The characteristics of mobile agents make them ideal for electronic commerce applications in open networks.Security is a fundamental precondition for the acceptance of mobile agent systems.In this paper

we analyze the effective route protection based on mobile agents given by Domingo J.and point that the protocol has security threat:it is not against collusion of malicious hosts.After that

using hash function

a secure itinerary protection of mobile agents based on Merkle trees is presented.Its and computational cost are discussed in detail.The results show that our method not only satisfies all security properties but also keeps the characters of the protocol existed.Finally

Our idea is extended to protect flexible itineraries too.