From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-1.v43.ch3.sourceforge.com ([172.29.43.191] helo=mx.sourceforge.net) by sfs-ml-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1Z2nOP-0007VJ-DN for bitcoin-development@lists.sourceforge.net; Wed, 10 Jun 2015 21:18:37 +0000 Received-SPF: pass (sog-mx-1.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.216.171 as permitted sender) client-ip=209.85.216.171; envelope-from=voisine@gmail.com; helo=mail-qc0-f171.google.com; Received: from mail-qc0-f171.google.com ([209.85.216.171]) by sog-mx-1.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1Z2nOO-0006pL-0A for bitcoin-development@lists.sourceforge.net; Wed, 10 Jun 2015 21:18:37 +0000 Received: by qcjl8 with SMTP id l8so3214613qcj.3 for ; Wed, 10 Jun 2015 14:18:30 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.140.239.129 with SMTP id k123mr7023804qhc.66.1433971110610; Wed, 10 Jun 2015 14:18:30 -0700 (PDT) Received: by 10.140.91.37 with HTTP; Wed, 10 Jun 2015 14:18:30 -0700 (PDT) In-Reply-To: References: Date: Wed, 10 Jun 2015 14:18:30 -0700 Message-ID: From: Aaron Voisine To: Mike Hearn Content-Type: multipart/alternative; boundary=001a1135a2f4aa90700518306a0a 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 (voisine[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: 1Z2nOO-0006pL-0A Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] Proposal: SPV Fee Discovery mechanism 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: Wed, 10 Jun 2015 21:18:37 -0000 --001a1135a2f4aa90700518306a0a Content-Type: text/plain; charset=UTF-8 The other complication is that this will tend to be a lagging indicator based on network congestion from the last time you connected. If we assume that transactions are being dropped in an unpredictable way when blocks are full, knowing the network congestion *right now* is critical, and even then you just have to hope that someone who wants that space more than you do doesn't show up after you disconnect. Aaron Voisine co-founder and CEO breadwallet.com On Wed, Jun 10, 2015 at 1:26 PM, Mike Hearn wrote: > I described an alternative way for SPV wallets to learn about fees some > time ago. It requires a new transaction version that embeds output values > into the signed data. Then an upgrade to the P2P protocol to send UTXO data > along with transactions when they are relayed. > > The idea is that the wallet sets a Bloom filter with an FP rate that > ensures it will see some random subset of all transactions being broadcast > on the network, and with the extra data, it can calculate the fee paid. > Once a transaction broadcast is observed the wallet includes that tx hash > in its next Bloom filter, thus it can see which block the tx confirmed in. > By measuring the amount of time that passed between a broadcast and it > appearing in a block, it can calculate its own tables of fee paid:time > taken. > > This has the advantage that you don't have to trust miners to publish data > accurately. However it requires some protocol upgrades and of course, a lot > of new code in SPV wallets. > > The way Bitcoin Wallet for Android handles fees currently is to just > update a hard coded value every so often. > > > ------------------------------------------------------------------------------ > > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development > > --001a1135a2f4aa90700518306a0a Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
The other complication is that this will tend to be a lagg= ing indicator based on network congestion from the last time you connected.= If we assume that transactions are being dropped in an unpredictable way w= hen blocks are full, knowing the network congestion *right now* is critical= , and even then you just have to hope that someone who wants that space mor= e than you do doesn't show up after you disconnect.


Aaron Voisine
co-founder = and CEO
breadwallet= .com

On Wed, Jun 10, 2015 at 1:26 PM, Mike Hearn = <= mike@plan99.net> wrote:
I described an alternative way for SPV wallets to learn about= fees some time ago. It requires a new transaction version that embeds outp= ut values into the signed data. Then an upgrade to the P2P protocol to send= UTXO data along with transactions when they are relayed.

The idea is that the wallet sets a Bloom filter with an FP rate that ensu= res it will see some random subset of all transactions being broadcast on t= he network, and with the extra data, it can calculate the fee paid. Once a = transaction broadcast is observed the wallet includes that tx hash in its n= ext Bloom filter, thus it can see which block the tx confirmed in. By measu= ring the amount of time that passed between a broadcast and it appearing in= a block, it can calculate its own tables of fee paid:time taken.

This has the advantage that you don't have to trust min= ers to publish data accurately. However it requires some protocol upgrades = and of course, a lot of new code in SPV wallets.

T= he way Bitcoin Wallet for Android handles fees currently is to just update = a hard coded value every so often.

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Bitcoin-develo= pment@lists.sourceforge.net
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