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 A4695B8A for ; Fri, 14 Apr 2017 02:22:27 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from forward2.bravehost.com (forward2.bravehost.com [65.39.211.66]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 107F319A for ; Fri, 14 Apr 2017 02:22:26 +0000 (UTC) X-Virus-Scanned: amavisd-new at bravehost.com Received: from [10.137.4.20] (unknown [199.249.223.40]) (Authenticated sender: cannon@cannon-ciota.info) by forward2.bravehost.com (Postfix) with ESMTPSA id D62DF210D; Thu, 13 Apr 2017 19:22:23 -0700 (PDT) To: =?UTF-8?Q?Emin_G=c3=bcn_Sirer?= , Bitcoin Dev References: <5b9ba6c4-6d8f-9c0b-2420-2be6c30f87b5@cannon-ciota.info> From: CANNON Message-ID: <40cc105b-80ee-4848-0624-f4a8f1070173@cannon-ciota.info> Date: Fri, 14 Apr 2017 02:22:18 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Icedove/45.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,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: Fri, 14 Apr 2017 03:28:24 +0000 Subject: Re: [bitcoin-dev] Defending against empty or near empty blocks from malicious miner takeover? 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, 14 Apr 2017 02:22:27 -0000 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 On 03/24/2017 04:27 PM, Emin Gün Sirer wrote: > Because there's no consensus on the contents of the mempool, this approach > is unsafe and will lead to forks. It also opens a new attack vector where > people can time the flood of new transactions with the discovery of a block > by a competitor, to orphan the block and to fork the chain. > I know this is a delayed reply. Without intending to revive an older thread, my intentions are to clarify what I have meant in my original post just in case anyone misinterprets where I said "For example would be something like this: If block = (empty OR <%75 of mempool) THEN discard This threshold just an example." I should have clarified that with this idea blocks would not be rejected if does not match what that nodes have in their mempool, because as you have said, there is no consensus on the contents of mempool and the mempool will vary from node to node. Instead what I have meant is that with this idea, nodes would only reject blocks if they are empty or less than a determined percentage when compared to what is in mempool. While this specific defense proposal I posted may or may not be a good idea, was only throwing this idea out there to create discussion on possible defenses against an empty or near empty block attack. - -- Cannon PGP Fingerprint: 2BB5 15CD 66E7 4E28 45DC 6494 A5A2 2879 3F06 E832 Email: cannon@cannon-ciota.info NOTICE: ALL EMAIL CORRESPONDENCE NOT SIGNED/ENCRYPTED WITH PGP SHOULD BE CONSIDERED POTENTIALLY FORGED, AND NOT PRIVATE. If this matters to you, use PGP. -----BEGIN PGP SIGNATURE----- iQIcBAEBCgAGBQJY8DIZAAoJEAYDai9lH2mwZKYP/jNJjyTeE09+IlsGolPV3Vp+ suJmUK26y8IbEzGxa8eVoX3w7407VNzqeT0jF8vK7oy97EPgszoiutbzYanKYH27 Rpck+FdW/Q5o6jqw59swX+KEvVao52ETPX3kV8ae5uA2txOBnn6C0qZbM5OxPVLN IHr7E0+bn9BQVuTzhep1wNWi4cDzyeIjYfRGArBTkuSBKxFtbPmTMLa67qsBGKVu JcGYm6rdDO0iVAR9od/Is9b+3gTW49x/3jBEdg7iCHc8KuGOilZaHfyU6xjt3fPo L2lxXxUuobFD68/f4ervFVMpAPpmPaS/MEkHMIhJex3szdlSe/WZsQm+2/j799Rg Ba62pMOYvSR43WwlwX8eySUlVsPtJNtObKnRvDBOmOICgsZ3T9tHKjI+9IPVi9Ib s7yBBA1LFw4+c8wirzu1aaeDroJ3icqfU+tRe+nadQN1PMepk6sBUMu13bm8B3E3 R8oo+jFZRRvJmx7HDDlJX9GHri8hktCNm/gtt0ksWwEgAQHixukmKoDVssAmsiZ4 BbiWIA3ULciSKM782zDH7/GvDBbOurtV8TeubnV7DDARIA86COwuGjjk30Ltf3ia 5gnFIicLkmdRMh4AU0jvvEpxrHWFFJmreoR+jnAXHMBGoA6ExVaqR2VQzcpb5SIb sqe/5499BqvJqS4ZFn7f =q+nx -----END PGP SIGNATURE-----