[Bitcoin-development] An initial replace-by-fee implementation is now available

Adam Back adam at cypherspace.org
Thu May 9 11:19:13 UTC 2013

In this thread discussing this idea


it is suggested that the approach risks making 0-confirm double-spends

I dont see why this should be.  Cant part of the validation of accepting a
fee revision be that every aspct of the revision except the reward must be
unchanged, otherwise the revision is considered invalid and discarded?

(ie same payment amount, same input coins, same recipient and same change


On Thu, May 09, 2013 at 09:58:50AM +0000, John Dillon wrote:
>Hash: SHA256
>After some consultation with affected sites by myself and Peter we have decided
>to release an initial replace-by-fee implementation and setup a server using
>those rules on testnet. This implementation does not include recursive fee
>evaluation, and is therefore vulnerable to DoS attack, so hopefully that will
>continue to allow adoption to proceed gradually. We can-not recommend mining on
>mainnet with it. It does not include an "undo" RPC command or an adjust fees,
>and Peter says he has not implemented one yet.  Patches are welcome.
>Specifically there were requests from vulnerable parties, which interestingly
>included a site that knew they had bugs related to replacement but not
>financial vulnerabilities, to put up a server on testnet to check wallet code.
>The vulnerable requested to remain undisclosed. An additional consideration was
>the upcoming anti-dust rules which are yet another example of why zero-conf is
>so much more dangerous to accept than single-conf. Two of the people contacting
>us brought up that issue in fact.
>The code is on github:
>    https://github.com/petertodd/bitcoin/tree/replace-by-fee
>and a replace-by-fee server operating on testnet is available at
>testnet-replace-by-fee.bitcoin.petertodd.org To test you will need to use the
>raw transaction API and manually create the replacement transaction. Do note
>that your wallet will retain the existing one and no mechanism yet exists to
>delete the old transaction from your wallet. Again, a certain amount of
>"cludgyness" to this is intentional to discourage premature non-testing use.
>Regarding the reward, I've decided Peter will collect the full amount even
>though the work is not %100 complete (the mempool aspect) due to his concern
>about staging an implementation properly, working with vulnerable sites, and
>overall genuine interest in the actual issues at hand rather than the reward.
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