Prime (Chess Team Adventure, #0.5)

Of course!

Arabic, like many Middle Eastern languages, was written from right to left. The Voynich manuscript however was clearly written in the manner of the Western world, from left to right. That was what al-Tusi meant by “in the fashion of the infidel.” The original text had been composed in Arabic, but then written backward, in the Western style, to confuse the uninitiated reader.

But the difference in language and composition style did not sufficiently explain the mystery. Read forward or backward, the text output from the manuscript remained without any sort of recognizable pattern.

He read the clue again. Indivisible numbers. The only whole numbers that could not be divided were the primes. Each one in turn. Could that be it?

A standard substitution cipher assigned a value for each letter of the alphabet: A=1, B=2 and so forth. With a cipher wheel, you could change the starting point: A=4, B=5 and on until you started the numbers over so that X=1, Y=2 and Z=3, but even this substitution could be easily defeated by looking at the frequency of certain oft-used letters. There were other ways to tweak the system, such as by using a keyword variation, but frequency analysis remained the Achilles heel of any substitution cipher. However, one way to render the cipher nearly unbreakable was to change the substitution pattern with every letter, rotating the cipher wheel a prescribed number of places with each letter. That way, letters and numbers would not correspond with any regularity.

Had al-Tusi done that, using prime numbers to adjust the cipher pattern with each new letter?

Parker plugged the new parameters into the decipherment subroutine and let it run. He tried to keep his expectations in check, and braced himself for yet another disappointment. When the screen finally displayed the results, he was stunned to discover that he was able to do something that nobody had done in over seven hundred years.

He was reading the Voynich manuscript.





FORTY-ONE


Maragheh, Iran



Bishop stomped the accelerator but had to brake just as quickly, when a sharp hairpin turn loomed ahead.

“You do realize,” he said in a low voice that was not altogether unlike the sound of rocks grinding together, “that just because I was born in Iran, it doesn’t mean I know my way around.”

Before King could respond, Deep Blue’s voice came over the net. “Bishop, I’m tracking you on GPS. I’ll guide you to the rendezvous point.”

“Well that’s handy,” Rook said.

“The road continues straight for about a quarter-mile, then there’s another sharp turn to the left.”

The play of light on the embankment behind them betrayed the fact that the second SUV was moving; they weren’t going to be able to just slip away. Bishop floored the gas pedal again, racing down the straight stretch, but before he got to the turn, a pair of headlights dawned in the rearview mirror.

King glanced back. “Knight, see if you can’t shoot out their radiator.”

Knight answered with a nod, and depressed the button to roll his window down as he twisted around in his seat. But as he started to lean out, something smacked into the rear window, shattering it. There were several more loud noises, the hammer-strike sound of bullets striking the rear of their stolen SUV. Knight pulled back without firing, and everyone ducked low, but Rook immediately popped back up, and aimed through the opening where the window had been. The sound-suppressed weapon made hardly any sound; the only indication that he was firing was the sudden storm of hot brass shell-casings that started pelting the other passengers.

The headlights started swerving back and forth as the other driver tried to evade the incoming fire, but then Bishop reached the turn, and for a moment, the pursuing vehicle was again lost from view.

King listened in as Deep Blue advised Bishop about the road ahead. There was another short straight stretch, followed by a hard right, but beyond that the road was straight for almost half-a-mile. King saw city lights ahead on the right; in less than a minute, they would be driving through an Iranian suburb.

“Let’s take ‘em on,” suggested Rook. “We’ve got the firepower.”

Queen chimed in as well. “I agree.”

King felt like saying. Great. When this is a democracy, I’ll be sure to count your votes. But instead, he just shook his head. “Negative. We can’t risk getting pinned down here. Shoot back if you can, but we’re not stopping.”

The headlights reappeared behind them, just as they came alongside the residential area. If the police were not already on their way, they would be as soon as the people in those shops and houses heard the sound of shots from the triad soldiers’ guns…or as soon as they started catching stray bullets.