© 2017 Over the last few years, we have seen the emergence of a wide range of Smart Grid architectures, technologies, and applications made possible by the significant improvements in hardware, software, and networking technologies. One of the challenges that has emerged in the Smart Grid environment is the privacy of Smart Grid users. Although several privacy-preserving techniques have been proposed recently for the Smart Grid environment, many of them suffer from high computation and communication costs, different types of attacks, and the use of complex key management schemes. To address these drawbacks, we propose an efficient, lightweight privacy-preserving data aggregation approach that makes use of symmetric homomorphic encryption and Diffie–Hellman (DH) or Elliptic Curve Diffie–Hellman (ECDH) key exchange methods. In contrast to previously proposed privacy-preserving schemes for the Smart Grid, we demonstrate the superiority of our proposed approach in terms of its low transmission and message overheads, and resiliency against a wide range of session key attacks, and ability to maintain data integrity against unauthorized modification or data forgery and to ensure authenticity of smart meters’ data.