QCSAS: A Quasi-Constant and Synchronized Aggregate Signature Scheme for AMI Networks

Smart grids must safeguard their critical infrastructures against both physical and cyber attacks. Therefore, real-time operation and cybersecurity are two fundamental requirements for smart grid systems. AMI (Advanced Metering Infrastructure) is a critical part of the smart grid that specifically deals with the measurement, collection, and analysis of electricity usage data. Digital signatures help prevent data tampering and ensure cybersecurity during AMI communications. However, as the number of smart meters and transactions in an AMI network increases, deploying digital signatures can lead to communication delays. This paper designs a quasi-constant and synchronized aggregate signature scheme (QCSAS), which can protect usage data without hash functions. The QCSAS scheme simplifies the synchronized aggregate signatures, and is proved secure against chosen message attacks in the random oracle model. The QCSAS scheme incorporates the features of synchronized aggregate signatures, such as the constant aggregate signature size, thereby minimizing the data management system’s storage space. Furthermore, the length of usage data does not exceed 12-bit, in compliance with existing governmental standards. The computational cost of multiplying a 12-bit integer is negligible compared to other cryptographic operations. Thus, the verification cost of the QCSAS scheme remains quasi-constant.