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From: Dustin Dettmer <dustinpaystaxes@gmail.com>
Date: Tue, 22 Jan 2019 08:33:23 -0800
Message-ID: <CABLeJxRmdccf2tVZ4MsdsEj6H9+NnOpp+AeMLZwYh-zTMkWJXw@mail.gmail.com>
To: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>, 
	ZmnSCPxj <ZmnSCPxj@protonmail.com>
Content-Type: multipart/alternative; boundary="000000000000f875fb05800e8961"
Subject: Re: [bitcoin-dev] Proof-of-Stake Bitcoin Sidechains
Precedence: list

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Wouldn=E2=80=99t a revealed private key for time locked funds create a race=
 to
spend? I imagine miners who are paying attention would have the advantage
but it would still just be a race.

Would be nice to have the funds destroyed or sent somewhere specific. Like
if somehow the revealed key was actually itself a presigned transaction. Or
perhaps a 32 byte piece of a tx needed to complete it.

On Tue, Jan 22, 2019 at 6:14 AM ZmnSCPxj via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> Good Morning Matt,
>
> > ### ZmnSCPxj,
> >
> > I'm intrigued by this mechanism of using fixed R values to prevent
> multiple signatures, but how do we derive the R values in a way where the=
y
> are
> unique for each blockheight but still can be used to create signatures or
> verify?
>
> One possibility is to derive `R` using standard hierarchical derivation.
> Then require that the staking pubkey be revealed to the sidechain network
> as actually being `staking_pubkey =3D P + hash(P || parent_R) * G` (possi=
bly
> with some trivial protection against Taproot).
> To sign for a blockheight `h`, you must use your public key `P` and the
> specific `R` we get from hierarchical derivation from `parent_R` and the
> blockheight as index.
>
>
>
> Regards,
> ZmnSCPxj
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>

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<div><div dir=3D"auto">Wouldn=E2=80=99t a revealed private key for time loc=
ked funds create a race to spend? I imagine miners who are paying attention=
 would have the advantage but it would still just be a race.</div></div><di=
v dir=3D"auto"><br></div><div dir=3D"auto">Would be nice to have the funds =
destroyed or sent somewhere specific. Like if somehow the revealed key was =
actually itself a presigned transaction. Or perhaps a 32 byte piece of a tx=
 needed to complete it.</div><div><br><div class=3D"gmail_quote"><div dir=
=3D"ltr">On Tue, Jan 22, 2019 at 6:14 AM ZmnSCPxj via bitcoin-dev &lt;<a hr=
ef=3D"mailto:bitcoin-dev@lists.linuxfoundation.org">bitcoin-dev@lists.linux=
foundation.org</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quote" st=
yle=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Good =
Morning Matt,<br>
<br>
&gt; ### ZmnSCPxj,<br>
&gt;<br>
&gt; I&#39;m intrigued by this mechanism of using fixed R values to prevent=
 multiple signatures, but how do we derive the R values in a way where they=
 are<br>
unique for each blockheight but still can be used to create signatures or v=
erify?<br>
<br>
One possibility is to derive `R` using standard hierarchical derivation.<br=
>
Then require that the staking pubkey be revealed to the sidechain network a=
s actually being `staking_pubkey =3D P + hash(P || parent_R) * G` (possibly=
 with some trivial protection against Taproot).<br>
To sign for a blockheight `h`, you must use your public key `P` and the spe=
cific `R` we get from hierarchical derivation from `parent_R` and the block=
height as index.<br>
<br>
<br>
<br>
Regards,<br>
ZmnSCPxj<br>
_______________________________________________<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></div>

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