Steve Berry - The Jefferson Key

He watched as Adventure’s crew took their cue from him and, to a man, echoed, “Whatever you want, Captain,” each grateful that it wasn’t him about to die. Normally, a captain never questioned the quartermaster in front of the crew or vice versa. But this was wartime, when the captain’s word went unquestioned.

“He’ll die at seven AM, with the entire company present.”

CASSIOPEIA DROVE AWAY FROM SHIRLEY KAISER’S NEIGHBORHOOD, found an empty shopping mall parking lot, and called the White House.

“You’re not going to like this,” she said to Edwin Davis.

And she told him everything, holding back only the last thing she and Kaiser had discussed.

“This has potential, though,” she said. “We could draw Hale out, if played right.”

“I see that.”

There was a lot more to say, but she was tired, and it could wait. “I’m going to get some sleep. We can talk in the morning.”

A moment of silence passed before Davis said, “I’ll be here.”

She ended the call.

Before she could restart the motorcycle and find a motel the phone dinged again. She checked the display. Cotton. About time.

“What happened?” she asked.

“Just another fun night. I need the Secret Service to run a license plate. But I think I already know who the car belongs to.”

He gave her information for a Maryland tag.

“But there’s a bright spot,” he said.

She could use one of those.

“The cipher’s been broken. I now know the message Andrew Jackson left for the Commonwealth.”

“Where are you?” she asked.

“Richmond. At a lovely hotel called The Jefferson.”

“I’m in Fredericksburg. Is that nearby?”

“About an hour away.”

“I’ll join you.”

found correspondence that Robert Patterson, a mathematics professor at the University of Pennsylvania, wrote to Thomas Jefferson in December 1801. By then, Jefferson was president of the United States. Both Patterson and Jefferson were officials at the American Philosophical Society, a group that promoted scholarly research in the sciences and humanities. Both were also enthusiasts of ciphers and codes, regularly exchanging them. Patterson wrote, “The art of secret writing has engaged the attention both of the statesman and philosopher for many ages.” But Patterson noted that most ciphers fall “far short of perfection.” For Patterson the perfect code came with four properties: (1) It should be adaptable to all languages; (2) be simple to learn and memorize; (3) easy to read and write; and (4) most of all, “be absolutely inscrutable to all unacquainted with the particular key or secret for deciphering.”

Patterson included with his letter an example of a cipher so difficult to decode that it “would defy the united ingenuity of the whole human race.” Bold words from a man of the 19th century, but that was before the existence of high-speed computer algorithms.

Patterson made the task especially difficult, explaining in his letter that, first, he wrote a message text vertically, in column grids, from left to right, using lowercase letters or spaces, with rows of 5 letters. He then added random letters to each line. To solve the cipher meant knowing the number of lines, the order in which those lines were transcribed, and the number of random letters added to each line.

Here are the letters from Andrew Jackson’s message:

The key to deciphering this code is a series of two-digit number pairs. Patterson explained in his letter that the first digit of each pair indicated the line number within a section, the second digit the number of letters added to the beginning of that row. Of course, Patterson never revealed the number keys, which has kept his cipher unsolved for 175 years. To discover this numeric key, I analyzed the probability of diagraphs. Certain pairs of letters simply do not exist in English, such as dx, while some almost always appear together, such as qu. To ascertain a sense of language patterns for Patterson and Jefferson’s time I studied the 80,000 letter characters contained in Jefferson’s State of the Union addresses and counted the frequency of diagraph occurrences. I then made a series of educated guesses such as the number of rows per section, which two rows belong next to one another, and the number of random letters inserted into a line. To vet these guesses I turned to a computer algorithm and what’s called dynamic programming, which solves massive problems by breaking the puzzle down into component pieces and linking the solutions together. The overall calculations to analyze were fewer than 100,000, which is not all that tedious. It’s important to note that the programs available to me are not available to the general public, which might explain why the cipher has remained unbroken. After a week of working the code, the computer discovered the numerical key.

To utilize the key, let’s return to the cipher rows themselves and lay them one after the other, per Patterson’s instructions:

If we apply the first numerical key, 33, to the letters we would count 3 over on the first row then identify the next 5 letters, FEETH. The next number, 3, indicates the original position of this letter row. Using 28, you would count 2 more letters over and identify 5 letters that would be placed in the row 8 position. By applying the remaining keys to the letters, the grid reappears in its original order:

The message can be read vertically down the 5 columns from left to right:

Malone read again Voccio’s report and Andrew Jackson’s coded message.

Jefferson Wheel.

Followed by twenty-six random letters and five symbols.

He’d already surfed the Internet and determined what the words Jefferson Wheel meant. Twenty-six wooden disks, upon which were carved the letters of the alphabet in random sequence. Each disk was numbered 1 through 26 and, depending on the order in which the disks were threaded onto an iron spindle, and the manner in which they were aligned, coded messages could be passed. The only requirement was that the sender and receiver had to possess the same collection of disks and arrange them in the same order. Jefferson conceived the idea himself from cipher locks he’d read about in French journals.

The problem?

Only one wheel still existed.

Jefferson’s own.

Which had been lost for decades but now was on display at Monticello, Jefferson’s Virginia estate. Malone assumed the twenty-six random letters in Jackson’s message would align the disks.

But what order should the disks be in?

Since none was specified, he would assume numerically. So when the disks were threaded in the correct sequence, then properly arranged, twenty-five lines would contain nonsense.

One would reveal a cohesive message.

He hadn’t told Cassiopeia what he’d found.

Not on the phone.

Monticello was less than an hour to the west.

They’d go there tomorrow.

establishment that came with a computer in the room. He figured in the not-too-distant future that accessory would be as standard as a hair dryer and a television.

He inserted the flash drive and read what Voccio had deciphered.

Smart guy.

A shame he was dead, but it was his own fault. Those men had come to herd them both to that waiting car. Just fire some shots, allow him to do his thing and think he succeeded, then wait and watch as the bomb took care of two problems at once.

Carbonell was covering her tracks. The NSA and CIA moving on him may have spooked her. One less witness against you was never a bad thing.