The Cipher Read online

  “No, no, hold it right there,” the chairman said, and Smiles had no choice but to stay put. “Berkeley, you say?” Skepticism dripped from his voice, and Smiles had a terrible premonition of what was coming next. “You must be one of Professor Taft’s favorites. Alice?”

  Oh no. Smiles hadn’t seen her, but there she was, emerging from a group of professors. Her dollish cheeks had been flush with wine, but they went pale at the sight of Smiles.

  He did the only thing he could. He thrust his plate of shrimp tarts into the chairman’s hand and said, “Sorry, Pete, I think I have food poisoning.”

  He dashed to the exit, never looking back.

  Smiles had three choices: left, right, or straight ahead to the casino lobby. The NSA agent didn’t appear in any of the hallways before him. Smiles quickly wrote off the one to the right. It led only to more conference rooms, and CRYPTCON had to be wrapping up for the day. Straight ahead was a good possibility. The shops, Starbucks, and casino all lay in that direction. But the hallway to the left led to an elevator bank—the same one the agent had appeared from that morning. His room was up there, and maybe he was headed back to it now.

  Smiles bolted to his left. If it wasn’t the right choice, the plan was already up in smoke. There would be no chance of catching him, and even if Ben had a number for the guy, it wasn’t likely Smiles could pull this off over the phone. He sprinted forward to the elevators. His ankle gave way as he made a ninety-degree turn at the elevator bank. As he hobbled forward, it appeared useless. There wasn’t a soul waiting for the six elevators, three on each side of the small area. Just Smiles, a bowl of artificial flowers, and another confirmation that he was generally useless.

  But then Smiles saw the green light ignited above one of the far elevators. Preparing to go up. The doors of the elevator began sliding closed. Quickly. Smiles stumbled forward and blindly thrust his hand between the door panels, just inches apart. They crunched together on his right hand, pinching his knuckles. After an excruciating moment, they pulled lazily apart.

  From inside the elevator, the copier salesman eyed him with concern. His eyes were set deep into a hawklike face, and he wore a squared-off crew cut with edges much sharper than those of his travel-worn suit. For a moment, Smiles was too relieved to speak. But then he had to, because the doors were closing again. He jammed his hand against the doorstop and said, “Could I talk to you for a sec?”

  It wasn’t the best introduction. He was still out of breath from the run, and the guy was tense with suspicion.

  “Talk to me?”

  “If you would. Just a sec?” Smiles threw out his left hand to the little elevator area, like he was welcoming the guy into his home. “I just came from the student reception. I was hoping to catch you there.”

  The agent exited the elevator but wasn’t happy about it. “Well, you missed me,” he said, checking his watch, “and I actually have some things—”

  “How much would a fast-factoring algorithm be worth to you?” The aggressive approach was a gamble, but it felt right. Smiles had to seize control of this conversation, and quick.

  The agent took a moment to absorb what he’d just heard, then laughed. “A lot. So would the Loch Ness monster and Santa Claus’s home address. Unfortunately they don’t exist.” He circled around Smiles and pressed the call button for the elevator.

  “It does exist, and I’ve got it. Can I prove it to you, or do you want to be the NSA agent who tried to turn away the most valuable information your agency will ever have?”

  That last part got to him. Smiles had annoyed the guy, but also gotten his interest. “Two minutes,” he said, holding up fingers in case the words didn’t get through. “Where do you want to talk?”

  “C’mon.” Smiles led him back the way he’d come, praying that neither the chairman nor his mother would appear down the hallway. He opened the door inside the alcove that he and Ben had hidden in earlier. It led to a classroom-sized space with more chairs lining the walls. Smiles flicked the lights and closed the door behind them.

  “Two minutes is all this will take,” he said.

  He and Ben had drawn up a script for this discussion, and so far Smiles had followed exactly none of it. But it was coming back to him now. From his back pocket, Smiles pulled some pages he and Ben had printed off the Internet at the business center. They listed the first five hundred prime numbers.

