Subject: Re: [Bitcoin-development] blind symmetric commitment for stronger byzantine voting resilience (Re: bitcoin taint & unilateral revocability)

From: Adam Back <[email-masked]>
Date: Wed, 15 May 2013 13:49:56 +0200

On Wed, May 15, 2013 at 07:19:06AM -0400, Peter Todd wrote:
>Protocols aren't set in stone - any attacker that controls enough
>hashing power to pose a 51% attack can simply demand that you use a
>Bitcoin client modified [to facilitate evaluation of his policy]

Protocol voting is a vote per user policy preference, not a CPU vote, which
is the point.  Current bitcoin protocol is vulnerable to hard to prove
arbitrary policies being imposable by a quorum of > 50% miners.  The blind
commitment proposal fixes that, so even an 99% quorum cant easily impose
policies, which leaves the weaker protocol vote attack as the remaining
avenue of attack.  That is a significant qualitative improvement.

The feasibility of protocol voting attacks is an open question, but you
might want to consider the seeming unstoppability of p2p protocols for a
hint.

Adam