LAUSR

Recently, Esfahani, Mantas, and Rodriguez proposed a homomorphic message authentication code (MAC) scheme for the random linear network coding (RLNC) to resist tag pollution attacks (TPAs), and also presented the security analysis. As Esfahani et al. said, their scheme is based on the null space properties of Kehdi and Li, and the main contribution lies in adding the process of swapping when generating the tags for data packets. However, in this paper, we first point out that Esfahani et al.’s swapping technique is not essential for the TPA security, because the underlying non-swapping homomorphic MAC scheme has been secure against TPA and the process of swapping only improves the TPA security with a non-negligible factor. More importantly, we find that the security proof of Esfahani et al. is incorrect and misguided. In particular, according to Esfahani et al. suggestion, one should enlarge the number of neighbor nodes to reduce the probability of the TPA. However, this paper gives contrary suggestions in Esfahani et al.’s work by presenting the precise proof for the proposed homomorphic MAC scheme.