But, “in this case, it doesn’t look like a merchant was defrauded,” said Nic Carter, co-founder of Coin Metrics, a data firm. “This doesn’t look sinister to me. My best guess is this is experimentation or a software bug.”
[1/2] There was a stale Bitcoin block today, at height 666,833. SlushPool has beaten F2Pool in a race.
It appears as if a small double spend of around 0.00062063 BTC ($21) was detectedhttps://t.co/o8lz9xagYG pic.twitter.com/IEdPu8JEjt
Bitcoin was created with the intention of being a digital currency that doesn’t require any centralized authority to back it or to oversee transactions. Instead of bank software handling electronic transfers, Bitcoin is transacted on a blockchain – basically a spreadsheet that logs when coins move and to where. Transactions are entered on the blockchain after an unaffiliated third party verifies the deal, often in exchange for partial coins.
The blockchain is supposed to be immutable, helping to prevent fraud and making transactions irreversible. A double-spend would effectively mean the blockchain had been manipulated, obviating Bitcoin’s heralded security claim. Merchants often wait for a payment to be verified as many as six times. In the case of the reported double-spend, the transfer was apparently verified only once, entered on the ledger, and then revoked.
It’s rare to consider a payment final after only one confirmation, said Carter. What likely happened is that two blocks – the crypto term for a verification – had the same transaction from the same address but that one entire block was ultimately excluded.
Still, online discussions over potential blockchain implications intensified, with Google searches for “Bitcoin double-spend” spiking.
Bitcoin fell as much as 11% on Thursday to trade around US$30,986 ($41,001.70). Other cryptocurrencies also sold off, with the Bloomberg Galaxy Crypto Index losing as much as 10%.
“The Bitcoin blockchain is operating exactly as designed, and has been operating exactly as designed for 12 years,” said Andreas Antonopoulos, an expert in Bitcoin and open blockchain technologies. “What we saw today was a one block reorganization. These occur on average every two weeks, and are a normal part of the consensus algorithm.”
