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 1XtxEb-00017a-Hc for bitcoin-development@lists.sourceforge.net; Thu, 27 Nov 2014 11:27:41 +0000 Received-SPF: pass (sog-mx-1.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.223.180 as permitted sender) client-ip=209.85.223.180; envelope-from=laanwj@gmail.com; helo=mail-ie0-f180.google.com; Received: from mail-ie0-f180.google.com ([209.85.223.180]) by sog-mx-1.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1XtxEZ-0002j5-Ov for bitcoin-development@lists.sourceforge.net; Thu, 27 Nov 2014 11:27:41 +0000 Received: by mail-ie0-f180.google.com with SMTP id rp18so4219545iec.25 for ; Thu, 27 Nov 2014 03:27:34 -0800 (PST) MIME-Version: 1.0 X-Received: by 10.42.130.7 with SMTP id t7mr20599293ics.25.1417087654477; Thu, 27 Nov 2014 03:27:34 -0800 (PST) Received: by 10.64.195.164 with HTTP; Thu, 27 Nov 2014 03:27:34 -0800 (PST) In-Reply-To: References: <54760A50.201@riseup.net> <20141127020947.A13D2E19A09@quidecco.de> Date: Thu, 27 Nov 2014 11:27:34 +0000 Message-ID: From: Wladimir To: Gregory Maxwell Content-Type: text/plain; charset=UTF-8 X-Spam-Score: -1.6 (-) 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 (laanwj[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record -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: 1XtxEZ-0002j5-Ov Cc: Bitcoin Development Subject: Re: [Bitcoin-development] Deanonymisation of clients in Bitcoin P2P network paper 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, 27 Nov 2014 11:27:41 -0000 On Thu, Nov 27, 2014 at 2:22 AM, Gregory Maxwell wrote: >> Since this attack vector has been discussed, I started making some >> measurements on how effective it is to connect to Bitcoin using Tor, >> and I found that the number of connections dropping to near-zero is >> a situation which occurs rather frequently, which suggests that there >> is still room to improve on the DoS handling. > > I'm confused by this, I run quite a few nodes exclusively on tor and > chart their connectivity and have seen no such connection dropping > behaviour. In my experience the problem has always been getting bootstrapped. Most nodes hardly give any hidden service nodes in their getaddr. (this has been improved in master by including a set of hidden service seed nodes) But this assumes -onlynet=tor. Tor with exit nodes should be less problematic, unless someone managed to DoSban all the exit nodes as described in the paper (but I've never seen such an attack myself). > Can you tell me more about how you measured this? > > [As an aside I agree that there are lots of things to improve here, > but the fact that users can in theory be forced off of tor via DOS > attacks is not immediately concerning to me because its a conscious > choice users would make to abandon their privacy (and the behaviour of > the system here is known and intentional). There are other mechanisms > available for people to relay their transactions than connecting > directly to the bitcoin network; so their choice isn't just abandon > privacy or don't use bitcoin at all.] Right, there's something to be said for splitting your own transaction submission from normal P2P networking and transaction relay. (esp for non-SPV wallets which don't inherently leak any information about their addresses) There was a pull request about this for Bitcoin Core one, maybe I closed it unfairly https://github.com/bitcoin/bitcoin/issues/4564 . Wladimir