An enhanced heterogeneous public key searchable encryption scheme supporting multiple keywords

Searchable encryption (SE) technology allows users to use keywords to retrieve encrypted data and ensure that useful plaintext information about encrypted data will not be disclosed. For a secure SE scheme, if it is able to meet the multi-trapdoor privacy (MTP), the security will be improved compared with the traditional SE scheme. However, there are few searchable encryption schemes that can meet the requirements of MTP. In addition to the security of the SE scheme, we should also strive to improve its practicability. Nowadays, many existing SE schemes use a single keyword to generate the keyword ciphertext and trapdoor for retrieving ciphertext, which will greatly reduce the accuracy of the search result. Another phenomenon deserves our attention. In recent years, public key cryptosystems such as certificateless cryptography (CLC) and public key infrastructure (PKI) have been widely used. If a SE scheme satisfies heterogeneity means that both sides of communication parties do not need to restrict the use of the same cryptosystems, the practicability of this scheme will be improved. Therefore, we propose a heterogeneous SE scheme that provides MTP. The new scheme supports multi-keyword search and allows the sender and receiver to be worked in different cryptosystems. Furthermore, it would obviously be impractical to use the same cryptographic system parameters between heterogeneous systems, so the communication parties in our scheme operate in different cryptosystems with different cryptographic system parameters. With the use of the random oracle model (ROM), we demonstrate the security of the proposed scheme, and we show the excellent performance of the proposed scheme at the end of the article.