[bitcoin-dev] BIP proposal: Increase block size limit to 2 megabytes

Peter Todd pete at petertodd.org
Sat Feb 6 21:11:58 UTC 2016

On Sat, Feb 06, 2016 at 12:45:14PM -0500, Gavin Andresen via bitcoin-dev wrote:
> On Sat, Feb 6, 2016 at 12:01 PM, Adam Back <adam at cypherspace.org> wrote:
> >
> > It would probably be a good idea to have a security considerations
> > section
> Containing what?  I'm not aware of any security considerations that are any
> different from any other consensus rules change.

I covered the security considerations unique to hard-forks on my blog:


> > , also, is there a list of which exchange, library, wallet,
> > pool, stats server, hardware etc you have tested this change against?
> >
> That testing is happening by the exchange, library, wallet, etc providers
> themselves. There is a list on the Classic home page:
> https://bitcoinclassic.com/

How do we know any of this testing is actually being performed? I don't
currently know of any concrete testing actually done.

> > Do you have a rollback plan in the event the hard-fork triggers via
> > false voting as seemed to be prevalent during XT?  (Or rollback just
> > as contingency if something unforseen goes wrong).
> >
> The only voting in this BIP is done by the miners, and that cannot be faked.

Are you unaware of Not Bitcoin XT?


> I can't imagine any even-remotely-likely sequence of events that would
> require a rollback, can you be more specific about what you are imagining?
> Miners suddenly getting cold feet?

See above.

Also, as the two coins are separate currencies and can easily trade
against each other in a 75%/25% split, it would be easy for the price to
diverge and hashing power to move.

In fact, I've been asked multiple times now by exchanges and other
players in this ecosystem for technical advice on how to split coins
across the chains effectively (easily done with nLockTime). Notably, the
exchanges who have asked me this - who hold customer funds on their
behalf - have informed me that their legal advice was that the
post-hard-fork coins are legally speaking separate currencies, and
customers must be given the opportunity to transact in them separately
if they choose too.  Obviously, with a 75%/25% split, while block times
on the other chain will be slower, the chain is still quite useful and
nearly as secure as the main chain against 51% attack; why I personally
have suggested a 99% threshold:


(remember that the threshold can always be soft-forked down)

It's also notable that millions of dollars of Bitcoin are voting agsast
the fork on the proof-of-stake voting site Bitcoinocracy.com While
obviously not comprehensive, the fact that a relatively obscure site
like it can achieve participation like that, even without an easy to use
user friendly interface.

> > How do you plan to monitor and manage security through the hard-fork?
> >
> I don't plan to monitor or manage anything; the Bitcoin network is
> self-monitoring and self-managing. Services like statoshi.info will do the
> monitoring, and miners and people and businesses will manage the network,
> as they do every day.

Please provide details on exactly how that's going to happen.

https://petertodd.org 'peter'[:-1]@petertodd.org
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