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From: Ruben Somsen <rsomsen@gmail.com>
Date: Mon, 27 Jun 2022 22:35:34 +0200
Message-ID: <CAPv7TjZ265K8oTaz=qum9w-HYMp-GPawq=TNcp-e_WsPcCQAOA@mail.gmail.com>
To: Bryan Bishop <kanzure@gmail.com>, 
 Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Content-Type: multipart/alternative; boundary="000000000000678f6a05e273ddc4"
Subject: Re: [bitcoin-dev] [BIP proposal] Private Payments
Precedence: list

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Hi Bryan,

>just publishing on a tor hidden service that other wallets check

The problem is that this data is critical to access the funds. By putting
it on-chain you're guaranteeing that it's always available when you restore
your funds from backup.

Cheers,
Ruben

On Mon, Jun 27, 2022 at 10:21 PM Bryan Bishop via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> Hi,
>
> On Mon, Jun 27, 2022 at 2:14 PM Alfred Hodler via bitcoin-dev <
> bitcoin-dev@lists.linuxfoundation.org> wrote:
>
>> 2. Notification transactions still exist but no longer leave a privacy
>> footprint on the blockchain. Instead, a notification transaction is simply
>> a single OP_RETURN containing a value that only Alice and Bob can
>> calculate. If Alice's notification transaction uses UTXOs not associated
>> with her identity, there is never a footprint showing that either her or
>> Bob are using private payments. If Alice uses tainted coins, only she is
>> exposed as a user of Private Payments but Bob still isn't.
>>
>
> That's a neat trick. What about not using OP_RETURN at all, and just
> publishing on a tor hidden service that other wallets check?  Alice
> wouldn't have to expose on-chain that she is a sender of a private payment.
>
> - 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 Bryan,<div><br></div><div>&gt;just publishing on a tor =
hidden service that=C2=A0other wallets check</div><div><br></div><div>The p=
roblem is that this data is critical=C2=A0to access the funds. By putting i=
t on-chain you&#39;re guaranteeing that it&#39;s always available when you =
restore your funds from backup.</div><div><br></div><div>Cheers,</div><div>=
Ruben</div></div><br><div class=3D"gmail_quote"><div dir=3D"ltr" class=3D"g=
mail_attr">On Mon, Jun 27, 2022 at 10:21 PM Bryan Bishop via bitcoin-dev &l=
t;<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org">bitcoin-dev@list=
s.linuxfoundation.org</a>&gt; wrote:<br></div><blockquote class=3D"gmail_qu=
ote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,20=
4);padding-left:1ex"><div dir=3D"ltr"><div>Hi,</div><br><div class=3D"gmail=
_quote"><div dir=3D"ltr" class=3D"gmail_attr">On Mon, Jun 27, 2022 at 2:14 =
PM Alfred Hodler via bitcoin-dev &lt;<a href=3D"mailto:bitcoin-dev@lists.li=
nuxfoundation.org" target=3D"_blank">bitcoin-dev@lists.linuxfoundation.org<=
/a>&gt; wrote:</div><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">
2. Notification transactions still exist but no longer leave a privacy foot=
print on the blockchain. Instead, a notification transaction is simply a si=
ngle OP_RETURN containing a value that only Alice and Bob can calculate. If=
 Alice&#39;s notification transaction uses UTXOs not associated with her id=
entity, there is never a footprint showing that either her or Bob are using=
 private payments. If Alice uses tainted coins, only she is exposed as a us=
er of Private Payments but Bob still isn&#39;t.<br></blockquote><div><br>Th=
at&#39;s a neat trick. What about not using OP_RETURN at all, and just publ=
ishing on a tor hidden service that=C2=A0other wallets check?=C2=A0 Alice w=
ouldn&#39;t have to expose on-chain that she is a sender of a private payme=
nt.</div><div><br></div><div>- Bryan<br></div></div><div dir=3D"ltr"><div d=
ir=3D"ltr"><a href=3D"https://twitter.com/kanzure" target=3D"_blank">https:=
//twitter.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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