From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-3.v43.ch3.sourceforge.com ([172.29.43.193] helo=mx.sourceforge.net) by sfs-ml-1.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1YtTtJ-0000Fe-1D for bitcoin-development@lists.sourceforge.net; Sat, 16 May 2015 04:40:01 +0000 Received-SPF: pass (sog-mx-3.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.192.50 as permitted sender) client-ip=209.85.192.50; envelope-from=stephencalebmorse@gmail.com; helo=mail-qg0-f50.google.com; Received: from mail-qg0-f50.google.com ([209.85.192.50]) by sog-mx-3.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1YtTtI-0007Af-9z for bitcoin-development@lists.sourceforge.net; Sat, 16 May 2015 04:40:01 +0000 Received: by qgfh8 with SMTP id h8so10504179qgf.3 for ; Fri, 15 May 2015 21:39:54 -0700 (PDT) X-Received: by 10.140.28.102 with SMTP id 93mr16578785qgy.78.1431751194885; Fri, 15 May 2015 21:39:54 -0700 (PDT) Received: from [192.168.0.4] (cpe-108-176-225-232.maine.res.rr.com. [108.176.225.232]) by mx.google.com with ESMTPSA id k19sm2499976qgd.3.2015.05.15.21.39.54 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 15 May 2015 21:39:54 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (1.0) From: Stephen X-Mailer: iPhone Mail (12F70) In-Reply-To: <20150509030833.GA28871@savin.petertodd.org> Date: Sat, 16 May 2015 00:39:53 -0400 Content-Transfer-Encoding: quoted-printable Message-Id: <9BBD3F51-2FE0-4861-B045-6ACFC48AA21D@gmail.com> References: <554BE0E1.5030001@bluematt.me> <20150508163701.GA27417@savin.petertodd.org> <20150509030833.GA28871@savin.petertodd.org> To: Peter Todd X-Spam-Score: -1.6 (-) 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 (stephencalebmorse[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record -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 0.0 AWL AWL: Adjusted score from AWL reputation of From: address X-Headers-End: 1YtTtI-0007Af-9z Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] Block Size Increase Requirements 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: Sat, 16 May 2015 04:40:01 -0000 Comments in line: > On May 8, 2015, at 11:08 PM, Peter Todd wrote: >=20 > Makes it trivial to find miners and DoS attack them - a huge risk to the > network as a whole, as well as the miners. >=20 > Right now pools already get DoSed all the time through their work > submission systems; getting DoS attacked via their nodes as well would > be a disaster. It seems that using a -miner flag to follow rules about smaller blocks would= only reveal miner nodes if one sent the node a solved block that that was v= alid in every way except the block size. While not impossible, I wouldn't ca= ll this trivial, as it still requires wasting an entire block's worth of ene= rgy.=20 >> When in "miner mode", the client would reject 4MB blocks and wouldn't bui= ld >> on them. The reference client might even track the miner and the non-min= er >> chain tip. >>=20 >> Miners would refuse to build on 5MB blocks, but merchants and general use= rs >> would accept them. >=20 > That'd be an excellent way to double-spend merchants, significantly > increasing the chance that the double-spend would succeed as you only > have to get sufficient hashing power to get the lucky blocks; you don't > need enough hashing power to *also* ensure those blocks don't become the > longest chain, removing the need to sybil attack your target. >=20 I think this could be mitigated by counting confirmations differently. We sh= ould think of confirmations as only coming from blocks following the miners'= more strict rule set. So if a merchant were to see payment for the first ti= me in a block that met their own size restrictions but not the miners', then= they would simply count it as unconfirmed.=20 If they get deep enough in the chain, though, the client should probably cou= nt them as being confirmed anyway, even if they don't meet the client nodes'= expectation of the miners' block size limit. This happening probably just m= eans that the client has not updated their software (or -minermaxblocksize c= onfiguration, depending on how it is implemented) in a long time.=20 I actually like Tier's suggestion quite a bit. I think we could have the def= ault client limit set to some higher number, and have miners agree out of ba= nd on the latest block size limit. Or maybe even build in a way to vote into= the blockchain.=20 Best,=20 Stephen=