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From: Tejaswi Nadahalli <nadahalli@gmail.com>
Date: Mon, 6 Jul 2020 13:13:47 +0200
Message-ID: <CAAifmATXTHcW2vL+M5TQbfVKj0Jd-YSXwKisgPcxurkKg21TeA@mail.gmail.com>
To: Itay Tsabary <sitay@campus.technion.ac.il>
Content-Type: multipart/alternative; boundary="000000000000a7b71f05a9c3f83b"
Cc: Matan Yehieli <matany@campus.technion.ac.il>,
 Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] MAD-HTLC
Precedence: list

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On Fri, Jul 3, 2020 at 1:49 PM Itay Tsabary <sitay@campus.technion.ac.il>
wrote:

> Note the required token amount for the collateral contract is low and
> independent of the required deposit tokens -- only a relatively small
> incentive is required to make "acting honestly" Bob's preferred choice.
> So, this is basically a negligible overhead, token-wise. As a downside, it
> does create slightly larger transactions (another UTXO, etc.).
>

I read the MAD-HTLC paper and I think it actually doesn't get into the size
of the collateral (v^{col}). I might have missed it though. Can you please
point me to the section in the paper where the amount is discussed?

I assumed that v^{col} has to be at least the size of v^{dep}. Otherwise,
Bob can threaten Alice with an HTLC bribery attack, and Alice knows that
Bob has very little to lose. Bob *should* have the same amount to lose, to
make it work - no?

>

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<div dir=3D"ltr"><div dir=3D"ltr">On Fri, Jul 3, 2020 at 1:49 PM Itay Tsaba=
ry &lt;<a href=3D"mailto:sitay@campus.technion.ac.il">sitay@campus.technion=
.ac.il</a>&gt; wrote:<br></div><div class=3D"gmail_quote"><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"><div dir=3D"ltr"><div>Note the required to=
ken amount for the collateral contract is low and independent of the requir=
ed deposit tokens -- only a relatively small incentive is required to make =
&quot;acting honestly&quot; Bob&#39;s preferred choice.</div><div>So, this =
is basically a negligible overhead, token-wise. As a downside, it does crea=
te slightly larger transactions (another UTXO, etc.).<br></div></div></bloc=
kquote><div><br></div><div>I read the=C2=A0MAD-HTLC paper and I think it ac=
tually doesn&#39;t get into the size of the collateral (v^{col}). I might h=
ave missed it though. Can you please point me to the section in the paper w=
here the amount is discussed?</div><div><br></div><div>I assumed that v^{co=
l} has to be at least the size of v^{dep}. Otherwise, Bob can threaten Alic=
e with an HTLC bribery attack, and Alice knows that Bob has very little to =
lose. Bob *should* have the same amount to lose, to make it work - no?</div=
><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border=
-left:1px solid rgb(204,204,204);padding-left:1ex"><div class=3D"gmail_quot=
e"><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;bord=
er-left:1px solid rgb(204,204,204);padding-left:1ex">
</blockquote></div>
</blockquote></div></div>

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