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 CE059B5A for ; Tue, 6 Jun 2017 23:20:24 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from azure.erisian.com.au (cerulean.erisian.com.au [139.162.42.226]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 8F2D417D for ; Tue, 6 Jun 2017 23:20:23 +0000 (UTC) Received: from aj@azure.erisian.com.au (helo=sapphire.erisian.com.au) by azure.erisian.com.au with esmtpsa (Exim 4.84_2 #1 (Debian)) id 1dINls-0006Ki-6H for ; Wed, 07 Jun 2017 09:20:21 +1000 Received: by sapphire.erisian.com.au (sSMTP sendmail emulation); Wed, 07 Jun 2017 09:20:15 +1000 Date: Wed, 7 Jun 2017 09:20:15 +1000 From: Anthony Towns To: bitcoin-dev@lists.linuxfoundation.org Message-ID: <20170606232015.GA11830@erisian.com.au> References: <31833011-7179-49D1-A07E-8FD9556C4534@taoeffect.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <31833011-7179-49D1-A07E-8FD9556C4534@taoeffect.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Spam-Score: -1.9 X-Spam-Score-int: -18 X-Spam-Bar: - X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org Subject: Re: [bitcoin-dev] Replay attacks make BIP148 and BIP149 untennable 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: Tue, 06 Jun 2017 23:20:24 -0000 On Tue, Jun 06, 2017 at 03:39:28PM -0700, Tao Effect via bitcoin-dev wrote: > - Mixing with 148 coinbase txns destroys fungibility. CoinJoin works as a method of both improving fungibility and mixing with coinbase transactions. You probably don't need to do anything clever to split a coin though: if you send a transaction with a standard fee it will get confirmed in a normal time on the higher hashrate chain, but won't confirm as quickly on the lower hashrate chain (precisely because transactions are valid on both chains, but blocks are found more slowly with the lower hashrate). When it's confirmed on one chain, but not on the other, you can then "double-spend" on the lower hashrate chain with a higher fee, to end up with different coins on both chains. (also, no double-n in untenable) Cheers, aj