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From: Ruben Somsen <rsomsen@gmail.com>
Date: Tue, 18 Oct 2022 14:40:38 +0200
Message-ID: <CAPv7TjYnM=3RMAwXe_Ssa-RXz5CxP0xAxxLdQVq79T5BYvT9mQ@mail.gmail.com>
To: rot13maxi <rot13maxi@protonmail.com>
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Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev]
	=?utf-8?q?Trustless_Address_Server_=E2=80=93_Outsou?=
	=?utf-8?q?rcing_handing_out_addresses_to_prevent_address_reuse?=
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Hi Rijndael,

I think your thoughts are pretty much compatible with this proposal, as
what I'm describing (the recipient signing their keys) is also essentially
a form of authentication.

It's a good observation that in general this makes the communication of
addresses more secure. I do wish to re-emphasize Bryan's remark that you
still need to ensure the pubkey itself is securely communicated.

>depending on the setup, this could be that the address server also has the
Address Authentication privkey for bob, or it could be that bob gets some
callback or notification, or that bob has pre-signed a batch of addresses

In my opinion the only meaningful distinction is whether Bob runs the
Trustless Address Server himself (full privacy) or not. In either case I
see no reason to diverge from the model where Bob deposits a batch of
signed keys to the server, ensuring that no malicious addresses can be
handed out.

Note I discussed the Trustless Address Server design in the first 20
minutes of this podcast:
https://twitter.com/bitcoinoptech/status/1580573594656333825

And I also brought it up in my presentation at Tabconf last Saturday, but
that video isn't online yet.

Cheers,
Ruben


On Tue, Oct 18, 2022 at 2:07 AM Bryan Bishop via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> On Mon, Oct 17, 2022 at 7:05 PM rot13maxi via bitcoin-dev <
> bitcoin-dev@lists.linuxfoundation.org> wrote:
>
>> Unbeknownst to them, the clipboard contents have been replaced with an
>> address controlled by some bad actor.
>>
> [snip]
>
>> Now imagine instead that the wallet has some address book with a pubkey
>> for each recipient the user wants to send bitcoin to.
>>
>
> Isn't this the same problem but now for copy-pasting pubkeys instead of an
> address?
>
> - Bryan
> https://twitter.com/kanzure
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>

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<div dir=3D"ltr">Hi=C2=A0Rijndael,<div><br></div><div>I think your thoughts=
 are pretty much compatible with this proposal, as what I&#39;m describing =
(the=C2=A0recipient signing their keys) is also essentially a form of authe=
ntication.</div><div><br></div><div>It&#39;s a good=C2=A0observation that i=
n general this makes the communication of addresses more secure. I do wish =
to re-emphasize Bryan&#39;s remark that you still need to ensure the pubkey=
 itself is securely communicated.</div><div><br></div><div>&gt;depending on=
 the setup, this could be that the address server also has the Address Auth=
entication privkey for bob, or it could be that bob gets some callback or n=
otification, or that bob has pre-signed a batch of addresses</div><div><br>=
</div><div>In my opinion the only meaningful distinction is whether Bob run=
s the Trustless Address Server himself (full privacy) or not. In either cas=
e I see no reason to diverge from the model where Bob deposits a batch of s=
igned keys to the server,=C2=A0ensuring that no malicious addresses can be =
handed out.</div><div><br></div><div>Note I discussed the Trustless Address=
 Server design in the first 20 minutes of this podcast:</div><div><a href=
=3D"https://twitter.com/bitcoinoptech/status/1580573594656333825">https://t=
witter.com/bitcoinoptech/status/1580573594656333825</a><br></div><div><br><=
/div><div>And I also brought it up in my presentation at Tabconf last Satur=
day, but that video isn&#39;t online yet.</div><div><br></div><div>Cheers,<=
/div><div>Ruben</div><div><br></div><div><br></div></div><br><div class=3D"=
gmail_quote"><div dir=3D"ltr" class=3D"gmail_attr">On Tue, Oct 18, 2022 at =
2:07 AM Bryan Bishop via bitcoin-dev &lt;<a href=3D"mailto:bitcoin-dev@list=
s.linuxfoundation.org">bitcoin-dev@lists.linuxfoundation.org</a>&gt; wrote:=
<br></div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8=
ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir=3D"ltr=
"><div dir=3D"ltr">On Mon, Oct 17, 2022 at 7:05 PM rot13maxi via bitcoin-de=
v &lt;<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" target=3D"_b=
lank">bitcoin-dev@lists.linuxfoundation.org</a>&gt; wrote:<br></div><div cl=
ass=3D"gmail_quote"><blockquote class=3D"gmail_quote" style=3D"margin:0px 0=
px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div =
style=3D"font-family:Arial;font-size:14px">Unbeknownst to them, the clipboa=
rd contents have been replaced with an address controlled by some bad actor=
.<br></div></blockquote><div>[snip]=C2=A0</div><blockquote class=3D"gmail_q=
uote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,2=
04);padding-left:1ex"><div style=3D"font-family:Arial;font-size:14px">Now i=
magine instead that the wallet has some address book with a pubkey for each=
 recipient the user wants to send bitcoin to.<br></div></blockquote><div><b=
r>Isn&#39;t this the same problem but now for copy-pasting pubkeys instead =
of an address?<br><br></div></div><div dir=3D"ltr"><div dir=3D"ltr">- Bryan=
<br><a href=3D"https://twitter.com/kanzure" target=3D"_blank">https://twitt=
er.com/kanzure</a></div></div></div>
_______________________________________________<br>
bitcoin-dev mailing list<br>
<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" target=3D"_blank">=
bitcoin-dev@lists.linuxfoundation.org</a><br>
<a href=3D"https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev" =
rel=3D"noreferrer" target=3D"_blank">https://lists.linuxfoundation.org/mail=
man/listinfo/bitcoin-dev</a><br>
</blockquote></div>

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