Usually, Nathan felt his cares lift a little as he turned the car onto Yuculta Crescent. Today, he had to resist an urge to drive past, even just go home.

Nathan passed parked RVs and sports cars as he looked for an empty spot. As he walked back to a modest ochre house, he heard voices: teenagers talking about trading items in some online-game world. Nathan hesitated again. I could still go back to the car, let Grace find out from somebody else. The temptation was almost overwhelming.

The image was still with him from this morning, of Alicia stabbing her spoon into her coffee cup as she paced in the kitchen. “It’s all our money, Nathan! You didn’t just put your savings into it; you convinced me to put mine in too. And now you tell me the bottom’s falling out?”

The day couldn’t get any worse after that; so Nathan started walking again.

At one time this part of town was full of white working-class families with shared values and expectations. Now, the houses were worth millions and, Grace said, nobody knew their neighbors. The two aboriginal kids sitting on the porch stared at Nathan suspiciously as he walked up.

“Is Grace here?” he asked.

“In the kitchen,” said one, jabbing a thumb at the door. Nathan went inside, past a small living room that had been remade as office space. Three more teens wearing AR glasses stood in the middle of the space, poking at the air and arguing over something invisible to Nathan. Dressed normcore, in jeans and T-shirts, each also bore a card-sized sticker, like a nametag. SMILE YOU’RE ON BODYCAM. Little yellow arrows pointing to a black dot above the words: a camera. The kids on the front porch, he realized, also wore something like that.

Grace Cooper was sitting in a pool of sunlight in the kitchen, reading a tablet, her smile easy and genuine as she rose and hugged him. “How’s my favorite coder?”

Nathan’s stomach tightened. Shall I just blurt it out? The currency is crashing, Grace. We’re about to lose everything. He couldn’t do it, so he sat.

Nathan had known Grace for almost two years, but it was a long time since he’d had to think of her as the client. In fact, she was just the representative; the real client was an aboriginal nation known as the Musqueam who’d lived on this land for thousands of years. Small matter that they’d invited him into their community, their lives. He should have kept his distance.

A few years before he immigrated, Grace’s people had won a centuries’ old land claim that included a substantial chunk of downtown Vancouver. The University golf course, Pacific Spirit Park and much of the port lands south of that were now band territory. That and other settlements had finally given the indigenous peoples of the west coast a power base, and they were building on it. Until today, everyone had benefited—including Nathan.

She sat down after him. The sunlight made her lean back to put her face into shade. “Did you see the news?” she said. “Says Gwaiicoin is doing better than the Canadian dollar.”

It was. He’d checked it fifteen minutes ago, and half an hour before that, and again before that. He’d been up all night watching the numbers, waiting for the change. He shrugged now, glancing away. “Well, the dollar’s a fiat currency,” he said neutrally. “They’re all in trouble since the carbon bubble burst.”

“And because they’re not smart,” she added triumphantly. “Thanks to you guys, we got the smartest currency on the planet.”

“Yeah. It’s been . . . quite a roller coaster.” Maybe if he talked about volatility, about how most cryptocurrencies had failed . . . Even the first, Bitcoin, had only been able to lumber its clumsy way forward for so long. But all of them had weathered the bursting of the carbon bubble better than the dollar, the pound, or the Euro.

One of those currencies was Gwaiicoin. Nathan had first heard about it while couch-surfing in Seattle. He and six other guys had struggled to make the rent on a two-bedroom apartment while housing prices soared. The smart programmers left, hearing that living was cheap on Vancouver Island, and just west of the Alaskan Panhandle in the archipelago known as the Haida Gwaii. As Seattle priced itself out of liveability, the islands where the iconic totem poles stood suddenly became crowded with restless coders.

One result had been Gwaiicoin—and, when Nathan arrived here, unexpected and welcome employment.

“Gwaiicoin’s about to be worth a lot more,” Grace was saying. “Once my recruits have added Vancouver to the Gwaii valuation.”

