A Research On Anti-wiretapping Secure Network Coding

Changing the "storage-and-forward" mode in the traditional network nodes, network coding makes the intermediate node encoding the received data. Therefore, network coding enable transmission rate in multicast network up to the maximum flow.In the communication network, eavesdroppers grab the message by tapping the network channel. Intermediate nodes receive and encode the message in network coding, and then send the coded message to the downstream link. The transmitted message is obfuscated in the network. Thus, network coding can improve the security of network transmission.Wiretapping is one of the main threats in the network. This thesis studies the anti-wiretapping network coding. This thesis describes two types anti-wiretapping network coding based on cryptography, the anti-wiretapping network coding of encrypting source message and encrypting coding coefficients.The main contributions of the thesis are as follows.1. This thesis proposes a higher anti-wiretapping secure scheme based on all or nothing transforms. It is a source message encryption based anti-wiretapping network coding. Firstly, this scheme processes the m—2dimensional message before using the m dimensional message. This process is similar to one-time pad in cryptography and makes the m—2dimensional message with a different random value. Then, this scheme uses AONT dealing with the m—1dimensional message. In the end, the last two dimensional message are encrypted. If the eavesdropper cannot get the key, he cannot recover the last two dimensional source messages. Therefore, the eavesdropper cannot get any source message.2. This thesis proposes two anti-wiretapping secure schemes based on secure practical network coding. One is the lower overhead of encryption:another is the lower bandwidth overhead. They are coding coefficients encryption based anti-wiretapping schemes. The former uses AONT dealing with the pre-coding coefficients and encrypts only one dimension pre-coding coefficient. This scheme reduces the computational overhead of the source node. The latter processes the source message with using a matrix of vandermonde and encrypts a symbol of one unit pre-coding coefficient achieving anti-wiretapping. This scheme reduces the bandwidth overhead of the transmission network.