The Apple cofounder Steve Wozniak said he had several bitcoins stolen by a scammer using a common technique.
The Economic Times reports that Wozniak discussed cryptocurrency during a talk at the newspaper's Global Business Summit last week.
"The blockchain identifies who has bitcoins," Wozniak said, referring to the technology underpinning cryptocurrencies like bitcoin.
He added: "That doesn't mean there can't be fraud though.
"I had seven bitcoins stolen from me through fraud. Somebody bought them from me online through a credit card, and they canceled the credit-card payment. It was that easy! And it was from a stolen credit-card number, so you can never get it back."
Wozniak's seven missing bitcoins would equate to about $74,000 (£53,000) at Tuesday's price — though that isn't likely to be a concern for Wozniak, who is worth about $100 million, according to an estimate by TheRichest.
Wozniak said he sold most of his remaining bitcoins.
"I didn't want to watch the price every day," he said, adding: "I sold all except one. It was enough to experiment."