Short Ciphertext-Size Privacy-Preserving Aggregation Against Malicious Aggregators

A privacy-preserving data aggregation protocol plays a crucial role in safeguarding user privacy in smart grid systems. However, existing protocols often rely on an honest-but-curious aggregator and have higher communication overhead, which weakens their security guarantees and makes them impractical for real-world applications. The aggregator, as a legal entity within the system, poses a threat of engaging in active attacks like deletion and tampering. To address these issues, we introduce a novel privacy-preserving data aggregation scheme with a concise ciphertext length to thwart malicious aggregators. This scheme not only reduces communication overhead for each smart meter but also provides resilience against active attacks. Furthermore, the proposed scheme can withstand partial aggregation attacks and maintains a ciphertext length of only 320 bits. Detailed security analysis confirms the scheme's fulfillment of essential security properties. Experimental results demonstrate its superiority in computational complexity and communication overhead compared to other existing schemes.