MIME-Version: 1.0
References: <rH1Js_T_UWcAg9lS9NDw_Qb6Js5bgs8rPILej69BjqsEZcJZwsvHhZRilkkOQZRGXabai63hrGgbTP2Yk99ojKEN6fU6HT4TmukiafqiKjo=@protonmail.com>
In-Reply-To: <rH1Js_T_UWcAg9lS9NDw_Qb6Js5bgs8rPILej69BjqsEZcJZwsvHhZRilkkOQZRGXabai63hrGgbTP2Yk99ojKEN6fU6HT4TmukiafqiKjo=@protonmail.com>
From: Bryan Bishop <kanzure@gmail.com>
Date: Mon, 27 Jun 2022 15:20:45 -0500
Message-ID: <CABaSBaxinzeVuOAmGRoVttMN9puQunZNy3MVuTxk1U3=bLrg6A@mail.gmail.com>
To: Alfred Hodler <alfred_hodler@protonmail.com>, 
 Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>,
 Bryan Bishop <kanzure@gmail.com>
Content-Type: multipart/alternative; boundary="0000000000006531d305e273a8c5"
Subject: Re: [bitcoin-dev] [BIP proposal] Private Payments
Precedence: list

--0000000000006531d305e273a8c5
Content-Type: text/plain; charset="UTF-8"

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

--0000000000006531d305e273a8c5
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr"><div>Hi,</div><br><div class=3D"gmail_quote"><div dir=3D"l=
tr" 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.linuxfoundation.org">bi=
tcoin-dev@lists.linuxfoundation.org</a>&gt; wrote:</div><blockquote class=
=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rg=
b(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" class=
=3D"gmail_signature"><div dir=3D"ltr"><a href=3D"https://twitter.com/kanzur=
e" target=3D"_blank">https://twitter.com/kanzure</a></div></div></div>

--0000000000006531d305e273a8c5--