A man has just two guesses left to access $240 million (£175 million) worth of Bitcoin.
Programmer Stefan Thomas - who received 7,002 bitcoins more than a decade ago as payment for a video explaining how cryptocurrency works - stored them in an IronKey digital wallet on a hard drive, but he has since lost the piece of paper he wrote the password down on.
As reported by the New York Times newspaper, he has just two more attempts and after a total of 10 failed attempts, the password will encrypt itself and the wallet becomes possible to access.
Thomas - born in Germany and living in San Francisco - told the publication: "The whole idea of being your own bank - let me put it this way, do you make your own shoes?
"The reason we have banks is that we don't want to deal with all those things that banks do."
Facebook's former head of security Alex Stamos - now a professor at the Standford Internet Observatory - has offered to help for a 10% cut.
He tweeted: "Um, for $220m in locked-up Bitcoin, you don't make 10 password guesses but take it to professionals to buy 20 IronKeys and spend six months finding a side channel or uncapping.
"I'll make it happen for 10%. Call me."
