MuseME: Multi-User Secure and Efficient Matchmaking Encryption for Mobile Devices

Data sharing technology plays an important role in sharing information on mobile devices, ensuring that users can preserve their privacy while guaranteeing secure data transmission. Matchmaking encryption is a novel cryptographic primitive that provides bilateral access control to maintain user trust and data integrity. However, this primitive faces a challenge in terms of achieving secure multi-receiver construction. In a multi-user environment, users need to encrypt the data many times, resulting in inefficiencies under this approach. To address this challenge, we focus on the underlying construction of identity-based broadcast matchmaking encryption (IBBME). This paper presents a new IBBME construction with $\textsf {DBDH}$ and $q\text {-}\textsf {SDH}$ assumptions under the standard model. Specifically, we propose a new approach that abandons the generalized transformations that already existed previously in multiple receivers. Specifically, we adopt the “two-level” method to guarantee privacy and authenticity, where the identity-based broadcast encryption (IBBE) level guarantees privacy, while the signature level guarantees authenticity. In addition, we present a strict security proof, which shows that our construction satisfies privacy and authenticity exactly. Moreover, we compare the existing ME constructions with our construction through theoretical and performance analysis. The analysis shows that the ciphertext size in our construction can be reduced to be independent of the number of receivers, which is more efficient.