From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-4.v43.ch3.sourceforge.com ([172.29.43.194] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1TfXnG-0001aT-Gg for bitcoin-development@lists.sourceforge.net; Mon, 03 Dec 2012 15:18:50 +0000 Received-SPF: pass (sog-mx-4.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.216.54 as permitted sender) client-ip=209.85.216.54; envelope-from=etotheipi@gmail.com; helo=mail-qa0-f54.google.com; Received: from mail-qa0-f54.google.com ([209.85.216.54]) by sog-mx-4.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1TfXnF-0005j2-La for bitcoin-development@lists.sourceforge.net; Mon, 03 Dec 2012 15:18:50 +0000 Received: by mail-qa0-f54.google.com with SMTP id j15so1533482qaq.13 for ; Mon, 03 Dec 2012 07:18:44 -0800 (PST) Received: by 10.224.95.196 with SMTP id e4mr17258342qan.88.1354547924261; Mon, 03 Dec 2012 07:18:44 -0800 (PST) Received: from [192.168.1.85] (c-76-111-96-126.hsd1.md.comcast.net. [76.111.96.126]) by mx.google.com with ESMTPS id em3sm9597559qab.12.2012.12.03.07.18.42 (version=SSLv3 cipher=OTHER); Mon, 03 Dec 2012 07:18:43 -0800 (PST) Message-ID: <50BCC28A.4060503@gmail.com> Date: Mon, 03 Dec 2012 10:17:30 -0500 From: Alan Reiner User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: bitcoin-development@lists.sourceforge.net References: <80648682-E34A-455E-B34A-6BC24652C3EA@ceptacle.com> <9CEDE4D4-3685-4F70-953E-15CC50A8AA3F@ceptacle.com> In-Reply-To: X-Enigmail-Version: 1.4.6 Content-Type: multipart/alternative; boundary="------------020109080207010107040606" X-Spam-Score: -0.6 (/) 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 (etotheipi[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 1.0 HTML_MESSAGE BODY: HTML included in message -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: 1TfXnF-0005j2-La Subject: Re: [Bitcoin-development] Chain dust mitigation: Demurrage based Chain Vacuuming 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, 03 Dec 2012 15:18:50 -0000 This is a multi-part message in MIME format. --------------020109080207010107040606 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 12/03/2012 10:02 AM, Gregory Maxwell wrote: > (1) Make client software aggressive about sweeping up dust inputs: > "Any time a transaction is created that has change keep adding in > extra inputs— smallest to largest— until an additional one would > increase the cost of the transaction by 0.0001 BTC or more" — the only > major complication is doing this without concurrently harming privacy > which is why it's not done yet in the reference client. FYI, Armory uses exactly this logic to try to clean up dust outputs in the user's transactions. However, there's enough conditions on it, that I don't know how often it triggers. Recommendations are welcome for how to improve it. Right now, if the transaction has less than 5 inputs, there exists dust UTXOs from addresses already included in the transaction, and those UTXOs are sufficiently small in priority, then the Armory will add them to the input side and increase the change accordingly. Looking it just made me realize I lost the last condition of making sure the tx already has a change output -- don't want to turn a free tx into a fee-needed tx just to do this. (reorganized the code recently, and must have fell through the cracks). Perhaps it could be improved by cleaning up dust from *any* address by default (not just ones already included in the tx), with the option for the user to disable that behavior. After all, anonymity was never a core feature of the network -- I think it makes sense that the logic would reduce anonymity by default in exchange for a cleaner network, with a clear option to "opt-out" of that logic if user cares. I think most users don't actually care... -Alan --------------020109080207010107040606 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit
On 12/03/2012 10:02 AM, Gregory Maxwell wrote:
(1) Make client software aggressive about sweeping up dust inputs: "Any time a transaction is created that has change keep adding in extra inputs— smallest to largest— until an additional one would increase the cost of the transaction by 0.0001 BTC or more" — the only major complication is doing this without concurrently harming privacy which is why it's not done yet in the reference client.


FYI, Armory uses exactly this logic to try to clean up dust outputs in the user's transactions.  However, there's enough conditions on it, that I don't know how often it triggers.  Recommendations are welcome for how to improve it.

Right now, if the transaction has less than 5 inputs, there exists dust UTXOs from addresses already included in the transaction, and those UTXOs are sufficiently small in priority, then the Armory will add them to the input side and increase the change accordingly.  Looking it just made me realize I lost the last condition of making sure the tx already has a change output -- don't want to turn a free tx into a fee-needed tx just to do this.  (reorganized the code recently, and must have fell through the cracks).

Perhaps it could be improved by cleaning up dust from any address by default (not just ones already included in the tx), with the option for the user to disable that behavior.  After all, anonymity was never a core feature of the network -- I think it makes sense that the logic would reduce anonymity by default in exchange for a cleaner network, with a clear option to "opt-out" of that logic if user cares.  I think most users don't actually care...

-Alan
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