By the way, I think the problem of double spending is a risk that can be managed, like the risk that a bank takes when a check is bounced. Exactly. There is some cost incurred by attempts to double-spend, no matter what the outcome. The costs are either direct, e.g. redemption of duplicated notes, or indirect. Indirect costs include the implementation of systems to get rid of double spending and the cost of dealing with rejected transactions when challenged. In any case, double spending creates costs. The culprit is identified, and it becomes a matter between the bouncee (however removed from the criminal transaction), the law, and the bouncer. Why does everyone think that the law must immediately be invoked when double spending is detected? Double spending is an informational property of digital cash systems. Need we find malicious intent in a formal property? The obvious moralism about the law and double spenders is inappropriate. It evokes images of revenge and retribution, which are stupid, not to mention of negative economic value. What is needed are techniques to prevent the possibility of double spending from taking down the system. These might include law, and hence also identity, but need not. What is the point of an anonymous system if identity is needed to make it stable? The contradiction here is enormous. The offline cash protocols suffer from this fatal design flaw, namely, anonymity for "good people" and identity for "bad people". Why invoke identity at all if you can do without it? Having a database of "spent money" is the primary technique for prevent direct costs from being a problem. So what is left are attempts to redeem multiple times the same note. They won't actually get redeemed, but if there's a negligible marginal cost for trying, well, then, some folks will try. One solution is clear and direct: charge for each redemption attempt. In that situation, multiple attempts get rejected, and the issuer is recompensed for the attempt. No morality need be invoked. There remains an issue as to the size of this redemption fee, which would have to be small. In order to optimize the transaction costs of charging this fee, a bank might be willing to accept identity in escrow for the transaction and to remove the fee for good transactions. Identity might be a pseudonym revealed after 10 bad attempts, say. This system removes the requirement for identity and substitutes it for an economic optimization based on identity. An anonymous depositor, however, can still use the system with zero risk to identity. Are there any non-proprietary, public sources of information on these legal and regulatory research efforts? Are there archives of the c'punks traffic on this subject that I can look at? The research efforts are basically my own, Hal's, and Perry's. There is no reference other than back traffic, which others can provide. Eric