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Date: Mon, 13 Jan 2014 14:59:08 -0500
From: Alan Reiner <etotheipi@gmail.com>
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Subject: Re: [Bitcoin-development] Stealth Addresses
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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
> <mailto: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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    How is this different from the proposal I have made?<br>
    <br>
    You distribute the root public key (but not chaincode!) of a BIP32
    branch.&nbsp; You can put your root key on a business card if you want.&nbsp;
    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).&nbsp; 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"). <br>
    <br>
    You can <i>choose</i> to reveal that a given payment address is
    linked to your root key without any compromise of privacy.&nbsp; Or you
    can choose to ignore it and just give them a bare address the old
    way and still maintain privacy.&nbsp; What advantages does "stealth
    addresses" have over this scheme?&nbsp; You could extend it using some
    kind of deterministic sub-branching and/or ECDH to create multiple
    payment addresses without querying the payee.&nbsp; <br>
    <br>
    I had planned to implement this system and push for people to accept
    it because I don't see any downsides to it.&nbsp; It can easily be
    integrated into a WoT (with signed root keys), or CA system
    piggybacking on SSL.<br>
    <br>
    -Alan<br>
    <br>
    <br>
    <div class="moz-cite-prefix">On 01/13/2014 02:44 PM, Drak wrote:<br>
    </div>
    <blockquote
cite="mid:CANAnSg30V01B_3LCJ09sTwcsYa4_WOg3sKd-=p6COZS6w0b-uA@mail.gmail.com"
      type="cite">
      <div dir="ltr">
        <div class="gmail_extra">
          <div class="gmail_quote">On 13 January 2014 19:40, Roy Badami
            <span dir="ltr">&lt;<a moz-do-not-send="true"
                href="mailto:roy@gnomon.org.uk" target="_blank">roy@gnomon.org.uk</a>&gt;</span>
            wrote:<br>
            <blockquote class="gmail_quote" style="margin:0 0 0
              .8ex;border-left:1px #ccc solid;padding-left:1ex">
              <div class="im"><span style="color:rgb(34,34,34)">At the
                  moment, I can give them a business card with a Bitcoin
                  address.</span><br>
              </div>
              Being able to give out a business card with a stealth
              address would be<br>
              a major advance.</blockquote>
            <div><br>
            </div>
            <div>My thoughts exactly.</div>
            <div><br>
            </div>
            <div>Drak&nbsp;</div>
          </div>
        </div>
      </div>
      <br>
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      <br>
      <pre wrap="">------------------------------------------------------------------------------
CenturyLink Cloud: The Leader in Enterprise Cloud Services.
Learn Why More Businesses Are Choosing CenturyLink Cloud For
Critical Workloads, Development Environments &amp; Everything In Between.
Get a Quote or Start a Free Trial Today. 
<a class="moz-txt-link-freetext" href="http://pubads.g.doubleclick.net/gampad/clk?id=119420431&amp;iu=/4140/ostg.clktrk">http://pubads.g.doubleclick.net/gampad/clk?id=119420431&amp;iu=/4140/ostg.clktrk</a></pre>
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      <fieldset class="mimeAttachmentHeader"></fieldset>
      <br>
      <pre wrap="">_______________________________________________
Bitcoin-development mailing list
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