The fast-growing smart meter installation enables utility providers to better track and manage the electricity use of end customers. However, the adoption of smart meter faces several challenges. In particular, collecting fine-grained electricity usage data raises privacy concerns by end customers; and the possibility of data manipulation by malicious customers threatens the data integrity for utility providers. In this article, a tampering-proof and privacy-preserving smart metering method is proposed. The proposed work consists of a new secure multi-party computation method to protect customer privacy and detect malicious data manipulation during real-time data aggregation of smart meter applications. Theoretical analysis proves that privacy preservation for customers and data tamper-proof for utility providers can be guaranteed. Experiments using real-world data demonstrate that the proposed work significantly improves the computation efficiency over a state-of-the-art homomorphic encryption based privacy-preserving smart metering approach, with minimal communication and storage overhead.