Do you know this (wo)man? Bitcoin miner overpays by £145,000

The accidental transaction fee is thought to have come from an old script

A bitcoin mining website is trying to get in touch with a user who accidentally paid a fee 40 times higher than expected. However, the inherent anonymity of blockchain technology is proving a sticking point.

BTC.com is a website that mines bitcoins (BTC); this means that it processes a series of transactions, composites them into a list called a block and then adds that to the blockchain. On a normal day, it expects to receive about 2BTC from all transactions (£3,725 at the time of writing), but this week found one block with a fee of 80BTC (£149,000) listed.

Alejandro De La Torre, president of business development at BTC.com, told IBTimes UK that the figure was "insanely high. Someone added way too high a transaction fee." In a blog post, De La Torre said that, considering the size of the transaction, the fee should have been around 2BTC.

Although BTC has tried to contact the user through its own site, Twitter and Reddit, the company hasn't had a (legitimate) response. Because all blockchain transactions are anonymous, it is impossible to track the user.

"We haven't heard back from anyone, which is very weird. We believe it is a mistake. The way they did it, they busted out a lot of transactions in one block using custom software. They must have had an error, put in a wrong value," De La Torre said.

He added, "We don't want to keep the money, if it was a mistake, we'd rather give it back. It's not ours. It was just by chance that we mined this particular block, it could have been a competitor." The company is offering to refund 78BTC.

As to why the fee was so high, there are a few possibilities; money laundering has been considered, but BTC's theory is that it was processed by an old script; because the user didn't know what the transaction fees would look like in the future, they entered a high fee to ensure that the block was confirmed.

The largest transaction fee ever recorded, also apparently an accident, was a 291BTC fee sent in April 2016, to mining pool BitClub. It is not known if this money was ever claimed back by the original sender.