Feedback-ID: i525146e8:Fastmail
Date: Wed, 24 Jan 2024 04:44:14 +0000
From: Peter Todd <pete@petertodd.org>
To: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Message-ID: <ZbCVnl8HbREQV5su@petertodd.org>
References: <Zalsq+Nq7RRr/CAR@petertodd.org>
 <9a89eca8-61fd-4156-825d-c9b718dc3034@murch.one>
 <Za7xkUsoeACMv6Fw@petertodd.org>
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In-Reply-To: <Za7xkUsoeACMv6Fw@petertodd.org>
Subject: Re: [bitcoin-dev] One-Shot Replace-By-Fee-Rate
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On Mon, Jan 22, 2024 at 10:52:01PM +0000, Peter Todd via bitcoin-dev wrote:
> An even simpler fix would be to just require that all unconfirmed inputs =
in a
> replacement come from the *same* replaced transaction. That would make ce=
rtain
> rare, but economically viable, replacements infeasible. But it would defi=
nitely
> fix the issue.

FYI I've implemented this fix, and pure replace-by-fee-rate with a minimum =
2x
fee-rate increate, in my Libre Relay fork:

https://github.com/petertodd/bitcoin/tree/libre-relay-v26.0

Similar to my full-RBF peering fork, it uses a new service bit to ensure it=
's
peering with other Libre Relay nodes to make transaction propagation actual=
ly
works.

I wouldn't call this a "public" release at this point. But people are welco=
me
to review the code and try it out. I have a few mainnet and testnet nodes
running it right now.

I'm *very* interested if anyone else can find any further exploits in the p=
ure
replace-by-fee-rate code. I'm also interested to see if anyone bothers to s=
pend
the money to do the well-known, and expensive, replace-by-fee-rate DoS atta=
cks.

The fun thing about this release, is Libre Relay also removes the restricti=
ons
on OP_Return, which I'm sure will make some people quite angry... So maybe
that'll give someone an incentive to attack it. :D I'm already sufficiently
well connected to get oversized OP_Return's mined. So if you want to do that
too, running a Libre Relay node will work.

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

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