Subject: Re: [Bitcoin-development]Fwd: Block Size Increase Requirements‏

From: Nathan Cook <[email-masked]>
Date: Tue, 2 Jun 2015 14:43:29 +0300

On 2 June 2015 at 14:26, Mike Hearn <[email-masked]> wrote:

> But the majority of the hashrate can now perform double spends on your
>> chain! They can send bitcoins to exchanges, sell it, extract the money and
>> build a new longer chain to get their bitcoins back.
>>
> Obviously if the majority of the mining hash rate is doing double spending
> attacks on exchanges then the Bitcoin experiment is resolved as a failure
> and it will become abandoned. This has been known since day one: it's in
> the white paper. The basic assumption behind Bitcoin is that only a
> minority of actors are dishonest - if the majority are then Satoshi's
> scheme does not work.
>
> So you are not stating anything new here.
>

It's both consistent and credible for an agent to commit to honesty on a
chain that it openly supports and dishonesty on a chain that it openly
opposes. (Moral? Legal? Perhaps not.) That said, majority hashpower doesn't
need to be dishonest to stop a change to large blocks. It just needs to
refuse to build on blocks that it doesn't like. The minority isn't going to
mine blocks larger than 1MB if it knows they'll be orphaned.