Research On Secure Network Coding Against Pollution Attacks

With the rapid development of computer technology, network communication technology is used in all aspects of people’s social life. Work and life becomes more and more dependent on a large number of network communication, and the demands of data transmission is growing quickly. However, the bandwidth of the network is limited, and how to transfer data more efficiently has become a major problem cannot be ignored. Meanwhile, the transmission mode of traditional network is difficult to achieve the maximum of the multicast network, but network coding technology brings another thinking way and then makes multicast network to achieve the maximum flow possible.On the other hand, there is a very serious security problem in network coding technology. Because network coding needs the intermediate nodes to encode the data, it is extremely vulnerable to pollution attacks. A small amount of pollution can lead a large number of legal messages to be polluted, which not only wastes the bandwidth, but also may make the message decoding of the receiving nodes error. Pollution attacks has become a huge obstacle to limit the wide range of applications of network coding, and secure network coding against pollution attacks has become an important aspect of the current research on network coding.This thesis focuses on the secure network coding against pollution attacks, and proposes two secure network coding scheme based on different verification ideas.Firstly, this thesis study a liner subspace based signature scheme, and analyzes some improvement ways and their advantages and disadvantages, and then propose a new secure network coding scheme based on the linear subspace signature. This scheme has the almost same efficiency of signing and verifying, and its security has been ensured. It does not need to update all the keys for each signature, and greatly reduces the length of the linear subspace signature.Next, this thesis studies a lightweight homomorphic signature scheme, analyzes its advantages and disadvantages, researchs an adaptive mechanism for message verification, and then proposes a new adaptive network coding scheme based on the homomorphic signature. By introducing the idea of adaptive verification, this scheme allows that the homomorphic signature can be more effectively applied to the actual network, with the improved verification efficiency. And, there are some improvements compared with the previous adaptive mechanism.