Date: Tue, 10 Jan 2023 17:10:37 +0000
To: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
From: alicexbt <alicexbt@protonmail.com>
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Subject: Re: [bitcoin-dev] Why Full-RBF Makes DoS Attacks on Multiparty
	Protocols Significantly More Expensive
Precedence: list

Hi Peter,

> Bringing up Whirlpool here is silly. Everyone knows Samourai has made, at=
 best,
> some rather insane technical decisions. Quite likely downright malicious =
with
> their xpub collection. Their opinion isn't relevant. Cite reputable sourc=
es.

I didn't want this thread to become a wasabi vs samourai debate instead wan=
ted to focus on full-rbf and how it affects different coinjoin implementati=
ons. Samourai wallet can be used with [dojo][0] that includes full node and=
 Whirlpool can be used in [sparrow Wallet][1] as well. There are several re=
asons to not use wasabi and consider their opinion irrelevant. Wasabi has m=
any privacy issues including address reuse and consolidation in a coinjoin =
tx. They completely lost their reputation after deciding to work with chain=
 analysis firms that help governments for censorship of some UTXOs.

Even _nothingmuch_ who has contributed to Wasabi's coinjoin implementation =
has [no major issues][2] with whirlpool if used properly. Some [tweets][3] =
in this thread even show their incompetence and major issues with wabisabi.

Anyway thanks for responding to other things I mentioned in last email.


[0]: https://code.samourai.io/dojo/samourai-dojo
[1]: https://sparrowwallet.com/docs/mixing-whirlpool.html
[2]: https://twitter.com/search?lang=3Den&q=3Dwhirlpool%20(from%3AmHaGqnOAC=
yFm0h5)&src=3Dtyped_query
[3]: https://twitter.com/mHaGqnOACyFm0h5/status/1538748210210013184


/dev/fd0
floppy disc guy

Sent with Proton Mail secure email.

------- Original Message -------
On Tuesday, January 10th, 2023 at 3:33 PM, Peter Todd <pete@petertodd.org> =
wrote:


> On Tue, Jan 10, 2023 at 09:19:39AM +0000, alicexbt wrote:
>=20
> > Hi Peter,
> >=20
> > > ## How Full-RBF Mitigates the Double-Spend DoS Attack
> > >=20
> > > Modulo tx-pinning, full-rbf mitigates the double-spend DoS attack in =
a very
> > > straightforward way: the low fee transaction is replaced by the highe=
r fee
> > > transaction, resulting in the latter getting mined in a reasonable am=
ount of
> > > time and the protocol making forward progress.
> >=20
> > Asking this question based on a discussion on twitter. How would you ge=
t extra sats to increase the fees?
>=20
>=20
> You're misunderstanding the issue. There is no need for extra sats to inc=
rease
> fees. Coinjoin transactions already have fees set at a level at which you=
'd
> expect them to be mined in a reasonable amount of time. Full-RBF ensures =
that,
> modulo tx pinning, either the coinjoin gets mined, or any double-spend ha=
s to
> have a high enough feerate that it will be mined in a reasonable amount o=
f time
> as well.
>=20
> > It seems this would be possible with Joinmarket, Wasabi and even joinst=
r although things would get worse for Whirlpool. Whirlpool coinjoin transac=
tions do not signal BIP 125 RBF so they were not replaceable earlier
>=20
>=20
> Bringing up Whirlpool here is silly. Everyone knows Samourai has made, at=
 best,
> some rather insane technical decisions. Quite likely downright malicious =
with
> their xpub collection. Their opinion isn't relevant. Cite reputable sourc=
es.
>=20
> Anyway, Wasabi would like to move to making coinjoins opt-in to RBF. Thou=
gh
> full-rbf may come sooner; for technical reasons opt-in RBF is ugly to imp=
lement
> now as activation needs to be coordinated accross all clients:
>=20
> https://github.com/zkSNACKs/WalletWasabi/issues/9041#issuecomment-1376653=
020
>=20
> > however attacker would be able to perform DoS attacks now by double spe=
nding their inputs used in coinjoin.
>=20
>=20
> As I explained, attackers can already do this with or without full-rbf si=
mply
> by picking the right time to broadcast the double spend. It's not an effe=
ctive
> attack anyway: with a UTXO you can already hold up a coinjoin round by si=
mply
> failing to complete stage #2 of the coinjoin. Actually doing a double-spe=
nd
> simply guarantees that you're spending money on it. It's only effective w=
ith
> low-fee double-spends in the absence of full-rbf.
>=20
>=20
> This tweet is nuts. Eg "Gives well connected mining pools an added advant=
age"
> is simply false. Full-RBF does the exact opposite.
>=20
> --
> https://petertodd.org 'peter'[:-1]@petertodd.org