Verifiable Conjunctive Keyword Search with Certificateless Searchable

Certificateless encryption solves the problems of key escrow in identity-based cryptography (IBC) and certificate management in traditional public key cryptography (PKC). This paper proposes a new verifiable certificateless public-key encryption scheme based on the conjunctive keywords, which can transfer files without using secure channels. The new authentication process developed in the scheme ensures the secure transmission of encrypted files in the open channel. At the same time, combining the conjunctive keyword into the scheme has the advantage of narrowing the scope of the query file and locating the file we need quickly and accurately. Furthermore, the strong security of our scheme is further analyzed and proved: in the random oracle model, the double indistinguishable characteristics of ciphertext and trapdoor are satisfied. We compared with other schemes in terms of performance analysis. Experiments show that the execution time and key size of our scheme can be reduced by a certain percentage in the Encryption, Trapdoor, and Test phases, which indicates that the structure of this scheme is more concise and has better security.