Multi-authority (t,n) threshold identity-based matchmaking encryption

In this work, we propose a Multi-authority (, ) t n Threshold Identity-based Matchmaking Encryption (MAT-IBME) scheme under the standard assumptions in the standard model, in which multiple authorities share the secrets for constructing users’ secret keys. The MAT-IBME scheme satisfies the requirement that the receiver can only get the decryption key with the "joint permission" of t ones among n authorities. Meanwhile, only when the identity of the sender satisfies the policy proposed by the receiver, and the identity of the receiver satisfies the policy proposed by the sender, the receiver can decrypt correctly. In this way, the scheme realizes precise ciphertext access control when deployed in cloud services. Security and performance analysis shows that MAT-IBME not only achieves authenticity security but also system-level robustness when no less than t authorities are alive in the system.