Privacy-Preserving Searchable Encryption Scheme Based on Public and Private Blockchains

While users enjoy the convenience of data outsourcing in cloud, they also face risks modification and private information leakage. Searchable encryption technology can perform keyword searches over encrypted while protecting their privacy guaranteeing integrity by verifying search results. However, some associated problems are still encountered, such as low efficiency verification uncontrollable query Accordingly, this paper proposes a Privacy-Preserving Encryption (PPSE) scheme based on public blockchains. First, we store an index blockchain corresponding documents to blockchain. The located through index. This method reduce storage overhead blockchains, improve transaction execution security stored data. Moreover, adopt smart contract introduce secondary access control mechanism restrict users' authorization for purpose correctness verification. Finally, analysis experimental results indicate that compared with existing schemes, proposed not only but guarantee query.