From: "David A. Harding" <dave@dtrt•org>
To: Jeremy <jlrubin@mit•edu>
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] A Replacement for RBF and CPFP: Non-Destructive TXID Dependencies for Fee Sponsoring
Date: Sat, 19 Sep 2020 13:24:17 -0400 [thread overview]
Message-ID: <20200919172417.ajlbqbmtuvk7t7be@ganymede> (raw)
In-Reply-To: <CAD5xwhjZt25Bx+0MqfuY4OLJRWYmKZrfof86pPUAfJRDDsBQWA@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 1267 bytes --]
On Sat, Sep 19, 2020 at 09:30:56AM -0700, Jeremy wrote:
> Yup, I was aware of this limitation but I'm not sure how practical it is as
> an attack because it's quite expensive for the attacker.
It's cheap if:
1. You were planning to consolidate all those UTXOs at roughly that
feerate anyway.
2. After you no longer need your pinning transaction in the mempool, you
make an out-of-band arrangement with a pool to mine a small
conflicting transaction.
> But there are a few simple policies that can eliminate it:
>
> 1) A Sponsoring TX never needs to be more than, say, 2 inputs and 2
> outputs. Restricting this via policy would help, or more flexibly
> limiting the total size of a sponsoring transaction to 1000 bytes.
I think that works (as policy).
> 2) Make A Sponsoring TX not need to pay more absolute fee, just needs to
> increase the feerate (perhaps with a constant relay fee bump to prevent
> spam).
I think it'd be hard to find a constant relay fee bump amount that was
high enough to prevent abuse but low enough not to unduly hinder
legitimate users.
> I think 1) is simpler and should allow full use of the sponsor mechanism
> while preventing this class of issue mostly.
Agreed.
Thanks,
-Dave
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
next prev parent reply other threads:[~2020-09-19 17:25 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-19 0:51 Jeremy
2020-09-19 1:39 ` Cory Fields
2020-09-19 16:16 ` Jeremy
2020-09-19 13:37 ` David A. Harding
2020-09-19 15:01 ` nopara73
2020-09-19 16:30 ` Jeremy
2020-09-19 17:24 ` David A. Harding [this message]
2020-09-19 18:39 ` Antoine Riard
2020-09-19 19:13 ` Antoine Riard
2020-09-19 19:46 ` Jeremy
2020-09-20 23:10 ` Antoine Riard
2020-09-21 14:52 ` David A. Harding
2020-09-21 16:27 ` Jeremy
2020-09-21 23:40 ` Antoine Riard
2020-09-22 18:05 ` Suhas Daftuar
2020-09-23 22:10 ` Jeremy
2020-09-24 4:22 ` Dmitry Petukhov
2020-09-22 6:24 ArmchairCryptologist
2020-09-22 13:52 ` Antoine Riard
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200919172417.ajlbqbmtuvk7t7be@ganymede \
--to=dave@dtrt$(echo .)org \
--cc=bitcoin-dev@lists$(echo .)linuxfoundation.org \
--cc=jlrubin@mit$(echo .)edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox