[bitcoin-dev] Making AsicBoost irrelevant

Timo Hanke timo.hanke at web.de
Wed May 11 22:42:35 UTC 2016

On Wed, May 11, 2016 at 3:47 AM, Jannes Faber <jannes.faber at gmail.com>

> On 11 May 2016 at 12:36, Henning Kopp <henning.kopp at uni-ulm.de> wrote:
>> On Wed, May 11, 2016 at 11:21:10AM +0200, Jannes Faber via bitcoin-dev
>> wrote:
>> > On 11 May 2016 at 05:14, Timo Hanke via bitcoin-dev <
>> > bitcoin-dev at lists.linuxfoundation.org> wrote:
>> >
>> > > There is no way to tell from a block if it was mined with AsicBoost or
>> > > not. So you don’t know what percentage of the hashrate uses AsicBoost
>> at
>> > > any point in time. How can you risk forking that percentage out? Note
>> that
>> > > this would be a GUARANTEED chain fork. Meaning that after you change
>> the
>> > > block mining algorithm some percentage of hardware will no longer be
>> able
>> > > to produce valid blocks. That hardware cannot “switch over” to the
>> majority
>> > > chain even if it wanted to. Hence you are guaranteed to have two
>> > > co-existing bitcoin blockchains afterwards.
>> > >
>> > > Again: this is unlike the hypothetical persistence of two chains
>> after a
>> > > hardfork that is only contentious but doesn’t change the mining
>> algorithm,
>> > > the kind of hardfork you are proposing would guarantee the
>> persistence of
>> > > two chains.
>> > >
>> >
>> > Assuming AsicBoost miners are in the minority, their chain will
>> constantly
>> > get overtaken. So it will not be one endless hard fork as you claim, but
>> > rather AsicBoost blocks will continue to be ignored (orphaned) until
>> they
>> > stop making them.
>> At least until a difficulty adjustment on the AsicBoost chain takes
>> place. From that point on, both chains, the AsicBoost one and the
>> forked one will grow approximately at the same speed.
> No: you are still assuming AsicBoost miners would reject normal blocks.
> They don't now and they would have to specifically code for that as a reply
> to AsicBoost being banned. So there won't be two chains at all, only the
> main chain with a lot (more than usual) of short (few blocks) forks. Each
> forks starts anew, it's not one long fork. Therefore there is no
> "difficulty adjustment on the AiscBoost chain".
> Now if they do decide to ban non-AsicBoost blocks as a response to being
> banned themselves, they're just another altcoin with a different PoW and no
> one would have a reason to use them over Bitcoin (apart from maybe selling
> those forked coins asap).

This is what I meant. If existing hardware gets forked-out it will
inevitably lead to the creation of an altcoin. Simply because the hardware
exists and can't be used for anything else both chains will survive. I was
only comparing the situation to a contentious hardfork that does not fork
out any hardware. If the latter one is suspected to lead to the permanent
existence of two chains then a hardfork that forks out hardware is even
more likely to do so (I claim it's guaranteed).

> You're confused about what "longest" means as well: it's not just the
> number of blocks, it's the aggregate difficulty that counts: so AsicBoost
> would never become "longer" (more total work) either.
> Hope this helps clear things up.
> --
> Jannes
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