SaTC: CORE: Small: Towards Practical Homomorphic Encryption: From Algorithms to System Design

Cloud computing has enabled individuals and organizations to delegate complex computations to external servers, which helps enhance scalability and reduce the need for local computational resources. Despite its significant advantages, cloud-based computation raises serious concerns about data privacy and security, especially when handling sensitive information. Homomorphic encryption (HE), which enables computations directly on encrypted data, provides a powerful approach to addressing these concerns. However, current HE schemes face major limitations in multi-user environments, such as limited support for dynamic participation, vulnerability to malicious users or servers, and high computational and communication overhead. This project will develop a novel threshold homomorphic encryption scheme that avoids the need for trusted setups, maintains constant cipher-text size regardless of the number of users, and supports asynchronous operations. The research will also include the development of protocols that ensure security in the presence of malicious clients and servers, support variable threshold access levels among users, and incorporate hardware-based security mechanisms to further enhance performance. These innovations will be applied to real-world scenarios such as federated learning and heavy hitter detection, with resulting tools implemented in a publicly available software library. The project will contribute to both the theory and practice of secure multiparty computation, offering broader impact across privacy-preserving data analysis, cybersecurity, distributed systems, finance, and healthcare. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.