Nathan looked through the serving window at the half-visible teens in the living room. “Recruits?”

She leaned forward, her nose stopping just short of the shaft of sunlight. “We’re talking with City Council about measuring the biomass in the Musqueam, Squamish and Tsleil-Waututh parts of the city. These kids are my warriors. They’re programming drones to measure the biomass.”

Nathan nodded towards the street, throat dry. “Good place to start.” His mind was darting about, looking for a way to bring her down gently. Then he realized what she was saying. “Wait—you want to add the local biomass to Gwaiicoin?” Unlike Bitcoin, which had value because of its miners and transaction volume, Gwaiicoin was backed by the value of the ecosystem services of its backers’ territories.

She nodded enthusiastically. “Even the Inuit want to get in on it. The more biomass we all commit, the bigger our Fort Knox gets. It’s brilliant.”

Should have seen this coming, Nathan thought. As the dollar crashed, Gwaiicoin had soared. The government wanted it, but since the Haida were backing the currency with land that the feds had formally ceded through constitutionally binding land-claims settlements, the feds were beggars at the table.

“You know, you spent a whole day trying to convince me that a potlatch currency was crazy. Remember that?” Grace grinned at him.

“Yeah.” He looked down. “Who’d have thought self-taxing money would take off?”

She sighed. “And still you call it a tax. That was the whole idea—you get eminence points for every buck that gets randomly redistributed to the other wallets.”

“Yeah.” Despite being a lead on the project, Nathan didn’t have much eminence. He wasn’t rich, so his wallet didn’t automatically trim itself—but even some of Grace’s poorer neighbors voluntarily put large chunks of their paychecks into redistribution every month, via the potlatch account everyone shared. Redistributed money was randomly scattered among the currency-users’ wallets, and in return the contributors got . . . nothing, or so he’d argued. What they got was eminence, a kind of social capital, but the idea that it could ever be useful had never made sense to Nathan.

Ironically, it made sense now. If Gwaiicoin were to vanish overnight, the people who’d given it away would still have their eminence points. These were a permanent record of how much a person had contributed to the community.

And he had none.

He took one last deep breath and said, “Grace. We have a problem.”

Somewhere nearby a phone rang. “Hold that thought,” said Grace as she hopped up and rummaged for a phone among the papers on the counter. “Hello?”

Nathan watched the flight of emotions cross her face; they settled on anger. “I’ll be there in half an hour,” she said tightly, and put down the phone.

She avoided Nathan’s gaze for a moment. Then she said, “Well. Jeff’s been arrested.”

• • • •

“I’m going downtown anyway,” said Nathan. “I’ll drop you at the station.”

“I could take a driverless,” she said as she hastily gathered up her stuff. “They got those new self-owned ones, too, just cruising around looking for a fare.”

“They’re creepy,” said Nathan, and she grinned briefly, nodding. As they passed the kids in the living room, Grace said, “Lock up if you go out.”

Nathan glanced back from the porch. “You know them well?”

“These ones? No. But to use this hackspace at all you gotta wear a badge.” She patted her own lapel. “And the house knows what’s in it, and what shouldn’t go out the door.”

Supposedly there was some new privacy protocol in play, but Nathan had been too immersed in Gwaiicoin protocols lately to explore the technology. The kids seemed comfortable having eyes on them all the time, but he wasn’t used to it, anymore than he was used to passing empty cars driving down the road.

He preferred to keep his own hands on the wheel, but as they drove now he found he was twisting his hands as if trying to strangle it. Grace didn’t seem to have noticed. “Who’s Jeff?” he made himself ask.

“One of the kids. He’s Haida, his uncle’s a carver on the Gwaii. Probably should introduce you.”

“But he’s been arrested . . . ?”

“It’s just harassment. You know they do that to us all the time.” She glared out the window, but her expression gradually softened. “It’s getting better. Gwaiicoin gives the poorest of us some money every month, and the richer the rest of us get, the more goes to them. No Department of Indian Affairs doling it out. Less harassment. It’s working, Nathan!” She rolled down the window and cool air curled in, teasing her hair.

