Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 569E7187D for ; Sat, 9 Jun 2018 13:03:04 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from outmail148096.authsmtp.net (outmail148096.authsmtp.net [62.13.148.96]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id ADCDC604 for ; Sat, 9 Jun 2018 13:03:03 +0000 (UTC) Received: from mail-c245.authsmtp.com (mail-c245.authsmtp.com [62.13.128.245]) by punt24.authsmtp.com. (8.15.2/8.15.2) with ESMTP id w59D2xfA052005; Sat, 9 Jun 2018 14:02:59 +0100 (BST) (envelope-from user@petertodd.org) Received: from petertodd.org (ec2-52-5-185-120.compute-1.amazonaws.com [52.5.185.120]) (authenticated bits=0) by mail.authsmtp.com (8.15.2/8.15.2) with ESMTPSA id w59D2uHD071944 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Sat, 9 Jun 2018 14:02:58 +0100 (BST) (envelope-from user@petertodd.org) Received: from [127.0.0.1] (localhost [127.0.0.1]) by petertodd.org (Postfix) with ESMTPSA id 96413400FB; Sat, 9 Jun 2018 13:02:56 +0000 (UTC) Received: by localhost (Postfix, from userid 1000) id 29A7122043; Sat, 9 Jun 2018 09:02:55 -0400 (EDT) Date: Sat, 9 Jun 2018 09:02:55 -0400 From: Peter Todd To: Sergio Demian Lerner Message-ID: <20180609130255.ngtnxumxlfqrutpn@petertodd.org> References: <20180607171311.6qdjohfuuy3ufriv@petertodd.org> <20180607222028.zbva4vrv64dzrmxy@petertodd.org> <20180609124516.6ms6t7r5t7ikved6@petertodd.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="7nyfmscui5cbuox5" Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) X-Server-Quench: 6ec1f7ef-6be5-11e8-a283-9cb654bb2504 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCd2Yg0TA1ZIVwkA IjsJECJaVQIpKltL GxAVKBZePFsRUQkR aQdMdgsUEkAaAgsB Am4bWlBeUF97XGs7 bghPaBtcak9QXgdq T0pMXVMcUwBhdR5E fmoeVRh7cwEIcXt0 ZQhkCyNaCkMvI1t7 EBtRCGwHMG99OWIX U11RJFFSdQcYLB1A alQxNiYHcQ5VPz4z GA41ejw8IwAXFD5I WR0AIRoXTFwIGjN0 WwoPEH0jEFUZR209 KAZuMVcSEQ4NIg0z N1AlREkZNBlwQhVE GEZDG2dGJkUBQDc3 RQoSRkkQDHVTRj1f agAA X-Authentic-SMTP: 61633532353630.1039:706 X-AuthFastPath: 0 (Was 255) X-AuthSMTP-Origin: 52.5.185.120/25 X-AuthVirus-Status: No virus detected - but ensure you scan with your own anti-virus system. X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,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-dev Subject: Re: [bitcoin-dev] Trusted merkle tree depth for safe tx inclusion proofs without a soft fork 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: Sat, 09 Jun 2018 13:03:04 -0000 --7nyfmscui5cbuox5 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, Jun 09, 2018 at 02:51:55PM +0200, Sergio Demian Lerner wrote: > Yo can fool a SPV wallet even if it requires a thousands confirmations > using this attack, and you don't need a Sybil attack, so yes, it impacts > SPV wallets also. The protections a SPV node should have to prevent this > attack are different, so it must be considered separately. There's hardly any cases where "thousands of confirmations" change anything. Anyway, SPV is a discredited concept and we shouldn't be concerning ourselv= es with it. > It should be said that a SPV node can avoid accepting payments if any > Merkle node is at the same time a valid transaction, and that basically > almost eliminates the problem. Indeed it does: between the number of txouts, scriptSig length, scriptPubKey length, and the upper bits of nValue we have ~32 known bits that we can use= to distinguish between inner nodes and transactions. That's a false positive r= ate of under one in a billion, so no issues there. --=20 https://petertodd.org 'peter'[:-1]@petertodd.org --7nyfmscui5cbuox5 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEFcyURjhyM68BBPYTJIFAPaXwkfsFAlsbz/sACgkQJIFAPaXw kft/LAf/a/Ft7Ol4f9Nn+gqBJHBDMNLoggy2QvZLWMUUOL5rzZnn3hIaupymU38U EZ3PBNrce631lsfzp471Qj/vFsHswcapD6gm690NYrnktYkiGg2jYxyWLJrckxF7 KuoN6jDh1cfg2y9sCZq0n3I1g462zmEbPvtKWHQpNMzbJP3dO7SQG7swUXBPFZkY YemCSQd/G5wWXjxvsFkD39SXNpcNdy83qR47jr41qksobK6q4y0kJvXn+Qd6lj6y L7v93e6W0FAtrSW9GHykCAY383mv5DceQPKEHlzS0YgUVxDt1vW0nHCmuF/67lbe WsIHfxE76cnsxw2PHu+z6TlRrSAoow== =4LRB -----END PGP SIGNATURE----- --7nyfmscui5cbuox5--