A Generic Construction of Homomorphic MAC for Multi-File Transmission in Network Coding

—Homomorphic message authentication codes (MAC) have been proposed to thwart pollution attacks in network coding. The existing schemes mainly are based on the vector inner product or trace function over finite fields. Recently, Wang and Hu presented a generic construction of homomorphic MAC scheme based on linear mapping over finite fields which is an excellent abstract of the vector inner product and the trace function. However, their construction can only be used for single-file transmission. In this paper, we convert their scheme into a new one that supports multi-file transmission. Moreover, our scheme needs shorter key when one wants to achieve the same security as that of Wang et al.