Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id BFE1AFB1 for ; Fri, 7 Sep 2018 12:51:37 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from hank.reardencode.com (hank.reardencode.com [206.125.169.162]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 5CC57A8 for ; Fri, 7 Sep 2018 12:51:37 +0000 (UTC) Received: by hank.reardencode.com (Postfix, from userid 1001) id 6CC3B2E005; Fri, 7 Sep 2018 05:51:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=reardencode.com; s=default; t=1536324695; bh=0jim6GmrXBevAp1AjgzmG0+bwoQIs1020vQCxw+tz0M=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=NgqOEldupH9HkuqKhKSUmBSWG6nMWIf7OsCPzNj7KjrwHo9L8XYTFeu7BDGuOQAuI ssTiYKstW6tBukpTSGJazFq1SuB7wX7D5SEDD4hdopLRtRLqEbyvWy4Q1qsvcXnQ/C AF37BwzidU5V3t6UpbMR9PKzstFSYaZILowLZQ7s= Date: Fri, 7 Sep 2018 05:51:35 -0700 From: Brandon Smith To: Alejandro Ranchal Pedrosa Message-ID: <20180907125135.GR62902@hank.reardencode.com> References: <3d4162e0-1f8b-0f23-85fc-9d18d4352cae@gmail.com> <20180906203244.GQ62902@hank.reardencode.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Operating-System: FreeBSD 10.4-RELEASE-p8 amd64 User-Agent: Mutt/1.9.5 (2018-04-13) X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU 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: Fri, 07 Sep 2018 13:45:23 +0000 Cc: Bitcoin Protocol Discussion , Onder.GURCAN@cea.fr Subject: Re: [bitcoin-dev] A BIP proposal for transactions that are 'cancellable' 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: Fri, 07 Sep 2018 12:51:37 -0000 I believe you may be missing the overall points in the "Nail In the Coffin" and "Temporary Discussion" sections. In summary: 1: Any UTXO spending a script with an expiration must be treated similarly to Coinbase (I proposed a solution to this, but it's complex and may have unforeseen implications). 2: All existing software assumes that a transaction once valid stays valid. Any proposal to change this must ensure that existing wallets and users aren't immediately open to being scammed by malicious actors sending low fee expiring transactions. The more tenable ways to move forward on improving the ecosystem around delayed transactions and refunds are: Lightning, improved fee estimation, and improved mempool eviction / re-propagation resistance. The original reason that I began looking into this is because I noticed that during high fee periods, transactions could re-propagate between mempools of differing policies resulting in coins being stuck unusable for far longer than the expected 1-2 week eviction. I don't know of any concrete work going into investigating or improving this. HTH, --Brandon On 2018-09-07 (Fri) at 09:12:40 +0200, Alejandro Ranchal Pedrosa wrote: > Hi all, > > Thank you for the link, and also to Gregory for the remarks. I did not > know about this previous proposal. I think the last paragraph of future > work is interesting: > > "It may be interesting to add enhance OP_CHECKSEQUENCEVERIFY > to > allow outputs that are spendable by Alice until time foo, always > spendable by Bob, and spendable by Joe only after time bar, or other > such cases" > > Perhaps it would allow this functionality, while keeping the validity of > coins, if the new OP_zzz took an additional argument than suggested, > such that the first one is the timelimit for Alice to keep the coin (say > in the first 24 hours), and after those 24 hours the ownership goes to > the third argument, say Bob. > > That is, it is not possible to use only specifying the owner in the > first 24 hours. Would this be considered harmful? > > Best, > > Alejandro. > > On 9/6/18 10:32 PM, Brandon Smith wrote: > > ade a similar proposal about 7 months ago, and documented some of the > > discussion points here: