Understanding the Bitcoin Cash hash war

Bitcoin Cash has undergone a hard fork this week after unresolved deliberations on a number of key upgrades, and tensions are running high.

Two of the largest Bitcoin Cash implementations (Bitcoin ABC and Bitcoin SV) are at odds over which features to include, and as a result, a “hash war” has broken out.

Bitcoin SV is led by Craig Wright (of nChain fame), while Bitcoin ABC is supported by the controversial crypto influencer Roger Ver. Both implementations are incompatible with each other, which means that in theory, only one can continue to be the “real” Bitcoin Cash.

A hash war consists of two competing sides that are boosting their computing power in a bid to gain increased influence (and show support for) a preferred implementation, with mining power being used as a weapon to potentially kill off another blockchain.

This is done using a pooling of hash power resources, which are the total computing resources assembled by a group of miners in the interest of keeping a blockchain secure.

If either side has more than 51% of the hashing power in Bitcoin Cash, the dominating side would in theory be able to launch debilitating attacks on the smaller chain. This represents a troubling turn of events for a community that’s been equal parts competitive and collaborative in recent years.

Perhaps most important here is that neither side has implemented replay protection in the lead-up to the hash war. Replay protection is what allows traders to safely spend their funds when a fork takes place, and without it, any hard fork can quickly become a dangerous proposition.

A lack of replay protection means that both chains intent to keep boosting their hash rate until the other loses, with the victor becoming the “one true chain” for Bitcoin Cash traders. Crypto investors on the losing side stand to lose a lot of money, and that’s part of what makes this war amidst a hard fork so risky.

On the exchanges front, most are already listing both Bitcoin Cash hard forks as trading pairs. Some (such as Poloniex) have suspended Bitcoin Cash trading altogether until the outcome is confirmed.

With a number of attacks that can be launched, both sides seem willing to fight to the death for the right to control Bitcoin Cash’s future. While it seems likely ABC will emerge as the victor in this hash war, SV could still execute an attack to destroy ABC.

Both blockchains are being pushed to their limits, and it’s a great way for the crypto community to see the pros and cons of each. To follow the hash war live, check out Hashware Live or read this primer on the battle.


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