Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id B936E8FE for ; Thu, 5 Nov 2015 22:46:41 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from outbound.mailhostbox.com (outbound.mailhostbox.com [162.222.225.12]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 30B6113D for ; Thu, 5 Nov 2015 22:46:34 +0000 (UTC) Received: from [0.0.0.0] (bolobolo1.torservers.net [96.47.226.20]) (using TLSv1 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) (Authenticated sender: s7r@sky-ip.org) by outbound.mailhostbox.com (Postfix) with ESMTPSA id BD6CB1A1202 for ; Thu, 5 Nov 2015 22:46:34 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sky-ip.org; s=20110108; t=1446763595; bh=PczeJh7diVBloTwFPWO+HhkFe6OVl3F3aK8bqoNEIng=; h=Reply-To:Subject:References:To:From:Date:In-Reply-To; b=HUpf2vCNusG7gmi7wQtAFJsX1FyUg3aVX3EMYeKoyCaL/Dpv2Rjhu5b1r7lUILDc5 4WchK05+gaTUeXiq4ZYKyOjLs493C5lQ5PMqc2THogBRLNBsMH45jtV3SELiBxUYjl xS6w0UzblTHSrdr+dNw2+8D46w4Y19nYG6CMw0Hc= Reply-To: s7r@sky-ip.org References: <201511032201.21047.luke@dashjr.org> <201511051936.09500.luke@dashjr.org> To: bitcoin-dev@lists.linuxfoundation.org From: s7r X-Enigmail-Draft-Status: N1110 Message-ID: <563BDC3B.6020601@sky-ip.org> Date: Fri, 6 Nov 2015 00:46:19 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit X-CMAE-Score: 0 X-CMAE-Analysis: v=2.1 cv=asYScXtV c=1 sm=1 tr=0 a=dFCltrIYHCDM1x7031pMDg==:117 a=dFCltrIYHCDM1x7031pMDg==:17 a=N659UExz7-8A:10 a=ehhEumZUPZRtsxQTCysA:9 a=oA0fkXM3nMcnUn1I:21 a=qCbUBD6GZuEECHOs:21 a=pILNOxqGKmIA:10 X-Scanned-By: MIMEDefang 2.72 on 172.18.214.92 X-Spam-Status: No, score=-0.3 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,URIBL_BLACK autolearn=no version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org X-Mailman-Approved-At: Thu, 05 Nov 2015 22:47:38 +0000 Subject: Re: [bitcoin-dev] [BIP] Normalized transaction IDs X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Development Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 05 Nov 2015 22:46:41 -0000 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Right. Wallets are covering malleability in acceptable ways. Normal user to user payments aren't (or at least shouldn't be) affected by malleability. Problems appear in second level and third level malleability, when Alice sends txB to Bob which spends from txA which is unconfirmed. If txA changes txid, txB becomes useless and invalidates Alice's payment. Looking at scriptPubKeys instead of transaction IDs doesn't help in this context. This is the reason why some type of contracts are not workable or not 100% safe. One can't pre-sign a refund transaction with an nLockTime in the future: the payer will provide the funding transaction ID from which the refund tx will spend, but if the transaction ID of the funding transaction is affected by malleability (third party malleability, since the signer doesn't have interest to do so) the refund tx becomes useless. On 11/5/2015 10:25 PM, Jorge Timón via bitcoin-dev wrote: > On Thu, Nov 5, 2015 at 8:36 PM, Luke Dashjr > wrote: >> Ok, then my point is that "signature malleability" is not >> particularly problematic or interesting alone, and the only way >> to get a practically-useful solution, is to address all kinds of >> malleability. > > I disagree. Segregated witnesses, for example, doesn't solve all > kinds of malleability and is very useful in some practical cases by > solving all signature malleability. As said, we don't want to > eliminate all forms of malleability (for example, replace by fee), > although we may want to "address them" at some level. As you have > said, wallets should be looking at scriptPubKeys, not transaction > ID, but that is orthogonal to SW, a normalized tx ID and signature > malleability. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (MingW32) iQEcBAEBCAAGBQJWO9w7AAoJEIN/pSyBJlsR2BsH+gMwxJ/isiWfJF12LJ9s4wat Bd/K2Ld+Lyk5BRs+6rQzv5NeeYjYC3FtNFV+z1Z1dMDd752cUfEZqQA9dt9nl0E7 BEia3RSFii1k2L/4xwiIWKZM20qoiykou41J56GZrJa9SoP+9kg8iLq8CokahakP PLjfBrTylJBsgq34foPPaOH9ckOa/RJpx3WHrRFTPhxbTCm1Ezv6jAZmYr9tTi1h afzU0YayzLUIb9xH8vfODY2qMJ91uguTUZYCGuopDYhom5GMw8zss0kG5FdEZrEQ Z7srQmKQ0SRMtiSlg6lg3d8TS5Mv1gIp1HcL+gtMFroi38pJS8dXT65nGjg0Epc= =ZhVA -----END PGP SIGNATURE-----