From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 1610A139B for ; Sun, 18 Mar 2018 07:08:02 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from APC01-SG2-obe.outbound.protection.outlook.com (mail-oln040092253062.outbound.protection.outlook.com [40.92.253.62]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id EBF7737D for ; Sun, 18 Mar 2018 07:08:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=live.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version; bh=lvLPG8WC3SwUco3LYtOvYPFnB/bqdF4LbfpwysWf8UY=; b=WCVdh3s3h8sJ9bzt+BUkpZcVRcot1pkk3Azd7rqeknv8tzw540TCk6A0/rsLm+VXhqG/NhP3CX3t+jWqrkXHy76m2dI/GamjLn3zxNOE2r3gQ+tep4y+P1gxcoXqgcLEreQjDIi5Yjqd0l18usA0DIC1trtii1Iaa7cfuKebzH6EA8kvEG0aFe3edYfpjUcqgMnMKKS8refBNF3JJuqMJos3DfRGXbjc7JecvVp95+2QDYNsC9gf8VVpDKh6AGZOp9R9Gn7/GuDb/ZVSwih4FiWV7wOtamlsnv4Mb80trJEe0eFi4+SABH44w1a271D76Cpzi4P0lC+7AgJwVsFNRg== Received: from PU1APC01FT112.eop-APC01.prod.protection.outlook.com (10.152.252.57) by PU1APC01HT141.eop-APC01.prod.protection.outlook.com (10.152.253.181) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.20.567.16; Sun, 18 Mar 2018 07:07:58 +0000 Received: from PS2P216MB0179.KORP216.PROD.OUTLOOK.COM (10.152.252.57) by PU1APC01FT112.mail.protection.outlook.com (10.152.252.234) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P256) id 15.20.506.19 via Frontend Transport; Sun, 18 Mar 2018 07:07:58 +0000 Received: from PS2P216MB0179.KORP216.PROD.OUTLOOK.COM ([10.171.225.19]) by PS2P216MB0179.KORP216.PROD.OUTLOOK.COM ([10.171.225.19]) with mapi id 15.20.0588.016; Sun, 18 Mar 2018 07:07:58 +0000 From: Damian Williamson To: Evan Klitzke , "bitcoin-dev@lists.linuxfoundation.org" Thread-Topic: [bitcoin-dev] feature: Enhance privacy by change obfuscation Thread-Index: AQHTvlhNAdeVyrmKfEykHDGYNxE3lqPVfV8AgAAUxAY= Date: Sun, 18 Mar 2018 07:07:58 +0000 Message-ID: References: , <874lleexud.fsf@eklitzke.org> In-Reply-To: <874lleexud.fsf@eklitzke.org> Accept-Language: en-AU, en-US Content-Language: en-AU X-MS-Has-Attach: X-MS-TNEF-Correlator: x-incomingtopheadermarker: OriginalChecksum:BF185927F6245C0E7C9D3DCE657141EBD718C9C3731B6405021C8F77AF70D3EC; UpperCasedChecksum:55379D30AB830824C7680168F74B21B2F34096DB3223E87E9F456756940DD277; SizeAsReceived:7132; Count:46 x-ms-exchange-messagesentrepresentingtype: 1 x-tmn: [VSyAzmV109DExQ2pmut4F1MgrguZttc1] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1; PU1APC01HT141; 6:WMKvKUyRPkBpNPCF3CVRx3Gy7LcV5p81h+YfqFRcowrIaxG3AF5PpDcudz54aU7o+Z183kPRGuhvKLceImWQjWYJVMEtEpnugx+yE+6VD406gLb3DAvLohSAwCfYTtlUrt15ICccqN+R05JeYZyRvZ7x8NkrPJDaDldm+YvEpDK0D2a3F39ATiqdqI5JuJH2fv2HnTziZdKYxY91BVV8S095ane/bvwAKA1Y0BZNpxff/4JDFPEwhwGTvyYQJT9kFfdBizqnXo702lQm521zEuHfSfPskl+PpgyGQtScz0dshjrYmuTHk6eMmcQNvQBywqXM3/F3D56Td8Wz11I9+UwR+x3XkQ1zn99YVGgmFcM=; 5:cbH2MPjCtbjFQ/H/ctNSgPyHER4L9EuUlmTcUT21gsjy7XL5jL22hFYSMbJY9yMHNh3Uc42JlFcHpx6YOJmuLNLtFR9R+4KIYwgXCkW13o32imliPCM5RM3rSjZ0KGA/qSZI5JTsYOWNroQICwWbeGtbj7BvGfF+ouIBXwaKkC8=; 24:Navb+4hE42PiNngrGvd96qHN/kd+zdnhAWLZuiHIF2t+B6BlpgbpkkRz1hodXVzRlqn2d8AVoNwwRNFfcSRKhu4gUCcokyB1wyLw+bLeC20=; 7:khldGiRIsxgGHJWWQPwUaTod7hSYhgZ5BufaVZ/9isVj5h7s1/wJvu15RfynuiFF01rde0Jqy1sUQp2JCtv0vKDxRZW3Azv3XP9BoWHTHfcHU9QIk4uOBpb4+1PEsQjwy59wPcU+b5QTtrlexBlNY+cqbp84zbht9PTMWoF5eCiGC30lcsMQ/Rmamk8Df96RbDi2i1jmtQbPL7TETn9LVO8dmkvAsCFapyVpBAY1qONTPIrcykxAArTX5qb+tTgF x-incomingheadercount: 46 x-eopattributedmessage: 0 x-microsoft-antispam: UriScan:; BCL:0; PCL:0; RULEID:(7020095)(201702061078)(5061506573)(5061507331)(1603103135)(2017031320274)(2017031324274)(2017031323274)(2017031322404)(1601125374)(1603101448)(1701031045); SRVR:PU1APC01HT141; x-ms-traffictypediagnostic: PU1APC01HT141: x-ms-office365-filtering-correlation-id: d6e81167-6df6-46c8-f51a-08d58c9efabf x-exchange-antispam-report-cfa-test: BCL:0; PCL:0; RULEID:(444000031); SRVR:PU1APC01HT141; BCL:0; PCL:0; RULEID:; SRVR:PU1APC01HT141; x-forefront-prvs: 06157D541C x-forefront-antispam-report: SFV:NSPM; SFS:(7070007)(98901004); DIR:OUT; SFP:1901; SCL:1; SRVR:PU1APC01HT141; H:PS2P216MB0179.KORP216.PROD.OUTLOOK.COM; FPR:; SPF:None; LANG:; x-microsoft-antispam-message-info: