The Absolution Read online

  Most recently, she found allegations that Italy was being specifically targeted by the NSA as a base for cyber-surveillance, with more secret listening stations than any other European country. From Italy, the US could eavesdrop on internet traffic right across Europe, North Africa and the Middle East.

  VIGILANCE, she read, the Virtual Intelligence Gathering Alliance, was America’s answer to the Snowden revelations. Instead of spying covertly on friendly nations, America was now inviting them to opt in to a massive “Golden Shield” covering the whole of the Western world. So far, only Britain had joined up.

  She saw, finally, what this cyber attack Tignelli had put in motion would do, and why America had been in no hurry to stop it.

  Just as in the darkest days of the Cold War, terror in Italy would be a lesson delivered to the rest of the world: without our protection, see what might happen. Violence that furthered America’s political agenda would be quietly facilitated, not curtailed.

  That was the reason Tignelli died when he did; why Flavio had been silenced; why the hacker had been forewarned. It was simple, cold-hearted realpolitik.

  She called Daniele.

  “Those attacks from within Carnivia,” she said. “I think it’s possible that America wants you to be the one responsible. That it isn’t just jihadists they mean to take the blame – it’s sites like yours, along with the very nature of the free internet. From their point of view, it’s a win-win situation: either you take down Carnivia yourself, or it’s utterly discredited. Either way, they get what they want.”

  There was a long silence. “I’m working on it,” he said at last. “Leave it with me.”

  He rang off.

  SIXTY-SIX

  HOLLY WENT BACK to her apartment and collected the other things she’d need. In particular, she took out a small carton from under the sink.

  Then she called home. As she waited for her mother to pick up, she walked out onto her little balcony. The night was a warm one, but there was always a breeze up here, looking over the rooftops towards the hills south of Vicenza.

  “Hey, Mom. What’s up?”

  “Hi, Holly.” Her mother’s voice turned curious. “What time is it with you? Isn’t it late over there?”

  “Not too late. How are you?”

  They chatted for a while before she said, “Put Dad on, would you?”

  “Sure. I’ll put the phone by his ear so he can hear you, OK?”

  “Hey, Dad.” She waited, as always, for him to answer before continuing. “Well, I found out who did this to you. Found those Autodin records as well, though I haven’t been able to read them yet. I don’t know exactly what you were planning to do with them. But you’d already written one report that had been buried, hadn’t you? So I figure whatever it was, it was going to be something no one could ignore.”

  Was it her imagination, or did the even pace of his breathing quicken slightly? Could he even recognise who was speaking to him?

  “You had all their top-secret cables, didn’t you?” she said, her voice cracking. “Every dirty operation the CIA planned, every bribe they paid out, every debrief and update, they all passed through the Autodin on their way back to Washington. I think you were going to put it all out there, Dad. I think you were going to blow the whistle on the whole corrupt mess.”

  She waited, listening. No: his breath was as regular, and as peaceful, as a sleeping child’s.

  “I’m going to finish it, Dad,” she whispered. “I’m going to see it through.”

  Per il miglior papà del mondo.

  SIXTY-SEVEN

  HE TRIED ALL the obvious things, the tools of the modern cryptographer – differential cryptanalysis, XSL, the sandwich attack, mod-n. But it was as he’d expected: nothing worked. He had made sure Carnivia was proofed against such methods when he created it.

  The only way asymmetric encryption like Carnivia’s could be penetrated was by a process known as complex integer factorisation – breaking down large numbers into many smaller, more workable divisors. But no one had ever devised a way to do that on a large scale. The only mathematician who’d come close was a man called Peter Shor, and his algorithm was so complex that it required imagining an entirely new kind of supercomputer, a quantum computer, to run it.

  It came back to the old conundrum of P=NP: you could look at a solution and quickly tell if it was correct, but you couldn’t do it backwards to create the solution.

  Even so, Daniele tried. He scribbled formulae, put together theorems, tried variations on Shor, all to no avail. The problem lay within the very nature of numbers themselves.

