A public, hours-long negotiation between hackers and a cryptocurrency firm on Sunday ended with the attackers keeping $47 million of a $320 million theft as a “reward” for identifying what they said was a bug in the company’s platform.

The trading platform Liquid Network said on Sunday that “purported white-hat hackers” withdrew 4,000 BTC ($320 million) from its own wallet. Blockstream, which runs Liquid, pledged to reach out to the hackers and said deposits and withdrawals were paused. Liquid supports a coin pegged to the price of bitcoin.

Over the next 12 hours, the company negotiated in public on the blockchain with the hackers, who initially wrote, “we are whitehats, contact us on chain” in a message attached to the…