get into, virtually impossible to get out of again. Still, public-key cryptography, as it was called, possessed one great virtue. Anybody could encrypt any message from the product of the primes—even, say, some harried member of the French Resistance in World War II, one step ahead of the Gestapo, with some crucial knowledge of where a bunch of panzer divisions were moving to. But only the people who knew what both those primes were could read the message.
Bledsoe took a sip of his rapidly cooling coffee. “The thing is, Subramanian,” he said, “we have some pretty important traffic going around the world right now—don’t ask me what it is. I have only a bare glimmering of a notion, and I can’t tell you even that much. But at this moment it is more important than ever that our code be unbreakable. Maybe there’s some way of decrypting that doesn’t involve all this factoring of prime numbers hocus-pocus. And if there is, we would like you to help us figure out what it is.”
Ranjit tried his best not to laugh. What he was being asked to do was what every code agency in the world had been working on ever since Diffie-Hellman had published their paper way back in 1975. “Why me?” he asked.
Bledsoe looked pleased with himself. “When I saw the news stories about your proof of Fermat’s Last Theorem, it rang a bell. All those mathematicians that work on this public-key stuff use what they call the Fermat test, right? So who would know more about that than the man who just proved his theorem? And there were others around who liked you, so we started the machinery going to recruit you for our team.”
When Ranjit considered all the ways in which Bledsoe’s notion was ridiculous, he was tempted to get up and walk away. Fermat’s test was certainly the basis for many more recent ways of identifying prime numbers. But to leap from that to the notion that the man who proved Fermat’s theorem would be any good at public-key code-cracking was, well, simply preposterous.