When they pulled into the police station’s parking lot, Nathan hesitated. “Why don’t you come in?” said Grace. “This won’t take long. Then you can meet Jeff.”

“All right.”

Of course, it took longer than it should have. Service systems hadn’t made it to the Vancouver Police Department yet; any other government office, and Grace could have called in her request or used her glasses and let the computers facilitate it. Here, she had to speak to a desk sergeant, and then they waited in the foyer with a number of other bored or frustrated looking people. While they stood there (all the plastic chairs were full), Nathan said, “Is Jeff a carver?”

She shook her head. “That’s his uncle’s thing. No, Jeff’s studying ecology and law, like any decent Haida these days. Today, he was supposed to be adding new sensors to the downtown mesh network.”

Nathan nodded and they sat there for a while. Finally, Nathan said, “Grace. There’s a problem with Gwaiicoin.”

She’d been chewing her lip and staring out the window. Now she focused all her attention on him. It was quiet in the waiting room, with no TV, no distractions. Nathan squirmed under her gaze.

“There’s been a Sybil attack,” he went on, feeling a strange mix of relief and panic that made the words impossible to stop now. “It’s supposed to be a one-person, one-wallet system. Otherwise the rich can just make millions of wallets for themselves and when their full wallets trigger a redistribution, chances are the funds will end up back in an empty wallet they already own.”

She crossed her arms. “I thought that’s why you made the deal with the government. It’s one wallet per Social Insurance Number.”

“Yeah,” he hesitated. “Somebody’s hacked the SIN databases. Made, well, about a million bogus citizens. And they’ve built wallets with them.”

Grace’s eyes went wide and she stood up, fists clenched.

“Maybe . . . Maybe it’s fixable,” he said, spreading his hands. “I mean, the Sybil attack . . . it’s never been solved, every cryptocurrency is vulnerable to it, we’re no worse than Bitcoin was in that sense but of course the potlatch system is critical in your case . . .” He knew he was babbling but under her accusing gaze he couldn’t stop himself. “I mean, when Microsoft looked at it they decided the only way to prevent Sybils was to have a trusted third party to establish identities, so, so—” He was desperate now. “That’s what we did, Grace! We used the best approach there was. And you know, it’s not just a problem for us, the government’s got to fix it or the whole SIN Number system is compromised . . .”

He could see she wasn’t listening anymore. Instead, she was putting together a reply. But just as she was opening her mouth and starting to point at Nathan, an officer behind the counter called out, “Grace Cooper!”

She glared at Nathan, snapped her mouth shut, then went behind the security screen with another officer. Nathan could see them through the glass, and debated whether he should just go. But he was a big name on the development team, and the others—well, they were all quiet today. Hiding in their beds, he’d bet. Leaving him to take the heat; but maybe that was the way it should be. He waited.

Grace’s conversation with the cop was surprisingly brief. The officer didn’t look happy, and when they bent over a laptop together and he read something there, he looked positively furious. Grace came out a few minutes later, looking darkly satisfied. “He’ll be right out.”

“What happened?”

“He was in one of the ravines in the University Endowment Lands, nailing sensors to trees. Somebody heard him or saw him and called the cops. They found five hundred dollars in his pocket. Figured an aboriginal kid wouldn’t have that kind of money ’cept by stealing it. So they trumped something up and brought him in.”

Nathan looked past her at the cop, who was now angrily talking to another officer behind the glass. “And what did you just do?”

“I fixed it.” She crossed her arms again and pinned Nathan with accusing eyes. “What are you going to do, Nathan?”

“Fix it! Of course, Grace, why do you think I came to you? All my money’s in Gwaiicoin! Mine and . . . Look, if this goes south I go down with it. I know I gotta fix it.”

She didn’t reply. A few minutes later a young man with shoulder-length black hair and a wide-cheekboned face came out, lugging a backpack. “Hiya, Grace,” he said, unsmiling. “Hell of a day.” Then he squinted at Nathan. “Hey.”

