After the Fork: How Competing Bitcoin Cash Blockchains Might Wage War

Bitcoin cash's ongoing war of words is set to reach a conclusion today.

That's when a planned technical update may lead two major bitcoin cash implementations - Bitcoin ABC and Bitcoin SV - to split into separate blockchains.

Rather than a future in which the two versions of bitcoin cash live in harmony, there's a degree of concern that, under a scenario in which two distinct blockchains emerge, that same mining power could be wielded as a weapon against one of the networks.

"An SV miner can even legally kill off a chain. That is the miner's right. This is what bitcoin is," Craig Wright, the controversial chief scientist behind nChain, the company that leads the Bitcoin SV implementation, tweeted.

Because of bitcoin cash's underlying architecture, a 51 percent dominance in hash power will allow Bitcoin SV to launch attacks against the minority chain - and Wright has suggested that such action isn't off the table.

According to Peter Rizun, the chief scientist of Bitcoin Unlimited, the upcoming hash war is a test of what is known as bitcoin's underlying security assumption, dubbed the "Honest majority."

When applied to a blockchain split, what this means essentially means is a fight to the death between the competing chains, where the last one standing would be considered the "True" bitcoin cash by nodes.

"Neither Bitcoin SV nor Bitcoin ABC have implemented transaction replay protection, as the intention is for only one chain to survive," nChain, the software company behind Bitcoin SV, wrote in a press release published earlier this month.

Still, in this case, Rizun depicted this attack as one of the least likely outcomes of the bitcoin cash fork, because, unlike hostile activity between competing chains, double-spends are "Blatantly criminal."

Such an attack would prevent ABC from activating and ensure that SV becomes dominate on the bitcoin cash blockchain.