Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 73547899 for ; Tue, 28 Jun 2016 18:35:31 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-wm0-f44.google.com (mail-wm0-f44.google.com [74.125.82.44]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 343C32D4 for ; Tue, 28 Jun 2016 18:35:30 +0000 (UTC) Received: by mail-wm0-f44.google.com with SMTP id r201so40334444wme.1 for ; Tue, 28 Jun 2016 11:35:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=voskuil-org.20150623.gappssmtp.com; s=20150623; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=Ft9O8t8gE9MPHiosnS2uQBNMncPSOyPuJH9OKp1haUU=; b=DqeAEeSgnzEU2MHhWs9vW+OYSx7lALd3N0rSEMmM+eZ/whIv8gd2YVYciXBr9RGl2Z zYcRVapLWvAxd9/vxFJNwIjqsHoL/AcWPd/07+GFfT+tHuDKlygoq9rUw6/7kGKTIsNj Dq3Qphh/rzg0yazyTtei+NtYrLAwRchH9R2sTl3CRMOL/8Y5ddR/srZqV3k4ixdMrUN1 FniZUjVFGHN8ijH+L+3Q/GQsjv3l80RVimIG2EgOFoUkhiouOvyeL64Glg712lz2Mwif FwMsKOBkrKLWc5bHuP1U8Xv+/QILA0IKB4O7DWoLx4dar1Sm6XTwBDpEV6DCdnORhXS6 lK4A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=Ft9O8t8gE9MPHiosnS2uQBNMncPSOyPuJH9OKp1haUU=; b=l6hjVqetpNpZ5+6e/hkgovQv4wFoTE1UVkzOklHubmlDpar8sKHbvxgVgZv063tpSx HK91pKRbS0n5W6DhXLkmwt3VmeOTUkpOgZbuCwGzuWGhRfUYCtAFRAN9NAB1Dp8tFsrk 0FVrdXbjDIeZOoWI2o0z1NVp6MwAK3mug6zWhIYxW7CBJTp4+yoiFx3HQYxZs1DsX3DP fERuyA2W8KlB+O8QSmvepqF7gYua5yDE9WCBV13JK0RlyWsUCWmZewYcNeCEYZCgvplt 3Fy6IKULaCzNw1UEZ6sEFfKP50gdiU1udwmm7d6V1NC4drvaS7Uc6R3zYXF6Mxxlu45u myAg== X-Gm-Message-State: ALyK8tL6FfoDh/SxKM0tzHOfwvG/8kAMOxcgQoRXY2vCy5grnH/FbL7fYbyOqCRcpINCeg== X-Received: by 10.28.66.204 with SMTP id k73mr16963801wmi.20.1467138928826; Tue, 28 Jun 2016 11:35:28 -0700 (PDT) Received: from [10.114.7.71] ([41.33.219.254]) by smtp.gmail.com with ESMTPSA id p191sm249290wme.7.2016.06.28.11.35.27 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 28 Jun 2016 11:35:28 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (1.0) From: Eric Voskuil X-Mailer: iPhone Mail (13F69) In-Reply-To: <20160628182202.GA5519@fedora-21-dvm> Date: Tue, 28 Jun 2016 20:35:26 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: References: <87h9cecad5.fsf@rustcorp.com.au> <1E86A00F-0609-4DBC-9543-94AE04CC13C9@voskuil.org> <577234A4.3030808@jonasschnelli.ch> <360EF9B8-A174-41CA-AFDD-2BC2C0B4DECB@voskuil.org> <20160628182202.GA5519@fedora-21-dvm> To: Peter Todd X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, MIME_QP_LONG_LINE, 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 Cc: Bitcoin Protocol Discussion Subject: Re: [bitcoin-dev] BIP 151 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: Tue, 28 Jun 2016 18:35:31 -0000 Hi Peter, What in this BIP makes a MITM attack easier (or easy) to detect, or increase= s the probability of one being detected? e > On Jun 28, 2016, at 8:22 PM, Peter Todd wrote: >=20 > On Tue, Jun 28, 2016 at 06:45:58PM +0200, Eric Voskuil via bitcoin-dev wro= te: >>> 1) Transaction censorship >>> ISPs, WIFI provider or any other MITM, can holdback/censor unconfirmed >>> transactions. Regardless if you are a miner or a validation/wallet node.= >>>=20 >>> 2) Peer censorship >>> MITM can remove or add entries from a "addr" message. >>>=20 >>> 3) Fingerprinting >>> ISPs or any other MITM can intercept/inject fingerprinting relevant >>> messages like "mempool" to analyze the bitcoin network. >>=20 >> Encryption alone cannot protect against a MITM attack in an anonymous and= permissionless network. This is accepted in the BIP (and your follow-up rep= ly). >=20 > Being able to easily detect MITM attacks is a _huge_ step forward that > shouldn't be underestimated; even if 99% of users aren't in a position to > detect the MITM you only need a small subset of users that do the necessar= y > checks to alert the wider community, who can then respond with stronger > security measures. Those measures are likely to be more costly - authentic= ated > systems are significantly harder than not - so better to save your efforts= > until the need for them is more obvious. >=20 > Also the fact that an attack has a reasonable probability of detection is a= big > disincentive for many types of attackers - note how one of the things reve= aled > in the Snowden leaks was the fact that the NSA generally tries quite hard t= o > avoid tipping off targets to the fact that they're being surveilled, with a= > myriad of carefully scripted policies to control when and how exploits are= used > against targets. >=20 > --=20 > https://petertodd.org 'peter'[:-1]@petertodd.org