“This is Nathan. He was just leaving.”

“Right. Just leaving. Listen, Grace, I . . .” Her face was an impenetrable mask. Nathan’s shoulders slumped and he turned away.

“I’ll talk to you soon.”

• • • •

Alicia was waiting for him when he walked in the door. “Tell me why I can’t pull my money!”

While Nathan visited one development team member after another, she had been texting him with this exact question, and he’d been fending her off as best he could.

“Because the news hasn’t hit yet,” he said as he kicked of his shoes. “Until this goes public, anything you or I do is going to look like insider trading. Hell, it would be insider trading. That’s why nobody else on the team has bought out yet.” He went straight to the kitchen and rooted around in the fridge for a beer. “But trust me, they’re all sitting at their desks with hands hovering over the mouse, waiting for the news to break.”

“But don’t you know when that’s going to happen? The bottom’s going to fall out of Gwaiicoin. We’ll lose everything if we don’t sell now.”

He stalked into the living room and sat down. The couch faced out over Blanca Street, and the forested campus of the University of British Columbia. You could see Musqueam lands from here. “We all know that.” He savagely yanked the cap off the bottle and took a deep pull, glaring at her. “It’s up to the government to make an official statement and they’re sitting on it for now. And for the rest of us . . . none of us can be seen to be the first to bail. Who’d want to be known as the guy who kicked off the biggest crash since the Great Depression?”

“It’s not that big,” she said.

“It is to us. To the Haida. And the Musqueam and the others.”

“So you’re all holding your breath. But should I?”

He blinked at her. “Insider trading. Besides, do you want to be known as the one who brought down Gwaiicoin?”

She thought about it. “I would if I had to. It’s my money.”

“And that’s why it’ll go all the way down when it goes. But your reputation—your career—isn’t riding on this. Mine is. Just . . . just hold off for an hour or two.” He made a patting gesture with both hands, as if to keep the whole issue down. “I’m sure it’ll hit the news tonight.”

Her lips thinned; she whirled, and went back to the kitchen, to bang around in the cupboards.

A year ago Nathan’s safety net had been this condo and another one—an investment property in the suburbs. No matter how the Gwaiicoin experiment did, he had wealth sunk in real estate. Now, housing prices were collapsing in the downtown core. There was general flight from one of the priciest markets on the continent. He’d seen little signs of the decay just now that only a local would notice: the paint was peeling on the garage doors, the exhaust fans in the wall weren’t running. Homeless people were living under the neighborhood’s bridges.

So he’d sold off his investment property and put the money into Gwaiicoin.

Rather than turn on the TV, he put on his AR glasses, went to stand on the balcony and gazed through the damp air at the park.

Shadows leaned in from the right as the sun neared the waters of the Strait. He loved to sit out here and watch the sunset proceed, the lights come on in their thousands as night fell. The city’s gone quiet even since I moved here. The incessant hum of distant internal combustion engines had become rare as electrics took over. Some said that quieter cars were also responsible for more people strolling, not walking, in evening light like this.

Nathan sighed and called up the Gwaii overlay in his glasses.

The heads-up display showed a silent aurora above the city, its rippling banners of light made of thousands of thin vertical lines. Each line signified ownership—of houses, cars, shops—inferred by algorithms that constantly rifled through public databases and commercial stats. The lines joined and rejoined overhead, becoming fewer, showing how most of the houses were really owned by this or that bank; how businesses were in debt to other businesses. All those relationships of ownership and debt consolidated and narrowed as the line rose, joining in private and public corporations, and these sprouted lines to names. Compared to the dizzying complexity at street level, there were very, very few names up there at the top.

Nathan hadn’t built this overlay, and didn’t know who had. Whoever it was, they designed in a subtle gray-white background that you could only see by standing in the dark and looking up. The image was one of the Art Deco cityscapes from the old movie Metropolis.

