9a7442a6ea72c405ce584b72289f5588ea4a2c
1 Received: from sog-mx-3.v43.ch3.sourceforge.com ([172.29.43.193] 2 helo=mx.sourceforge.net) 3 by sfs-ml-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) 4 (envelope-from <andyparkins@gmail.com>) id 1QerJ0-000402-Fn 5 for bitcoin-development@lists.sourceforge.net; 6 Thu, 07 Jul 2011 16:19:58 +0000 7 Received-SPF: pass (sog-mx-3.v43.ch3.sourceforge.com: domain of gmail.com 8 designates 74.125.82.53 as permitted sender) 9 client-ip=74.125.82.53; envelope-from=andyparkins@gmail.com; 10 helo=mail-ww0-f53.google.com; 11 Received: from mail-ww0-f53.google.com ([74.125.82.53]) 12 by sog-mx-3.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) 13 (Exim 4.76) id 1QerIx-0004r2-FG 14 for bitcoin-development@lists.sourceforge.net; 15 Thu, 07 Jul 2011 16:19:56 +0000 16 Received: by wwf26 with SMTP id 26so1013174wwf.10 17 for <bitcoin-development@lists.sourceforge.net>; 18 Thu, 07 Jul 2011 09:19:49 -0700 (PDT) 19 Received: by 10.216.54.197 with SMTP id i47mr6713177wec.48.1310055589292; 20 Thu, 07 Jul 2011 09:19:49 -0700 (PDT) 21 Received: from dvr.localnet (mail.360visiontechnology.com [92.42.121.178]) 22 by mx.google.com with ESMTPS id c17sm7006305wbh.12.2011.07.07.09.19.46 23 (version=TLSv1/SSLv3 cipher=OTHER); 24 Thu, 07 Jul 2011 09:19:47 -0700 (PDT) 25 From: Andy Parkins <andyparkins@gmail.com> 26 To: bitcoin-development@lists.sourceforge.net 27 Date: Thu, 7 Jul 2011 17:19:39 +0100 28 User-Agent: KMail/1.13.6 (Linux/2.6.38-2-686; KDE/4.6.3; i686; ; ) 29 References: <201107071049.48131.andyparkins@gmail.com> 30 <CANEZrP0L-8PmwLma4DJdfoj+NefXS0kH8wvVFe-vuyRnpF-+mw@mail.gmail.com> 31 In-Reply-To: <CANEZrP0L-8PmwLma4DJdfoj+NefXS0kH8wvVFe-vuyRnpF-+mw@mail.gmail.com> 32 MIME-Version: 1.0 33 Content-Type: multipart/signed; boundary="nextPart3210105.bXfVgRihYC"; 34 protocol="application/pgp-signature"; micalg=pgp-sha1 35 Content-Transfer-Encoding: 7bit 36 Message-Id: <201107071719.45416.andyparkins@gmail.com> 37 X-Spam-Score: -1.6 (-) 38 X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. 39 See http://spamassassin.org/tag/ for more details. 40 -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for 41 sender-domain 42 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider 43 (andyparkins[at]gmail.com) 44 -0.0 SPF_PASS SPF: sender matches SPF record 45 -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from 46 author's domain 47 0.1 DKIM_SIGNED Message has a DKIM or DK signature, 48 not necessarily valid 49 -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 50 0.0 T_TO_NO_BRKTS_FREEMAIL To: misformatted and free email service 51 X-Headers-End: 1QerIx-0004r2-FG 52 Subject: Re: [Bitcoin-development] Suggestion for enhancements to getblock 53 X-BeenThere: bitcoin-development@lists.sourceforge.net 54 X-Mailman-Version: 2.1.9 55 Precedence: list 56 List-Id: <bitcoin-development.lists.sourceforge.net> 57 List-Unsubscribe: <https://lists.sourceforge.net/lists/listinfo/bitcoin-development>, 58 <mailto:bitcoin-development-request@lists.sourceforge.net?subject=unsubscribe> 59 List-Archive: <http://sourceforge.net/mailarchive/forum.php?forum_name=bitcoin-development> 60 List-Post: <mailto:bitcoin-development@lists.sourceforge.net> 61 List-Help: <mailto:bitcoin-development-request@lists.sourceforge.net?subject=help> 62 List-Subscribe: <https://lists.sourceforge.net/lists/listinfo/bitcoin-development>, 63 <mailto:bitcoin-development-request@lists.sourceforge.net?subject=subscribe> 64 X-List-Received-Date: Thu, 07 Jul 2011 16:19:58 -0000 65 66 --nextPart3210105.bXfVgRihYC 67 Content-Type: Text/Plain; 68 charset="utf-8" 69 Content-Transfer-Encoding: quoted-printable 70 71 On 2011 July 07 