Flexible and Efficient Multi-Keyword Ranked Searchable Attribute-Based Encryption Schemes

Abstract

Currently, cloud computing has become increasingly popular and thus, many people and institutions choose to put their data into the cloud instead of local environments. Given the massive amount of data and the fidelity of cloud servers, adequate security protection and efficient retrieval mechanisms for stored data have become critical problems. Attribute-based encryption brings the ability of fine-grained access control and can achieve a direct encrypted data search while being combined with searchable encryption algorithms. However, most existing schemes only support single-keyword or provide no ranking searching results, which could be inflexible and inefficient in satisfying the real world’s actual needs. We propose a flexible multi-keyword ranked searchable attribute-based scheme using search trees to overcome the above-mentioned problems, allowing users to combine their fuzzy searching keywords with AND–OR logic gates. Moreover, our enhanced scheme not only improves its privacy protection but also goes a step further to apply a semantic search to boost the flexibility and the searching experience of users. With the proposed index-table method and the tree-based searching algorithm, we proved the efficiency and security of our schemes through a series of analyses and experiments.

A Review on Searchable Encryption Functionality and the Evaluation of Homomorphic Encryption

“…The evolution from single-keyword searches to multi-keyword searches has been accompanied by efforts to reduce computational overhead, increase efficiency, and enhance security. Research in this area includes the combination of multi-keyword searches with fuzzy and semantic searches, ranked searchable Attribute-Based Encryption (FEMRSABE), and access control in a cloud environment maintaining encrypted data (MRSF) [6,23,24].…”

“…When a document is needed, a search token with a keyword is sent to the cloud provider, which uses it to locate and retrieve the document [30]. Another approach involves building a "Secure Index" by extracting keywords from plaintext files, encrypting the plaintext with symmetric encryption, transforming keywords into trapdoors, and matching an authorized user's trapdoor to the Secure Index for search results [23].…”

“…A different type of index search is tree searches. They provide a range of searches and can be tailored to numerical data sets and incorporated into FHE schemes [23]. Tree-based searching methods offer efficiency and are used in combination with other functionalities, such as fuzzy and semantic searches.…”

“…Several additional functionalities in encrypted data use have seen improvement without exhaustive enumeration. This encompasses semantics (words with similar meanings) [23], multiple data owners collaborating with multiple users [43], deduplication of data [44], comparison of multi-dimensional data between users without revealing the data [9], querying encrypted datasets with heterogeneous data sources [45], and clustering encrypted unstructured big data [46].…”