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 1Ucr7T-0006BE-3g for bitcoin-development@lists.sourceforge.net; Thu, 16 May 2013 05:52:51 +0000 Received-SPF: pass (sog-mx-4.v43.ch3.sourceforge.com: domain of lavabit.com designates 72.249.41.33 as permitted sender) client-ip=72.249.41.33; envelope-from=calebdelisle@lavabit.com; helo=karen.lavabit.com; Received: from karen.lavabit.com ([72.249.41.33]) by sog-mx-4.v43.ch3.sourceforge.com with esmtp (Exim 4.76) id 1Ucr7Q-0004Rc-ON for bitcoin-development@lists.sourceforge.net; Thu, 16 May 2013 05:52:50 +0000 Received: from a.earth.lavabit.com (a.earth.lavabit.com [192.168.111.10]) by karen.lavabit.com (Postfix) with ESMTP id 6CBD711BDE3 for ; Thu, 16 May 2013 00:52:43 -0500 (CDT) Received: from 192.168.1.3 (c-174-62-136-247.hsd1.ct.comcast.net [174.62.136.247]) by lavabit.com with ESMTP id 7IAKPAQ0Y78Z for ; Thu, 16 May 2013 00:52:43 -0500 Message-ID: <51947429.8010100@lavabit.com> Date: Thu, 16 May 2013 01:52:41 -0400 From: Caleb James DeLisle User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130404 Thunderbird/17.0.5 MIME-Version: 1.0 To: bitcoin-development@lists.sourceforge.net References: <20130514115151.GA21600@netbook.cypherspace.org> <20130514140902.GA22447@netbook.cypherspace.org> <20130515102509.GA3401@netbook.cypherspace.org> <20130515111906.GA26020@savin> <20130515114956.GA5863@netbook.cypherspace.org> <5193825B.20909@lavabit.com> <20130515162129.GB6156@netbook.cypherspace.org> <20130515234030.GA17920@netbook.cypherspace.org> In-Reply-To: X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Score: -0.1 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. 2.1 FSL_HELO_BARE_IP_2 FSL_HELO_BARE_IP_2 -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for sender-domain -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [72.249.41.33 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -0.6 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -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 X-Headers-End: 1Ucr7Q-0004Rc-ON Subject: Re: [Bitcoin-development] blind symmetric commitment for stronger byzantine voting resilience (Re: bitcoin taint & unilateral revocability) 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, 16 May 2013 05:52:51 -0000 Not only does the size of the proof grow endlessly as the coin is passed around, the size of the UTXO set grows endlessly as more and more of the already spent coins cannot be proven to have been spent because the proofs are passed out-of-band. I never said the idea was good, just interesting :) Thanks, Caleb On 05/15/2013 10:45 PM, Gregory Maxwell wrote: > On Wed, May 15, 2013 at 7:22 PM, Mike Hearn wrote: >> Conceptually it sounds a lot like ZeroCoin (not in implementation)? > > Zerocoin conceals the connection from everyone forever, assuming the > underlying trapdoor problem is computational infeasible, but at great > cost. > > Adamcoin, depending on how its done, at most conceals the transactions > from people who aren't a party to them... though as time goes on > eventually everyone becomes a party to a sufficiently old coin, and > avoiding publication creates quadratic costs in evaluating a private > clique's claims.... so instead an implementation would make the > identities public but only once they're burred a bit. > > Perhaps an extreme version of the idea is easier to understand. Ignore > DOS attacks for a moment and pretend there is never any address reuse: > > Everyone creates txouts paying a P2SH addresses that have a OP_PUSH > nonce in them and tell you recipient the nonce out of band. > > When the recipients spend those coins they provide the script but not the nonce. > > The recipient knows what coins he's spending, but the public does not. > > The public can tell there is no double spend though, because they'd > see the same script twice. The person he's paying may be skeptical > that he actually has any coin and didn't just mine some gibberish, but > our spender tells that their receiver the nonce, and that person can > see the coin available for spending in the chain and also see that > there are no double spends. > > This could actually go on forever with no ambiguity over who owns > what, but the out of band proofs that you have to give people when you > spend coins would grow with the history of the coins. > > Since there wouldn't be much privacy once a transaction was > sufficiently split up in any case, you instead just publish the > unblindings once transactions are sufficiently buried. Thus bounding > the growth of the proofs. The reason I say I need to internalize > this more is mostly that I need to think about attacks on the > publication for 'tained' transactions being more or less isomorphic > to just refusing to allow spending of the 'tainted' coins in any case. > > ------------------------------------------------------------------------------ > AlienVault Unified Security Management (USM) platform delivers complete > security visibility with the essential security capabilities. Easily and > efficiently configure, manage, and operate all of your security controls > from a single console and one unified framework. Download a free trial. > http://p.sf.net/sfu/alienvault_d2d > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development >