Subject: Re: [bitcoin-dev] New BIP: Dealing with OP_IF and OP_NOTIF malleability in P2WSH

From: "Russell O'Connor" <[email-masked]>
Date: Tue, 16 Aug 2016 18:36:24 -0400

On Tue, Aug 16, 2016 at 6:30 PM, Pieter Wuille <[email-masked]>
wrote:

> On Aug 17, 2016 00:23, "Russell O'Connor via bitcoin-dev" <
> [email-masked]> wrote:
>
> > If one's goal is to mess with an transaction to prevent it from being
> mined, it is more effective to just not relay the transaction rather than
> to mess with the witness.  Given two transactions with the same txid and
> different witness data, miners and good nodes ought to mine/relay the
> version with the lower cost (smaller?) witness data.
>
> That implies that everyone will see both versions and be able to make that
> choice. Unfortunately, those two versions will be definition be in conflict
> with each other, and thus only one will end up paying a fee. We're can't
> relay two transactions for the price of one, or we'd expose the p2p network
> to a very cheap DDoS attack: just send increasingly small versions of the
> same transaction.
>
Can I already do something similar with replace by fee, or are there limits
on that?