The quest to liberate $300,000 of bitcoin from an old ZIP file

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In October, Michael Stay got a weird message on LinkedIn. A total stranger had lost access to his bitcoin private keys-and wanted Stay's help getting his $300,000 back.

It wasn't a total surprise that The Guy, as Stay calls him, had found the former Google security engineer. Nineteen years ago, Stay published a paper detailing a technique for breaking into encrypted zip files. The Guy had bought around $10,000 worth of bitcoin in January 2016, well before the boom. He had encrypted the private keys in a zip file and had forgotten the password. He was hoping Stay could help him break in.

In a talk at the Defcon security conference this week, Stay details the epic attempt that ensued.

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