On Wed, May 15, 2013 at 07:38:27AM -0400, Peter Todd wrote:
> 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.

Oh, and while we're at it, a good starting point for your work would be
Gavin's spendfrom utility in the contrib/spendfrom directory in the
Bitcoin-QT respository.

Also please do keep in mind that it's much better for the community if
an attack is demonstrated first, followed by releasing the code some
time later.

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