  Smiles passed it over to the guy. “Could I ask your name?”

  “Ken Gary. And yours?”

  “Pick any two of those numbers, Mr. Gary. And don’t show me.”

  Agent Gary squinted at him. “What is this, a magic trick?”

  Ben said the agent would see the logic of the demonstration right away, and despite the guy’s moaning, Ben was right. His interest was piqued.

  “Pick the two numbers, multiply them together, and tell me what you get.”

  Multiplying the two numbers would create a public key—a gate key. If Ben’s algorithm worked, using that public key alone he’d be able to identify the two prime numbers the agent had picked—the private key, the house key. It would be solid proof that they could defeat public-key encryption.

  Smiles didn’t even have to explain it to him. The agent pulled out his phone and opened a calculator app. Smiles turned away till the guy coughed, ready to show him the display.

  Smiles copied the number into a text message on his own phone and prayed. Ben had written a quick program that would execute the algorithm on his computer. He called it a cipher. When he received the text, he was going to use the cipher and text back the two primes that the agent had picked. It was all in Ben’s hands now, and if he was somehow wrong about his discovery, Smiles was going to look like the biggest ass in the world.

  He pressed send and waited. The only delay, Ben told him, would be typing the number into his computer. Once he did that, the prime factors would spit right out.

  The agent barely had time to check his watch before an incoming text bleeped onto Smiles’s screen. It had two numbers in it.

  “17 and 2203,” Smiles said.

  The agent crossed his arms, and Smiles knew that Ben had gotten it right. “Is this some parlor game? You have these memorized or something? You have them written down somewhere?”

  “There are five hundred numbers on that page. That’s two hundred and fifty thousand combinations. That’s a lot to memorize, or write down.”

  “Who’s on the other end of the phone?”

  “My associate. He’s just keeping the cipher safe.” Smiles liked that. Associate. Pretty badass.

  The agent inspected the pages, like there might be invisible ink on them or something. Smiles had his full attention now.

  “Here’s what’s going to happen,” Smiles said. “You’re going to give me a line where I can reach you. Keep it open at eleven a.m. tomorrow. I’ll tell you where to meet me.”

  “What happens when I meet you?” The guy was trying to sound amused, but it wasn’t working.

  “Bring ten public keys with you,” Smiles said, getting back on script. “They can be a hundred digits, two hundred digits, however long you like. No parlor games, no magic. You choose the numbers. I’ll produce the private keys for you in seconds.”

  The agent sighed and scribbled a number at the top of the pages Smiles had given him. He gestured to Smiles’s phone. “How many people am I dealing with here?”

  “Two. Just me and my associate.”

  “And you’ll do the calculation in seconds?”

  “Seconds.”

  “And then?”

  “And then you’ll have three hours to wire seventy-five million US dollars to a numbered account in exchange for the cipher.”

  A pause. “Seventy-five million?”

  “You got it,” Smiles said, and walked out.

  71

  TWO HOURS LATER, they wer
e still giddy in the casino buffet. Smiles could hardly believe it had worked.

  Of course, they still had a long way to go, and of course, his plan never would have worked so well if it weren’t for Ben’s little touches. Like the idea for how they could demonstrate the algorithm, with Ben keeping it safe in their room. Or how Ben had told Smiles to ask for seventy-five million US dollars. Like they needed to clarify that. Those kinds of things, they made all the difference.

  Ben got up for another pass at the dessert spread, and Smiles looked out to a craps table swarmed by a bachelorette party. A girl in a white veil tossed the dice, cheered on by friends in identical blue T-shirts (TEAM LIZZIE) sucking down drinks from fluorescent cups. Smiles watched them and felt a desire to call Melanie. That always happened when he felt good about something. He couldn’t do it now, though. It was past eleven o’clock already, and besides, she’d just broken up with him.

