Null Keys: Limiting Malicious Attacks Via Null Space Properties of Network Coding
The performance of randomized network coding can suffer significantly when malicious nodes corrupt the content of the exchanged blocks. Previous work have introduced error correcting codes by generalizing some well known bounds in coding theory. Such codes are based on introducing redundancy in space domain. Other approaches require the use of homomorphic hashing functions, which are computationally expensive. In this paper, the authors present a novel and computationally efficient security algorithm, referred to as Null Keys, to detect and contain malicious attacks based on the subspace properties of random linear network coding. The participating nodes verify the integrity of a block by checking if it belongs to the subspace spanned by the source blocks.