A Lightweight Certificateless Multi-User Matchmaking Encryption for Mobile Devices: Enhancing Security and Performance

The technology for securely sharing data has grown extensively in recent years. Many users are willing to share their lightweight mobile device data via social networks or the cloud. A novel matchmaking encryption primitive was proposed in CRYPTO'19, whose potential for privacy protection and data sharing security was introduced. However, matchmaking encryption technology faces challenges in flexibly realizing critical functions, such as one-to-many non-interactive scenarios, no key escrow problem, stronger security, lightweight computation and low communication overheads for mobile devices, which impede their widespread application. To achieve the above functions, we present a lightweight certificateless multi-user matchmaking encryption (LC-MUME) for mobile devices, which enhances security flexibly and performance based on standard hard assumptions and low-consumption pairing-free technology, while also avoiding one-by-one encryption for each user. The proposed LC-MUME scheme enjoys minor computation and communication overheads in a one-to-many non-interactive certificateless cryptosystem. We prove that our scheme achieves indistinguishability-based chosen-ciphertext attack (IND-CCA) security, the existential unforgeability under a chosen message attack (EU-CMA) security and anonymity-CCA security under the random oracle model. Our LC-MUME scheme outperforms the state-of-the-art schemes regarding efficiency and flexibility, as demonstrated by the performance comparison and analysis, and therefore is a practical solution for resource-constrained mobile devices.