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Nathaniel Sackett was key to the success of their spy ring, and Ben wanted to throw him into Long Island Sound.
“After the incident last month, we need to make sure our intelligence is safe from prying eyes. Your letters to Mr. Woodhull must be encrypted,” Sackett said. Ben felt his temper rise. He didn’t need to be reminded of “the incident,” a British raid on his camp during which his horse, and more importantly, his saddlebags containing letters from Abe, had been stolen. Washington’s stern reprimand for the loss of intelligence and possible exposure of one of his agents had been humiliating enough. He still worried that Abe’s identity and location had been revealed to the enemy.
Ben and Sackett had been debating for nearly an hour about the best way to keep the information Abe supplied secure. Caleb seemed to find the whole argument tremendously entertaining, and Ben did not refuse when Caleb handed him his flask. The strong spirit made Ben’s eyes water and burned all the way down, but Ben felt calmer by the time it settled in his stomach.
“Perhaps you could use an Ave Maria, or Lovell’s cipher. One of those should provide sufficient security,” Sackett suggested.
Ben shook his head “They’re both too complicated,” he said, pausing to drink from Caleb’s flask. “Abraham doesn’t speak Greek or Latin,” Ben said. “Neither does Caleb. We need something simple to use and efficient to protect us if our letters are intercepted.” Ben handed Caleb his plate of half-eaten supper and moved a stack of reports to uncover his worn copy of Entick’s Spelling Dictionary.
“About time you found a use for that,” Caleb said around a mouthful of Ben’s leftover potatoes. “Seeing as you’ve been hauling it around with you since the war started. What cavalry officer needs a dictionary?”
“Not all of us had the benefit of your fine New Haven education,” Ben replied. He opened a blank notebook and traced several columns on each page.
“I’ve been reading about cryptography. I think the old French system would be best,” Ben explained. “I’ll pick words we’re most likely to use and give them each a number.” He filled a column with numbers and wrote a word next to each number, creating his cipher. “When Abe writes to us, he’ll use numbers instead of words to keep the most important parts of his messages concealed.”
“That’s clever, Benny,” Caleb said.
“Clever, yes, but highly insecure,” Sackett said. “It would never stand up to a trained cryptanalyst.”
“There many of those running about?” Caleb asked. Sackett huffed a sigh and sat heavily on Ben’s foot locker, knowing he had lost this debate. They simply did not have time or resources to train every member of the ring in advanced methods of cryptography. Caleb leaned over Ben’s shoulder. “What if we need a word you don’t put in your book?”
“I’ll include a simple substitution cipher,” Ben explained. “Abe can spell whatever he needs.” Caleb took a drink from his flask before handing it back to Ben.
“Have some more of this and no one will be able to break your code,” Caleb said.
“Cipher,” Sackett corrected without looking up from the book he was annotating. Caleb ignored him. He sank into the chair opposite Ben and kicked his feet up onto Ben’s desk, leaning his chair back on two legs.
“I think you forgot officers,” Caleb said, as Ben finished writing office and moved on to operative. Ben blinked and rubbed his eyes, the text blurring in front of him. It was getting harder to see as the sun went down and his ink-smeared fingers were cramping around his pen.
“Damn,” Ben said. “I’ll have to add it back in.”
“Well, gentlemen, it’s getting late,” said Sackett, rising. “You seem to have this well in hand.” Ben was so absorbed in his work that he barely noticed Sackett leave.
Ben laid his pen down and took a long drink from Caleb’s flask. He had lost track of how long they had been working on the code book, and the flask felt much lighter than he remembered. The sun had set hours ago and his candle had burned down to a stub. Caleb had fallen asleep, tilted precariously in his chair with his hat over his face.
Whatever Caleb had in that flask was potent stuff, and Ben’s text seemed to wiggle off the page. It was well past midnight and if he kept going he was likely to make mistakes. He pushed Caleb’s boots off of his desk and Caleb’s chair hit the ground, jolting him awake from his nap.
“All done?” Caleb asked.
“Nearly,” Ben said, taking a last drink and handing Caleb his empty flask. He rose from his desk, feeling his spine and knees crack as he straightened. He was unused to sitting still for hours. The tent swam a little and he stumbled as he took a step toward his cot. Caleb caught his elbow.
“Listing a little to port there, Tall-boy. You should probably turn in. Abe will have an easier time with your code book if he can read it,” Caleb said.
“Yeah,” Ben agreed. “Come by tomorrow morning and I’ll have it finished.”
Morning found Ben at his writing desk, making the final corrections to Abe’s copy of the code book. The bright sun made his head throb and his stomach churned unpleasantly. A mug of steaming coffee thumped down in front of him. Ben felt his stomach twist at the smell. Caleb grinned at him.
“Looking a little green around the edges, Benny-boy,” he said, sprawling across Ben’s cot. “Rough night?”
“What the hell was in that flask?” Ben asked, squeezing his eyes shut and rubbing his temples. He didn’t touch his coffee. He hadn’t been so hungover in years. If he did vomit, he decided he was aiming for Caleb’s boots.
“Don’t remember,” Caleb said. “Seemed to agree with you though. Last night, at least. Not so much this morning, from the looks of it.” Ben closed the codebook and wrapped it in a square of waxed cloth. He handed it to Caleb.
“Show Abe how to use this,” he said. “He needs to know we’ll keep him safe.”
“Maybe using your code book will make the poor bastard less jumpy,” Caleb said. “You and Mr. Sackett should cook up some invisible ink for him too. He’d like that.”
“Sackett probably has some,” Ben said. “He’s paranoid enough.”
Caleb climbed out of Ben’s cot and slipped the code book into his pocket. “I’ll be sure to tell Woody all about how you made up a secret code while you were dead drunk.”
Ben pinched the bridge of his nose. “Please don’t,” he pleaded.
“Should have thought about that before you made us your chain of agents, Tall-boy. We all share the same secrets now.” Caleb thumped Ben’s shoulder as he strode out of the tent. “Finish your coffee, you’ll feel better.”
Ben was feeling better, though it had nothing to do with Caleb’s horrible coffee. He had secured Washington's man in New York, and his cipher would help keep his fledgling spy ring safe.