Subject: Re: [bitcoin-dev] BIP proposal: Inhibiting a covert attack on the Bitcoin POW function

From: Peter Todd <[email-masked]>
Date: Wed, 5 Apr 2017 22:31:23 -0400

On Wed, Apr 05, 2017 at 09:37:45PM +0000, Gregory Maxwell via bitcoin-dev wrote:
> On that basis, I offer the following BIP draft for discussion.
> This proposal does not prevent the attack in general, but only
> inhibits covert forms of it which are incompatible with
> improvements to the Bitcoin protocol.
> 
> I hope that even those of us who would strongly prefer that
> ASICBOOST be blocked completely can come together to support
> a protective measure that separates concerns by inhibiting
> the covert use of it that potentially blocks protocol improvements.

While I'm in favour of blocking covert usage of ASICBOOST, there's every reason
to block non-covert usage of it as well. In a low margin business like mining,
the advatange it gives is enormous - quite possibly 10x your profit margin -
and given that barrier free access to being able to purchase ASICs is already
an archilles heal for Bitcoin there is every reason to eliminate this legal
vulnerability. Additionally, it's a technical vulnerability as well: we want
getting into the ASIC manufacturing and design business to have as low barriers
to entry as is feasible, and the ASICBOOST exploit significantly increases the
minimum capital requirements to do so.

Remember that the whole purpose of PoW is to destroy value on a level playing
field. Anything that inhibits a level playing field is an exploit. While this
isn't standard crypto - we can't fix every exploit completely - since we're
going to do a technical change to partially mitigate the ASCIBOOST exploit
there is every reason to fully mitigate it.

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