  A phrase drifted back into his mind. Something Carole Tataro had reminded him of. You said, “Every number is infinite . . .”

  It was true, in a way: every number not only represented a finite quantity, it had other properties too. There were prime numbers, Gaussian numbers, transcendental numbers, Fibonacci numbers, Pell numbers . . . the list went on and on. And, as Ramanujan had pointed out to Hardy, even those few numbers that were apparently without any interesting features were so rare that they became fascinating in themselves.

  Suppose that instead of writing 1, 2, 3, 4, you wrote . . . what?

  One is the only number that is both its own square and its own cube.

  Two is the only even prime number.

  Three is the only number which is both a Fermat and a Mersenne prime.

  Four is the smallest squared prime.

  And so on – every number unlocked, not by what it was, but by what was contained within it. It was like breaking an atom down into its neutrons, or a cell into its DNA.

  DNA.

  He thought about the spiral pattern within DNA. And he glanced at the wall.

  Many years ago, his father had hung the walls of Ca’ Barbo with modern paintings from his collection. Although the Barbo Foundation had put most into storage, a few still remained. It amused Daniele to cover them with Post-it notes bearing his favourite mathematical formulae. To him, the equations were just as beautiful, and far more expressive of genius, than the art underneath.

  Near his computer was a portrait of a woman by the Italian modernist Modigliani. Its only merit, as far as Daniele was concerned, was that the artist had clearly understood that the symmetry of a human face was determined by the laws of the Golden Section, or phi. So Daniele had stuck over the woman’s face a note depicting the ratio that phi expressed.

  And then, quite without warning, he saw it. It was so simple, obvious even, that he almost laughed out loud. Of course numbers had their own DNA, just as cells did. And of course they followed the same graceful, endlessly repeating pattern that characterised the whole universe, from the tiniest seeds to the mightiest galaxies.

  P=NP was not a theorem, but a shape. It was phi.

  It will be beautiful.

  He allowed himself a brief moment to savour this triumph. He had solved a puzzle that had baffled the world’s greatest mathematicians. Or perhaps, he admitted to himself, he hadn’t so much solved it as hit upon a solution. Like Einstein’s theory of relativity or Newton’s gravitational constant, a single moment of creative insight had illuminated everything, and inspiration had tumbled unbidden into his head.

  But there was no time to think about that now. He set to work turning his discovery into an algorithm that would tear the masks from Carnivia’s millions of users.

  SIXTY-EIGHT

  HOLLY DROVE THROUGH the dark Veneto countryside to the villa where Ian Gilroy lived. Once, it had been where the Barbo family spent their summers, away from the stink and humidity of Venice. But somehow, when Daniele’s father had transferred his art collection to a charitable trust, the villa had been transferred along with it.

  She wondered if that had been planned as well, or whether it was a happy accident. She doubted that much in Gilroy’s life was accidental.

  Leaving her car by the big wrought-iron gates, she slung the laundry bag over her shoulder and walked up the lawn towards the house. For the f
irst time she pondered the apparent lack of security. Was it there, but hidden? Or was Gilroy simply the sort of spymaster who preferred crypsis and misdirection to tripwires and alarms?

  She thought how appropriate it was that he had chosen Venice as his stamping ground. A place of mists and watery reflections, of shifting surfaces and deceptive, glittering façades. An ambiguous, impossible city, one that had dreamed itself into existence in defiance of all reason or logic.

  It wasn’t only Daniele Barbo who had created his own version of reality. Ian Gilroy had done it too.

  Twenty yards from the house, she took out the M4, slotted the magazine into place, and pulled the first round into the chamber. The handgun and holster she fastened around her waist.

  She tried the front door. It wasn’t locked.

  He was sitting at the back of the grand entrance hall, in an antique wooden chair that looked as if it might once have been the throne of some doge or duke. Watching her, his eyes hooded. One hand cupped his chin. The other, his left, lay casually across his lap. On either side, on the painted panels that lined the walls, trompe l’oeil nymphs and mischievous fauns eyed her lasciviously.

