<div dir="ltr">> Do I understand correctly that this attack only applies if Alice<br>> attempts to fee bump her batch transaction? In short, is this the<br>> attack:<div><br></div><div>Fundamentally, yes. This attack is primarily targeting all transaction flows with a fee bump.</div><div><br></div><div>See section 6.4 of the joined paper for more characterization of the "Transaction Traffic Hijack", while no quantitative analysis of the average % txn affected has been done so far.</div><div><br></div><div>There could also be UTXO-sharing flows that are affected, where the attacker is propagating first, and preventing the other tx to propagate, before evicting his own package.</div><div><br></div><div>However no test and no thoughts has been given to this "block-first-at-the-UTXO-root" alternative, the fee bump is more concerning.</div><div><br></div><div>Best,</div><div>Antoine</div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">Le lun. 27 janv. 2025 à 22:17, David A. Harding <<a href="mailto:dave@dtrt.org">dave@dtrt.org</a>> a écrit :<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex">On 2025-01-27 05:22, Antoine Riard wrote:<br> > As soon as Alice's batch transaction starts to propagate, Mallet<br> > consumes its 2 outputs with 2 chain of junk transactions to reach max<br> > package limits (25 descendants) and block the carve-out. The junk<br> > transactions are of size 150 bytes and feerates 2 satoshis per virtual<br> > byte and they have 2 parents: one Alice's payout UTXO and one Mallet's<br> > UTXO.<br> > <br> > Starting from this point, Alice's exchange server logic should either<br> > (a) attempts a CPFP or (b) attempts a RBF on the batch transaction. As<br> > there is no global mempool, Alice is uncertain on the explanation for<br> > the lack of propagation of her batch transaction [...]<br> <br> Do I understand correctly that this attack only applies if Alice<br> attempts to fee bump her batch transaction? In short, is this the<br> attack:<br> <br> - Alice broadcasts a transaction.<br> - Mallet pins Alice.<br> - Alice doesn't realize she's been pinned and bumps the fees.<br> - The bump doesn't propagate due to the pin, but Mallet receives it<br> anyway somehow.<br> - Mallet mines the fee bump, but nobody else mines it because it didn't<br> propagate. Mallet thus makes more money than other miners.<br> <br> Thanks,<br> <br> -Dave<br> </blockquote></div> <p></p> -- <br /> You received this message because you are subscribed to the Google Groups "Bitcoin Development Mailing List" group.<br /> To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:bitcoindev+unsubscribe@googlegroups.com">bitcoindev+unsubscribe@googlegroups.com</a>.<br /> To view this discussion visit <a href="https://groups.google.com/d/msgid/bitcoindev/CALZpt%2BHyQyj6EUf39JX3nuD3izsmBSG9XUcV-EVrC05o2T%3Du7A%40mail.gmail.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/bitcoindev/CALZpt%2BHyQyj6EUf39JX3nuD3izsmBSG9XUcV-EVrC05o2T%3Du7A%40mail.gmail.com</a>.<br />