A securely fair non-repudiation protocol with TTP load lightly

With the development of electronic, the requirements of the electronic commerce protocols are higher. Non-repudiation is an important property of electronic commerce protocols. The non-repudiation services mainly include the non-repudiation of origin, nonrepudiation of receipt, non-repudiation of submission and non-repudiation of transport. Generally the nonrepudiation service evidence is provided by nonrepudiation protocol. In this paper we discuss nonrepudiation services, non-repudiation tokens and related applications, fair non-repudiation protocols. We compare and analyze the related non-repudiation protocols, such as FNP, NRMPR, CEM, CMP1, CMP2, FNRP, in the following aspects: (1) transfer messages in a run; (2) depend on mail relay; (3) generate NROT after a run; (3) generate the NRRT after a run; (4) TTP is a delivery authority; (5) TTP generates the NROT; (6) TTP generates the NRRT; (7) need RSA; (8)need DES; (9) fairness; (10) TTP knows message; (11) message confidentiality; (12) TTP load lightly. Secondly we propose a securely fair non-repudiation protocol, which transports less data, has better confidentiality of message, lighter load of TTP, better fairness. Thirdly we analyze its non-repudiation with the authentication logics framework introduced by Kessler & Neumann and fairness.