SFPDA: Secure Fault-Tolerant and Privacy-Enhanced Data Aggregation Scheme for Smart Grid Without TA

With the rapid development of smart grids (SGs), designing a data aggregation scheme that ensures both data availability and privacy security has become an urgent necessity. Particularly, considering the potential failures of smart meters (SMs), ensuring fault tolerance in data decryption has become a significant challenge in the design. Recently, Wu et al. proposed a fault-tolerant data aggregation scheme FPDA that excels in privacy protection and fault tolerance. However, like most data aggregation schemes in SG, FPDA relies on a trust authority (TA), which is difficult to find in real-world scenarios. Furthermore, the scheme is vulnerable to delay attacks, posing a risk of individual meter privacy leakage. Therefore, this article first designs an attack for FPDA scheme which capable of achieving 100% plaintext recovery when users delays, with an attack time of only 518 ms. Subsequently, we propose a secure fault-tolerant and privacy-enhanced data aggregation scheme for SG without TA (SFPDA). By employing multiuser Diffie-Hellman key exchange (MDHKE), we eliminate the need for a trusted third party, Additionally, we utilize dual masking to resist delay attacks. We conduct a security analysis of the scheme, which demonstrates that SFPDA can resist delay attacks and provide enhanced privacy protection. Finally, experimental results show that SFPDA reduces encryption time by approximately 40% and decryption time by approximately 83.3%, while offering better fault tolerance, making it more suitable for grid environments where the number of residents remains constant, but the failure rate of meters fluctuates.