From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-3.v43.ch3.sourceforge.com ([172.29.43.193] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1XJtyH-0002uZ-1N for bitcoin-development@lists.sourceforge.net; Wed, 20 Aug 2014 00:41:49 +0000 Received-SPF: pass (sog-mx-3.v43.ch3.sourceforge.com: domain of petertodd.org designates 62.13.149.77 as permitted sender) client-ip=62.13.149.77; envelope-from=pete@petertodd.org; helo=outmail149077.authsmtp.com; Received: from outmail149077.authsmtp.com ([62.13.149.77]) by sog-mx-3.v43.ch3.sourceforge.com with esmtp (Exim 4.76) id 1XJtyF-0008Ml-To for bitcoin-development@lists.sourceforge.net; Wed, 20 Aug 2014 00:41:48 +0000 Received: from mail-c235.authsmtp.com (mail-c235.authsmtp.com [62.13.128.235]) by punt15.authsmtp.com (8.14.2/8.14.2/) with ESMTP id s7K0fWxI094006; Wed, 20 Aug 2014 01:41:32 +0100 (BST) Received: from android-61a40235731d80b6.lan (76-10-178-110.dsl.teksavvy.com [76.10.178.110]) (authenticated bits=0) by mail.authsmtp.com (8.14.2/8.14.2/) with ESMTP id s7K0fTbP012846 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 20 Aug 2014 01:41:30 +0100 (BST) User-Agent: K-9 Mail for Android In-Reply-To: References: <0C0EF7F9-DBBA-4872-897D-63CFA3853726@ricmoo.com> <33D4B2E3-DBF0-444E-B76A-765C4C17E964@ricmoo.com> <53F37635.5070807@riseup.net> <53F38AC9.4000608@corganlabs.com> <53F3DFF7.9070709@jrn.me.uk> <3476b0a1-e08a-46bf-9ee4-ef56fcb02d72@email.android.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 From: Peter Todd Date: Tue, 19 Aug 2014 20:41:27 -0400 To: Jeff Garzik Message-ID: X-Server-Quench: ba4201b9-2802-11e4-b396-002590a15da7 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCd2Yg0TA1ZNQRgX IjsJECJaVQIpKltL GxAVKBZePFsRUQkR bgdMdAIUGUATAgsB AmIbW1VeVFx7WmM7 bAxPbAVDY01GQQRr UFdNRFdNFUsrBmcB UHpMMhlzdQ1CfjBx Y05rWz4JDUB4dUcv S1NWHW0EeGZhPWQC AkNRcR5UcAFPdx8U a1UrBXRDAzANdhES HhM4ODE3eDlSNilR RRkIIFQOdA4zBDkk QAsLGWdnMEsOXTQr M1QsK0IXG0cXekA/ KkAoVl8DWwA8 X-Authentic-SMTP: 61633532353630.1023:706 X-AuthFastPath: 0 (Was 255) X-AuthSMTP-Origin: 76.10.178.110/465 X-AuthVirus-Status: No virus detected - but ensure you scan with your own anti-virus system. X-Spam-Score: -1.5 (-) 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 SPF_PASS SPF: sender matches SPF record X-Headers-End: 1XJtyF-0008Ml-To Cc: Bitcoin Development , Justus Ranvier Subject: Re: [Bitcoin-development] Proposal: Encrypt bitcoin messages 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: Wed, 20 Aug 2014 00:41:49 -0000 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 19 August 2014 20:21:35 GMT-04:00, Jeff Garzik wrote: >On Tue, Aug 19, 2014 at 8:16 PM, Peter Todd wrote: >> That is simply incorrect. The resources required to do that kind of >monitoring are very high; even the NSA can't pull it off consistently >for > >Hardly. For example, when a new block arrives on the network, a >single observer at a single location may obtain a binary "likely|not >bitcoin protocol" decision from a spike in usage correlated with >sudden, global network activity after a period of inactivity. I'll >not detail all such metrics. Emphasis on "likely", at best. Forcing you adversary to rely on uncertain statistics is a huge improvement over the status quo. Secondly your example is of a new block; the more general concern is determining where a given transaction originated. In the best of circumstances determining the origin of a few hundred bytes of days interspersed in dozens of kB/s of buffered data streams is very difficult and expensive even without padding and/or random delay features. Again, I've spoken to people like Jacob Applebaum about this who have a solid understanding of what the NSA is actually capable of, and they've confirmed the above. Don't let perfect be the enemy of good. Of course, that's not to say we shouldn't cost-benefit analysis the implementation; not using straight OpenSSL for this is a wise decision. Hence the suggestion of using the existing and tested Tor support to encrypt by default. -----BEGIN PGP SIGNATURE----- Version: APG v1.1.1 iQFQBAEBCAA6BQJT8+62MxxQZXRlciBUb2RkIChsb3cgc2VjdXJpdHkga2V5KSA8 cGV0ZUBwZXRlcnRvZGQub3JnPgAKCRAZnIM7qOfwhZe/CADI+XvuCzK6N0/UUieD WzrGexWQsqNxX2hYQpzAiYT3Y5k4CCJ3yvett0udYKS3Piqd/ihvj9RfjWe5nO+d snPGNwFU7jSRJ+hwPdnlHfFW99LCkKOzBX0hgC+qg11SyLKcsBwE3qaiFM47G1hy r4f1qX3Te2Kt0bUxP65d1M0Js1M0x+qLxXs6e9Gy3scFSpDjeoamgliJ6jBeeX9U 8H0mambip5CZ+diGbaMeCCRJd19XH7Nz0QgcznYScmz/3krQhtIdEJKts7bs87vh vZyH7M4wVCiIDmDNxAIO2slo3+eopEvbOPgqjT7L72jrQgp3zVUtbJDzpSAgcB+M vLhB =AuCe -----END PGP SIGNATURE-----