From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-4.v43.ch3.sourceforge.com ([172.29.43.194] helo=mx.sourceforge.net) by sfs-ml-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1Uedoa-0007qE-1M for bitcoin-development@lists.sourceforge.net; Tue, 21 May 2013 04:04:44 +0000 X-ACL-Warn: Received: from zinan.dashjr.org ([173.242.112.54]) by sog-mx-4.v43.ch3.sourceforge.com with esmtp (Exim 4.76) id 1UedoY-0002BR-Kn for bitcoin-development@lists.sourceforge.net; Tue, 21 May 2013 04:04:44 +0000 Received: from ishibashi.localnet (unknown [IPv6:2001:470:5:265:222:4dff:fe50:4c49]) (Authenticated sender: luke-jr) by zinan.dashjr.org (Postfix) with ESMTPSA id C778027A2965 for ; Tue, 21 May 2013 04:04:36 +0000 (UTC) From: "Luke-Jr" To: bitcoin-development@lists.sourceforge.net Date: Tue, 21 May 2013 04:04:28 +0000 User-Agent: KMail/1.13.7 (Linux/3.9.0-gentoo; KDE/4.10.2; x86_64; ; ) References: <519AB8EB.5000103@monetize.io> In-Reply-To: <519AB8EB.5000103@monetize.io> X-PGP-Key-Fingerprint: E463 A93F 5F31 17EE DE6C 7316 BD02 9424 21F4 889F X-PGP-Key-ID: BD02942421F4889F X-PGP-Keyserver: hkp://pgp.mit.edu MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201305210404.31843.luke@dashjr.org> X-Spam-Score: -1.1 (-) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -1.1 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain X-Headers-End: 1UedoY-0002BR-Kn Subject: Re: [Bitcoin-development] UUID to identify chains (payment protocol and elsewhere) 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: Tue, 21 May 2013 04:04:44 -0000 Bitcoin currently uses raw hashes extensively as UUIDs; whether the payment protocol should be influence by that or not, I've not given thought to yet. Some alt coins may share a blockchain, or even merely the genesis block (two currently do; despite one of those being a scamcoin, I think the possibility should not be dismissed). Because of this, requiring a 1:1 mapping between genesis block and chain or coin seems non-ideal. On Monday, May 20, 2013 11:59:39 PM Mark Friedenbach wrote: > At the developer round-table it was asked if the payment protocol would > alt-chains, and Gavin noted that it has a UTF-8 encoded string > identifying the network ("main" or "test"). As someone with two > proposals in the works which also require chain/coin identification (one > for merged mining, one for colored coins), I am opinionated on this. I > believe that we need a standard mechanism for identifying chains, and > one which avoids the trap of maintaining a standard registry of > string-to-chain mappings. > > Any chain can be uniquely identified by its genesis block, 122 random > bits is more than sufficient for uniquely tagging chains/colored assets, > and the low-order 16-bytes of the block's hash are effectively random. > With these facts in mind, I propose that we identify chains by UUID. > > So as to remain reasonably compliant with RFC 4122, I recommend that we > use Version 4 (random) UUIDs, with the random bits extracted from the > double-SHA256 hash of the genesis block of the chain. (For colored > coins, the colored coin definition transaction would be used instead, > but I will address that in a separate proposal and will say just one > thing about it: adopting this method for identifying chains/coins will > greatly assist in adopting the payment protocol to colored coins.) > > The following Python code illustrates how to construct the chain > identifier from the serialized genesis block: > > from hashlib import sha256 > from uuid import UUID > def chain_uuid(serialized_genesis_block): > h = sha256(serialized_genesis_block).digest() > h = sha256(h).digest() > h = h[:16] > h = ''.join([ > h[:6], > chr(0x40 | ord(h[6]) & 0x0f), > h[7], > chr(0x80 | ord(h[8]) & 0x3f), > h[9:] > ]) > return UUID(bytes=h) > > And some example chain identifiers: > > mainnet: UUID('6fe28c0a-b6f1-4372-81a6-a246ae63f74f') > testnet3: UUID('43497fd7-f826-4571-88f4-a30fd9cec3ae') > namecoin: UUID('70c7a9f0-a2fb-4d48-a635-a70d5b157c80') > > As for encoding the chain identifier, the simplest method is to give > "network" the "bytes" type, but defining a "UUID" message type is also > possible. In either case bitcoin mainnet would be the default, so the > extra 12 bytes (vs: "main" or "test") would only be an issue for > alt-chains or colored coins. > > Kind regards, > Mark Friedenbach > > --------------------------------------------------------------------------- > --- Try New Relic Now & We'll Send You this Cool Shirt > New Relic is the only SaaS-based application performance monitoring service > that delivers powerful full stack analytics. Optimize and monitor your > browser, app, & servers with just a few lines of code. Try New Relic > and get this awesome Nerd Life shirt! http://p.sf.net/sfu/newrelic_d2d_may > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development