There’s more information in the world than ever before. In August 2010 Google’s then CEO, Eric Schmidt, told an audience an astounding statistic: every two days we create as much data as humanity did from the dawn of civilisation up until 2003.

Even more astoundingly, this new data is liquid. It costs virtually nothing to reproduce and share. It is, as Forbes writer Andy Greenberg points out in This Machine Kills Secrets, ‘frictionlessly mobile, fundamentally leakable’.

Leaks, and the way leaking has transformed over the past forty years, are at the heart of this book. Greenberg takes the view that technology means leaking is now inevitable, and that since information is power, this entails an inevitable power shift from elites to the masses. Hence his title, which came to him when he saw a musician busking in his Brooklyn neighbourhood with the same sticker on his guitar as Woody Guthrie had: ‘This Machine Kills Fascists’. He writes: ‘That sentence, to me, brought to mind the ideological arrow I see from [Daniel] Ellsberg to [Julian] Assange and beyond: a revolutionary protest movement bent not on stealing information, but on building a tool that inexorably coaxes it out.’

This is a story others have told before and Greenberg hits all the transparency-tour hotspots: San Francisco, Reykjavik, Berlin, London, Sweden. His reportage is detailed, compelling and solid. He tracks down not only the usual suspects but forgotten or shadowy figures who played pivotal roles in the rise of the radical transparency movement.

One of these is Tim May, a physicist who retired from his job at Intel at the grand old age of 34 and went on to indulge his passions for libertarianism and cryptography. He tried writing a novel about how encryption and anonymity were revolutionising society but it didn’t take off. Instead, he explains: ‘I wanted to actually build this elaborate world I was imagining.’

What he created was the prototype for WikiLeaks, called BlackNet. BlackNet, he announced in a 1990s mailing list, was a place where information could be leaked untraceably: ‘Unless you tell us who you are (please don’t), or inadvertently reveal information which provides clues, we have no way of identifying you, or you us.’ BlackNet was an information market, a guerrilla bazaar for buying, selling and distributing the world’s secrets: the ‘classified of classifieds’.

But it remained undeveloped. It never actually existed fully, and May wasn’t interested in becoming a whistleblower advocate. ‘I had the opportunity to either light a candle or teach people how to make candles. I had the ideas but the idea of trying to be Julian Assange gives me the creeps.’

Some of the ‘crypto-anarchists’ were even more radical. Jim Bell, an engineer and chemist, had the wild idea for ‘Assassination Politics’ – an anonymous, secure site where anyone could place a ‘bet’ on the death of one of a list of ‘violators of rights, usually either government employees, officeholders, or appointees’. Bell speculated that professional killers would join the game. The idea didn’t go down well in the crypto-anarchist community and Bell is now in prison, where the dogged Greenberg interviewed him.

These are just two of the intriguing characters one finds in the book, though there are many more. Despite the depth of information and the large cast, the book holds together and flows smoothly. It’s a compelling read and Greenberg’s expertise shows through in his deft descriptions of technical processes that don’t divert, but rather advance, the story.

The last third of the book is more problematic. Here the author lets his hack’s sensibility for spectacle overwhelm his careful reportage. To make his story satisfying, Greenberg needs Assange to be at least partially heroic. Unfortunately, the reality is more pedestrian and ugly.

He takes Assange’s word too often without challenge or investigation, whether it’s Assange’s reasons for dropping out of university, not getting a job, abandoning his kids or failing to go to Sweden to answer charges of sexual assault. He parrots Assange’s propagandised version of his bail-term conditions as ‘house arrest’.

This is surprising, since Greenberg himself documents at least half a dozen instances when Assange’s claims and the subsequently revealed truth are at odds. When a source is this unreliable, it is usual for a reporter to treat what he says with a high degree of scepticism. Yet Greenberg opens the book with Assange and appears in thrall to the former hacker, who boasts that he’s sitting on tens of thousands of internal emails that would ‘take down a bank or two’. These have never materialised.

However, this doesn’t stop Greenberg digging into the real reasons for the disintegration of WikiLeaks. At a hacker camp in Germany, he tracks down the man who built WikiLeaks’s anonymous submissions platform. Known only as ‘The Architect’, he eventually pulled the plug on the submissions system. ‘I wanted to do something good. And if someone corrupts that I’ll pull the plug,’ he says. ‘I didn’t mind that [Assange] likes media attention, or even the thing with the girls, but I don’t believe he’s able to handle the basic law that first, you protect the sources.’

WikiLeaks may have degenerated into a circus sideshow, but the march towards radical transparency continues, and Greenberg ends on an optimistic note: ‘We don’t yet know the names of the architects who will build the next upgrade to the secret-killing machine. But we’ll know them by their work.’