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-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1QerJ0-000402-Fn for bitcoin-development@lists.sourceforge.net; Thu, 07 Jul 2011 16:19:58 +0000 Received-SPF: pass (sog-mx-3.v43.ch3.sourceforge.com: domain of gmail.com designates 74.125.82.53 as permitted sender) client-ip=74.125.82.53; envelope-from=andyparkins@gmail.com; helo=mail-ww0-f53.google.com; Received: from mail-ww0-f53.google.com ([74.125.82.53]) by sog-mx-3.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1QerIx-0004r2-FG for bitcoin-development@lists.sourceforge.net; Thu, 07 Jul 2011 16:19:56 +0000 Received: by wwf26 with SMTP id 26so1013174wwf.10 for ; Thu, 07 Jul 2011 09:19:49 -0700 (PDT) Received: by 10.216.54.197 with SMTP id i47mr6713177wec.48.1310055589292; Thu, 07 Jul 2011 09:19:49 -0700 (PDT) Received: from dvr.localnet (mail.360visiontechnology.com [92.42.121.178]) by mx.google.com with ESMTPS id c17sm7006305wbh.12.2011.07.07.09.19.46 (version=TLSv1/SSLv3 cipher=OTHER); Thu, 07 Jul 2011 09:19:47 -0700 (PDT) From: Andy Parkins To: bitcoin-development@lists.sourceforge.net Date: Thu, 7 Jul 2011 17:19:39 +0100 User-Agent: KMail/1.13.6 (Linux/2.6.38-2-686; KDE/4.6.3; i686; ; ) References: <201107071049.48131.andyparkins@gmail.com> In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart3210105.bXfVgRihYC"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Message-Id: <201107071719.45416.andyparkins@gmail.com> 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 (andyparkins[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 0.0 T_TO_NO_BRKTS_FREEMAIL To: misformatted and free email service X-Headers-End: 1QerIx-0004r2-FG Subject: Re: [Bitcoin-development] Suggestion for enhancements to getblock 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, 07 Jul 2011 16:19:58 -0000 --nextPart3210105.bXfVgRihYC Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On 2011 July 07 Thursday, Mike Hearn wrote: > On Thu, Jul 7, 2011 at 11:49 AM, Andy Parkins wro= te: > > Imagine this situation though. I am a light weight client. I store the > > block headers only. I am only interested in the history of my own > > wallet addresses. I receive a block broadcast with a transaction that > > sends coins to one of my addresses. That transaction references other > > transactions (of course), but I haven't stored any transactions. So; I > > want to request those transactions and ensure they are all valid and in > > blocks. I can't. >=20 > Everyone writing an alternative client goes through this thought > process :-) There's no point in doing it, you cannot prove your > transaction is not a double spend. That requires knowledge (ie, an > index) of all transactions. Ah; you mistake me. I'm not interested in double spend prevention, in this= =20 case I'd be willing to trust the full node to return whatever block it thin= ks=20 contains that transaction, and that it has already done double spend=20 prevention. What I want to be able to do though is calculate a balance for an aribtrary= =20 address. Not every address; just the particular ones that the client is=20 interested in. It's complete overkill to require the whole block chain jus= t=20 to calculate the balance of a few addresses. > You have to treat appearing deep in the chain as ipso-facto proof of > validity. Lightweight/SPV clients simply must have that trust, it > cannot be done any other way. See this article: Not entirely. If I ask for "the block that contains transaction with hash= =20 12345678abcd..." then when I get that full block, I can verify the merkle t= ree=20 myself. I do have to trust that the peer hasn't been adding double spends = in,=20 but not that the transaction is actually in the chain. > > It should be possible to request the current pending transaction list. >=20 > I think it'd be better to implement the filtering suggestions that > have been made. It doesn't scale to download the entire memory pool - I'm sorry, I've only started watching this list in the last few days. I'm = not=20 familiar with the filter suggestions. I'm not entirely sure I see how a filter helps. If I've been offline for t= en=20 minutes then I need all the transactions pending in the last ten minutes. = No=20 amount of filtering makes that list any smaller. > a better approach is to give the remote node a filter to match against > transactions then have it only relay those. After setting a filter, > transactions pending and matching would be sent in one big inv and you > can then keep the connection open to learn about new transactions > without needing to "drink from the firehose". Filters can be > probabilistic and set on many different nodes to reduce the privacy > implications. That would be fine. My reason for suggesting using getblocks was that it=20 didn't introduce a new command. Andy =2D-=20 Dr Andy Parkins andyparkins@gmail.com --nextPart3210105.bXfVgRihYC Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iEYEABECAAYFAk4V3JsACgkQwQJ9gE9xL22VkACgx/J/sUIn5Vuuoehh3VLzMewR SKgAn3qgesWy6GzvBvrqlWTJ6k4syNoz =j5wG -----END PGP SIGNATURE----- --nextPart3210105.bXfVgRihYC--