Fault-Tolerant Privacy-Preserving Data Aggregation for Smart Grid

In smart grids (SG), data aggregation is widely used to strike a balance between data usability and privacy protection. The fault tolerance is an important requirement to improve the robustness of data aggregation protocols, which enables normal execution of the protocols even with failures on some entities. However, to achieve fault tolerance, most schemes either sacrifice the aggregation accuracy due to the use of differential privacy or substitution strategy or need to rely on an online trusted entity to manage all user blinding factors. In this paper, a (k,n) threshold privacy-preserving data aggregation scheme named (k,n)-PDA is proposed, which reconciles data usability and data privacy through the BGN cryptosystem and achieves fault tolerance with accurate aggregation using Shamir's secret sharing without any online trusted entity. Besides, our scheme supports the efficient changing of users' membership. Specifically, the dynamic secrete key is distributed tonsmart meters (SMs) through the threshold secret sharing algorithm. Whenkor more meters participate in the aggregation, the data service center (DSC) can reconstruct the key to compute the aggregate results, and less thankSMs cannot recover the key. Thus, our solution still works functionally even if up ton-kSMs fail; also, it resists attacks from the collusion of less thankSMs. Moreover, system and performance analyses demonstrate that our scheme achieves privacy, fault tolerance, and membership dynamics with high efficiency.