Privacy-Preserving Bilateral Multi-receiver Matching with Revocability for Mobile Social Networks

Mobile social networks (MSNs) offer convenient and ubiquitous services to expand social circles, share information, etc. These services require strict security measures to prevent the spread of deceptive content, misleading information, and malicious behavior. Achieving bilateral access control, message confidentiality and authenticity, and identity privacy can establish a positive network environment. Identity-based matchmaking encryption (IB-ME) with all the above features is a promising cryptographic primitive for MSNs. However, IB-ME can only specify one receiver. To share data with multiple users, the sender needs to encrypt the same message many times, resulting in higher frequencies of communication. Moreover, in multi-receiver scenarios, revocation of decryption permission may be necessary due to the possibility of malicious behavior, organization changes, or discontinuing subscription services. To our knowledge, no cryptographic primitives have been developed that satisfy these requirements. To address these challenges, we introduce the concept of revocable multi-receiver IB-ME and formalize its syntax and security definitions. We propose a revocable multi-receiver IB-ME scheme that provides privacy and authenticity in the random oracle model. Our evaluation demonstrates that it is efficient, and the sizes of system parameters and secret keys are independent of the number of receivers and revoked receivers.