Thursday, Mike Hearn wrote: 72 > On Thu, Jul 7, 2011 at 11:49 AM, Andy Parkins <andyparkins@gmail.com> wro= 73 te: 74 > > Imagine this situation though. I am a light weight client. I store the 75 > > block headers only. I am only interested in the history of my own 76 > > wallet addresses. I receive a block broadcast with a transaction that 77 > > sends coins to one of my addresses. That transaction references other 78 > > transactions (of course), but I haven't stored any transactions. So; I 79 > > want to request those transactions and ensure they are all valid and in 80 > > blocks. I can't. 81 >=20 82 > Everyone writing an alternative client goes through this thought 83 > process :-) There's no point in doing it, you cannot prove your 84 > transaction is not a double spend. That requires knowledge (ie, an 85 > index) of all transactions. 86 87 Ah; you mistake me. I'm not interested in double spend prevention, in this= 88 =20 89 case I'd be willing to trust the full node to return whatever block it thin= 90 ks=20 91 contains that transaction, and that it has already done double spend=20 92 prevention. 93 94 What I want to be able to do though is calculate a balance for an aribtrary= 95 =20 96 address. Not every address; just the particular ones that the client is=20 97 interested in. It's complete overkill to require the whole block chain jus= 98 t=20 99 to calculate the balance of a few addresses. 100 101 > You have to treat appearing deep in the chain as ipso-facto proof of 102 > validity. Lightweight/SPV clients simply must have that trust, it 103 > cannot be done any other way. See this article: 104 105 Not entirely. If I ask for "the block that contains transaction with hash= 106 =20 107 12345678abcd..." then when I get that full block, I can verify the merkle t= 108 ree=20 109 myself. I do have to trust that the peer hasn't been adding double spends = 110 in,=20 111 but not that the transaction is actually in the chain. 112 113 > > It should be possible to request the current pending transaction list. 114 >=20 115 > I think it'd be better to implement the filtering suggestions that 116 > have been made. It doesn't scale to download the entire memory pool - 117 118 I'm sorry, I've only started watching this list in the last few days. I'm = 119 not=20 120 familiar with the filter suggestions. 121 122 I'm not entirely sure I see how a filter helps. If I've been offline for t= 123 en=20 124 minutes then I need all the transactions pending in the last ten minutes. = 125 No=20 126 amount of filtering makes that list any smaller. 127 128 > a better approach is to give the remote node a filter to match against 129 > transactions then have it only relay those. After setting a filter, 130 > transactions pending and matching would be sent in one big inv and you 131 > can then keep the connection open to learn about new transactions 132 > without needing to "drink from the firehose". Filters can be 133 > probabilistic and set on many different nodes to reduce the privacy 134 > implications. 135 136 That would be fine. My reason for suggesting using getblocks was that it=20 137 didn't introduce a new command. 138 139 140 141 Andy 142 143 =2D-=20 144 Dr Andy Parkins 145 andyparkins@gmail.com 146 147 --nextPart3210105.bXfVgRihYC 148 Content-Type: application/pgp-signature; name=signature.asc 149 Content-Description: This is a digitally signed message part. 150 151 -----BEGIN PGP SIGNATURE----- 152 Version: GnuPG v1.4.10 (GNU/Linux) 153 154 iEYEABECAAYFAk4V3JsACgkQwQJ9gE9xL22VkACgx/J/sUIn5Vuuoehh3VLzMewR 155 SKgAn3qgesWy6GzvBvrqlWTJ6k4syNoz 156 =j5wG 157 -----END PGP SIGNATURE----- 158 159 --nextPart3210105.bXfVgRihYC-- 160 161