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From: Johnson Lau <jl2012@xbt.hk>
To: Eric Voskuil <eric@voskuil.org>,
	bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] BIP30 and BIP34 interaction (was Re: [BIP Proposal] Buried Deployments)
Date: Thu, 17 Nov 2016 23:40:05 +0800	[thread overview]
Message-ID: <FA128F93-7E79-47FE-8270-225D07DD6FEF@xbt.hk> (raw)
In-Reply-To: <34949746-c0c9-7f14-0e92-69d5a7d44b04@voskuil.org>


> On 17 Nov 2016, at 20:22, Eric Voskuil via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote:
> 
> 
> Given that hash collisions are unquestionably possible, 

Everything you said after this point is irrelevant.

Having hash collision is **by definition** a consensus failure, or a hardfork. You could replace the already-on-chain tx with the collision and create 2 different versions of UTXOs (if the colliding tx is valid), or make some nodes to accept a fork with less PoW (if the colliding tx is invalid, or making the block invalid, such as being to big). To put it simply, the Bitcoin protocol is broken. So with no doubt, Bitcoin Core and any implementation of the Bitcoin protocol should assume SHA256 collision is unquestionably **impossible**. If some refuse to make such assumption, they should have introduced an alternative hash algorithm and somehow run it in parallel with SHA256 to prevent the consensus failure.

jl2012


  reply	other threads:[~2016-11-17 15:44 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-17  0:06 [bitcoin-dev] BIP30 and BIP34 interaction (was Re: [BIP Proposal] Buried Deployments) Jorge Timón
2016-11-17  0:10 ` Eric Voskuil
2016-11-17  0:31   ` Tier Nolan
2016-11-17  0:43     ` Eric Voskuil
2016-11-17  0:53       ` Eric Voskuil
2016-11-17  8:44       ` Peter Todd
2016-11-17  9:58         ` Eric Voskuil
2016-11-17 10:22       ` Tier Nolan
2016-11-17 11:22         ` Eric Voskuil
2016-11-17 11:38           ` Alex Morcos
2016-11-17 12:22             ` Eric Voskuil
2016-11-17 15:40               ` Johnson Lau [this message]
2016-11-17 17:01                 ` Eric Voskuil
2016-11-17 17:22                   ` Johnson Lau
2016-11-17 17:49                     ` Eric Voskuil
2016-11-17 18:08                       ` Johnson Lau
2016-11-18  3:20                         ` Eric Voskuil
2016-11-18 14:43                           ` Johnson Lau
2016-11-18 16:47                             ` Eric Voskuil

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