A rogue block on the Bitcoin blockchain was identified on Thursday morning, but it remains unclear whether it was a fault in the software, or a more malicious motive.
At block height 584,802, bitcoin miner AntPool attempted to publish an invalid block on the network. The error was identified by all eight validation nodes at forkmonitor.info.
Bitcoin had an invalid block at height 584,802, as spotted by @juscamarena— BitMEX Research (@BitMEXResearch) July 10, 2019
All 8 nodes at https://t.co/WKQ8hPDGON identified the block as invalid:
Bitcoin Core 0.18.0
Bitcoin Core 0.17.1
Bitcoin Core 0.16.2
Bitcoin Core 0.10.3
Bitcoin Knots 0.14.2
Transaction Fees but No Transactions
The erroneous block was submitted at 14.35:27 UTC, 21 seconds after the previous block and contained no transactions, although the coinbase value of the block suggested it included transaction fees.
The coinbase value was too high, presumably because this included the transaction fees, but due to some error the transactions themselves were not includedhttps://t.co/gQRh3Gmdor— BitMEX Research (@BitMEXResearch) July 10, 2019
BitMEX Research noted that the invalid block submission coincided with a drop in the price of bitcoin, but admitted it was probably just a coincidence.
The timestamp of the invalid block was 14:35:27 UTC, 21 seconds after the previous block— BitMEX Research (@BitMEXResearch) July 10, 2019
This appears to have coincided with a drop in the Bitcoin price, however this is probably only a coincidence. (The blue line in the below image represents the timing of the invalid block) pic.twitter.com/PA8EbOY1G9
AntPool eventually mined the valid block number 584,802, suggesting an error in the software had been responsible for its invalid submission. However, adding to the confusion of the episode, the valid block number 584,802 contained a total of 2,455 transactions, but fees of just 0.64968988 - only about 50% of the attempted charge of the invalid block.
Bug to Blame?
An expensive mistake, then. Jameson Lopp, a blockchain developer, suggested a "bug in the block template generator" was responsible.
Yes, it looks like the block was found just seconds after the previous block. My guess would be that there was a bug in the block template generator that failed to clear out the txn fees from the previous template being worked upon.— Jameson Lopp (@lopp) July 10, 2019
This leaves the question hanging: could we be seeing more episodes of this kind? AntPool declined to comment or make a statement about the incident.