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 744BB94A for ; Mon, 19 Sep 2016 16:13:47 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-pa0-f48.google.com (mail-pa0-f48.google.com [209.85.220.48]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 0C38A198 for ; Mon, 19 Sep 2016 16:13:46 +0000 (UTC) Received: by mail-pa0-f48.google.com with SMTP id wk8so50039275pab.1 for ; Mon, 19 Sep 2016 09:13:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=thinlink-com.20150623.gappssmtp.com; s=20150623; h=subject:references:from:to:message-id:date:user-agent:mime-version :in-reply-to:content-transfer-encoding; bh=XJAZuK/QJHFuTaEOAtwT94BbD+VfsXH6xYtBzn5V/xA=; b=lu/PqpjLmCCf1lVy3QRkuiStrOR4UL9B4qgxa9cC+gBo2nOyOBJT0wF6CERrh2Hk1m S5lapnnB/bJlH9K37UkMHfNu3/Gl3w/ZcKQ3RLeWy+9u5gBmi0bBCzqx2WCRwErmkVZs 70wMt7KRzUP54S9OmTgiiC7tRPZHZyIF9TK1aANqS2Z/CLmnQNks5hCKrFeiQU5CGn4Z PJWbxHUZDqZ7WAhPhoWLUPvf99NTIgJSgYgZdpiFc7Z6gkwLOg+4m3zRZgsezYJlNFix D4drfGLe7bGvTWIFqdZ5G1jKgkhH12BEvS2JyzJ+DyBpo4ufI8kA1GycskVK44N8NHZZ xF1w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:references:from:to:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding; bh=XJAZuK/QJHFuTaEOAtwT94BbD+VfsXH6xYtBzn5V/xA=; b=BB26aIJZ4ABTyp/+aRdH4VknuUH+WCHbeTEMbURwA3CTrTIKqU6hUJoB3/e44vQFUz GuEFsxQqU1vL/qYe0PQs6DJw6TSSPE7BhdzFhyr3WB6OJwQpJDziYA7Vw6Q13T5wzaMz Q7vdJhRhXsVMJMU+h7MhKwqKYdnDmi5CQCD+5I3ftcOZhkGWncSNbGaNg/R7KjTRuzNA cXVhodoVrBuB9a9ZHfG9yFeD9XFwkRLfU0IMjSueu85mXks9xFlCP7FeRBOU3KBxRfNo lrimLRDiZq3DamQZ3qkClmfhEEXZwLSaaMw3p0x03fxnbI3wpXswTg+pAz6PX78u9ZCb /l5Q== X-Gm-Message-State: AE9vXwOrE1MymLcE/D6xfwWI9p5GFin1dsBKNis1nHwQEtGX4LjAbc7Ppa8nV+l4uHTjdYxA X-Received: by 10.66.43.230 with SMTP id z6mr12969019pal.150.1474301626399; Mon, 19 Sep 2016 09:13:46 -0700 (PDT) Received: from [192.168.1.89] (99-8-65-117.lightspeed.davlca.sbcglobal.net. [99.8.65.117]) by smtp.googlemail.com with ESMTPSA id e187sm72732404pfa.58.2016.09.19.09.13.45 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 19 Sep 2016 09:13:45 -0700 (PDT) References: <20160918042001.GA9076@fedora-21-dvm> From: Tom Harding To: Bitcoin-Dev Message-ID: <7ff1a87d-2916-2024-ea05-d6413bd17767@thinlink.com> Date: Mon, 19 Sep 2016 09:13:40 -0700 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <20160918042001.GA9076@fedora-21-dvm> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,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: Mon, 19 Sep 2016 16:22:48 +0000 Subject: Re: [bitcoin-dev] Interpreting nTime for the purpose of Bitcoin-attested timestamps 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: Mon, 19 Sep 2016 16:13:47 -0000 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 9/17/2016 9:20 PM, Peter Todd via bitcoin-dev wrote: > The probability that all N blocks are found by dishonest miners is q^N, That's the probability that dishonest miners find N blocks in a row immediately. What you want is the probability that they can build a chain N blocks long, taking the random-walk into account. So use Satoshi's formula from bitcoin.pdf, section 11. The results are remarkably different. In particular, q=.5 is totally insecure, since for any N, both factions are guaranteed to eventually possess a chain of length N anchored at x at some point during the wild reorg melee. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJX4A60AAoJEG/AI00/Ca/qLmEP/0fg+XJQNexTTrS/aPqcIY00 KStPNIruJD4QA9zgyx4K3fCst85/L9rsmv/9Xo6tyn8oneAMjjVY57mTG3smhiXA Qfu9/tG0AHneRxEpRNDA/x4IwCrr1xACOaO26gEqs9zVIszIVQq4z3Vc54gj39VD 9Jpc0653RVqHhJFT4ozZkAzg2CcPMHOxi45ufBtScaJO2AwtcLvtVYaC1BE9itDM wDdAS175jq+LlV20Igaf/s4Cc9G3LWnrNqzVCPBr/ua4U60ZO+r3nLr9gYtYNR0H 37xgktNZA8D/YI8gjYZ5p11bIqCs4lRyI5LP3Rvh/+5zQu4hdi25HMoUMys/lw4c ABuUVLaCa2r7pH7QczUx4jWJslaHlZ4M6tMUJ7bGZpVcPmA8FOk0j+DLTfUmYVYi Eqc5cf2Z+PEc9kBmvsxQ351WjT7fq3OtZCcMH5dhpGv4NMuVBwQ38Dh3Pz8rhBPe pIXMUPkmdWdczjoACpjOHbhYffCI7zCvsypydnImF7FReohWPFSKdaeoSHxotHzb cy2EWZS2IM009qY3+jF1j3uj4bJfPSlgLgfUE23Bmvsp9PJi9W+FARbKJKxr6HaB vvMg6rMfU8uWElQqz19ixI55PUDmtugwXccyWvhcr0ueN1P6fpNxF36Q9zwS6/+D 4orUC+rp1yNTeddvaYDv =HS6r -----END PGP SIGNATURE-----