Review: The digital sleuths who demystified cryptocurrency

“Tracers In The Dark" by Andy Greenberg (Doubleday)

The year was 2011. Cryptocurrency was a little-understood novelty, and Sen. Chuck Schumer called a news conference to vent outrage over a one-stop online shop for illegal drugs whose technology made sellers “virtually untraceable.”

The New York lawmaker’s description of Silk Road helped seed a persisting myth that technology reporter Andy Greenberg exhaustively dispels in “Tracers in the Dark,” that transactions of Bitcoin and other cryptocurrencies can’t be tracked.

Greenberg sketches the evolution of a wholly new discipline in the surprisingly lively real-life police procedural, following law officers and programmers who invent and deploy cryptocurrency-tracking tools to catch a new breed of criminal. They take down Silk Road and other “dark web” markets and merchants, finger crypto money launderers and snare the sysadmin and users of Welcome to Video, a major South-Korea-based distributor of child sexual abuse material.

Best of the action are two takedown dramas. A young Quebecois behind the AlphaBay dark web market, Alexandre Cazes, lives large in Thailand, rocketing around in a Lamborghini, running up $12,000 restaurant bills and boasting of adulterous sexploits online. The other takedown is of a DEA agent and a Secret Service agent who illegally enriched themselves off Silk Road while investigating it – each wholly on their own.

But Greenberg is more interested in the uber-geeks blazing this new digital law enforcement trail as they track cryptocurrency on the so-called blockchain, where every transaction is recorded. The people making the transactions may not be immediately identifiable and often use so-called “mixers” to try to obscure them. But painstaking digital sleuthing – and carelessness – foils many...