From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 66242282 for ; Wed, 11 May 2016 18:28:47 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-lf0-f54.google.com (mail-lf0-f54.google.com [209.85.215.54]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 16F03192 for ; Wed, 11 May 2016 18:28:46 +0000 (UTC) Received: by mail-lf0-f54.google.com with SMTP id m64so58648496lfd.1 for ; Wed, 11 May 2016 11:28:45 -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=KI88IwZlQJQRn4yEJdTLRNaqar0z3Ls4l99QKXGXgjU=; b=mlZHdWAu3cJdop+inbOT9WuME/wpbCh+5i0ve+PtsMAIVM3wrm5dVTzt/GC+g2NhMF oH97Dwn8CKZv7R07jAkXhWX8sMiJceaTvvtsi/pDbZprglIiXVFrqxDTkTtL0hPNf8du 63V7C1Q9M+UyJ+DufFFIB3sPmr/9JJIQR9fzTKCDiqHoRCpO5n6OmLEZjZkmVGdCxfnW KTKnaomygMWgg935dO/MN5g1TRvPCAeK6hz8tqu+UBhqb+OFOVGWgijp6qcVuhHE7N7w rSzyVswynSV3Nq78Ye6KCwx5c+hgKonNgZrCvQ9msXVCYYIdzRvB0E+WtuEeo4R8ohPZ D2gw== X-Gm-Message-State: AOPr4FWzil2+O31Sg3x9zPANGaELAtZNqpkilADdlx1bj7ZDwOzB7K6GI+qOVf4StqciUg== X-Received: by 10.25.88.12 with SMTP id m12mr2339449lfb.42.1462991324288; Wed, 11 May 2016 11:28:44 -0700 (PDT) Received: from mail-lf0-f44.google.com (mail-lf0-f44.google.com. [209.85.215.44]) by smtp.gmail.com with ESMTPSA id q137sm1490457lfq.24.2016.05.11.11.28.43 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 11 May 2016 11:28:43 -0700 (PDT) Received: by mail-lf0-f44.google.com with SMTP id j8so58523214lfd.2 for ; Wed, 11 May 2016 11:28:43 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.112.95.114 with SMTP id dj18mr2294318lbb.136.1462991323102; Wed, 11 May 2016 11:28:43 -0700 (PDT) Received: by 10.25.144.8 with HTTP; Wed, 11 May 2016 11:28:42 -0700 (PDT) In-Reply-To: References: <20160510185728.GA1149@fedora-21-dvm> <201605111428.25918.luke@dashjr.org> Date: Wed, 11 May 2016 11:28:42 -0700 X-Gmail-Original-Message-ID: Message-ID: From: Timo Hanke To: Luke Dashjr , Bitcoin Protocol Discussion Content-Type: multipart/alternative; boundary=001a11360dae1f85b8053295363b 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 18:28:47 -0000 --001a11360dae1f85b8053295363b Content-Type: text/plain; charset=UTF-8 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 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 >> > > --001a11360dae1f85b8053295363b Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Sorry, you must have meant all 12 bytes. That makes findin= g a collision substantially harder. However, you may have to restrict yours= elf to 10 bytes because you don't know if any hardware does timestamp r= olling on-chip. Also you create an incentive to mess around with the versio= n bits instead, so you would have to fix that as well. So it basically mean= s a new mining header with the real blockheader as a child header.=C2=A0

On Wed, May 11= , 2016 at 9:24 AM, Timo Hanke <timo.hanke@web.de> wrote:
=
Luke, do you mean to replac= e 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 assu= me you don't care about 12 bytes but rather those 4 bytes.)

This does not work. All it does is adding another computational ste= p 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 &l= t;bitcoin-dev@lists.linuxfoundation.org> wrote:
On Wednesday, May 11, 2016 12:20:55 PM Sergio Demian L= erner 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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