Abstract: With the rapid development of cloud storage technology,the existing cloud storage architectures and storage patterns are presented in a static way to users and attackers,making the data face more security threats.This paper proposed a duplicate dynamic storage scheme based on Random Binary Extension Code (RBEC).The scheme uses a network code to store the data blocks on the cloud nodes.The data information of the nodes can be changed randomly and time-varying by the node data transformation based on Binary Random Extension Code.By changing the attack surface,it can increase the complexity and cost of the attacker,reduce the vulnerability exposure and the probability of being attacked,and improve the flexibility of the system.The theoretical analysis and simulation results show that the coding computation time cost of this method is not high in the whole dynamic transformation,and its main time cost is the transmission of data encoding blocks between nodes.In addition,the performance of this method was compared with the general regenerative code mimetic transformation schemes.Because of the characteristics of REBC,that is,the probability of the regenerated encoding matrix satisfying the MDS property is almost 1,the performance overhead of this method is better than that of general regenerative code which may transform many times in the encoding process.

Key words: Attack surface, Moving target defense, Network coding, Random binary extensive code, Replica storage