The files contained the private keys to what had been roughly $12,500 in BTC when the Russian purchased the coins during 2016. “Now they were worth upwards of $300K and he couldn’t remember the password,” says Stay.

“Luckily, he still had the original laptop and knew exactly when the encryption took place. Because InfoZip seeds its entropy using the timestamp, that promised to reduce the work enormously—”only” 10 quintillion—and made it quite feasible, a matter of a couple of months on a medium GPU farm.”

We made a contract and I got to work,” he adds.

After several months of testing, including the discovery of a bug in his GPU farm, Stay claims to have cracked the file and returned the private key to the Russian.