Jointly padding for subspace orthogonality against tag pollution

Homomorphic Message Authentication Code (HMAC) is a low-complexity low-delay scheme for pollution detection is a Random Linear Network Coding (RLNC) enabled network. However, HMAC is vulnerable to tag pollution, in which an adversary node merely randomly modifies some MAC tags appended at the end of data packets. Existing tag pollution resistant solutions cause either high computation efforts long delay at relay nodes or substantial communication burden, or additional requirements such as synchronization at all nodes. In this paper, we combine the core ideas of two pollution detection schemes: “padding for orthogonality” and “Null key”, and propose a new pollution detection method by “jointly padding for subspace orthogonality” that is immune to tag pollution, remains low-complexity low-delay, low communication overhead, and no timing requirements.