Research On Coding Matrix Construction Of Multilevel Secure Network Coding Based On Information Theory

The routers use the store and forward mode to transfer the messages in the traditional network. In this mode, for the upper bound of capacity that Shannon proposed that based the theory of maximum flow minimum cut, the unicast rate of point to point can reach the upper bound. But multicast rate of point to multi-point can not reach the theoretical upper bound. Network coding uses the encode and forward mode to transfer the messages. As people research the network coding in-depth, using the network coding mode can not only reach theoretical upper bound,but also improve the security of network. While it can come out of the secure network coding. The current secure network coding exits two methods that information-theoretic security and cryptography security.Many scholars research the secure network coding theoretically in-depth. But more and more encoding scheme will be applied to the project and more clear the value of the construction methods of the encoding matrix. In the thesis, be based on the in-depth analysis of the network coding technology, we study how to construct the encoding matrix of the relay node. The thesis combines the multi-level network coding with the triangle matrix and proposes a multi-level secure network coding scheme(MSNC) based on the information-theoretic. The innovative work of the thesis has the following two points:For the demand of the security of the network environment, the thesis points out that the current encoding scheme of the relay node is to use the random linear network coding(RLNC) to generate the encoding matrix. But this method does not ensure that the resulting matrix must be full rank and affects the decoding rate. In the MSNC scheme, on the relay node, let the node that the degree is greater than or equal to2as coding node, using multi-level network coding can make the message encode mix better. The encoding nodes generate the full rank lower triangular matrix and the full rank upper triangular matrix randomly. Then we use their product as an encoding matrix, this scheme will ensure encoding matrix must be full rank, the receiving node can successfully decode the data.The thesis analyzes the MSNC scheme instantiated. At the same time, the simulation analysis shows that MSNC scheme can protect the security of data.