SNKC: An Efficient On-the-Fly Pollution Detection Scheme for Content Distribution with Network Coding

Linear network coding (LNC) has attracted significant attention because it has the potential to achieve the throughput capacity of a network. However, transmission systems with LNC are vulnerable to pollution attacks in which normal packets will be corrupted by malicious relay nodes and participate in normal encoding process. The null keys based error detection schemes have been designed to efficiently defend against the pollution attacks, in which null keys is a set of vectors sent from source to relay nodes to verify the correctness of the coded packets. However, the existing Null Key based schemes either cannot efficiently distribute the null keys in large scale networks or defend against collusion attacks. In this paper, we design a Short Null Keys Compression (SNKC) scheme. It is designed to reduce the required amount of null keys distributed by the source, so as to defend against collusion attacks efficiently. Specifically, through the design of SNKC scheme, the size of linear space spanned by all null keys will be significantly reduced.