Search with privacy-preserving guarantee has been a critical issue for commercial cloud storage. Data owners outsource a large number of encrypted sensitive data to cloud and allow data users to search and retrieve encrypted data in cloud. Recently, Cao et al. [1] proposed a scheme to enable multi-keyword ranked search over encrypted data. In this paper, we focus on practical factors and incremental update in cloud.
We utilize document replication and partition with one-to-many order preserving encryption to achieve privacy-preserving guarantees. We also introduce an index structure to provide efficient incremental update. Under a reasonable practical situation, the proposed scheme is more efficient than previous works and has lower communication overhead.