Garden of Secrets Past

TWENTY-TWO


Kingston printed it out. He was relieved to see that all the letters were readable, though some had faded somewhat. He studied them closely. With the nine lines separated by a vertical arrow, he reasoned that there were probably two separate codes and that solving the first would provide information that unlocked the key to the second. To begin, he decided to focus on the first two lines:



There was no longer any question in his mind that it was a cipher, a code of some kind. If so, what sort of message? Short sentences? Places? People? Geographic coordinates? Directions? He closed his eyes for several seconds, dredging up what he knew about codes, the fundamentals he’d been taught in army intelligence. Cryptography generally, he knew, could be divided into two branches, known as transposition and substitution. If this were a transposition cipher, the letters of the message would have been rearranged systematically, effectively generating an anagram. If it were a substitution cipher, each letter of the Roman alphabet would have been paired with a different letter.

There was only one problem, and it was significant. To decipher the code, the receiver must possess what is commonly referred to as a “key,” a shift pattern that specifies the exact details of how the encryption or code was devised.

The Winterborne code, as he’d decided to call it, represented a huge potential breakthrough but, as it stood, the string of letters meant nothing without the key. He thought of calling the man at GCHQ who had looked at the message found on Endicott’s body, knowing that he could probably make faster progress, but he decided against it for now. In any case, without the key, he doubted that even the most expert cryptanalyst could do anything with the letters on the envelope.

About to close down the computer, there was a ding announcing another e-mail. It was from Muriel Williams, secretary of the Midlands Dahlia Society. A response to his query, he hoped.

Dear Dr. Kingston,

In answer to your inquiry regarding Mr. William Endicott and Mr. Tristan Veitch, I am sad to report that both men were victims of recent homicides. I can provide the following information, which we sent recently to the Nottinghamshire police who made a similar inquiry:

Both men exhibited and won awards in several local dahlia shows in the years between 2002 and 2005. Mr. Endicott won prizes at the National, Royal Bath & West Show at Shepton Mallet in 2003 and again in 2005. Mr. Veitch won similar local awards and a National award at Harrogate in 2004.

Both were members of the National Dahlia Society and the Brookside Garden Club in Derby.

I hope this helps in your inquiry.

Sincerely,

Muriel Williams

Secretary, Midlands Dahlia Society

Kingston printed the letter and read it a second time, always a habit. For starters, it confirmed that Wheatley had followed through on the garden connection between Veitch and Endicott. “Interesting,” he muttered, recalling Wheatley’s saying that this thread had led nowhere. Nevertheless, he still intended to follow up. The police were not always right.

Establishing a direct relationship between Endicott and Veitch represented a critical step in the case. Apart from anything else, it meant that the probability of Endicott having worked with Veitch on his project had increased exponentially. But something puzzled him. It was logical to assume that Veitch had been killed to silence him and to steal the volatile information that he’d dredged up, but what motive could those same people have for killing Endicott? It seemed far-fetched that their both belonging to the same garden club held the answer.

Putting the letter aside, he decided to call Ms. Williams sooner rather than later and try to arrange for a meeting with one of the officers of Brookside Garden Club. Perhaps he could arrange for a visit with Amanda as well, since he’d be in the area anyway.

* * *

Later that evening, he and Andrew met for dinner and a couple pints in the upstairs bar at the Antelope. While they were waiting for their food, Kingston reached in his pocket and took out the sequence of letters copied from Holbrook’s envelope. He placed the paper on the table in front of Andrew.

“What do you make of this?” he said.

Andrew studied it for a few seconds, then looked up, frowning. “What are those letters supposed to be? Welsh postal codes?”

Kingston smiled. “Good try. No, I believe they’re ciphertexts—codes of some sort.”

“Really? How did you come by it?”

“They were written on an envelope that contained historical papers found concealed in the wall of an old house near Banbury—behind a frieze, actually.”

“This has to do with the Sturminster case, I take it?”

“I’ve reason to believe it does. The house dates back to the early part of the eighteenth century, so it’s reasonable to conclude that the envelope could have been placed there a long time ago.”

“Over two hundred years?”

“Maybe.”

“How did you find out about all this?”

“The house and the frieze were mentioned in Veitch’s notes. No details, just a brief comment. The frieze was also mentioned in the hidden historical papers.”

“So how are these cipher things decoded, deciphered, whatever the word is?”

“It requires what is called a key phrase. It’s like a PIN, in a manner of speaking. Only two parties have access to it, usually the sender and the receiver. Though it could be composed of numbers, it’s invariably a series of letters, a word or phrase that can be committed to memory.”

“How do you know all this stuff?”

