IMPROVING SMART HOME ACCESS CONTROL MECHANISMS TO ACCOUNT FOR COMMUNITY-BASED SHARING BEYOND THE HOME

Abstract

The rapid proliferation of smart home devices has reshaped daily living, offering convenience and enhanced security. However, extending access to these devices beyond household boundaries introduces significant challenges, including balancing privacy, security, and usability. Through three studies, this dissertation investigates these challenges and proposes solutions to improve access control mechanisms for sharing smart home devices with external individuals. First, we conducted 26 co-design interviews with 50 smart home device owners to understand their perspectives on co-monitoring in emergencies with trusted external contacts. Participants emphasized benefits such as enhanced safety, reduced material loss, and peace of mind through swift responses and threat verification. However, privacy concerns, burdening others, and unauthorized access highlighted the complexity of implementing such systems. These insights informed the development of design considerations, emphasizing flexibility, granular controls, and fail-safe mechanisms to mitigate these concerns and address user needs effectively. Building on these insights, we systematically analyzed 11 existing smart home management systems and two open-source platforms to evaluate how they support external sharing. The analysis uncovered significant limitations, such as reliance on rigid "all-or-nothing" access models, limited granularity in permissions, and insufficient transparency. These findings highlighted the need for more adaptable and user-centered mechanisms that empower users to manage access securely and intuitively while addressing privacy and usability concerns. To address these gaps, we developed and evaluated a novel mobile application, "MiSu," to enable flexible and secure smart home device sharing. MiSu introduced features like time-based permissions, device specific access, and real-time activity logs to accommodate diverse sharing scenarios. Then, we conducted a user study involving 15 smart home users and their trusted external contacts (N=30), revealing that participants valued the app’s precision and transparency but encountered usability challenges and privacy concerns, such as potential misuse of permissions and overexposure of personal spaces. These findings highlight the need for intuitive, user-centered designs that balance advanced functionality with privacy protection.