Received: from sog-mx-4.v43.ch3.sourceforge.com ([172.29.43.194] helo=mx.sourceforge.net) by sfs-ml-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1VvCUp-0004cA-Al for bitcoin-development@lists.sourceforge.net; Mon, 23 Dec 2013 20:53:03 +0000 Received-SPF: pass (sog-mx-4.v43.ch3.sourceforge.com: domain of pathwayintelligence.com designates 209.85.128.43 as permitted sender) client-ip=209.85.128.43; envelope-from=robin@pathwayintelligence.com; helo=mail-qe0-f43.google.com; Received: from mail-qe0-f43.google.com ([209.85.128.43]) by sog-mx-4.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1VvCUo-0003ru-5r for bitcoin-development@lists.sourceforge.net; Mon, 23 Dec 2013 20:53:03 +0000 Received: by mail-qe0-f43.google.com with SMTP id jy17so5621633qeb.2 for ; Mon, 23 Dec 2013 12:52:56 -0800 (PST) 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:date :message-id:subject:from:to:cc:content-type; bh=4Iuxx1ohEBA9ew4Mq4RIvXbIpQEoWzwU3aX83d5GahE=; b=eYthJrv+S1vTItKuy5zaJCxdzF8P7uM4UG5UQumI0/q8ARuDkf7CWn+ZnoO06XqDFY N3UqroJhi0K3tdLOG1J2ZkBTXRXwgdCVrtIa52Z3G5RVakP7AIkKD+2wylDaqH/IIwjY WjGPredAd0pvMmsV/UETLFpbL2M/a1GdA7w3ZyBiqnsOiBiksBp0abxccMboBGYgB3bg NJCM30Rmtfcy3PiOeVVr3FIK2BPXGkmZMv3vkpKtxRO+E7aLVlJntYgsvEs2bWI+KcD/ PqjJqeg8Gxdg+psRuHYE4dEV+FMO9QdEqZNxiY35z31djr5dLOQXMxHSD1LtdA1Ib7eM O/cQ== X-Gm-Message-State: ALoCoQlMAmmEAdm7ZmSorfYzF1j/OLSZQJ0+mPaNBGqc+qLaNybLS6IjOWF8RsYAfzNq/IpQVQWP MIME-Version: 1.0 X-Received: by 10.224.171.196 with SMTP id i4mr45961762qaz.38.1387830169824; Mon, 23 Dec 2013 12:22:49 -0800 (PST) Sender: robin@pathwayintelligence.com Received: by 10.229.170.1 with HTTP; Mon, 23 Dec 2013 12:22:49 -0800 (PST) X-Originating-IP: [24.207.115.167] In-Reply-To: <52B7AC86.9010808@monetize.io> References: <52B7AC86.9010808@monetize.io> Date: Mon, 23 Dec 2013 12:22:49 -0800 X-Google-Sender-Auth: p93iLzRxqhd__u1N174EyL-rZbk Message-ID: From: Robin Ranjit Singh Chauhan To: Mark Friedenbach Content-Type: multipart/alternative; boundary=001a11c2ef544811bf04ee396450 X-Spam-Score: -0.5 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. 0.0 URIBL_BLOCKED ADMINISTRATOR NOTICE: The query to URIBL was blocked. See http://wiki.apache.org/spamassassin/DnsBlocklists#dnsbl-block for more information. [URIs: doubleclick.net] -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for sender-domain -0.0 SPF_PASS SPF: sender matches SPF record 1.0 HTML_MESSAGE BODY: HTML included in message 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature X-Headers-End: 1VvCUo-0003ru-5r Cc: Bitcoin Dev , Ryan Carboni Subject: Re: [Bitcoin-development] Bitcoin difficulty sanity check suggestion 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: Mon, 23 Dec 2013 20:53:03 -0000 --001a11c2ef544811bf04ee396450 Content-Type: text/plain; charset=ISO-8859-1 Mark, thank you for a very clear explanation of why this proposal would be dangerous. What I have noted in many discussions regarding blockchain security and proof-or-work schemes, is there is a wide gulf between those few people who can clearly reason about it, and those who have a lot trouble with it (I mostly fall into the later camp). I wonder if anyone can point to resources who can help "the rest of us" reason clearly about these types of proposals, prior to bringing them to this list or a senior dev. Ideally it would illustrate various past proposals, explain why they would and wouldnt work, and build up some fundamental concepts, like a "Newtons laws of blockchain security" that would help us evaluate such ideas on our own. Blockchain stuff is often counterintuitive. On Sun, Dec 22, 2013 at 7:22 PM, Mark Friedenbach wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Ryan, these sort of adjustments introduce security risks. If you were > isolated from the main chain by a low-hashpower attacker, how would > you know? They'd need just three days without you noticing that > network block generation has stalled - maybe they wait for a long > weekend - then after that the block rate is normal but completely > controlled by the attacker (and isolated from mainnet). > > There are fast acting alternative difficulty adjustment algorithms > being explored by some alts, such as the 9-block interval, 144-block > window, Parks-McClellan FIR filter used by Freicoin to recover from > just such a mining bubble. If it were to happen to bitcoin, there > would be sophisticated alternative to turn to, and enough time to make > the change. > > On 12/22/2013 07:10 PM, Ryan Carboni wrote: > > I think Bitcoin should have a sanity check: after three days if > > only four blocks have been mined, difficulty should be adjusted > > downwards. > > > > This might become important in the near future. I project a > > Bitcoin mining bubble. > > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.14 (GNU/Linux) > Comment: GPGTools - http://gpgtools.org > Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ > > iQIcBAEBAgAGBQJSt6yGAAoJEAdzVfsmodw4SegQAIJAWW0OgSjediSWq+EpkReS > qMvC2Y9dmVHtowYLdJVcgwFWbpU8RhA6ApQ1Ks2XF4t0hFCObYDecG6Nl3OIaLfb > snz24v8ymdxYXKNtzHHUP0VBgsaoRghIpkbf7JMUXC22sxPoPOXFt5RevLgJHrvc > oGFZSIcEcGgwhwZ745CgFZLwaKuSmg5+wFFcrjIihlHKJOl47Z7rzeqnD6mf2Oi3 > hDpRuVbuhlGMliYcmhk1E6oV0in2R4Purw1WtoY8C9DxrSP2za7W1oeCkmlFfJZS > to6SzRj7nEIl0LFaPGsIdBrRdDHfvu6eP2OecI+GNLEwLY6qE5v5fkh47mcDkrN0 > 02PmepoX5PRzBqp4sx8WaFKuRbmTRRr3E4i9PGoyzTckkZzq+zFmb1y5fwOy17hE > C+nP+DyuaPzjypjdo6V+/oGzUKtuKPtqcB1vurbm+WBl5C1jWosAXv5pR87mdCUJ > +0e14wPra5blV6yBVqX7yx+2heDGymPKfHJ8i76Dtix7XVOJWKVY4OpIxO7YrYv8 > IKcIswoKhZdSDOJLcjm4Qp4hrzgCHAHWx6vN71r5r2T6zaJTOvp98GS04Yy7VGAr > j38hojcwvJC1ahER3LV/vC0cqO+fxrvY8Q9rW2cUxCnzxzjjG0+Z/gjW8uh73lXN > DOTF7jpt0ZmCm7uhG9z7 > =5Q2H > -----END PGP SIGNATURE----- > > > ------------------------------------------------------------------------------ > Rapidly troubleshoot problems before they affect your business. Most IT > organizations don't have a clear picture of how application performance > affects their revenue. With AppDynamics, you get 100% visibility into your > Java,.NET, & PHP application. Start your 15-day FREE TRIAL of AppDynamics > Pro! > http://pubads.g.doubleclick.net/gampad/clk?id=84349831&iu=/4140/ostg.clktrk > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development > -- Robin R Chauhan CEO, Pathway Intelligence Inc robin@pathwayi.com Office: 778-588-6217 Ext. 201 Cell: 604-865-0517 Fax: 778-588-1042 http://pathwayi.com/ --------------------------------------------------------------------- This transmission (including any attachments) may contain confidential information or constitute non-public information. Any use of this information by anyone other than the intended recipient is prohibited. If you have received this transmission in error, please immediately reply to the sender and delete this information from your system. Use, dissemination, distribution, or reproduction of this transmission by unintended recipients is not authorized and may be unlawful. --001a11c2ef544811bf04ee396450 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
Mark, thank you for a very clear explanation of why this p= roposal would be dangerous.

