Variable-security-level secure network coding

In network coding theory, when wiretapping attacks occur, secure network coding is introduced to prevent information from being leaked to adversaries. In practical network communications, secure constraints vary with time. How to effectively deal with information transmission and information security simultaneously under different security-levels is introduced in this paper as variable-security-level secure network coding problem. In order to solve this problem efficiently, we propose the concept of local-kernel-preserving variable-security-level secure linear network codes, which have the same local encoding kernel at each internal node. We further present an approach to construct such a family of SLNCs and give an algorithm for efficient implementation. This approach saves the storage space at both source node and internal nodes, and resources and time on networks. Subsequently, an example is given to illustrate our constructive algorithm. Finally, the performance of the proposed algorithm is analyzed, including the field size, computational and storage complexities.