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-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1UcDlz-0005IH-QA for bitcoin-development@lists.sourceforge.net; Tue, 14 May 2013 11:52:03 +0000 Received-SPF: pass (sog-mx-4.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.215.169 as permitted sender) client-ip=209.85.215.169; envelope-from=adam.back@gmail.com; helo=mail-ea0-f169.google.com; Received: from mail-ea0-f169.google.com ([209.85.215.169]) by sog-mx-4.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1UcDly-0007Vj-CL for bitcoin-development@lists.sourceforge.net; Tue, 14 May 2013 11:52:03 +0000 Received: by mail-ea0-f169.google.com with SMTP id m14so263773eaj.14 for ; Tue, 14 May 2013 04:51:56 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=x-received:date:from:to:cc:subject:message-id:mime-version :content-type:content-disposition:user-agent:x-hashcash:x-hashcash; bh=faxTSgqeFtSTTBw/NfcXhXFplpdYVfG/djamv5zbO5E=; b=BjSigjAmLnirvqCWRbNxdjhvmZeXTLRvQW2k3WDqplq3n8FsbFMyo5EEcQf8cAvUTj qcTW+jSoRI3ziBx1R9M5ht8y2W70tmvBsz62cG15zrGpi9KHcF7UKsuJDgl3XHgNJ8wg eJdQTQ+p2zn1oL7OMcNW9dt2RJdOvCX7dsl+bRy4OcbXtI+FhhrP7g7e35qcHFtBKFJz Ye33QVWPLesrpuUxPUV74xVIzql1TlO8yeM0gSi8UVX/aaqa+Q5qAGb/teu3fGk0JCJq 6KeEyPGrJS8FeKf3GtvhzaZAcOQOUcKPJ19PfA5efRdnz/fgoWxktC2/OM0yS9k6OWBI vpnQ== X-Received: by 10.15.52.70 with SMTP id o46mr90749421eew.14.1368532315992; Tue, 14 May 2013 04:51:55 -0700 (PDT) Received: from netbook (c83-90.i07-21.onvol.net. [92.251.83.90]) by mx.google.com with ESMTPSA id w52sm28959172eev.12.2013.05.14.04.51.54 for (version=TLSv1.1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 14 May 2013 04:51:55 -0700 (PDT) Received: by netbook (Postfix, from userid 1000) id 004752E05AB; Tue, 14 May 2013 13:51:52 +0200 (CEST) Received: by flare (hashcash-sendmail, from uid 1000); Tue, 14 May 2013 13:51:52 +0200 Date: Tue, 14 May 2013 13:51:51 +0200 From: Adam Back To: Bitcoin-Dev Message-ID: <20130514115151.GA21600@netbook.cypherspace.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-Hashcash: 1:20:130514:bitcoin-development@lists.sourceforge.net::QqbszoZTKtirL mt1:000000000000000000001Ghb X-Hashcash: 1:20:130514:adam@cypherspace.org::zueNzsX+ZmbBkNT0:00000000000000000 0000000000000000000000004/2P X-Spam-Score: -1.5 (-) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for sender-domain 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (adam.back[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record X-Headers-End: 1UcDly-0007Vj-CL Subject: [Bitcoin-development] ecash and 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: Tue, 14 May 2013 11:52:03 -0000 So back in 1999, in an ecash thread on cypherpunks I claimed: http://marc.info/?l=cypherpunks&m=95280154629900&w=2 > I wouldn't say ecash has to use blinding, but I would argue it would be a > misuse of the word "ecash", if something which was revocable were dubbed > ecash. This was in the context of a discussion of digigold (e-gold stored the physical gold, digigold offered "ecash" backed in that physical gold). Digigold ran on Systemics payment server/sox protocol. Because of inferred regulatory concerns and patent licensing issues digigold & systemics were not using blind signatures. However with systemics sox server, like bitcoin, you could create multiple accounts on demand and shuffle payments around for a degree of privacy. The bitcoin analogy would be the transaction log lived in the systemics server, so it had a central failure point, but arguably more privacy as the log was not public. Also systemics SOX protocol (Ian Grigg & Gary Howland) had some aspect of bitcoins smart contract concepts - ricardian contracts. http://iang.org/papers/ricardian_contract.html (Btw the anonymous reply itself was interesting - http://marc.info/?l=cypherpunks&m=95280154629912&w=2 that could have been Nakamoto, the only missing thing from the parts on the discussion room floor to bitcoin is mathematical inflation control.) The thread actually started here http://marc.info/?l=cypherpunks&m=95280154629912&w=2 and then continues here http://marc.info/?l=cypherpunks&m=95280154629900&w=2 because of a subject line change and then http://marc.info/?l=cypherpunks&m=95280154629916&w=2 and http://marc.info/?l=cypherpunks&m=95280154629948&w=2 more subject line change confusion. A related thread a few days later also covers Sander & Ta-Shma (which zerocoin is based on): http://marc.info/?l=cypherpunks&m=95280154630167&w=2 there were many more threads about various ecash technologies. Adam