Timeliness optimistic fair exchange protocol based on key-exposure-free chameleon hashing scheme

In ESS2008, Yang et al. suggested a key-exposure-free chameleon hashing scheme, and it can be used to design signature and some other cryptography mechanism. In this paper, we construct a new timeliness optimistic fair exchange protocol based on this key-exposure-free chameleon hashing scheme. The new scheme does not require the use of interactive zero-knowledge proofs in the exchange phase. In our scheme, both parties can contact the trusted third party and settle the argument before the deadline. Moreover, the new scheme achieves fairness and timeliness.