Bitcoin ABC has proposed a hard fork of the Bitcoin Cash protocol to correct problems associated with the cryptocurrency’s Emergency Difficulty Adjustment (EDA) algorithm.
The Problem With the Bitcoin Cash EDA
Ever since Bitcoin Cash forked away from the main Bitcoin blockchain on August 1, its network has experienced wild hashrate and block time fluctuations. The reason for this is that the EDA automatically adjusts in response to network conditions to help ensure that Bitcoin Cash remains profitable to mine.
However, because miners can easily switch between Bitcoin and Bitcoin Cash — and some mining pools are set up to automatically mine the most profitable chain — they exploit the EDA by mining Bitcoin until the Bitcoin Cash difficulty plummets and profitability increases. Then, they switch a significant amount of hashpower over to Bitcoin Cash, causing blocks to be found almost every minute. Eventually, this triggers another EDA, which makes Bitcoin Cash less profitable to mine, and most of the miners transition back to Bitcoin, making the block time increase to an unreasonable level for a currency that claims to be built for everyday transactions.
Bitcoin ABC’s Proposal
Bitcoin ABC is proposing a hard fork that will activate an updated Difficulty Adjustment Algorithm (DAA) that is based on the D601 algorithm developed by Bitcoin ABC’s Amaury Sechet. According to the Bitcoin ABC announcement, the new DAA seeks to accomplish the following goals:
- Adjust difficulty to hash rate to target a mean block interval of 600 seconds.
- Avoid sudden changes in difficulty when hash rate is fairly stable.
- Adjust difficulty rapidly when hash rate changes rapidly.
- Avoid oscillations from feedback between hash rate and difficulty.
- Be resilient to attacks such as timestamp manipulation.
Bitcoin Classic says the updated software will be available by November 1 and the hard fork will activate on November 13.
Classic Developer Criticizes Proposal
However, although the need to update the DAA is widely-accepted within the bitcoin cash community, Bitcoin ABC has received criticism for this specific proposal. Bitcoin Classic developer Tom Zander, for instance, did not mince words about the proposal, stating in a blog post that he found it “very worrying”. Specifically, he objected that the decision to implement the D601 algorithm was “closed-door decision” made for “political” purposes, not technical efficiency.
On reddit, he accused Bitcoin ABC of using the same tactics to force through the new DAA as it allegedly used to implement the EDA in the first place:
“I have not seen any simulation, no responses to criticisms made on the mailinglist, not even a statement of what the design goals were. When the outcome is to pick your own algo, and not provide any research on why, then we should be asking hard questions. I’m seeing a repeat of the EDA, same person ignoring feedback and doing a last moment political movement.”
“Even Core did better than this,” he concluded, alluding to the common assertion by bitcoin cash proponents that Bitcoin is governed by an elite group of developers rather than decentralized community consensus.