From: ZmnSCPxj <ZmnSCPxj@protonmail•com>
To: Matt Corallo <lf-lists@mattcorallo•com>
Cc: Bitcoin Protocol Discussion
<bitcoin-dev@lists•linuxfoundation.org>,
lightning-dev <lightning-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] [Lightning-dev] RBF Pinning with Counterparties and Competing Interest
Date: Thu, 23 Apr 2020 12:46:59 +0000 [thread overview]
Message-ID: <62P_3wvv8z7AVCdKPfh-bs30-LliHkx9GI9Og3wqIK6hadIG0d6MJJm077zac1erpPUy31FqgZjkAjEl9AQtrOCg4XA5cxozBb7-OIbbgvE=@protonmail.com> (raw)
In-Reply-To: <67334082-5ABA-45C7-9C09-FF19B119C80D@mattcorallo.com>
Good morning Matt,
> > - C directly contacts miners with an out-of-band proposal to replace its transaction with an alternative that is much smaller and has a low fee, but much better feerate.
>
> Or they can just wait. For example in today’s mempool it would not be strange for a transaction at 1 sat/vbyte to wait a day but eventually confirm.
That introduces the possibility that the entire tree (with high total fee, remember) gets confirmed, so it would be better for C to replace it with an alternative to a different address C still controls, with a slightly better fee rate but smaller (no child transactions) and lower total fee, so an economically-rational C will make that effort (and if there are still other transactions in the mempool, an economically-rational miner will accept this proposal).
But in any case this is a minor detail and the attack will work either way.
>
> > - Miners, being economically rational, accept this proposal and include this in a block.
> >
> > The proposal by Matt is then:
> >
> > - The hashlock branch should instead be:
> > - B and C must agree, and show the preimage of some hash H (hashlock branch).
> > - Then B and C agree that B provides a signature spending the hashlock branch, to a transaction with the outputs:
> > - Normal payment to C.
> > - Hook output to B, which B can use to CPFP this transaction.
> > - Hook output to C, which C can use to CPFP this transaction.
> > - B can still (somehow) not maintain a mempool, by:
> > - B broadcasts its timelock transaction.
> > - B tries to CPFP the above hashlock transaction.
> > - If CPFP succeeds, it means the above hashlock transaction exists and B queries the peer for this transaction, extracting the preimage and claiming the A->B HTLC.
>
> Note that no query is required. The problem has been solved and the preimage-containing transaction should now confirm just fine.
Ah, right, so it gets confirmed and the `blocksonly` B sees it in a block.
Even if C hooks a tree of low-fee transactions on its hook output or normal payment, miners will still be willing to confirm this and the B hook CPFP transaction without, right?
Regards,
ZmnSCPxj
next prev parent reply other threads:[~2020-04-23 12:47 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-21 2:43 [bitcoin-dev] " Matt Corallo
2020-04-22 4:12 ` [bitcoin-dev] [Lightning-dev] " ZmnSCPxj
2020-04-22 4:18 ` Olaoluwa Osuntokun
2020-04-22 6:08 ` ZmnSCPxj
2020-04-22 8:01 ` Antoine Riard
2020-04-22 8:55 ` Bastien TEINTURIER
2020-04-22 23:05 ` Olaoluwa Osuntokun
2020-04-22 23:11 ` Olaoluwa Osuntokun
2020-04-22 16:56 ` Matt Corallo
2020-04-22 4:13 ` [bitcoin-dev] " Olaoluwa Osuntokun
2020-04-22 11:51 ` David A. Harding
2020-04-27 21:26 ` Rusty Russell
2020-04-22 16:50 ` Matt Corallo
2020-04-22 23:13 ` Olaoluwa Osuntokun
2020-04-22 23:20 ` Matt Corallo
2020-04-22 23:27 ` Olaoluwa Osuntokun
2020-04-23 1:10 ` Matt Corallo
2020-04-23 4:50 ` [bitcoin-dev] [Lightning-dev] " ZmnSCPxj
2020-04-23 6:21 ` Matt Corallo
2020-04-23 12:46 ` ZmnSCPxj [this message]
2020-04-23 22:47 ` Matt Corallo
2020-06-19 7:44 ` Bastien TEINTURIER
2020-06-19 19:58 ` David A. Harding
2020-06-19 20:52 ` David A. Harding
2020-06-20 8:54 ` Bastien TEINTURIER
2020-06-20 10:36 ` David A. Harding
2020-06-20 16:01 ` ZmnSCPxj
2020-06-21 2:10 ` ZmnSCPxj
2020-06-22 7:35 ` Bastien TEINTURIER
2020-06-22 8:15 ` ZmnSCPxj
2020-06-22 8:25 ` Bastien TEINTURIER
2020-06-24 8:32 ` Matt Corallo
2020-04-23 1:18 ` [bitcoin-dev] " Jeremy
2020-04-22 18:24 ` David A. Harding
2020-04-22 19:03 ` Antoine Riard
2020-04-22 20:28 ` David A. Harding
2020-04-22 22:53 Matt Corallo
2020-04-23 9:59 ` David A. Harding
2020-04-23 12:52 ` [bitcoin-dev] [Lightning-dev] " ZmnSCPxj
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