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| author | Ryan Perkins <riperk@protonmail.com> | 2019-04-22 19:22:52 +0000 |
|---|---|---|
| committer | bitcoindev <bitcoindev@gnusha.org> | 2019-04-22 19:23:02 +0000 |
| commit | fd564e3c0a81731967f52b1b217f29bea4e61f4b (patch) | |
| tree | 4f7d2b595308df4e71d14063a453361f58b631a1 /0e | |
| parent | 4e85de36ef6968501ed2e73cd793e7a92d5183bd (diff) | |
| download | pi-bitcoindev-fd564e3c0a81731967f52b1b217f29bea4e61f4b.tar.gz pi-bitcoindev-fd564e3c0a81731967f52b1b217f29bea4e61f4b.zip | |
[bitcoin-dev] CoinJoin Jigsaw
Diffstat (limited to '0e')
| -rw-r--r-- | 0e/39bb9718ad48c8f9484746f01e1ceb988ec56e | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/0e/39bb9718ad48c8f9484746f01e1ceb988ec56e b/0e/39bb9718ad48c8f9484746f01e1ceb988ec56e new file mode 100644 index 000000000..171a12f87 --- /dev/null +++ b/0e/39bb9718ad48c8f9484746f01e1ceb988ec56e @@ -0,0 +1,85 @@ +Return-Path: <riperk@protonmail.com> +Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org + [172.17.192.35]) + by mail.linuxfoundation.org (Postfix) with ESMTPS id 9B64CD7F + for <bitcoin-dev@lists.linuxfoundation.org>; + Mon, 22 Apr 2019 19:23:02 +0000 (UTC) +X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 +Received: from mail-40132.protonmail.ch (mail-40132.protonmail.ch + [185.70.40.132]) + by smtp1.linuxfoundation.org (Postfix) with ESMTPS id D0501829 + for <bitcoin-dev@lists.linuxfoundation.org>; + Mon, 22 Apr 2019 19:23:01 +0000 (UTC) +Date: Mon, 22 Apr 2019 19:22:52 +0000 +DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; + s=default; t=1555960979; + bh=LdZLure/+KEalIxgiOA0P9E8XJAU3dYqGPU6S3qGIP4=; + h=Date:To:From:Cc:Reply-To:Subject:Feedback-ID:From; + b=DWNYpN0eucoX/7itCaCQU6Rer9S93VbPrP5/Sy+8YPyqonuAptNBIL1H/7Iu0VSM9 + y1tMbimBLOX9iE1UrqY8LH4ynG6t93Oi2Ng3CjOfxmeAQ8jSaOg56MMJ129HDol7oh + mDGtykRbUUrIB9Ige35p6IWcUcKwp2Ae7+IvlAq8= +To: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org> +From: Ryan Perkins <riperk@protonmail.com> +Reply-To: Ryan Perkins <riperk@protonmail.com> +Message-ID: <kZwZOekiYq3oxv7wgNj57KJqpOP0a2lkwM-TXsROtIDW5M8VunVV7majgvia4uo_bF3LxJn-8IOYN3IHBy25gjEN-OmPt-T47068L6s5ycE=@protonmail.com> +Feedback-ID: RdfuD--Ffc-FNb_4UIG1XA3s5stj1f6Yt84KENdha_3WoiW3STYpu7X5uGR72LvTfQZpxEhSRHGSlNfV5XM5RA==:Ext:ProtonMail +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: quoted-printable +X-Spam-Status: No, score=-2.7 required=5.0 tests=BAYES_00,DKIM_SIGNED, + DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM, + RCVD_IN_DNSWL_LOW 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: Tue, 23 Apr 2019 14:47:54 +0000 +Subject: [bitcoin-dev] CoinJoin Jigsaw +X-BeenThere: bitcoin-dev@lists.linuxfoundation.org +X-Mailman-Version: 2.1.12 +Precedence: list +List-Id: Bitcoin Protocol Discussion <bitcoin-dev.lists.linuxfoundation.org> +List-Unsubscribe: <https://lists.linuxfoundation.org/mailman/options/bitcoin-dev>, + <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=unsubscribe> +List-Archive: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/> +List-Post: <mailto:bitcoin-dev@lists.linuxfoundation.org> +List-Help: <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=help> +List-Subscribe: <https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev>, + <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=subscribe> +X-List-Received-Date: Mon, 22 Apr 2019 19:23:02 -0000 + +Earlier today ZmnSCPxj posted to the mailing list with an interesting post = +about payjoin. In it he mentioned: + +> Any non-equal-value coinjoin is easily solvable via [value sudoku](https:= +//www.coinjoinsudoku.com/advisory/). + +Which doesn't seem right to me. + +I came up with something I call a "CoinJoin Jigsaw". A "CoinJoin Jigsaw" is= + send-to-self coinjoin transaction in which every input is ambiguously asso= +ciated with an output (i.e. every transaction input must belong to at least= + one subset of every output amount). + + +For simplicity I've used minizinc to model this. To make it clean, I decide= +d to model as two users (affectionately called 'A' and 'B') who trust a com= +mon party to orchestrate the CoinJoin Jigsaw for them. A and B don't trust = +each other, so they want to get all their money atomically in this one tran= +saction. We also want the "CoinJoin Jigsaw" to have exactly 2 outputs. One = +for A, and one for B. That way at first approximation it looks like a prett= +y standard bitcoin payment. (Of course the problem is substantially easier = +to solve if we allow A and B to have N outputs, but that creates an ugly tr= +ansaction). + +We also need to make sure that both A and B are paying a fee proportional t= +o the amount of inputs they added, and the total transaction fee is satisfa= +ctory. + +So I've modelled it as A and B provide their utxo to the orchestrater. The = +orchestrater will pick the largest subset of A's and B's utxo and such that= + satisfies our CoinJoin Jigsaw properties. I ended up copy-and-pasting a lo= +t more than I'd like: + +https://gist.github.com/riperk/7be6698f291e865ad5c930d0edb0cd5a + +I'm not sure it has much practical utility, but it's kind of cool. Maybe. + |