Who wants to be a millionaire

[Nomen Nescio]

> > Bin laden demolitions has authorised me to offer you a once in a lifetime deal.
> > 1million dollars untracable digital cash will be paid to an account/s of
> > your choice
> > for enough intelligence to proceed with further superpower implosions.
> > Insider info preffered but not essential,leave packet online in freenet
> > transient node...
>
> Is there any way to solve this transaction problem without a
> mutually-trusted third party?

It would be necessary to reduce the criteria used by the purchaser into
algorithmic form.  Write a program which would take the data and produce
a yes/no answer.  The program has to be such that even if the seller knows
the program, he can't produce fake data which would fool the program.

Then the seller can commit to his data and produce a zero-knowledge
proof that the committed data satisfies the criteria in the program.
This can be done reasonably efficiently for moderate sized programs.
It will leak no information about the data other than the yes/no answer
from the program.