From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-1.v43.ch3.sourceforge.com ([172.29.43.191] helo=mx.sourceforge.net) by sfs-ml-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1WxjNi-00011u-BU for bitcoin-development@lists.sourceforge.net; Thu, 19 Jun 2014 20:56:26 +0000 X-ACL-Warn: Received: from mail-vc0-f179.google.com ([209.85.220.179]) by sog-mx-1.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1WxjNg-0002eq-LI for bitcoin-development@lists.sourceforge.net; Thu, 19 Jun 2014 20:56:26 +0000 Received: by mail-vc0-f179.google.com with SMTP id id10so2718164vcb.24 for ; Thu, 19 Jun 2014 13:56:19 -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:sender:in-reply-to:references:from :date:message-id:subject:to:cc:content-type; bh=rcr0cVjoXYA2z1cTvQwQEt3IxUmMTQWfOF/EdB7PVUI=; b=LHXh9ZIQyUFA/8dZ616eKLazq/VTV9ynVIOh+zr7F84Fp0uNHYOj34gQ+fsOrKwkOb mcJL/6OK1tXTcJyevtiKvuEpHCPMLTbU9G/DJCky4n/XALv+W6IVpqOXuPkpUfzmCxsa S//RMm6zAGNwAvoxMiEEl/paseAehVaFceYAJvnHKUPEY845gBoXH4YEW/uoDvOPW7/9 X4yr4RuYLfJjWEKdzt797fPkqV6O58qNDbN5MrkbSXHuUfNWodtP1jUjCvT4E3bdAUzW 6iHr2G/9hHGMojAc9GVRrnt7t/qxyYJU2Dr8pTFu83qzkjzzT1ibZBuLqM0ueDmqFNDd q4kA== X-Gm-Message-State: ALoCoQng8jJJ+YYmIc3tGV//fCR+5yqSJO3k5u9o2G3K/6SQVEXMcBk4LmI/ga0VAEr7+wHaGxDv X-Received: by 10.52.191.68 with SMTP id gw4mr40486vdc.65.1403211379035; Thu, 19 Jun 2014 13:56:19 -0700 (PDT) MIME-Version: 1.0 Sender: marek@palatinus.cz Received: by 10.58.218.36 with HTTP; Thu, 19 Jun 2014 13:55:48 -0700 (PDT) In-Reply-To: <53A34A71.2090106@monetize.io> References: <53A316BE.5040508@certimix.com> <53A31B3E.7020906@monetize.io> <53A34A71.2090106@monetize.io> From: slush Date: Thu, 19 Jun 2014 22:55:48 +0200 X-Google-Sender-Auth: UnFaRVg5Jr0G-rX-iCu7kqQ3QN0 Message-ID: To: Mark Friedenbach Content-Type: multipart/alternative; boundary=089e013a219ccb086804fc369bf7 X-Spam-Score: 1.0 (+) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (slush[at]centrum.cz) 1.0 HTML_MESSAGE BODY: HTML included in message X-Headers-End: 1WxjNg-0002eq-LI Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] BlockPow: A Practical Proposal to prevent mining pools AND reduce payoff variance: X-BeenThere: bitcoin-development@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 19 Jun 2014 20:56:26 -0000 --089e013a219ccb086804fc369bf7 Content-Type: text/plain; charset=ISO-8859-1 Miner issues are just one thing what came to my mind. What about validating transactions? How the pool can be sure that miner is running up to date bitcoind which do full validation of transactions? Not talking that if every miner takes his own set of transaction, pool need to calculate merkle root for every submit, to check its correctness. I don't think it *cannot* be done, it is just extremely hard and there's no economic motivation for such complication on pool side. Just see current pools, they are full of security and stability bugs even while using such trivial protocol like Stratum... slush On Thu, Jun 19, 2014 at 10:39 PM, Mark Friedenbach wrote: > Do you need to do full validation? There's an economic cost to mining > invalid blocks, and even if that were acceptable there's really no > reason to perform such an attack. The result would be similar to a block > withholding attack, but unlike block withholding it would be trivially > detectable if/when full validation was performed. > > To protect yourself and to detect incorrect mining software you could > stochastically validate a randomly selected sample of shares, as your > hardware requirements allow. > > On 06/19/2014 01:26 PM, slush wrote: > > With GBT, simply hashing the block header is not enough, because pool > > cannot rely on anything provided by the client. Its not only about > > things like withdrawal attacks, but more about hidden bugs in various > > miners. It is extremely hard to do full validation for *every* of > > submitted shares. > --089e013a219ccb086804fc369bf7 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
Miner issues are just one thing= what came to my mind. What about validating transactions? How the pool can= be sure that miner is running up to date bitcoind which do full validation= of transactions? Not talking that if every miner takes his own set of tran= saction, pool need to calculate merkle root for every submit, to check its = correctness.

I don't= think it *cannot* be done, it is just extremely hard and there's no ec= onomic motivation for such complication on pool side. Just see current pool= s, they are full of security and stability bugs even while using such trivi= al protocol like Stratum...

slush
=

On Thu, Jun 19, 2= 014 at 10:39 PM, Mark Friedenbach <mark@monetize.io> wrote:
Do you need to do full validation? There'= ;s an economic cost to mining
invalid blocks, and even if that were acceptable there's really no
reason to perform such an attack. The result would be similar to a block withholding attack, but unlike block withholding it would be trivially
detectable if/when full validation was performed.

To protect yourself and to detect incorrect mining software you could
stochastically validate a randomly selected sample of shares, as your
hardware requirements allow.

On 06/19/2014 01:26 PM, slush wrote:
> With GBT, simply hashing the block header is not enough, because pool<= br> > cannot rely on anything provided by the client. Its not only about
> things like withdrawal attacks, but more about hidden bugs in various<= br> > miners. It is extremely hard to do full validation for *every* of
> submitted shares.

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