What I have noted in many discussions re= garding blockchain security and proof-or-work schemes, is there is a wide g= ulf between those few people who can clearly reason about it, and those who= have a lot trouble with it (I mostly fall into the later camp).

I wonder if anyone can point to resources who can help "= ;the rest of us" reason clearly about these types of proposals, prior = to bringing them to this list or a senior dev. =A0

Ideally it would = illustrate various past proposals, explain why they would and wouldnt work,= and build up some fundamental concepts, like a "Newtons laws of block= chain security" that would help us evaluate such ideas on our own.

Blockchain stuff is often counterintuitive.
<= br>


On Sun, Dec 22, 2013 at 7:22 PM, Mark Friedenbach <<= a href=3D"mailto:mark@monetize.io" target=3D"_blank">mark@monetize.io&g= t; wrote:
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Ryan, these sort of adjustments introduce security risks. If you were
isolated from the main chain by a low-hashpower attacker, how would
you know? They'd need just three days without you noticing that
network block generation has stalled - maybe they wait for a long
weekend - then after that the block rate is normal but completely
controlled by the attacker (and isolated from mainnet).

There are fast acting alternative difficulty adjustment algorithms
being explored by some alts, such as the 9-block interval, 144-block
window, Parks-McClellan FIR filter used by Freicoin to recover from
just such a mining bubble. If it were to happen to bitcoin, there
would be sophisticated alternative to turn to, and enough time to make
the change.

On 12/22/2013 07:10 PM, Ryan Carboni wrote:
> I think Bitcoin should have a sanity check: after three days if
> only four blocks have been mined, difficulty should be adjusted
> downwards.
>
> This might become important in the near future. I project a
> Bitcoin mining bubble.
>
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---------------------------------------------------------------------------= ---
Rapidly troubleshoot problems before they affect your business. Most IT
organizations don't have a clear picture of how application performance=
affects their revenue. With AppDynamics, you get 100% visibility into your<= br> Java,.NET, & PHP application. Start your 15-day FREE TRIAL of AppDynami= cs Pro!
http://pubads.g.doubleclick.net/gam= pad/clk?id=3D84349831&iu=3D/4140/ostg.clktrk
_______________________________________________
Bitcoin-development mailing list
Bitcoin-develo= pment@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/bitcoin-de= velopment



--
Robin R Chauhan
CEO, Pathway Intelligence Inc
robin@pathwayi.com=
Office: 778-588-6217 Ext. 201
Cell: 604-865-0517
F= ax: 778-588-1042
-------------------------------------= --------------------------------
This transmission (including any attachments) may con= tain confidential
information or constitu= te non-public information. Any use of this
information by anyone other than the intended recipient is prohibited.
If you have received this transmission in error, plea= se immediately
reply to the sender and de= lete this information from your system.=A0
Use, dissemination, distribution, or reproduction of this transmission=A0=
by unintended recipients is not authorized and may be= unlawful.

--001a11c2ef544811bf04ee396450--