Multi-Vendor PayWord with Payment Approval

摘要

One of the most well known micropayment scheme is the PayWord scheme. It is designed to be one-vendor, so if we apply it for multiple vendors, it does not protect against double spending. We extended the PayWord scheme, it supports shopping at multiple vendors without an on-line broker or an on-line secure database. The proposed credit-based system uses one hash chain, hence besides the secret signature key only the seed and a random value should be securely stored. Our scheme is analyzed in applied pi calculus, we prove that it fulfills payment approval, secure payment authorization, secrecy of payment information and unreusability.