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From: Timo Hanke <timo.hanke@web.de>
To: Luke Dashjr <luke@dashjr.org>,
	 Bitcoin Protocol Discussion
	<bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Making AsicBoost irrelevant
Date: Wed, 11 May 2016 11:28:42 -0700	[thread overview]
Message-ID: <CAH6h1LsRgZEar8JDR2m-hsTc-DE+=A6BzOq_X2CHSya=bxFRQQ@mail.gmail.com> (raw)
In-Reply-To: <CAH6h1LuVSSxZtOFNGP-Etx-UQGnWMxp1FL0E137yo7D+Wtcs7A@mail.gmail.com>

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Sorry, you must have meant all 12 bytes. That makes finding a collision
substantially harder. However, you may have to restrict yourself to 10
bytes because you don't know if any hardware does timestamp rolling
on-chip. Also you create an incentive to mess around with the version bits
instead, so you would have to fix that as well. So it basically means a new
mining header with the real blockheader as a child header.

On Wed, May 11, 2016 at 9:24 AM, Timo Hanke <timo.hanke@web.de> wrote:

> Luke, do you mean to replace the first 4 bytes of the second chunk (bytes
> 64..67 in 0-based counting) by the XOR of those 4 bytes with the first 4
> bytes of the midstate? (I assume you don't care about 12 bytes but rather
> those 4 bytes.)
>
> This does not work. All it does is adding another computational step
> before you can check for a collision in those 4 bytes. It makes finding a
> collision only marginally harder.
>
> On Wed, May 11, 2016 at 7:28 AM, Luke Dashjr via bitcoin-dev <
> bitcoin-dev@lists.linuxfoundation.org> wrote:
>
>> On Wednesday, May 11, 2016 12:20:55 PM Sergio Demian Lerner via
>> bitcoin-dev
>> wrote:
>> > On Tue, May 10, 2016 at 6:43 PM, Sergio Demian Lerner <
>> > sergio.d.lerner@gmail.com> wrote:
>> > > You can find it here:
>> > >
>> https://bitslog.wordpress.com/2014/03/18/the-re-design-of-the-bitcoin-blo
>> > > ck-header/
>> > >
>> > > Basically, the idea is to put in the first 64 bytes a 4 byte hash of
>> the
>> > > second 64-byte chunk. That design also allows increased nonce space in
>> > > the first 64 bytes.
>> >
>> > My mistake here. I didn't recalled correctly my own idea. The idea is to
>> > include in the second 64-byte chunk a 4-byte hash of the first chunk,
>> not
>> > the opposite.
>>
>> What if we XOR bytes 64..76 with the first 12 bytes of the SHA2 midstate?
>> Would that work?
>>
>> Luke
>> _______________________________________________
>> bitcoin-dev mailing list
>> bitcoin-dev@lists.linuxfoundation.org
>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>>
>
>

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  reply	other threads:[~2016-05-11 18:28 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-10 18:57 [bitcoin-dev] Making AsicBoost irrelevant Peter Todd
2016-05-10 20:27 ` Tier Nolan
2016-05-10 21:35   ` Matt Corallo
2016-05-10 21:43   ` Sergio Demian Lerner
2016-05-10 22:59     ` Matt Corallo
2016-05-11 12:20     ` Sergio Demian Lerner
2016-05-11 13:08       ` Marek Palatinus
2016-05-11 21:01         ` Matt Corallo
2016-05-11 22:16           ` Simon Liu
2016-05-11 22:50             ` Peter Todd
2016-05-11 14:28       ` Luke Dashjr
2016-05-11 16:24         ` Timo Hanke
2016-05-11 18:28           ` Timo Hanke [this message]
2016-05-11 22:49             ` Timo Hanke
2016-05-12  2:27     ` Tom Harding
2016-05-12  2:31       ` Allen Piscitello
2016-05-12  2:33       ` Peter Todd
2016-05-12  4:01         ` Tom Harding
2016-05-10 21:49 ` Marco Pontello
2016-05-10 22:17 ` Sergio Demian Lerner
2016-05-10 22:27   ` Chris Riley
2016-05-11  3:14 ` Timo Hanke
2016-05-11  9:21   ` Jannes Faber
2016-05-11 10:36     ` Henning Kopp
2016-05-11 10:47       ` Jannes Faber
2016-05-11 22:42         ` Timo Hanke
2016-05-11 22:58           ` Gregory Maxwell
2016-05-12  7:29             ` Tom
2016-05-12 11:05           ` Jorge Timón
2016-05-11 14:07   ` Jorge Timón
2016-05-11 14:18     ` Sergio Demian Lerner
2016-05-11 14:30       ` Jannes Faber
2016-05-11 20:50   ` Matt Corallo
2016-05-11 22:00     ` James Hilliard
2016-05-11 23:01   ` Peter Todd
2016-05-12  0:02     ` Gregory Maxwell
2016-05-12  1:23       ` Russell O'Connor
2016-05-12  1:58         ` Peter Todd
2016-05-12  1:58         ` Matt Corallo

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