On Thu, Oct 20, 2005 at 07:34:34PM -0400, R.A. Hettinga wrote:
At 12:32 AM +0200 10/21/05, Daniel A. Nagy wrote:
Could you give us a reference to this one, please?
Google is your friend, dude.
Before making unitary global claims like you just did, you might consider consulting the literature. It's out there.
With all due respect, this was unnecessarily rude, unfair and unwarranted. Silvio Micali is a very prolific author and he published more than one paper on more than one exchange protocol. I am actually familiar with some of his work on the subject. I was, however, specifically interested in which particular one did you have in mind. I can think of several exchange protocols that would do the job, though I don't particularly like them, because the infrastructure for carrying them out is not in place and they require more communication than is strictly necessary for obtaining a receipt. In general, I think that one should be very careful with piling up cryptographic operations and additional back-and-forth communication steps in a payment protocol, because it may easily render it unpractical. There are reasons why there are no cash-like digital payment systems, and it's not for the lack of trying (you know that better than anybody else in the world, I guess) or the lack of demand. Making it sufficiently simple is one of the most difficult challenges. -- Daniel