  She raised the carbine. “Show me your other hand.”

  He raised his left hand and waved it ironically. Unarmed.

  “You were expecting me, then.”

  “Oh, Holly,” he said, his voice cracking with what sounded strangely like relief. “I’ve been waiting for this moment for many, many years.”

  SIXTY-NINE

  “I THINK I’VE done it,” Daniele said to Kat. “But there’s a problem.”

  He had written his algorithm and sent it into Carnivia. He’d watched, appalled, as the hacker’s chosen targets spilled across his screen. Power plants, hospitals, hydroelectric dams, air-traffic-control systems . . . An elevator in Milan’s tallest building that would have crashed to the ground, killing everyone inside it. A cooling fan in the electrical substation of a subway system that would have burst into flames. A vulnerability in the Italian stock exchange that would trigger automatic selling. The tram system in Rome. He’d been astonished to discover just how easy it had been for the hacker to line up so many simultaneous acts of destruction.

  One by one, his own code extracted the botmaster’s instructions from the infected computers, like pulling out a weed along with all its roots.

  And he had seen, too, what kind of users Carnivia had. Stripped of their anonymity, he had glimpsed pornographers and the consumers of pornography; drug dealers and drug buyers; gossips and trolls and cyberbullies. But he had also seen a network of gay men in Saudi Arabia, using it to share information that would get them three years in jail and five hundred lashes if done openly; an underground democratic movement in Egypt; an endangered Christian congregation in Iraq. He saw whistleblowers using it to denounce corruption and abuse of power around the world; celebrities using it to escape the pressures of fame; the shy using it to speak out and those who were burdened with secrets to confess.

  “So you’ve beaten it?” Kat said.

  “Not quite. I’ve been looking for the master computer, the source of the infection. And I think I’ve found it. But I can’t access it.”

  “Meaning what, exactly?”

  “Meaning it’s probably the hacker’s own computer. For some reason, this one target is so important that he’s taken personal charge of it. That implies it’s something highly complex that needs to be controlled moment by moment, rather than just by turning off a few switches.”

  “Any idea what?”

  “At first I thought it could be a plane – if he were on board, and had found a way to hack the on-board electronics, he could override any attempt by the captain to resolve the problem. But since 9/11, aeroplanes have had additional countermeasures to prevent that from happening.”

  “What about a ship?” she said slowly.

  “Why do you say that?”

  “It’s always bothered me that the hacker was enrolled at that technical college, when he quite clearly knew more about computers than all the other students put together. When he disappeared, we assumed he’d slipped out of Sicily by getting a job on board a cruise ship. But what if getting on board that ship was the whole point of going to Sicily in the first place?” She paused. “What if he’s somehow found a way to hijack it?”

  SEVENTY

  IT WAS PAST three in the morning when Kat called Aldo Piola. She asked him to wake General Saito and Prosecutor Marcello and get them to come to Campo San Zaccaria.

  “What else do you need?”

  “About a dozen carabinieri. A major incident room. And a technical expert, someone who knows about ships and explosives. But the most urgent thing is a couple of bright young officers to help me identify which ship the hacker could be on.”

  “Who would you like?”

  “Panicucci and Bagnasco,” she answered without hesitation. There was silence at the other end when she mentioned the second name.

  “I don’t like her, but she’s clever,” Kat explained. “And she’s thorough. She won’t panic.”

  “All right. I’ll speak to General Saito and Marcello.”

  The explosives expert, Major Tasso, reached Campo San Zaccaria at the same time she did.

  “Is what I’m suggesting feasible?” she asked him. “Could one man hijack a cruise ship?”

  “It depends how technically sophisticated he is,” he replied cautiously. “But assuming he’s found a way to evade the ship’s own security systems, it’s certainly possible, yes.”

