A New Research on Verifiable and Searchable Encryption Scheme Based on Blockchain

Abstract

Cloud storage attracts more and more individuals and enterprises to outsource and store data on cloud servers due to its advantages of high efficiency, speed, low economic cost and on-demand access. Due to privacy requirements, data files need to be uploaded after being encrypted. Current searchable encryption technology enables retrieval of encrypted data, but lacks verification of searched results. In response to the above problem, this paper proposes a new searchable encryption scheme based on blockchain, which supports multi-keyword ranked search together with verification of searched results. Concretely, the scheme first encrypts the data and uploads it to the cloud server, then builds the index via blockchain. By calling the smart contracts to execute the search algorithm, the search result is returned to the user and the hash value is verified, which ensures the integrity and accuracy of the searched result. Secondly, by combining the vector space model and BM25 model to construct the index and query of encrypted data, the ranked search for multiple keywords is realized, in which the keyword balanced binary tree index is established to improve the retrieval efficiency. Experimental results show that the improved scheme has higher search accuracy while ensuring retrieval efficiency.