Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id E44E0411 for ; Wed, 11 May 2016 16:24:17 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-lf0-f47.google.com (mail-lf0-f47.google.com [209.85.215.47]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 07EEC11D for ; Wed, 11 May 2016 16:24:17 +0000 (UTC) Received: by mail-lf0-f47.google.com with SMTP id m64so55112664lfd.1 for ; Wed, 11 May 2016 09:24:16 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc; bh=nQli84Dm63wMD/byNsuqdzkotGvyYeEMGgEuTzrCsWk=; b=DEGBzExyEt6Lv70HJOj78iOk6ixNBaF3h50v7zyNR0umLEpADJmFTZ8aPTXk3AcRHd uXqABi+QW476bV1zpaz1qYtbH2sZPQWdrSJCluvVlBoggTyr3JPcQLkSXdL1R1vOAgYB 8x9AWBPHmb+HGLc1X6vE93PoG/UTtdYicugj7HsUjTPs/UTLrV5RUlEzGQ5wXanREuiz NIJ39DoTaTNsl73xtTsg/fEukkcmaY44mEuX4ak4Pa0OwmSFCW0jQxO0uU7K74fIoRhY yv33Ae3iNR/OtIQz/4JKyxphziAyiomOweFPJHekppxAcdTyx1YFmEiijx+jscX72vEy R55A== X-Gm-Message-State: AOPr4FWGsH8d01hxgHFjEC9bvYSHugRSxON57XkmYm4okmrnIE58kRaXDIk+cvTmfOqgpA== X-Received: by 10.112.171.98 with SMTP id at2mr1737613lbc.124.1462983855094; Wed, 11 May 2016 09:24:15 -0700 (PDT) Received: from mail-lf0-f47.google.com (mail-lf0-f47.google.com. [209.85.215.47]) by smtp.gmail.com with ESMTPSA id n8sm1403170lbc.17.2016.05.11.09.24.14 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 11 May 2016 09:24:14 -0700 (PDT) Received: by mail-lf0-f47.google.com with SMTP id m64so55111948lfd.1 for ; Wed, 11 May 2016 09:24:14 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.112.10.9 with SMTP id e9mr1983219lbb.142.1462983853919; Wed, 11 May 2016 09:24:13 -0700 (PDT) Received: by 10.25.144.8 with HTTP; Wed, 11 May 2016 09:24:13 -0700 (PDT) In-Reply-To: <201605111428.25918.luke@dashjr.org> References: <20160510185728.GA1149@fedora-21-dvm> <201605111428.25918.luke@dashjr.org> Date: Wed, 11 May 2016 09:24:13 -0700 X-Gmail-Original-Message-ID: Message-ID: From: Timo Hanke To: Luke Dashjr , Bitcoin Protocol Discussion Content-Type: multipart/alternative; boundary=001a1136069cecd65b053293783f X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,FREEMAIL_FROM, HTML_MESSAGE,RCVD_IN_DNSWL_LOW autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org Subject: Re: [bitcoin-dev] Making AsicBoost irrelevant X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 11 May 2016 16:24:18 -0000 --001a1136069cecd65b053293783f Content-Type: text/plain; charset=UTF-8 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 > --001a1136069cecd65b053293783f Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Luke, do you mean to replace the first 4 bytes of the seco= nd chunk (bytes 64..67 in 0-based counting) by the XOR of those 4 bytes wit= h 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 co= llision in those 4 bytes. It makes finding a collision only marginally hard= er.

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 Demi= an 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.w= ordpress.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 spa= ce 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/mail= man/listinfo/bitcoin-dev

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