Secure Data Dissemination In VANETS Based On Network Coding

Vehicle Ad Hoc Network is widely used including safety message warning, resource sharing, music downing and etc, which attacks many research. However the nodes in VANETs travel fast. The connections are short. And the network structure changes quickly. The density of the nodes in different areas is quite different. They all lead to the low quality in communication. Network coding can use the network resources effectively, balance the network load and make the data dissemination more reliable, which is widely used in data dissemination in VANETs. Therefore, the data dissemination in VANETs based on coding becomes a hot topic.Intermediate nodes in network coding will code the received blocks, which makes network coding more sensitive to pollution attack. Many researchers proposed linear subspace signature scheme to defend pollution attack. The scheme is simple, but still has many problems, such as the long-size signature, the coarse validating and etc. In this paper, we modify the linear subspace signature scheme and propose a secure dissemination protocol. Adopting the padding skill and generation dividing skill, we reduce the length of the signature making it easy to transfer. And all coded packets in a generation have the same signature. So the signature can validate the every packet. With DSRC technology, the signature is transferred to neighbors before the coded packets, which solves the transfer problem.We use the Network Simulator 2 and VanetMobiSim to verify the effectiveness of our protocol. And we analyse the storage overhead and the time complexity of the protocol. From the delay in the dissemination, dissemination speed and throughput, the number of packets dropped, we judge the performance of the protocol. According to the results, pollution attack will dramatically lower the network performance, even makes the network paralysis. Compared to other schemes, our protocol has faster dissemination speed, lower dissemination delay, larger dissemination throughput and smaller packets dropped.