Warren Buffett doubled down on his criticism of bitcoin Wednesday during an interview with CNBC, where he said he's almost certain the cryptocurrency craze "will end badly" and that the current runup in value will be fleeting.

But paradoxically, he also admitted that he "doesn't know anything" about digital currencies after saying he would eagerly buy five-year puts on "every one of the cryptocurrencies."

"In terms of cryptocurrencies, generally, I can say with almost certainty that they will come to a bad ending," said Buffett, the chairman and CEO of Berkshire Hathaway.

"When it happens or how or anything else I don't know," he added in an interview on CNBC's "Squawk Box" from Omaha, Nebraska.

"But I know this: If I could buy a five year put on every one of the cryptocurrencies, I’d be glad to do it but I would never short a dime’s worth."

While explaining why he wouldn't take a short position, he said he "gets into enough trouble with things I know something about..."

"I get into enough trouble with things I think I know something about," Buffett said. "Why in the world should I take a long or short position in something I don't know anything about."

His comments notably come a day after JP Morgan Chase & Co. CEO Jamie Dimon said he "regrets calling bitcoin a fraud." Dimon last fall famously compared bitcoin to the Dutch tulip mania and threatened to fire any JPM trader caught buying or trading digital currencies.

Buffett added that his remarks are purely hypothetical. "We'll never own a position in them," he said.

Still, Buffett admitting that he'd be a seller even though he "doesn't know anything about" bitcoin - he even claimed he wouldn't be able to explain bitcoin to a classroom of young students - should signal that readers should take his comments with a grain of salt.

After all, by his own admission, Buffett doesn't know what he's talking about.