A fair non-repudiation security protocol with off-line TTP

A fair non-repudiation security protocol can provide non-repudiation proof for two parts of the exchange at the same time, or both get nothing. But many protocols performed weak in logical analysis. In this paper, a group of new protocols(with 3 sub-protocols) with off-line The Third Party(TTP) are presented. We analysis them with a new Kailar logic analytical method. Finally, the proposed protocols are proved to satisfy the fairness, non-repudiation and efficiency from the theory. And they propose some protections for the networks which have merely physical securities such as Internet, and provide some realistic reference values to the establishment of security mobile ad-hoc networks.