Defcon Speaker Discusses Liberating $300K Worth of Bitcoin From an Encrypted File

This year due to the coronavirus outbreak the world-famous hackers’ convention Defcon held it’s 28th annual event with virtual presentations in “safe mode.” One of the presentations was from an executive from Pyrofex, Michael Stay, who discussed how he broke into an encrypted file to liberate $300,000 worth of bitcoin for a Russian investor.

Defcon 28 “safe mode” presentations got interesting on August 5, when ex-Google employee Mike Stay told a story about how he rescued $300k worth of bitcoin (BTC) from an encrypted zip file.

Stay is the CTO of Pyrofex Corp, a blockchain development firm that launched in 2016. During a speech last Wednesday, May told the story of how he was contacted not too long ago, so he could help someone retrieve their crypto assets.

“About six months ago, a Russian guy contacted me on Linkedin with an intriguing offer,” May said on Youtube. “He had hundreds of thousands of dollars in Bitcoin keys locked in a zip file, and he couldn’t remember the password. Could I break into it for him?”

The story Stay told was quite intriguing, as the anonymous Russian investor wanted access to the bitcoins worth roughly $300,000. Stay said the anonymous client found his name when he stumbled upon an old cryptanalysis paper he wrote 20 years ago.

Defcon Speaker Discusses Liberating $300K Worth of Bitcoin From an Encrypted File

The cryptographer also explained that the Russian purchased all the coins in 2016 for around $10k. However, the investor put the bitcoin into an encrypted zip file and after some time passed, he forgot his password.

“In that attack, I needed five files to break into a zip archive,” Stay recalled. “This one only had two files in it. Was it possible? How much would it cost? We had to modify my old attack with some new cryptanalytic techniques and rent a GPU farm, but we pulled it off.”

According to the cryptographer it cost him around $7k to pull off the attack against the encrypted zip file. Stay said that he also had help from the CEO of Pyrofex Nash Foster who is also an ex-Google…

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