Robust authenticated encryption scheme with message linkages

An authenticated encryption scheme is a message transmission scheme, which sends messages in a secure and authentic way. In large message transmission, traditional authenticated encryption scheme has the disadvantage that the communication and the computation costs are too high. In 2002, Tseng-Jan proposed an efficient authenticated encryption scheme with messages linkage; that is, only a random number was used and the communication costs and the computational complexity were better than previously proposed schemes. The current paper, however, points out that Tseng-Jan's scheme suffers from serious security faults such that any adversary can easily forge valid signature blocks and pass the receiver's verification, and the scheme does not provide forward secrecy and non-repudiation. We also propose an improvement to the scheme to overcome the weaknesses.