From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1RhqZC-0001Lf-6K for bitcoin-development@lists.sourceforge.net; Mon, 02 Jan 2012 22:41:18 +0000 Received-SPF: pass (sog-mx-2.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.220.175 as permitted sender) client-ip=209.85.220.175; envelope-from=gmaxwell@gmail.com; helo=mail-vx0-f175.google.com; Received: from mail-vx0-f175.google.com ([209.85.220.175]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1RhqZB-000790-Aq for bitcoin-development@lists.sourceforge.net; Mon, 02 Jan 2012 22:41:18 +0000 Received: by vcbf1 with SMTP id f1so15588421vcb.34 for ; Mon, 02 Jan 2012 14:41:11 -0800 (PST) MIME-Version: 1.0 Received: by 10.220.228.201 with SMTP id jf9mr28381097vcb.8.1325544070469; Mon, 02 Jan 2012 14:41:10 -0800 (PST) Received: by 10.220.4.68 with HTTP; Mon, 2 Jan 2012 14:41:10 -0800 (PST) In-Reply-To: References: Date: Mon, 2 Jan 2012 17:41:10 -0500 Message-ID: From: Gregory Maxwell To: Elden Tyrell Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable 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 (gmaxwell[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: 1RhqZB-000790-Aq Cc: bitcoin-development@lists.sourceforge.net Subject: Re: [Bitcoin-development] does "stubbing" off Merkle trees reduce initial download bandwidth? 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: Mon, 02 Jan 2012 22:41:18 -0000 On Mon, Jan 2, 2012 at 5:23 PM, Elden Tyrell wrote= : > On 2012-01-02 05:31:19 -0800, Christian Decker said: >> Later full blocks would be required to detect usable inputs for future >> outgoing transactions. > > Er, yes, this is what I meant; I guess I should have been more specific. > > So, a paranoid client cannot confirm reciept of coins until it has an > unstubbed copy of the entire chain. =C2=A0It can do other things (like se= nd > coins) using a stubbed chain, but it needs the whole unstubbed chain in > order to be sure that incoming coins haven't already been spent. > > Thanks for confirming this. Er, no=E2=80=94 if a node controls the private keys for a transaction, and that transaction makes it into the chain then it can safely assume that its unspent (at least once its buried a few blocks into the chain). This is the essence of a SPV node. What it can't do is perform this function for txn which aren't its own. Though the system could be extended in a compatible manner to make this possible: https://bitcointalk.org/index.php?topic=3D21995.0