Design and implementation of privacy-enhanced operation history middleware for smartphones

Operation history middleware collects various operation data on smartphones. Because of privacy concerns about sensitive operation data, it needs to meet fine-grained collection needs including collection based on temporal-spatial conditions and temporary suppression of the collection of specific operation types. The on-demand collection method proposed herein dynamically determines the minimum collection set of operation types and their storage period. We develop an Android-based prototype that implements five collection techniques and a selective encryption function to protect sensitive data in the local database. Our evaluation shows that the collection techniques incur low overhead. Encryption overhead in recording is less than 26 milliseconds.