Subject: [bitcoin-dev] The Nuclear Option: BIP148 + MR POWA

From: John Hardy <[email-masked]>
Date: Wed, 5 Jul 2017 09:18:36 +0000

This idea is highly contentious as it would guarantee a viable chain of Bitcoin with SegWit activated whether BIP148 gained sufficient support or not. I am not necessarily advocating it - just putting it out for discussion. While the downside is that it could permanently split the network, the upside is that it could heap additional pressure on miners to follow the BIP148 chain and ensure a minimally disruptive upgrade. This is pure game theory.

MR POWA (Mining Reactive Proof of Work Addition) is a method to introduce an additional proof of work to a blockchain in response to a detected mining behaviour.

In the case of BIP148, the criteria for activation could be when the software detects a non-BIP148 compliant chain that is 144 blocks (24 hours) ahead of a BIP148 compliant chain.

At this stage the software would change its consensus rules (hard fork) to do two things:

  *   Lower the difficulty for existing PoW method (SHA256).

  *   Introduce a second POW method, such as Scrypt or Ethash, that is incompatible with SHA256 hardware but already has an established mining industry for altcoins.

The difficulty should be low, and blocks will initially be found much more quickly than every 10 minutes until the difficulty adjusts. Each method would have its own difficulty. It could be a requirement that POW methods alternate to neutralise attacks from the other chain.

This would guarantee SegWit activation. Anybody who is already running a BIP148 node could just as easily run a BIP148 + MR POWA node. This could not realistically be supported by Core and would have to be implemented in a grassroots movement, similar to BIP148.

Ideally, it would just force the miners to follow the BIP148 chain (or risk the value of their hardware being hurt) and the code would never be activated. MR POWA would mean BIP148 miners would no longer need to “hold their nerve” as they would be guaranteed a viable chain and rewarded for their early support.

Regards,

John Hardy

[email-masked]