Date: Fri, 18 Feb 2022 18:50:07 -0500
From: Peter Todd <pete@petertodd.org>
To: Jeremy Rubin <jeremy.l.rubin@gmail.com>
Message-ID: <YhAwr7+9mGJAe2/p@petertodd.org>
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 <YgS3sJvg6kG3WnVJ@petertodd.org>
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Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>,
 lightning-dev <lightning-dev@lists.linuxfoundation.org>,
 Jeremy <jlrubin@mit.edu>
Subject: Re: [bitcoin-dev] [Pre-BIP] Fee Accounts
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On Thu, Feb 10, 2022 at 12:08:59AM -0800, Jeremy Rubin wrote:
> That's not really pinning; painning usually refers to pinning something to
> the bottom of the mempool whereas these mechanisms make it easier to
> guarantee that progress can be made on confirming the transactions you're
> interested in.

As I said, it's a new kind of pinning attack, distinct from other types of
pinning attack.

> Often times in these protocols "the call is coming inside the house". It's
> not a third party adding fees we are scared of, it's a direct party to the
> protocol!

Often times that is true. But other times that is not true! I gave examples=
 of
use-cases where being able to arbitrary add fees to transactions is harmful;
the onus is on you to argue why that is acceptable to burden those users wi=
th a
new class of attack.

> Sponsors or fee accounts would enable you to ensure the protocol you're
> working on makes forward progress. For things like Eltoo the internal
> ratchet makes this work well.
>=20
> Protocols which depend on in mempool replacements before confirmation
> already must be happy (should they be secure) with any prior state being
> mined. If a third party pays the fee you might even be happier since the
> execution wasn't on your dime.

"Must be able to deal with" is not the same thing as "Must be happy". While
those use-cases do have to deal with those exceptional cases happening
occasionally, it's harmful if an attacker can harass you by making those
exceptional cases happen frequently.

--=20
https://petertodd.org 'peter'[:-1]@petertodd.org

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