On Wed, Nov 23, 2005 at 08:31:46PM -0500, R. A. Hettinga wrote:
At 1:54 AM +0100 11/24/05, Daniel A. Nagy wrote:
spot-checks
This also is not new.
We were discussing this in relation to millidollar streaming cash at least 5 years ago. We've discussed this privately, and on public mail lists, with the likes of Nicko van Someren, Ron Rivest, Adi Shamir, and Mark Manasse.
Those two ideas are not new, and I know that. What is new is the publication of a signed transaction log by the issuer; the splitting of public and private information in such a way that allows for transparent issuer governance without invading privacy. In the electronic cash literature, governance issues have rarely been raised, let alone properly addressed. Systematic treatment of transparent governance in digital payments begun, AFAIK, with the research of Ian Grigg. For a (long) while, both Ian and I were convinced that transparent governance and blind signatures don't mix well. It was cyphrpunk in this discussion, who pointed out the essential similarity between the proto-coin in chaumian schemes and the cryptographic challenge in my paper. It came up in the context of invoicing, but -- as we recently realized -- it can also be used for governance, when coupled with these two old ideas. In short, the basic idea is for the issuer to _publish_ in an undeniable manner the responses (with some additional info) to exchange requests instead of sending the information back to the requesting party using a private channel. I do think (in agreement with several reviewers of my work) that the setup proposed in the discussed paper, where the communication between the users and the issuer is such that the issuer's responses to users' requests are broadcast and archived in public records is novel.
Even the delineation between universally-checked blind-signature "notes", and stochastically tested "coins" is at least five years old and has been discussed on most of the usual email lists.
We use "notes" and "coins" in a completely different sense. There are no blind signatures in notes; notes are traceable to some extent, just like IRL. Cheers, -- Daniel