Adaptation of proxy certificates to non-repudiation protocol of agent-based mobile payment systems

Non-repudiation of a mobile payment transaction ensures that when a buyer (B) sends some messages to a seller (S), neither B nor S can deny having participated in this transaction. An evidence of a transaction is generated by wireless PKI mechanism such that B and S cannot repudiate sending and receiving the purchase order respectively. The buyer generates a mobile agent which carries encrypted purchase order to the seller. This mobile agent is also issued a proxy certificate by the buyer; this certificate guarantees the binding relationship between them. One trusted third party acts as a lightweight notary for evidence generation. One advantage of this agent-based non-repudiation protocol is to reduce inconvenience for mobile clients such as connection time; it causes difficulty for fair transaction for mobile payments.