Riptide

Chapter 24

The following afternoon, as Hatch came up the path from the dock after treating a diver's sprained wrist, he heard a crash resound from the direction of Wopner's hut. Hatch sprinted into Base Camp, fearing the worst. But instead of finding the programmer pinned beneath a large rack of equipment, he found him sitting back in his chair, a shattered CPU at his feet, eating an ice-cream sandwich, an irritated expression on his face.

"Is everything all right?"

Wopner chewed noisily. "No," he said.

"What happened?"

The programmer turned a pair of large, mournful eyes toward Hatch. "That computer impacted with my foot, is what happened."

Hatch looked around for a place to sit, remembered there was none, and leaned against the doorway. "Tell me about it."

Wopner shoved the last piece in his mouth and dropped the wrapper on the floor. "It's all messed up."

"What is?"

"Charybdis. The Ragged Island network." Wopner jerked a thumb in the direction of Island One.

"How so?"

"I've been running my brute-force program against that goddamn second code. Even with increased priority, the routines were sluggish. And I was getting error messages, strange data. So I tried running the same routines remotely over on Scylla, the Cerberus computer. It ran lickety-split, no errors." He gave a disgusted scoff.

"Any idea what the problem is?"

"Yeah. I got a good idea. I ran some low-level diagnostics. Some of the ROM microcode was rewritten. Just like when the pumps went haywire. Rewritten randomly, in bursts of a regular Fourier pattern."

"I'm not following you."

"Basically, it's not possible. Follow that? There's no known process that can rewrite ROM that way. And on top of that, in a regular, mathematical pattern?" Wopner stood up, opened the door to what looked like a refrigerated corpse locker, and slipped out another ice-cream bar. "And the same thing's happening to my hard disks and magneto-opticals. It only happens here. Not on the boat, not in Brooklyn. Just here."

"You can't tell me it's not possible. I mean, you saw it happen. You just don't know why yet."

"Oh, I know why. The frigging Ragged Island curse."

Hatch laughed, then saw Wopner was not smiling.

The programmer unwrapped the ice cream and took a massive bite. "Yeah, yeah, I know. Show me another reason, and I'll buy into it. But everyone who's come to this goddamn place has had things go wrong. Unexplainable things. When you get right down to it, we're no different from the rest. We just have newer toys."

Hatch had never heard Wopner talk like this. "What's gotten into you?" he asked.

"Nothing's gotten into me. That priest explained the whole thing. I ran into him at the post office yesterday."

So Clay's been talking to Thalassa employees, now, spreading his poison, Hatch thought, surprised at the strength of his anger. The man's an irritant. Someone ought to squeeze him like a sebaceous cyst.

His thoughts were interrupted when St. John appeared in the doorway. "There you are," he said to Hatch.

Hatch stared back. The historian was dressed in a bizarre combination of muddy Wellingtons, old tweed, and Maine oilcloth. His chest was heaving from exertion.

"What is it?" Hatch asked, rising instinctively, expecting to hear that there had been another accident.

"Why, nothing serious," said St. John, self-consciously smoothing down the front of his sou'wester. "Isobel sent me to bring you to our dig."

"Our dig?"

"Yes. You probably know I've been helping Isobel with the excavation of the pirate encampment." Isobel this, Isobel that. Hatch found himself mildly annoyed by the historian's familiar attitude toward Bonterre.

St. John turned to Wopner. "Did the program finish executing on the Cerberus computer?"

Wopner nodded. "No errors. No luck, either."

"Then, Kerry, there's no choice but to try—"

"I'm not going to rewrite the program for polyalphabetics!" Wopner said, giving the ruined CPU a childish kick. "It's too much work for nothing. We're running out of time as it is."

"Just a minute," Hatch said, trying to defuse the argument before it started. "St. John was telling me about polyalphabetic codes."

"Then he was wasting his breath," Wopner replied. "They didn't become popular until the end of the nineteenth century. People thought they were too error-prone, too slow. Besides, where would Macallan have hidden all his code tables? He couldn't have memorized the hundreds of letter sequences himself."

Hatch sighed. "I don't know much about codes, but I know a little about human nature. From what Captain Neidelman's been saying, this Macallan was a real visionary. We know he changed codes halfway through in order to protect his secret—"

"So it stands to reason he would have changed to a more difficult code," St. John interrupted.

"We know that, dummy," Wopner snapped. "What do you think we've been trying to crack for the last two weeks?"

"Hush up a minute," Hatch went on. "We also know that Macallan switched to a code containing all numbers."

"So?"

"So Macallan wasn't only a visionary, he was also a pragmatist. You've been approaching this second code as just a technical problem. But what if there's more to it than that? Could there be some pressing reason why Macallan used only numbers in the new code?"

There was a sudden silence in the hut as the cryptologist and the historian fell into thought.

"No," Wopner said after a moment.

"Yes!" St. John cried, snapping his fingers. "He used numbers to conceal his code tables!"

"What are you talking about?" Wopner grumbled.

"Look, Macallan was ahead of his time. He knew that polyalphabetics were the strongest codes around. But to use them, he needed several cipher alphabets, not just one. But he couldn't leave a lot of alphabet tables lying around where they might be discovered. So he used numbers! He was an architect and an engineer. He was supposed to have lots of numbers around. Mathematical tables, blueprints, hydraulic equations—any one of those could have done double duty, concealing a code table, and nobody would have been the wiser!"

St. John's voice had a clear, excited ring to it, and there was an eager flush on his face Hatch hadn't seen before. Wopner noticed it, too. He sat forward, the forgotten ice-cream sandwich melting into a brown-and-white pool on his desk.

"You might have something there, Chris old boy," he muttered. "I'm not saying you do, but you might." He pulled the keyboard toward him. "Tell you what. I'll reprogram the Cerberus computer to try a chosen-plaintext attack on the code. Now you boys let me be, okay? I'm busy."

Hatch accompanied St. John out of the hut and into the drizzle that cloaked Base Camp. It was one of those New England days when the moisture seemed to congeal out of the air itself.

"I should thank you," the historian said, pulling the sou'wester tighter around his plump face. "That was a good idea you had, you know. Besides, he'd never have listened to me. I was thinking about bringing the Captain into it."

"I don't know if I did anything, but you're welcome." Hatch paused. "Didn't you say that Isobel was looking for me?"

St. John nodded. "She said to say we've got a patient for you at the far end of the island."

Hatch started. "Patient? Why didn't you tell me first thing?"

"It's not urgent," said St. John with a knowing smile. "No, I wouldn't call it urgent, at all."