Also, E-commerce applications that require payment and delivery present two new
problems. While digital cash has been used for some applications, it is still not widely accepted. Also, today's delivery services
require an address to which merchandise can be shipped. It is conceivable that privacy concerns may result in the reemergence of
digital cash or "single-use" credit card numbers and the creation of trusted delivery services that accept deliveries to a one-time
pseudonym, but these services do not yet exist.