MIME-Version: 1.0
From: Antoine Riard <antoine.riard@gmail.com>
Date: Sun, 22 Oct 2023 03:27:37 +0100
Message-ID: <CALZpt+HwmacQ9VFu+SfmKms363ZU1xYZe+9o8TsoemTVQLprLg@mail.gmail.com>
To: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>, 
 "lightning-dev\\\\@lists.linuxfoundation.org"
 <lightning-dev@lists.linuxfoundation.org>
Content-Type: multipart/alternative; boundary="000000000000fcb8ca060844d95b"
Cc: security@ariard.me
Subject: [bitcoin-dev] On solving pinning,
 replacement cycling and mempool issues for bitcoin second-layers
Precedence: list

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Hi,

I think if Gleb Naumenko and myself allocate our research time on this
issue, we should (hopefully) be able to come with a strong sustainable fix
to the lightning network, both systematically solving pinnings and
replacement cycling attacks (and maybe other mempools issues or things
related like massive force-closure beyond available blockspace can absorb
before pre-signed transactions timelocks expiration as mentioned in the
original paper).

I have not yet probed Gleb's mind on this, though we both studied those
cross-layer issues together as early as 2019 / 2020, and I think we have
built an intuitive understanding of the problem-space, with both practical
experience of bitcoin core and rust-lightning codebases and landmark
research in this area [0] [1]. If Gleb isn't too busy with Erlay in core,
I'm sure he'll be enthusiastic to contribute research time at his own pace
(and I might probe a bit of Elichai Turkel time to verify the maths of all
sustainable lightning fixes we might propose and the risks models). All
soft commitments and assuming the interest of the bitcoin community.

One good advantage of long-term sustainable fixes, it should
(optimistically yet to be demonstrated) lower the fee-bumping reserve value
and number of UTXOs lightning users (and maybe bandwidth) have to lock
continuously to use this worldwide 24 / 7 payment system.

Reopened the issue on coordinated security issues handling in the LN
ecosystem:
https://github.com/lightning/bolts/pull/772

While I'll stay focused on solving the above problems at the base-layer
where they're best solved, at least I'll stay around for a few months
making transitions with the younger generation of LN devs.

For transparency, I don't have any strong solution design yet at all,
neither code, conceptual draft or paper ready, and game-theory and nodes
network processing resources changes will have to be weighted very
carefully, all under the bitcoin open and responsible process we currently
have. Overall, this will take reasonable time (e.g package relay design
discussions have been started in 2018 and we're only now at the hard
implementation and review phase) to carry on forward.

Looking forward to hearing thoughts of the Bitcoin and Lightning
development protocols community.

[0]
https://lists.linuxfoundation.org/pipermail/lightning-dev/2020-February/002569.html
[1] https://arxiv.org/pdf/2006.01418.pdf

"They who face calamity without wincing, and who offer the most energetic
resistance, these, be they States or individuals, are the truest heroes". -
Thucydides.

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<div dir=3D"ltr">Hi,<div><br></div><div>I think if Gleb Naumenko and myself=
 allocate our research time=C2=A0on this issue, we should (hopefully) be ab=
le to come with a strong sustainable fix to the lightning network, both sys=
tematically=C2=A0solving pinnings and replacement cycling attacks (and mayb=
e other=C2=A0mempools issues=C2=A0or things related like massive force-clos=
ure beyond available blockspace can absorb before pre-signed transactions t=
imelocks expiration as mentioned in the original=C2=A0paper).</div><div><br=
></div><div>I have not yet probed Gleb&#39;s mind on this, though we both s=
tudied those cross-layer issues together as early as 2019 / 2020, and I thi=
nk we have built an intuitive=C2=A0understanding of the problem-space, with=
 both practical experience=C2=A0of bitcoin core and rust-lightning codebase=
s and landmark research in this area [0] [1]. If Gleb isn&#39;t too busy wi=
th Erlay in core, I&#39;m sure he&#39;ll be enthusiastic to contribute rese=
arch time at his own pace (and I might probe a bit of Elichai Turkel time t=
o verify the maths of all sustainable lightning fixes we might propose and =
the risks models). All soft commitments and assuming=C2=A0the interest of t=
he bitcoin community.</div><div><br></div><div>One good advantage of long-t=
erm sustainable fixes, it should (optimistically yet to be demonstrated) lo=
wer the fee-bumping reserve value and number of UTXOs lightning users (and =
maybe bandwidth) have to lock continuously to use this worldwide 24 / 7 pay=
ment system.</div><div><br></div><div>Reopened the issue on coordinated sec=
urity issues handling in the LN ecosystem:</div><div><a href=3D"https://git=
hub.com/lightning/bolts/pull/772">https://github.com/lightning/bolts/pull/7=
72</a><br></div><div><br></div><div>While I&#39;ll stay focused on solving =
the above problems at the base-layer where they&#39;re best solved, at leas=
t I&#39;ll stay around for a few months making transitions with the younger=
 generation of LN devs.</div><div><br></div><div>For transparency, I don=
9;t have any strong solution design yet at all, neither code, conceptual dr=
aft or paper ready, and game-theory and nodes network processing resources =
changes will have to be weighted very carefully, all under the bitcoin open=
 and responsible process we currently have. Overall, this will take reasona=
ble time (e.g package relay design discussions have been started in 2018 an=
d we&#39;re only now at the hard implementation and review phase) to carry =
on forward.</div><div><br></div><div>Looking forward to hearing thoughts of=
 the Bitcoin and Lightning development protocols community.</div><div><br><=
/div><div>[0] <a href=3D"https://lists.linuxfoundation.org/pipermail/lightn=
ing-dev/2020-February/002569.html">https://lists.linuxfoundation.org/piperm=
ail/lightning-dev/2020-February/002569.html</a></div><div>[1] <a href=3D"ht=
tps://arxiv.org/pdf/2006.01418.pdf">https://arxiv.org/pdf/2006.01418.pdf</a=
></div><div><br></div><div>&quot;They who face calamity without wincing, an=
d who offer the most energetic resistance, these, be they States or individ=
uals, are the truest heroes&quot;. - Thucydides.</div></div>

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