Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1W2nfH-0002yF-UG for bitcoin-development@lists.sourceforge.net; Mon, 13 Jan 2014 19:59:15 +0000 Received-SPF: pass (sog-mx-2.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.128.50 as permitted sender) client-ip=209.85.128.50; envelope-from=etotheipi@gmail.com; helo=mail-qe0-f50.google.com; Received: from mail-qe0-f50.google.com ([209.85.128.50]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1W2nfG-0003Av-Va for bitcoin-development@lists.sourceforge.net; Mon, 13 Jan 2014 19:59:15 +0000 Received: by mail-qe0-f50.google.com with SMTP id 1so7595512qec.37 for ; Mon, 13 Jan 2014 11:59:09 -0800 (PST) X-Received: by 10.49.15.202 with SMTP id z10mr43002448qec.46.1389643149559; Mon, 13 Jan 2014 11:59:09 -0800 (PST) Received: from [192.168.1.85] (c-76-111-96-126.hsd1.md.comcast.net. [76.111.96.126]) by mx.google.com with ESMTPSA id t10sm16171882qef.23.2014.01.13.11.59.09 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 13 Jan 2014 11:59:09 -0800 (PST) Message-ID: <52D4458C.6010909@gmail.com> Date: Mon, 13 Jan 2014 14:59:08 -0500 From: Alan Reiner User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: bitcoin-development@lists.sourceforge.net References: <20140106120338.GA14918@savin> <20140110102037.GB25749@savin> <20140113194049.GJ38964@giles.gnomon.org.uk> In-Reply-To: X-Enigmail-Version: 1.6 Content-Type: multipart/alternative; boundary="------------080904050301060403060505" X-Spam-Score: -0.6 (/) 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 (etotheipi[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 1.0 HTML_MESSAGE BODY: HTML included in message -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: 1W2nfG-0003Av-Va Subject: Re: [Bitcoin-development] Stealth Addresses 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: Mon, 13 Jan 2014 19:59:16 -0000 This is a multi-part message in MIME format. --------------080904050301060403060505 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit How is this different from the proposal I have made? You distribute the root public key (but not chaincode!) of a BIP32 branch. You can put your root key on a business card if you want. Then when someone wants to pay you, you simply give them the multiplier and root key (they already have the root key, but should verify). The multiplier does not reveal the chaincode, thus keeping it private, but it does allow them to confirm that the final address they are paying is derived from that root key they know belongs to you ("Please pay address X; oh btw, X=rootKey*mult"). You can /choose/ to reveal that a given payment address is linked to your root key without any compromise of privacy. Or you can choose to ignore it and just give them a bare address the old way and still maintain privacy. What advantages does "stealth addresses" have over this scheme? You could extend it using some kind of deterministic sub-branching and/or ECDH to create multiple payment addresses without querying the payee. I had planned to implement this system and push for people to accept it because I don't see any downsides to it. It can easily be integrated into a WoT (with signed root keys), or CA system piggybacking on SSL. -Alan On 01/13/2014 02:44 PM, Drak wrote: > On 13 January 2014 19:40, Roy Badami > wrote: > > At the moment, I can give them a business card with a Bitcoin address. > Being able to give out a business card with a stealth address would be > a major advance. > > > My thoughts exactly. > > Drak > > > ------------------------------------------------------------------------------ > CenturyLink Cloud: The Leader in Enterprise Cloud Services. > Learn Why More Businesses Are Choosing CenturyLink Cloud For > Critical Workloads, Development Environments & Everything In Between. > Get a Quote or Start a Free Trial Today. > http://pubads.g.doubleclick.net/gampad/clk?id=119420431&iu=/4140/ostg.clktrk > > > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development --------------080904050301060403060505 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit How is this different from the proposal I have made?

You distribute the root public key (but not chaincode!) of a BIP32 branch.  You can put your root key on a business card if you want.  Then when someone wants to pay you, you simply give them the multiplier and root key (they already have the root key, but should verify).  The multiplier does not reveal the chaincode, thus keeping it private, but it does allow them to confirm that the final address they are paying is derived from that root key they know belongs to you ("Please pay address X; oh btw, X=rootKey*mult").

You can choose to reveal that a given payment address is linked to your root key without any compromise of privacy.  Or you can choose to ignore it and just give them a bare address the old way and still maintain privacy.  What advantages does "stealth addresses" have over this scheme?  You could extend it using some kind of deterministic sub-branching and/or ECDH to create multiple payment addresses without querying the payee. 

I had planned to implement this system and push for people to accept it because I don't see any downsides to it.  It can easily be integrated into a WoT (with signed root keys), or CA system piggybacking on SSL.

-Alan


On 01/13/2014 02:44 PM, Drak wrote:
On 13 January 2014 19:40, Roy Badami <roy@gnomon.org.uk> wrote:
At the moment, I can give them a business card with a Bitcoin address.
Being able to give out a business card with a stealth address would be
a major advance.

My thoughts exactly.

Drak 


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