He turned on Fountain View, and now the lines pulsed faintly in rising waves. Those ascending glimmers represented money. Some of it rose only to fall again, but some kept on rising, clustering, concentrating, fleeing far over the horizon or ending in the tangle of names above the city. You could change the lights into numbers, and they would show more money going up than was coming down.

Lately Nathan imagined an invisible line coming out of his own head, gutting him like a hooked fish. It was his debt, tugging on him day and night. Money flowed up that line and never came back. If not for the Gwaii, it would suck up his car and his condo; so he turned on that view. It usually reassured him.

A different tangle of lines sprouted from the darkening city—gold, not that wan green, and sparser. Value rose up those bright lines, too, and twined and knotted over the city. But it fell, too, in fine thin lines like a mist of rain. If you converted the lines to numbers, you’d see that almost as much fell back as rose. It concentrated, but in the middle rather than at the top. And coins that flew off over the horizon were usually matched by others coming back.

“Help me with this,” called Alicia. Nathan went back in to chop onions, but he kept the overlay active.

One of the Gwaiicoin experiments he’d been involved in was a vase on the corner of the counter. He’d bought it entirely with Gwaiicoin, and it had a virtual tag on it that was different from the others sprouting from his furniture, dishes and clothes. The tag said he wasn’t the owner of the vase, but its steward. Such stewardship contracts were the default in any transfer of assets managed entirely through Gwaiicoin. The contract was registered in the Gwaiicoin blockchain, forever beyond the reach of hackers or thieves. It said that the vase was subject to potlatch like his Gwaiicoin, and someday, its virtual tag might change, telling him that the thing had a new steward—somebody picked at random by the algorithm of the coin. He would gain eminence if he gave it to that person. He’d been reluctant to try that out, and Alicia had suspiciously called it “voluntary communism.”

Communism. Such a quaint old word. A twentieth-century notion, a square peg for the 21st century’s round hole. Still, right now the vase was changing its tag—the invisible one in Nathan’s imagination. From being a sign of his triumph, it was rapidly becoming a symbol of his defeat.

There was nothing on the evening news, but the pressure kept growing inside him. He stood, he paced. Alicia watched, arms folded, from the couch. He monitored the Gwaiicoin developers’ chat room, but nobody was there. They were all waiting. Somebody would have to make the first move.

Finally, at eight o’clock, social media started lighting up. Sybil Attack. Gwaiicoin compromised. As the tweets and posts began flying fast and furious he turned to Alicia and said, “Do it.”

As she raced to get her laptop, Nathan sat down and dismissed all his overlays. He called up his financial app and sat for a long time looking at the impressive balance on the Gwaiicoin side, and the nearly empty one in dollars. Below his Gwaiicoin balance was a link for voluntary transfers to the potlatch account.

I could drop my coins back into dollars, and just walk away. Across the room, the clattering of Alicia’s laptop told him what she was doing.

He stared at the other link. He was partly responsible for dragging thousands of people—mostly poor to begin with—into this fiasco. If he put his money into potlatch, he would lose it as surely as if he’d burned wads of dollar bills. The coins would instantly appear in others’ wallets, randomly scattered among the emptiest of them. Some would be lost to the Sybil attackers, but most would go to real people. Then, those people could cash out in dollars, and end the Gwaiicoin experiment with just a little more than they’d had this morning.

And he would have nothing. Except, in the form of eminence, proof that he’d tried to help. Not monetary capital, but social capital.

Nathan sat there for a long time. Then he slowly reached out, and made a transfer.

• • • •

At ten, he went for a walk.

It wasn’t raining, and it was summer; so you walked. He’d always enjoyed strolling along Blanca, with its tall walls of trees and hedges, the suggestion of darkness over the western streets that came from the presence of the UBC forest lands. You passed through that forest on your way to the campus, which dominated the end of the peninsula. Taking University Boulevard, you could peek past the trees lining it to the golf course on either side.

Except he never went that way. It was all Musqueam territory, and while they were clients and friends, they had also filled the place with cameras and drones. These didn’t bother him so much around Grace’s house, but here, as a solitary walker, he became self-conscious.

