Subject: Re: [bitcoin-dev] We need to fix the block withholding attack

From: Tier Nolan <[email-masked]>
Date: Sat, 26 Dec 2015 16:09:18 +0000

On Sat, Dec 26, 2015 at 8:23 AM, Eric Lombrozo via bitcoin-dev <
[email-masked]> wrote:

> Unfortunately, this also means longer confirmation times, lower
> throughput, and lower miner revenue. Note, however, that confirmations
> would (on average) represent more PoW, so fewer confirmations would be
> required to achieve the same level of security.
>

No, the re-target compensates so that the number of blocks in the last two
weeks is 2016.  If a soft fork forces miners to throw away 25% of their
blocks, then the difficulty will drop by 75% to keep things balanced.
Throwing away 75% of blocks has the same effect on difficulty as destroying
75% of mining hardware.

The block interval will only increase until the next re-target.

Slowly increasing the fraction of blocks which are thrown away gives the
re-target algorithm time to adjust, so it is another advantage.

If the rule was instantly changed so that 95% of blocks were thrown away,
then there could be up to 40 weeks until the next retarget and that would
give 200 minute block times until the adjustment.