At 12:09 PM +0300 4/16/01, Sampo Syreeni wrote:

On Sun, 15 Apr 2001, Tim May wrote:

...

The canonical example is of an escrow agent handling a deposit by a buyer of an untraceable killing. When the killer presents the appropriate form of evidence that this happened, and that he or she was "there" (*), the escrow holder pays.

True. This is a case where Esther *can* verify that Bob's goods aren't tainted: there's a body and it's common knowledge. Try this in case the hit must be kept a secret. And how about trade in KP, and other sensitive information? Since anonymous cash is likely to develop online, if at all, I think infotrade is an important part of the picture.

Sure, I agree that information trade (bits, not bodies) is important. I gave the example I did to show how in at least some cases it is easy to see how a third party escrow agent can work and still maintain mutual untraceability between Alice, Bob, and Esther. For information trading, there are many kinds of information. In some cases, the information _might_ be so valuable as to induce Esther to defect (i.e., to steal). I think this is the case you presented, where the escrow agent should not be able to see the plaintext of the information being traded, which means Bob the Buyer may _claim_ that what he received from Alice was junk and Esther cannot decide whether to release the funds. However, many other forms of information sales are amenable to straightforward escrow use. The credit data base example. To first (and probably second, third) order, it doesn't matter if Esther can see specific credit queries, as she cannot build up the complete data base from isolated queries. That is, the bought information has presumably value for Bob the Buyer, but not much for Esther. (As in all escrow or surety bond calculations, the issue is whether a particular transaction is worth it for Esther to defect, to skip out and "burn" her own reputation. Between Esther not being able to cash the digital check and sparseness issues, and her estimated long term revenue stream, these all enter into the equation.) As I have said, the precise form the protocols will take for various kinds of information markets is not fruitful at this time. Structures will evolve. What's important is to realize that the means already exist (Blacknet showed this, trivially) to move transactions into cypherspace. Details will evolve. --Tim May -- Timothy C. May tcmay@got.net Corralitos, California Political: Co-founder Cypherpunks/crypto anarchy/Cyphernomicon Technical: physics/soft errors/Smalltalk/Squeak/agents/games/Go Personal: b.1951/UCSB/Intel '74-'86/retired/investor/motorcycles/guns