“What do you mean gone.”
“The Bitcoin,” she said. “The target. It moved. It’s in a block.”
“Okay.” He sat up, his body slowly catching up with his brain. In the darkness, he said, “Okay. Walk me through it. Start at the top.”
As he listened, he realized Persephone, the algorithm Sam had been working on, had returned a real private key off a real public one. She’d pointed his harness at the address to double-check. The harness had spent the coins.
His harness.
He skipped past that, avoiding the implication.
“So Persephone works,” he said.
“Marcus —”
“No, I hear you, it’s out, I get that. I’m just — it works. Persephone works.”
The silence on the line told him she’d already been all the way around this loop and out the other side.
He got up and walked to the window. The town of Basalt was fast asleep. The dark shape of the mountains loomed in the background.
Sam had done the math, but he needed to do the next part. He’d raised eleven million dollars telling rooms full of serious people a story about a machine that might one day do something useful with very cold atoms. Most of the people in the rooms understood the implication — a real quantum computer ended RSA, ended all digital locks in the world. Everyone thought this was a decade away, needed a giant machine, and was someone else’s problem. He let them believe this. But Sam hadn’t built the giant machine. She’d figured out the math that meant nobody needed one. And it now worked.
Shit. It worked.
Every signed software update. Every certificate behind every padlock in every browser. The login at his own bank, which he’d checked from an unencrypted network at CC’s Cafe yesterday. Ugh, that was dumb.
He knew she could. But he hadn’t thought much about what happened after that. He hadn’t been careful with the harness because he didn’t think it would just work.
The proof was now published and couldn’t be taken back. It was a fact now, sitting in a block that would be discovered quickly.
He needed to tell their investors. No, not all of them. Just someone. Someone other than the three of them needed to know. Someone with experience and a cool head, who’d take it seriously but would know what to do. The short list of people he thought of quickly converged on one. Seth.
Seth was the steady one. Seth was experienced enough to have watched a lot of things go sideways without flinching. He was loyal. He was only four hours away in Boulder. If this was going to get loud and complicated, he wanted Seth in his corner before it did. Seth needed to know before it got out.
He took the phone from his ear and thumbed out a text. We have figured out something monumental — call me when you wake up.
He hesitated. He was being careful — not really saying anything. He left it at the one line.
He sent it and put the phone back to his ear.
Marcus realized Sam wasn’t saying anything. He could hear her breathing. She was waiting for him.
“How long,” he said, “before someone smart sees it for what it is.”
“Minutes probably. Maybe an hour. It depends who’s looking. The transaction’s anonymous. There’s no name on it.”
“There’s no name on it yet,” he said, gently, because she was the smartest person he knew and she was also exhausted and scared and wanting it to be smaller than it was.
Then his phone buzzed against his ear. A notification.
While he’d installed Signal two years ago for a paranoid reporter, he never really got into it. Sam rode him constantly that he wouldn’t keep the encrypted stuff running, wouldn’t do the dance, used green-bubble texts, and used his actual name for everything. He was CEO — being reachable was his job.
The sender had a name he didn’t know. Daniel. No last name. No photo.
“Sam, hang on, I just got a Signal message.”
Marcus — saw what moved tonight. Quite a thing. You’ve got more friends than you think, and fewer than you’ll need. Before anyone else gets to you, we should talk. There’s a clean version of how this goes for you and your partner. I’d hate for you to find the other one first.
He read it to Sam.
Sam said, “Shit. The coins have been in a block for less than ten minutes. Who is Daniel?”
“I have no idea. He’s a stranger. You know I don’t use Signal.”
He stared at the message. Your partner. Not a co-founder. Not the company. Partner, like the man had been in the room.
Silence. The warm part of him, the part that woke first, wanted very badly to type back.