He walked, head down, and didn’t look at the overlays. He imagined it anyway: the slow, ponderous collapse of that pyramid of golden light that he’d seen hovering above the city earlier. The first rats leaping off the ship would alert everybody else, and by now everybody would be selling. It would be a classic financial collapse, and he had helped set it off. Who was going to hire him now?

Somehow his feet had carried him south to 10th Avenue and University. Off to the right, the golf course gleamed in the evening light. The BC Golf House was also alight and its parking lot full, mostly with pickup trucks and new model electrics, not the pricey sedans you usually saw there.

He saw a car pull in, stop, and Grace Cooper got out.

Now he remembered: there was supposed to be a social tonight. The councils were coming together to talk about their successes. Grace had told him about socials last week. “They used to have them in the Maritimes and prairies all the time. You just rent a hall, buy a liquor license and find some garage band that’s willing to come out and play. Then call all your friends, and they call their friends . . .”

The hall’s front doors were wide open and people were standing around laughing and talking on the walk. Nathan ran under the weave of electric bus wires that canopied the street, and came up behind Grace just as she was about to enter. “Grace!”

She whirled. “What the hell are you doing here?”

He stopped, hesitated, then squared his shoulders. “I got us into this mess. Are any of the other developers here?”

She shook her head.

“Somebody has to take responsibility—” He made to enter the hall, but she stopped him.

“You’re not going to talk about it, and I’m not going to either because that’s not what tonight’s about. I don’t want you to make it about this. We’re celebrating other things here—things we actually accomplished.” He flinched from her emphasis. It was suddenly obvious why the social was happening at the Golf House. Tiny it might be, but it was on Musqueam land. Land they had taken back.

“What’s done counts,” she said. “What we tried . . .” She shrugged. “Not so much.” Then she moved out of his way. “Go on in, I can’t stop you.”

He almost turned away, but whatever he told himself, these people were not just clients. He wanted to be able to look them in the eyes after all this was done. “I won’t bring it up,” he said. “But others will, and they’ll want to know what I’m doing about the situation.”

“Which is?”

He opened his mouth, throat dry, and couldn’t say it. He just pushed on past her, into the hall.

A folk ensemble was playing. There were tables around the sides of the hall and people roved, chatting. Nobody was dancing but the atmosphere was upbeat. And it should be; here were the inheritors of stubborn cultures that, after five hundred years of often-systematic oppression, were still here.

And were they ever. For the next hour Nathan passed from table to table, saying hi to people he barely knew and, through them, meeting other focused and determined citizens of Canada’s youngest and fastest growing demographic. These were kids in their late twenties and early thirties who’d made great money in the oil sands and northern mines, and were now here starting families and pouring their wealth into the Maa-Nalth Treaty Association, the St’at’imc Chiefs Council or the Carrier Sekani Services. Several of these organizations were rapidly mutating into shadow governments in central B.C. There were so many historical groups, so many unpronounceable names and treaty claims that you’d think it was all chaos. There was an emergent order to it all, though. Gwaiicoin and the blockchain were supposed to be helping with that.

He could see it in their eyes; everybody knew about the Sybil attack. They knew what it meant, but nobody confronted him. Somehow, that hurt more than if they’d beaten him and thrown him into the parking lot.

After a while, exhausted, he found himself sitting across from Jeff. Casting about for something—anything—other than Gwaiicoin to talk about, Nathan asked, “How did Grace get you out so quickly today? Or shouldn’t I ask?”

Jeff pried the material of his shirt forward to show his bodycam. “I told the cops myself, but they wouldn’t listen. This thing has been uploading a low-frame‒rate video stream constantly for the past month. Every frame is signed with a hash and What3Words coordinate and timestamped in the GPB. That’s the, uh, Global Positioning Blockchain. The GPB can verify where I was every second of every day and prove I didn’t break into anybody’s house. When I told them that, they wanted to see the video, but I told them to fuck off. They didn’t have the right. So we were . . .” He seemed to choose his next words delicately. “At an impasse.