TkTPgdU7WjgsMWwTdXjDG6FG3F7sUOH4rYVQxu9RadXrZdsREraWtHHTasr7q2nFW3lMBVb+P3JdzdDJHAIwgyRaI7NEgTixQzqSh+WHPlFumHoAxUw8HxbqXQMFyNrEUEeasCxIk0FeaJDC3PoFk4Ah8JRZDaNZcFYbEv/k6ywj2o/ohUyZ0ws40aSMU8Mu spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: multipart/alternative; boundary="_000_PS2P216MB017905271ED76F964F4615829DD50PS2P216MB0179KORP_" MIME-Version: 1.0 X-OriginatorOrg: outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: d6e81167-6df6-46c8-f51a-08d58c9efabf X-MS-Exchange-CrossTenant-originalarrivaltime: 18 Mar 2018 07:07:58.1929 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Internet X-MS-Exchange-CrossTenant-id: 84df9e7f-e9f6-40af-b435-aaaaaaaaaaaa X-MS-Exchange-Transport-CrossTenantHeadersStamped: PU1APC01HT141 X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, HTML_MESSAGE, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org X-Mailman-Approved-At: Sun, 18 Mar 2018 12:13:29 +0000 Subject: Re: [bitcoin-dev] feature: Enhance privacy by change obfuscation 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: Sun, 18 Mar 2018 07:08:02 -0000 --_000_PS2P216MB017905271ED76F964F4615829DD50PS2P216MB0179KORP_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Alright, but even if two (or more) of the change outputs were linked in a f= uture transaction, no-one can tell if they are still linked to your wallet = or not unless there is also an additional re-used address on the new transa= ction input side that has also been previously linked to one of the inputs = on the transaction creating the change. Yes, I understand the additional cost but still thought it worthy of consid= eration. Regards, Damian Williamson ________________________________ From: Evan Klitzke Sent: Sunday, 18 March 2018 4:50:34 PM To: Damian Williamson; Bitcoin Protocol Discussion Subject: Re: [bitcoin-dev] feature: Enhance privacy by change obfuscation Damian Williamson via bitcoin-dev writes: > Operation: Provide a user selectable 'Enhanced privacy' option for > transaction creation, when true the transaction randomly distributes > change across up to twenty output addresses (minimum five?), provided > each output is not dust. This would be really expensive for the network due to the bloat in UTXO size, a cost everyone has to pay for. Not to mention the fact that it doesn't really seem that private, as the wallet is likely going to have to rejoin those inputs in future transactions (and the user will have to pay a high transaction fee as a result). -- Evan Klitzke https://eklitzke.org/ --_000_PS2P216MB017905271ED76F964F4615829DD50PS2P216MB0179KORP_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Alright, but even if two (or more= ) of the change outputs were linked in a future transaction, no-one can tel= l if they are still linked to your wallet or not unless there is also an ad= ditional re-used address on the new transaction input side that has also been previously linked to one of the = inputs on the transaction creating the change.


Yes, I understand the additional = cost but still thought it worthy of consideration.


Regards,

Damian Williamson

From: Evan Klitzke <evan= @eklitzke.org>
Sent: Sunday, 18 March 2018 4:50:34 PM
To: Damian Williamson; Bitcoin Protocol Discussion
Subject: Re: [bitcoin-dev] feature: Enhance privacy by change obfusc= ation
 

Damian Williamson via bitcoin-dev
<bitcoin-dev@lists.linuxfoundation.org> writes:
> Operation: Provide a user selectable 'Enhanced privacy' option for
> transaction creation, when true the transaction randomly distributes > change across up to twenty output addresses (minimum five?), provided<= br> > each output is not dust.

This would be really expensive for the network due to the bloat in UTXO
size, a cost everyone has to pay for. Not to mention the fact that it
doesn't really seem that private, as the wallet is likely going to have
to rejoin those inputs in future transactions (and the user will have to pay a high transaction fee as a result).

--
Evan Klitzke
https://eklitzke.org/
--_000_PS2P216MB017905271ED76F964F4615829DD50PS2P216MB0179KORP_--