Bitcoin and encryption: A race between criminals and the FBI

Whether it was gangsters a century ago speeding off in faster getaway cars or terrorists and hackers in recent decades who shielded their communications through encrypted apps, criminals have perennially exploited technology to stay a step ahead of law enforcement.

The FBI struck back in the past week with a pair of victories: a seizure of most of the $4 million ransom in Bitcoin that Russian hackers extorted from a US pipeline operator and the announcement of a years-long sting where thousands of suspects were duped into using a messaging app secretly controlled by authorities. More than 800 people were arrested in more than a dozen countries.

The breakthroughs came in part because law enforcement officials learned how to leverage two rapidly advancing technologies — encryption and cryptocurrencies — that had previously been a boon for criminals.