Darren New:
If I give you a dollar for an online newspaper and the newspaper never gets to me, or I give you $50 for a textbook and the textbook never shows up in the mail weeks later, who do I go to to get my money back?
This is a bad-case scenario, since it involves long delay and delivery of goods that, unlike information, have a nontrivial marginal cost to the merchant. These both give the merchant incentive to skip the delivery step. For this kind of business, there are several possibilities, none of which is mature enough to have actually been deployed yet (which is why ecash is currently aimed at small, immediately delivered goods and services). * Escrow services, which take responsibility for delivery each way (and develop a public reputation for reliably doing this). This has the value that it still allows the parties to be mutually anonymous (although additional tools are needed to actually have strongly anonymous connections, the payment/delivery protocol doesn't preclude it). * Ripped bill protocols might be able to substitute for escrows. (these are quite esoteric, but can again be hidden behind a nice metaphor). * Deal only with a jurisdictionally reachable merchant and hope the law is on your side (often not an available solution on the global Internet, but usually assumed by identified payment schemes, so it's a reasonable fallback from that point of view). For smaller transactions with rapid delivery times, complaining loudly and publicly on Usenet will soon put the business out of it. Receipts will give such complaints more credibility, and will also allow the clearing agent to credibly get involved. (Obviously in these cases anonymity is lost for a particular transaction, but unlinkability with one's unchallenged transactions remains). Finally, in a few markets the value add of confidentiality is enough to outweigh the risks for even large transactions. Nick Szabo szabo@netcom.com