Subject: Re: [Bitcoin-development] deterministic transaction expiration

From: Mike Hearn <[email-masked]>
Date: Tue, 5 Aug 2014 20:54:08 +0200

>
> The user experience of unconfirming transactions setting around in limbo
> is just horrible.  Bitcoin software by necessity has gotten better about
> attaching fees so this sort of behavior is uncommon, but that does not
> eliminate the problem.
>

Yes, indeed. I suspect there's a quick hack that could make this problem a
lot better though.

I think I brought up this idea before, but can't quite remember. Anyway I'm
willing to bet that if we analysed the data some more, we'd discover that
most "legitimate" i.e. non-DoS unconfirmed transactions that sit around for
ages are linked back to the block chain within two hops and not more. That
is people send a transaction that uses up their coin age, and then
immediately those coins are immediately respent again, but then those final
new coins are not spent.

On the other hand DoS attacks look like bouncing your coins around over and
over forever, i.e. more than two or three hops back to the chain.

So I wonder if making priority look back two or three transactions but not
more would help real users a lot, whilst not opening up any significant new
potential for DoS.