“Grace knew something about it I didn’t, though.”

Nathan had heard of the GPB—in that passing way he’d heard of about a million other applications of blockchain technology. GPB was an attestation system, providing the spatial equivalent to a timestamp. It was a secure, decentralized, autonomous way for people all over the world to identify and track specific objects or people. Nathan had shied away from it because to him it had always seemed like the backdoor to some creepy surveillance society.

“What did Grace know that you didn’t?”

Jeff shook his head ruefully. “The whole lifelog’s encrypted with something called FHE. Fully homo-something encryption. Every frame of the lifelog is encrypted in the camera, before it’s uploaded, using a key that needs at least three people to unlock it. One of them being me, I guess.” He shrugged. “Anyway, because of FHE, the GPB can query that encrypted frame for the answer to specific questions—like, was I in somebody’s house by the ravine—without decrypting the data.”

Fully homomorphic encryption. It was all the rage in some circles, the way Bitcoin had been around 2010. It really did let untrusted third parties analyze your data without decrypting it. You could trust them because they couldn’t even in principle have seen what those results were, even though they’d done the work to generate them. Only you could open the returned file.

Nathan was happy for this mathematical distraction. “Let me get this straight,” he said. “Because the GPB’s a transparent blockchain, we can prove the encrypted frames haven’t been tampered with or replaced once they’re uploaded. And we can analyze each frame to find out whether any of them show you straying off the path . . . But how do we know you didn’t switch bodycams with somebody else?”

“Because the frame rate’s high enough that if I swapped it, that would have been visible. The GPB can attest to the whole path I took through the day—” Jeff swooped his hand over the tabletop. “—without us having to show any of the frames to the cops. Which alibis me out while securing my privacy.”

“Wow.” The video feed was effectively also a blockchain, the truth of each new frame attested to by the ones that preceded it. Still . . . “You could hack it,” Nathan decided. “The camera’s the vulnerable point. If you mess with that . . .”

Jeff was shaking his head. “You forget the mesh network. It was uploading data about me the whole time. The trees were watching. And the security cameras on the telephone poles—you know this was near Musqueam land—they feed the same frames to our security company that owns them and to the GPB at the same time. So it’s like having multiple witnesses who can say they saw you somewhere. Difference is we don’t have to show that proof to a cop or a judge to make it official. Once you’ve got enough independent witnesses, it’s just effectively impossible for all of them to have been compromised.” He grinned. “The cops at the station didn’t get that, but they phoned somebody else who did. And that’s how it went down.”

Nathan shook his head. “Cool.” With the GPB, FHE, and enough independent cameras, you could turn supposedly ephemeral internet images into proof of position for any object on Earth, while guaranteeing anonymity for that object. You could do it for people, for trees, briefcases full of cash, cars . . .

Too bad, he mused, you couldn’t also do it for something virtual, like a game character.

Or a piece of software . . .

Nathan stood up so suddenly he nearly knocked over the bench. “Shit!”

Jeff looked up, eyebrows raised. “What?”

“I gotta go.” Nathan turned, and practically ran from the hall.

• • • •

Nathan realized Alicia was talking to him, and had been for some time. He glanced over; she was standing there in a bathrobe, hair tangled, looking at him with a really worried expression on her face.

“One sec,” he said. He laid his hands on the keyboard and entered COMMIT. Then he hit RETURN, leaned back, and sighed.

“You’ve been crazy typing for three hours,” she said. “What’s wrong?”

He looked at the clock in the corner of his monitor screen. It was two a.m. He was wide awake, practically jumping out of his skin with energy, though he knew how that went: the mental crash, when it came, would have him sleeping most of tomorrow.

“Fixed it,” he said. “Now I gotta . . .” He turned from her to text the rest of the team.

Her hand on his shoulder pulled him back to the moment. “Fixed what? Nathan, what the fuck are you doing? You’re scaring me.”

