Revocable identity-based matchmaking encryption in the standard model

Identity-based Matchmaking Encryption (IB-ME) is an extension notion of matchmaking encryption (CRYPTO 2019), where a sender and a receiver can specify an access policy for the other party. In IB-ME, data encryption is performed by not only a receiver identity but also a sender's encryption key. Nevertheless, previous IB-ME schemes have not considered the problem of efficient revocation. Hence, the authors introduce a new notion of revocable IB-ME (RIB-ME) and formalise the syntax and security model of RIB-ME. In particular, the authors give an effective and simple construction of RIB-ME in the standard model, whose security is reduced to the hardness of decisional bilinear Diffie—Hellman problem and computational Diffie—Hellman problem. In addition, the authors show two extensions of our RIB-ME scheme to consider chosen-ciphertext security and forward privacy.