A Searchable Encryption Scheme Based on Lattice for Log Systems in Blockchain

With the increasing popularity of cloud storage, data security on the cloud has become increasingly visible. Searchable encryption has the ability to realize the privacy protection and security of data in the cloud. However, with the continuous development of quantum computing, the standard Public-key Encryption with Keyword Search (PEKS) scheme cannot resist quantum based keyword guessing attacks. Further, the credibility of the server also poses a significant threat to the security of the retrieval process. This paper proposes a searchable encryption scheme based on lattice cryptography using blockchain to address the above problems. Firstly, we design a lattice-based encryption primitive to resist quantum keyword guessing attacks. Moreover, blockchain is to decentralize the cloud storage platform's jurisdiction of data. It also ensures that the traceability of keyword retrieval process and maintains the credibility of search result, which malicious platforms are prevented as much as possible from deliberately sending wrong search results. Last but not least, through security analysis, our proposed scheme satisfies the credibility and unforgeability of the keyword ciphertext. The comprehensive performance evaluates that our scheme has certain advantages in terms of efficiency compared with others.