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.

I. Introduction

A smartphone is a personal and versatile device that always is close to its user and offers various applications. Collecting a continuous stream of information about the user operation history enables diverse types of personalized applications including user interface customization, monitoring of user activities, presentation of personalized information based on past activities[1]. Our goal is to realize operation history middleware collecting various types of operation data for such applications. This paper deals with two categories of operation data: active operation and passive operation. Active operations include calling, taking pictures, browsing, using applications such as navigation and gaming. Passive operations include sensory data collection like GPS and acceleration and terminal status data such as battery state and silent mode activation.