Substring Position Search over Encrypted Cloud Data Using Tree-Based Index

Existing Searchable Encryption (SE) solutions are able to handle simple boolean search queries, such as single or multi-keyword queries, but cannot handle substring search queries over encrypted data that also involves identifying the position of the substring within the document. These types of queries are relevant in areas such as searching DNA data. In this paper, we propose a tree-based Substring Position Searchable Symmetric Encryption (SSP-SSE) to overcome the existing gap. Our solution efficiently finds occurrences of a substrings over encrypted cloud data. We formally define the leakage functions and security properties of SSP-SSE. Then, we prove that the proposed scheme is secure against chosen-keyword attacks that involve an adaptive adversary. Our analysis demonstrates that SSP-SSE introduces very low overhead on computation and storage.