“The, the Sybil attack. I found a fix.” Fix hardly summed up what he’d just done, but right now he was having a bit of trouble with natural languages, like English. Nathan’s head was full of the object code he’d been putting together, and that he’d just committed to a new fork of the Gwaiicoin wallet system.

He rubbed his eyes. “Just one sec, and I’ll tell you all about it.” He texted the team; they’d mostly be asleep, but the buzz of their phones would wake a few, and if nobody got back to him in the next few minutes he’d start phoning them.

The sell-off of Gwaiicoin was in full swing, and he’d been keeping an eye on it while he worked. Luckily, it hadn’t been as bad as he’d feared, for the simple reason that transactions above a certain size were taxed by the currency itself. When Alicia had moved her money from Gwaiicoin to dollars, some of those funds had been transferred to thin Gwaiicoin wallets. Until the poorest wallets divested, a goodly chunk of the money was going to stay in the system.

Still, once the rich had divested the poor would follow, and then the system really would collapse.

He hit SEND, then turned to Alicia. “What if you could prove that each Gwaiicoin user was a human being and had one unique wallet?”

“Oh, God.” She rummaged through her hair, then leaned back against the office wall. “No Sybil attack. Is that it?” She stopped, blinked at him. “I thought you couldn’t do that. You need a trusted third party and that was supposed to be the Social Insurance System. And they crapped out. They got hacked.”

“What if you didn’t need that third party? If you identified each person as a unique position in spacetime, and that person’s one and only wallet is at that same position? Each wallet has a position and it has to correspond to a person’s position. Only one wallet is allowed for any position. So: unique person, unique wallet. Sybil attack solved.”

She shook her head. “Just make up fake people.”

Nathan laughed and jumped up. “But you can’t! That’s what’s so great about it!” The more bodycams, cop-cams, security cams, GPS-sensing sports and health trackers that uploaded their data to the Global Positioning Blockchain, the more witnesses there were to attest to peoples’ existence and location. FHE encryption meant you could hide the data from prying eyes, but still prove your identity in full public view.

“It’ll take a while for the fix to work,” he admitted. “Weeks, months maybe, until everyone using the coin is accounted for. Once they all are, though, Sybil attacks will be impossible. Meanwhile . . .” He frowned at the growing divestment numbers.

Alicia was wide awake now. “It won’t matter if it all goes south tonight.” She had put on her glasses and was staring out the window—probably watching in AR as the gold lines of Gwaiicoin pulled back from house after darkened house, like candle flames going out. “Though I suppose if the team reinvests it’ll send a strong signal . . .” She turned to him and raised her glasses. “That what you’re going to do now?”

Nathan sat there, gazing at the jumble of windows in the monitor. “No.” Giddiness battled with despair.

He hadn’t told Grace what he’d done, though she’d find out soon enough. He couldn’t avoid Alicia, though.

“I didn’t divest,” he said, still staring at the screen. “I could have. Should have, I guess. Maybe I panicked, I dunno, I—”

“Nathan.” She came to lean on the table next to him. “What did you do?”

“I gave it away.” A half-hysterical laugh rose out of him. “All of it. Straight into the potlatch account—swoosh!” He zoomed his hand over the keyboard, like Jeff had earlier.

The look of horror on Alicia’s face was perfect. The rest of the laugh burst its way out of Nathan, battling tears.

He’d given away all his savings.

“I gave it to the people, and now all I have . . .” He clicked over to his Gwaiicoin wallet. “. . . is a hell of a lot of eminence.”

“So you didn’t divest. You—”

“Invested. And if this crash turns around . . .”

“Oh, Nathan, what have you done?”

He slumped back, shaking his head, but smiling.

“I don’t know. But just maybe . . .”

He turned to look at the city skyline, picturing the fountaining flow of currencies: money, power, influence and, joining them, a quality that those other media had never been able to carry: trust.

“Maybe,” he murmured, half to himself, “I’ve found a new way to be rich.”