At 10:47 PM 12/06/94, Paul Ste. Marie wrote:

Isn't there a problem with net-based distribution of ecash? It would seem that Eve could intercept the ecash and spend it first. Encrypted email return of the ecash would seem to violate the anonymity of the ecash. Some sort of one-time encrypted return address would seem to be necessary, but better yet would be a vending machine that took a floppy disk and some currency and stuck the ecash on the floppy.

Diffie-Hellman would seem appropriate here. Look it up in Schneier. Vending machines seem a good idea too, but one unlikely to develop any time soon. Or possibly ever, if the net becomes so prevalent that no one would think of doing anything offline that could just as well be done online.