An efficient multi-user multi-keyword fuzzy search scheme over encrypted cloud storage

As more and more enterprises and individuals choose to outsource their encrypted private data to the cloud, Searchable Encryption (SE), which solves the issue of keyword-searching over encrypted data, is becoming much more important. To overcome typos and semantic diversity existing in query requests, fuzzy search is introduced to achieve a misspelling-tolerate search-supported encryption scheme. However, current schemes of fuzzy search over encrypted data not only bring in high computing and communication overhead in multi-user scenarios but also are unable to cover all kinds of error types under the premise of an effective accuracy. In this paper, we thus propose a multi-user multi-keyword fuzzy searchable encryption scheme. Specifically, we introduce the permuterm index to support multi-keyword wildcard search which can solve more kinds of misspelling with a higher degree of correctness. Moreover, by letting the cloud server re-encrypt indexes user encrypt, our scheme supports unshared-key multi-user fuzzy search, reducing users' computing overhead effectively and improving the level of privacy-preserving. The results of experiments demonstrate that, compared with existing schemes, our scheme not only has a better accuracy rate, but also supports more varieties of misspelling keyword search with acceptable computational overhead.