  “And then what? Could he threaten to sink it? Run it aground? Blow it up?”

  “Again, it depends on a number of factors, such as what kind of fuel it uses. Some of the most modern cruise ships burn gas oil, which is more environmentally friendly than heavy fuel. The downside, though, is that it’s much more explosive.”

  “How explosive?”

  “Think back to 9/11,” he said quietly, “and remember what around seventy tons of airplane fuel exploding inside a skyscraper looked like. Then consider that a fully laden cruise liner might be carrying over two thousand tons of gas oil, which is just as flammable. If that went up, it wouldn’t be a question of fires or sinking. The ship itself – the hull, the sides, the plating – would be like the nails in a nail bomb. They’d add to the blast, not contain it.”

  “Wait a minute,” she said, doing the maths. “Are you saying an explosion on a passenger ship could be thirty times bigger than the ones that brought down the Twin Towers?”

  He nodded. “And if by some miracle a passenger did survive the blast, that kind of explosion creates a thermobaric vacuum – it’s effectively a fuel-air bomb, one that would rupture the lungs of anyone within range. What that range would be, it’s hard to say, but we’re certainly talking hundreds of yards, even in the open sea.”

  “Porco Dio.” She thought of the behemoths she saw daily chugging in and out of Venice. Campaigners worried about the environmental damage, but why had no one thought about the security risks?

  Suddenly her blood ran cold. “And what would happen,” she said slowly, “if the explosion weren’t in the open sea? What if it took place in a more confined space?” She gestured in the direction of the waterfront, fifty yards away. “Somewhere like the Bacino di San Marco?”

  He shrugged. “Let’s just say, I doubt if any of us would still be standing here afterwards.”

  She was following a simple train of logic, but even so, she couldn’t quite believe where it was taking her. Grimaldo had told her that Tignelli’s plans involved positioning himself as the saviour of Venice. And Tignelli had mentioned to her himself, the first time she went to La Grazia, just how much damage cruise ships had done to his eel farm. You could hardly find a more emotive subject for Venetians, or one that better symbolised the need for change.

  Panicucci and Bagnasco arrived. She explained the situation in a few sentences. “I need you to find out if any of the cruise ships currently in the Adriatic run on g
as oil. Look for references to ‘green’ or ‘environmentally friendly’ on their websites. And then look at their schedules, and see where they’re headed. In particular, see if any of them have Venice as their next port of call.”

  She turned back to Major Tasso. “You mentioned 9/11, Major. I think it’s possible this man doesn’t only want to hijack this ship, or even just to blow it up. I think . . .” She hesitated, reluctant even to put the thought into words. “I think he may mean to use it to attack Venice as well.”

  SEVENTY-ONE

  “WON’T YOU SIT down, Holly?”

  “I prefer to stand.” She kept the carbine trained on him.

  “Are you going to tell me what I’m supposed to have done?”

  “Really?” she said incredulously. “You can’t remember? Or are you simply wondering which bits I know and which I don’t?”

  He regarded her calmly. “I’m not going to lie to you, Holly. I have taken some hard decisions in the service of my country. That was my job.”

  “You ordered the mutilation of a child in order to grab newspaper headlines and demonise the Red Brigades. You had a former prime minister assassinated to stop him entering into a power-sharing coalition with the communist party. You summoned up atrocities like marketing executives book advertising campaigns. Even recently, you had Count Tignelli killed, and Kat’s boyfriend blown to pieces in front of her when he got too close to finding out why.”

  “Yes,” he said simply. “Yes, I gave those orders. Sometimes not in so many words, but those were my wishes, and they were carried out.”

  “And you arranged for my father to be given blood-thinning medication, in the hope that it would kill him.”

  “No,” he said, raising his hand. “No, that’s the irony in all this, Holly. I never ordered that. I took his report and told him I’d pass it on, that’s all. We don’t kill Americans.”

  She saw then what he was going to do – admit everything she was certain of, but deny the one thing that would make her pull the trigger.