AntPool, a prominent Bitcoin mining pool, has made headlines by agreeing to refund an unusually high transaction fee of $3 million.
This decision follows the accidental payment of this fee by a Bitcoin user, setting a new record for a single transaction fee in US dollar terms.
A Bitcoin Anomaly And AntPool’s Response
The incident unfolded last week when a Bitcoin transaction included a fee of 83.65 BTC, equivalent to roughly $3.1 million, to transfer 55.77 BTC worth around $2.1 million. This extraordinary fee, amounting to over 120,528 times the usual rate, was initially frozen by AntPool’s risk control system.
The transaction, which drastically reduced the sender’s balance before the transaction of 139.42 BTC worth $5.2 million, was processed in block 818,087 mined by AntPool. Until recently, the mining pool had not publicly addressed the incident.
In a statement released on November 30th, AntPool clarified that it had temporarily frozen the fee upon detecting the unusual transaction. The mining pool has since invited the transaction’s originator to reach out before December 10th, 2023, to verify their identity and claim the refund.
To facilitate this, AntPool has advised the owner to work out a signing tool, such as Electrum or Bitcoin Core, using the private key associated with the address that initiated the transaction. The process involves signing the message “AntPool” and forwarding the signed text to AntPool’s support email.
Victim Claims And Security Concerns
Following the incident, a Bitcoin user claimed to be the victim of the exorbitant transaction fee, alleging that their wallet had been hacked. The user, identified as “83_5BTC” on X, stated that they had transferred 139 BTC to a new cold wallet, which was immediately redirected to another wallet.
It was my BTC that paid the high fee.
I created a new cold wallet, transferred 139BTC to it and it got transferred out to another wallet immediately. 😵
I can only imagine that someone was running a script on that wallet and that the script had a weird fee calculation. ☹️
— Hackers_paid_83.5BTC_fee_with_my_money (@83_5BTC) November 24, 2023
This hacking claim adds complexity to AntPool’s task of refunding the fee, as they need to ascertain the true owner of the funds.
Mononaut, a pseudonymous developer behind the Bitcoin explorer Mempool, indicated that the hack might have originated from a “low-entropy wallet,” potentially a brain wallet. Such wallets, formed with “inadequate” randomness, are especially susceptible to security breaches.
6/ Since the wallet is compromised, this message could have been signed by either the victim or attacker (or anyone else who brute-forced the bad entropy).
If @AntPoolofficial returns the fee, they’ll need another way to verify the victim’s identity.https://t.co/18wKhzuYux
— mononaut (@mononautical) November 27, 2023
Mononaut further elaborated that given the wallet’s compromised status, the message’s signature could have originated from the victim, the attacker, or any other individual who exploited the wallet’s weak security.
Therefore, AntPool would require an alternative method to authenticate the identity of the rightful owner before proceeding with the fee refund.
Meanwhile, Bitcoin’s market behavior has shown a gradual yet consistent upward trend. The crypto notably breached the $38,000 mark, demonstrating a bullish momentum. However, it has since experienced a slight pullback, with its current trading price hovering around $37,930 at the time of writing.
Featured image from Unsplash, Chart from TradingView