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 1UFSUA-0007Cb-FI for bitcoin-development@lists.sourceforge.net; Tue, 12 Mar 2013 16:55:34 +0000 Received-SPF: pass (sog-mx-1.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.219.50 as permitted sender) client-ip=209.85.219.50; envelope-from=etotheipi@gmail.com; helo=mail-oa0-f50.google.com; Received: from mail-oa0-f50.google.com ([209.85.219.50]) by sog-mx-1.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1UFSU8-0008Hk-05 for bitcoin-development@lists.sourceforge.net; Tue, 12 Mar 2013 16:55:34 +0000 Received: by mail-oa0-f50.google.com with SMTP id l20so61744oag.37 for ; Tue, 12 Mar 2013 09:55:26 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.182.118.1 with SMTP id ki1mr13088639obb.2.1363107326579; Tue, 12 Mar 2013 09:55:26 -0700 (PDT) Received: by 10.76.98.234 with HTTP; Tue, 12 Mar 2013 09:55:26 -0700 (PDT) In-Reply-To: <201303121210.34515.luke@dashjr.org> References: <513ED35A.8080203@gmail.com> <201303121210.34515.luke@dashjr.org> Date: Tue, 12 Mar 2013 12:55:26 -0400 Message-ID: From: Alan Reiner To: Luke-Jr Content-Type: multipart/alternative; boundary=f46d0447f240fddc8d04d7bd272f X-Spam-Score: -0.6 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for sender-domain 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (etotheipi[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 1.0 HTML_MESSAGE BODY: HTML included in message -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 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: 1UFSU8-0008Hk-05 Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] Some PR preparation 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: Tue, 12 Mar 2013 16:55:34 -0000 --f46d0447f240fddc8d04d7bd272f Content-Type: text/plain; charset=ISO-8859-1 On Tue, Mar 12, 2013 at 8:10 AM, Luke-Jr wrote: > > > I think we should be careful not to downplay the reality either. > For a number of hours, transactions could have received up to N > confirmations > and then still been reversed. While we could contact the bigger payment > processors, I saw people still trying to buy/sell on OTC, whom could have > been > scammed even by taking standard precautions. > > I don't want to misrepresent what happened, but how much of that was really a risk? The block was rejected, but the transactions were not. Any valid transactions to hit the network would get added to everyone's memory pool and mined in both chains. Thus all nodes would still reject double-spend attempts. As far as I understood it, you would've had to have majority mining power on one of the chains (and both had non-negligible computing power on them), so double-spending still required an exceptional amount of resources -- just not the normal 50% that is normally needed. Perhaps... 10%? But how many people can even have 10%? In addition to that, a victim needs to be found that hasn't seen the alert, is willing to execute a large transaction, and is on the wrong side of the chain. Is this incorrect? Yes, there was less resources needed to execute an attack -- but it still required a very powerful attacker, way outside the scope of "regular users." --f46d0447f240fddc8d04d7bd272f Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
On T= ue, Mar 12, 2013 at 8:10 AM, Luke-Jr <luke@dashjr.org> wrote:<= br>


I think we should be careful not to downplay the reality either.
For a number of hours, transactions could have received up to N confirmatio= ns
and then still been reversed. While we could contact the bigger payment
processors, I saw people still trying to buy/sell on OTC, whom could have b= een
scammed even by taking standard precautions.


<= /div>I don't want to misrepresent what happened, but how much of that was= really a risk? =A0The block was rejected, but the transactions were not. = =A0Any valid transactions to hit the network would get added to everyone= 9;s memory pool and mined in both chains. =A0Thus all nodes would still rej= ect double-spend attempts. =A0As far as I understood it, you would've h= ad to have majority mining power on one of the chains (and both had non-neg= ligible computing power on them), so double-spending still required an exce= ptional amount of resources -- just not the normal 50% that is normally nee= ded. =A0Perhaps... 10%? =A0 But how many people can even have 10%? =A0In ad= dition to that, a victim needs to be found that hasn't seen the alert, = is willing to execute a large transaction, and is on the wrong side of the = chain.

Is this inc= orrect? =A0Yes, there was less resources needed to execute an attack -- but= it still required a very powerful attacker, way outside the scope of "= ;regular users."
=A0
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