“We do.” She returned to the kitchenette and stirred the kheer. “The Babylon Casino has a keno computer from 2002. Old but reliable—just what casinos like. The manufacturer has excellent documentation online, so I know exactly how the random qbit values will be made into random numbers. Running that operation on our own qbits will give us those same random numbers. That algorithm is the ‘agreement in advance.’”
“Why not entangle all the qbits and not just the long-term storage ones?”
She tasted the kheer. Just right. “Entanglement isn’t permanent. Those magic dice I was talking about? They only work once. After that roll, the spell is broken, and they have nothing to do with each other. If you roll them again, there will be no magic. Just two random numbers. So you get one roll—just one—where you know how the other die will be affected.”
“I see,” Prashant said. “So I assume the normal function of the 707 reuses qbits over and over?”
She served a generous portion of kheer into a bowl. Prashant loved sweet food and always wanted more than he claimed. “Yes. The casino’s keno machine would exhaust our supply of entangled qbits in seconds. So the trick is making them use the long-term memory as RAM and striking right at that moment.”
Prashant pushed his plate aside to make room for the bowl. “How do we do that?”
“The 707 does a coherence self-check once a week. When you install the system, make sure those settings are set to do the self-check this Sunday night at 11:58 p.m.”
She adjusted her sari. American clothes certainly looked nice on Americans, but she preferred traditional clothing. “The self-check takes about five minutes. During that time, if the system is asked to do qbit operations, it uses the qbits in the long-term storage unit because the normal RAM is busy. The Babylon does keno draws every fifteen minutes—there’ll be a draw at precisely midnight on Sunday. That’s when we strike. We only have one attempt, though. The long-term memory has 512 qbits, and a keno draw is twenty eight-bit numbers.”
Prashant raised a finger. “Twenty numbers would only be 160 qbits. So we have, like, three tries before it eats all 512.”
She shook her head. “The numbers each have to be unique, and they’re all in the range of one through eighty. There will be a lot of duplicates drawn. The computer will have to generate random numbers until twenty unique numbers are drawn.”
“Ah.”
“Once the system hits the end of the long-term memory, it’ll loop around, re-randomizing, and reusing the already-measured qbits. We’ll have no information on any of that.” She sighed. “This all would be much simpler if I could modify the computer itself before you install it.”
“We’d never get away with it,” said Prashant. “There’s a factory seal over every entry point, and the OS is on a ROM. Same with the long-term memory module. It was easy enough to sneak it here for you to prepare it, but if we try to open it or modify the hardware, the casino will know when they look over the system.”
She set the kheer in front of him, along with a fresh spoon. “Are you sure they would even notice?”
He nodded. “Pretty sure. I spoke to the Babylon’s IT manager on the phone. He’s . . . very diligent. He’s extremely thorough.”
“Then this is the only way,” she said. “Fortunately, the long-term memory comes pre-superpositioned. The system will skip the Hadamard operation on first use.”
“I didn’t understand that at all.”
“All that matters is that the system has a minor performance optimization that creates the security hole we’re going to take advantage of.” She returned to the living room and sat at the computer. “Now is as good a time as any to get the numbers . . .”
“Wait, what?” he said. “Now? I don’t understand.”
She typed a few commands on the console. “Entanglement is a two-way street. I can measure one storage unit’s values right now, and the others will be the same whenever the Babylon measures them.”
“So you’re basically . . . generating the keno numbers for Sunday night right now?”
“Yes.” She hit the “Enter” key. A stream of numbers showed up on-screen. She stared at the screen intently, memorizing the output. Ganesh had blessed her with an excellent memory.
“Those are it? The numbers?”
“Yes,” she said, keeping her eyes locked on the screen.
“You’re memorizing them?” he asked. “Why not just save them to a file or take a pic with your phone?”
“No.” She shook her head. “No digital trail. Everything is purely in my mind from here on out.”
“Ah, right. Makes sense.”
She closed her eyes and visualized the numbers. All twenty of them were clear in her mind. She opened her eyes to double-check against the screen, and she’d gotten them all correct. Perfect.
Prashant stirred his kheer. Uncharacteristic of him not to dig right in.
She turned the swivel chair toward her husband. “What’s wrong, honey? You still seem unsettled.”