On 15 May 2013 13:38, Peter Todd <pete@petertodd.org> wrote:

> Now that I have the replace-by-fee reward, I might as well spread the
> wealth a bit.
>
>
> So for all this discussion about replace-by-fee and the supposed
> security of zero-conf transactions, no-one seems to think much about how
> in practice very few vendors have a setup to detect if conflicting
> transactions were broadcast on the network simultaneously - after all if
> that is the case which transaction gets mined is up to chance, so much
> of the time you'll get away with a double spend. We don't yet have a
> mechanism to propagate double-spend warnings, and funny enough, in the
> case of a single txin transaction the double-spend warning is also
> enough information to allow miners to implement replace-by-fee.
>
>
> So I'm offering 2BTC for anyone who comes up with a nice and easy to use
> command line tool that lets you automagically create one version of the
> transaction sending the coins to the desired recipient, and another
> version sending all the coins back to you, both with the same
> transaction inputs. In addition to creating the two versions, you need
> to find a way to broadcast them both simultaneously to different nodes
> on the network. One clever approach might be to use blockchain.info's
> raw transaction POST API, and your local Bitcoin node.
>
> If you happen to be at the conference, a cool demo would be to
> demonstrate the attack against my Android wallet. I'll buy Bitcoins off
> of you at Mt. Gox rates + %10, and you can see if you can rip me off.
> Yes, you can keep the loot. :) This should be videotaped so we can put
> an educational video on youtube after.
>

Isnt it potentially inviting trouble by encouraging people to insert double
spends into the block chain?

Sure, zero conf isnt 100% safe, we all know that.

But neither is the postal service.  Doesnt mean we should be going around
promoting the creation of tools to go into people's maiilboxes and open
their letters!


>
> --
> 'peter'[:-1]@petertodd.org
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>
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