Received: from sog-mx-3.v43.ch3.sourceforge.com ([172.29.43.193] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1UaOmN-0004Ia-V4 for bitcoin-development@lists.sourceforge.net; Thu, 09 May 2013 11:12:56 +0000 X-ACL-Warn: Received: from vps7135.xlshosting.net ([178.18.90.41]) by sog-mx-3.v43.ch3.sourceforge.com with esmtp (Exim 4.76) id 1UaOmM-0002Rv-KJ for bitcoin-development@lists.sourceforge.net; Thu, 09 May 2013 11:12:55 +0000 Received: by vps7135.xlshosting.net (Postfix, from userid 1000) id 6E35933CE14; Thu, 9 May 2013 13:12:48 +0200 (CEST) Date: Thu, 9 May 2013 13:12:48 +0200 From: Pieter Wuille To: Peter Todd Message-ID: <20130509111247.GA18521@vps7135.xlshosting.net> References: <20130508234422.GA30870@savin> <20130509011338.GA8708@vps7135.xlshosting.net> <20130509015731.GA26423@savin> <20130509024244.GA5474@savin> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130509024244.GA5474@savin> X-PGP-Key: http://sipa.ulyssis.org/pubkey.asc User-Agent: Mutt/1.5.21 (2010-09-15) X-Spam-Score: 0.0 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (pieter.wuille[at]gmail.com) 0.0 DKIM_ADSP_CUSTOM_MED No valid author signature, adsp_override is CUSTOM_MED -1.2 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 1.2 NML_ADSP_CUSTOM_MED ADSP custom_med hit, and not from a mailing list X-Headers-End: 1UaOmM-0002Rv-KJ Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] 32 vs 64-bit timestamp fields 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: Thu, 09 May 2013 11:12:56 -0000 On Wed, May 08, 2013 at 10:42:44PM -0400, Peter Todd wrote: > Ah, shoot, I just realized we both got missed Pieter's point entirely: > he means to change the meaning of the header timestamp to be relative > time passed since the last block... No, though that's also a possibility, but a backward-incompatible one. What I mean is have a well-defined 64-bit timestamp for each block, but only put the lowest 32 bit in the header. Under the condition: * There is never a gap of more than 136 years between two blocks. The actual 64-bit timestamp can be deterministically derived from the header, by prefixing it with the lowest 32-bit value that does not cause the result to violate the at-least-above-the-median-of-the-previous-11-blocks rule. -- Pieter