“I thought you knew—courtesy of Her Majesty. I took intelligence courses at JSSI, Joint Services School of Intelligence, in Ashford, back in the fifties.”

“Like Bletchley?”

“Somewhat. Let me show you the basic methodology.” He took a pen from his inside pocket and wrote the alphabet in capital letters on an empty space on the paper place mat.

ABCDEFGHIJKLMNOPQRSTUVWXYZ





“All right,” he said. “Cryptography 101. First I’ll show you a substitution cipher used by Julius Caesar. As you might guess, it’s referred to as the Caesar shift cipher or simply the Caesar shift.”

“Cipher meaning…?”

“In simple terms, a system of substituting letters or symbols. A secret way of writing or a code.”

Andrew nodded, looking only mildly interested, and sipped his beer.

“One type of substitution cipher our friend Julius used—and it’s well documented, by the way—was to replace each letter in the message with the letter three or more places farther along the alphabet. Like this,” he said, writing under the plain alphabet. “This is referred to as the cipher alphabet.”

ABCDEFGHIJKLMNOPQRSTUVWXYZ





DEFGHIJKLMNOPQRSTUVWXYZABC


“So if the message to be sent—the plaintext, as it’s called—is ‘Key is under mat,’ the cipher text would be: NHB LV XQGHU PDW.” He wrote a check mark above the paired letters to further demonstrate.



“Even I can understand that,” said Andrew, now appearing more interested. “To decipher the code you’d have to know how many letters to shift.”

“Exactly. However, therein lies a small problem. If the sender and receiver keep the shift number or cipher alphabet written on a piece of paper, enemies could capture it or someone could steal it, discover the key, and immediately read any communications encrypted with it.” He put down the pen and looked at Andrew. “You’re a high-tech sort. Think of it much in the same way as today’s passwords. Rarely are they numerical, they’re nearly always a word or name, or a combination thereof—one that’s easy to remember.” He paused to take a sip of beer and continued. “So the emperor soon realized that a key phrase, easily committed to memory by both the sender and the receiver, was essential. Here’s what he did.”

Kingston quickly scribbled another plain alphabet on the place mat, then glanced at Andrew to make sure that he wasn’t losing interest, which he wasn’t. “To make it easy,” he said, “I’m going to use the emperor’s name as the password—the key phrase, or key for short.” He wrote JULIUS CAESAR on the corner of the place mat, then continued. “For it to function as a cipher, we must eliminate any letters in the password that are duplicated, which leaves us with JULISCAER.” He looked at Andrew again. “Are you with me, so far?”

“Yes, Professor.” Andrew smiled.

“Good. Instead of the simple three-letter shift we used before, we substitute our key phrase followed by the remaining letters of the alphabet after the R, making sure not to repeat any that already appear in our key phrase.” He wrote quickly as he spoke. “Like this.”

ABCDEFGHIJKLMNOPQRSTUVWXYZ





JULISCAERTVWXYZBDFGHKMNOPQ





Andrew leaned closer, studying the two rows of letters. “Clever,” he muttered. “The lower row contains all the letters of the alphabet with no duplicates.”

“Exactly,” Kingston replied, handing Andrew his pen. “Now let’s see if you can create the ciphertext, the code for our original message: ‘Key is under mat.’”

“Piece of cake,” said Andrew, starting to pair off the letters. Within thirty seconds he’d written, VSP RG KYISF XJH.

“Excellent,” said Kingston. “You’ve earned another beer.”

“Much obliged, but I see the problem already.”

“You do, eh?”

“You now have a Winterborne ciphertext but no key. No password. Right?”

“Go to the top of the class.”

“How can you … we find it?”

“I wish I knew. If I were to hazard a guess, I’d say it has something to do with Winterborne Manor or, more specifically, the frieze, since that’s where it was hidden.”

“What does this frieze look like?”

Kingston described the alphabet frieze and what little he knew of its history, mentioning the Holbrooks and how cooperative they’d been. By now, each had consumed two pints of Chiswick Bitter and had finished a bottle of Muscadet with dinner. Kingston recognized that it was now pointless to go on talking about Winterborne and the basics of cryptography. This was borne out when he looked up from signing the credit card slip to see Andrew trying to make eye contact with a redhead seated across the crowded room with another woman. Kingston smiled, wondering what Andrew’s reaction was going to be if they turned out to be partners and not just friends. Ten minutes later, they left the warmth of the Antelope, feeling no pain, braced for the walk back to Cadogan Square. Kingston opened the pub’s door to face a howling gale and drenching rain.

“I have a key phrase for this,” Andrew yelled over the tumult.

“I don’t want to hear it,” Kingston shouted back. “Let’s call for a cab.”