  Then an even stranger feeling washed over him. For a second, it paralyzed him. Actually wanting to talk to his dad—it almost knocked him out right there at the table. It was a comfortable feeling—a great feeling—but it came from such a buried place that it stopped him cold. It felt like those odd occasions when he caught a whiff of macaroni and cheese and memories of Rose, his true mom, flooded through him out of nowhere.

  Smiles extracted his cell and dialed the hospital. Shanti answered the line at the neuro-oncology unit. “Hey, what are you doing there so late?” he said.

  “Wrapping up a long day, darling.” He could hear her exhaustion. “How are you?”

  “Not too bad. I left town for the weekend, but I was wondering if maybe my dad was still up?”

  “That’s sweet,” Shanti said. “I know he’d love to hear from you, but honestly he had a sort of rough one and just got to sleep.”

  “Yeah, sure, okay.” He wondered if it was worse than she was letting on. But then he bantered with Shanti awhile, and Ben brought a huge slice of cake back to the table, and he felt better.

  Before he hung up, Smiles took a wedge of cake that Ben offered and told Shanti, “Hey, I’m having some birthday cake after all.”

  “Good, ’cause we finished yours in the break room tonight,” Shanti said, and he could hear the smile in her voice. He clicked off and dove into the cake. He and Ben grinned stupidly at each other while they demolished the red velvet.

  It tasted like triumph.

  She was sitting on the carpet by the door to their room. Still and defeated—like a room service tray put out for the night.

  Her head hung down between her knees, her thin streaks of butterscotch hair sagging to the floor. He had given her his room number earlier, hoping that she’d ditch Zach and pay him a late-night visit. But something wasn’t right here.

  Smiles held Ben back. She hadn’t seen them yet.

  He knelt as he approached, wondering if maybe she’d just gone to sleep waiting for him.

  “Erin?”

  She sniffled, then slowly raised her head. Her hair fell back and he could see her face, beautiful even with the swollen red eyes that she turned to him.

  “What happened?”

  “Can I stay with you?”

  Smiles liked the way she asked it right out—no big preamble, no need to explain herself. She’d been crying for hours, but she had steel inside her.

  “Yeah, sure.” Now they wouldn’t be able to go over their plans tonight. Ben would have to deal with it, though—Smiles wasn’t about to turn Erin away.

  Ben just stood there staring down at them, failing to pick up the social cues that 99 percent of the population would have acted on by now. “Give us a sec, huh?” Smiles said from his crouch.

  “Oh, yeah, okay.”

  Ben slipped into the room, and Smiles gave Erin a hand up. She had a hipster-ish messenger bag across her shoulder. You could barely see its green canvas through all the patches from jazz festivals and buttons about the virtues of biking (REAL GIRLS RIDE HARD, etc. etc.). The knit shoulder strap was biting into her delicate shoulder. Smiles eased it off her and down to the floor. They stood awkwardly close to each other for a second, with Smiles feeling protective of her in a way he never did with Melanie. Melanie never needed that. She was always ten steps ahead, charting a smooth course through life while he went off the map. Without thinking he wrapped Erin in a hug. She held him tight, desperately tight, crushing the air out of him until he got a slight high from lack of oxygen.

  “He’s a bastard,” Erin said into his chest.

  It probably wasn’t right, but Smiles couldn’t help thinking, Jackpot.

  “God may not play dice with the universe, but something strange is going on with the prime numbers.”

  —Paul Erdös

  SATURDAY

  “I think I’ll go to Boston

  I think I’ll start a new life

  I think I’ll start it over

  Where no one knows my name.”

  —Augustana, “Boston”

  73

  THE FIRST HINT of sunrise peeked through her window just after six o’clock. Melanie never needed an alarm clock to wake up, least of all today. She’d been stirring since four thirty a.m. The pale radiance against her curtains was the only excuse she needed to hop out of bed and into the shower.

  When she went downstairs, her dad was standing at the kitchen island with the Boston Globe splayed out on the marble countertop. There was something commanding in that stance, the way he surveyed the paper from above like a battlefield map. He saw her at the edge of the room as he sipped from his coffee mug.

