Abstract: In cloudbased singlekeyword searchable encryption schemes, cloud servers are not completely trusted, and the existing singlekeyword retrieval cannot accurately return search results. Therefore, a multikeyword searchable encryption scheme is constructed by using blockchain technology. Our scheme uses the symmetrical encryption algorithm to improve the encryption efficiency, takes advantage of blockchain technology to solve the problem of dishonest search in cloud server, and also improves the accuracy of search results based on multikeyword index structure. The scheme is proved secure against indistinguishably chosen keyword attack (INDCKA) under the random oracle model. Furthermore, the performance analysis shows that our proposals are secure and efficient.

Key words: searchable encryption, cloud storage, blockchain, distributed ledgers