Bitcoin Cash hard fork creates rogue chain
Chain error calls into question blockchain’s immutability
A rogue chain has developed during a planned Bitcoin Cash hard fork, as an old chain and new chain battle it out for supremacy.
The on-going chain war should have been resolved by Bitcoin’s proof-of-work (PoW) protocols. However, problems arose when an unknown mining pool neglected to update the new chain’s software.
The hard fork occurred on Friday at block number 609,135. Two additional blocks broke into two different chains that have been mined, creating a total of four new blocks, according to BitMEX Research’s Fork Monitor.
The old chain (Bitcoin ABC 0.19.0), which was mined by the unknown pool, thinks the new chain is invalid. But the new chain (Bitcoin ABC 0.20.06), which was mined by BTC.com, considers the old chain invalid.
Under the Nakamoto Consensus, which is a set of rules that govern Bitcoin, the chain with the longest history is considered to be the trusted ledger, thereby invalidating the new rogue chain.
While these rules are in place to ensure the blockchain is immutable, it doesn't take into account human error during the PoW process.
A hard fork requires all nodes or miners to upgrade to the latest version of the protocol software. Once a user upgrades their software, that version rejects all transactions from older software, effectively creating a new branch of the blockchain. However, if they forget to update the software there is a parallel set of transactions, across two different chains.
According to BitMEX Research, mining the wrong chain could cost up to 25 BCH, or about $6,600.
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But much more worrying than the financial implications, the rogue Bitcoin chain raises questions about the blockchain’s ability to remain an indelible ledger of transactions.
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