  “Early start,” he said approvingly. “One for the road?”

  “Yeah, thanks.” She dropped her suitcase but didn’t bother taking off the laptop case strapped over her shoulder. She wanted to get going.

  Her dad gestured to the computer as he poured her a travel mug of coffee. “You’re not planning on doing work up there, are you?” He was always worried she spent too much time on homework.

  “Nah,” Melanie said. “Just in case I need it for something.”

  What that something might be, she didn’t say. She hadn’t even admitted it to herself yet.

  Instead she flipped through the other paper on the counter, The New York Times, and tried to savor this moment with her dad. Every morning he read the Globe, the Times, and The Wall Street Journal. When she was little, her favorite part of the day had been sitting on his lap at the breakfast table, feeling the comfort of his terry-cloth robe as he read the news before heading out on his important business. Last year he’d bought her a monogrammed bathrobe for Christmas. It felt adult; it felt like a new chapter in their morning tradition.

  But the Andrei Tarasov story had made her question everything about her father. She didn’t know what she would discover about him next, and this morning, this coffee together, didn’t feel like a new chapter. It felt like an ending.

  She touched the plush robe and gave him a kiss on the cheek.

  “Good-bye, Dad,” she said.

  For an hour, she went through the motions of driving to Smith College.

  Katie’s expecting you.

  It’s rude to break plans at the last minute.

  What if Dad found out?

  The tug of guilt was just about the only thing keeping her on the Mass Pike toward Smith. And normally, guilt could make her do anything. But now it was competing with the unanswered questions about her dad. Questions about why he had kept the Tarasov suicide from her. And what it all might have to do with Alice’s letter to Smiles.

  She passed a sign announcing an exit in one mile. The symbols running at the bottom promised a gas station and restaurants. She had made this decision unconsciously last night, after being shooed away from Andrei Tarasov’s house. But only now, as her car angled onto the off-ramp and slowly separated her from the highway, did she realize she was really going through with it.


  She was just pulling off the Pike, but it struck her as a momentous event, as if she were somehow leaving the track that her life had been on for seventeen years. The Pike fell away to her left and the exit ramp rose to a desolate street running straight in both directions. The yellow line in the middle had nearly faded to nothing. It was seven o’clock in the morning, and life hadn’t started here yet, wherever she was.

  The red traffic light tilted in the morning breeze. It felt pointless to wait for it—like the apocalypse had come, the rules had gone out the window, and all the traffic lights and highway signs and road markings were nothing more than curiosities of a bygone age. Still, she waited at the vacant intersection for the ridiculously long light.

  Melanie had never felt so alone, so untethered from her dad and Smiles and anything else that mattered. Sitting there at the empty intersection, waiting for the light, she began to cry.

  Finally it clicked green. Melanie turned right arbitrarily, and through her tears saw a coffee shop down the road. The kind of place that might have free wireless. She knew what she was going to do there: search Rose’s email account for any more messages about Tarasov or the mystery letter from Alice, Smiles’s birth mother.

  She nosed her car into a parking space. The sunrise was in full flower now, glancing off the Camry’s hood in indigos and pinks. She’d never done anything this irresponsible in her life. She was going to break her plans with Katie without telling her parents or even having the first clue of where she would stay tonight. This was crazy. But the beautiful dawn assured her it would be okay.

  Maybe it was just her biorhythms, or stress. Either way, she seized the delirious confidence that came over her. Her heart lifted as she got out of the car. Her cheeks dried in the wind, and she laughed out loud in the parking lot, giddy in a way that only happened when she stayed up too late or studied for ten hours straight.

  The coffee shop was lonely at this hour but filled with a consoling bakery smell. They had made it cozy, with low tables and soft chairs running the length of the shop. Melanie sat down and got out her phone. She was cutting herself loose from the world, and for that moment it felt like freedom.