Yingjiu Li

This book investigates tradeoff between security and usability in designing leakage resilient password systems (LRP) and introduces two practical LRP systems named Cover Pad and ShadowKey. It demonstrates that existing LRP systems are subject to both brute force attacks and statistical attacks and that these attacks cannot be effectively mitigated without sacrificing the usability of LRP systems. Quantitative analysis proves that a secure LRP system in practical settings imposes a considerable amount of cognitive workload unless certain secure channels are involved. The book introduces a secure and practical LRP system, named Cover Pad, for password entry on touch-screen mobile devices. Cover Pad leverages a temporary secure channel between a user and a touch screen which can be easily realized by placing a hand shielding gesture on the touch screen. The temporary secure channel is used to deliver a hidden message to the user for transforming each password symbol before entering it on the touch screen. A user study shows the impact of these testing conditions on the users' performance in practice. Finally, this book introduces a new LRP system named ShadowKey. Shadow Key is designed to achieve better usability for leakage resilient password entry. It leverages either a permanent secure channel, which naturally exists between a user and the display unit of certain mobile devices, or a temporary secure channel, which can be easily realized between a user and a touch screen with a hand-shielding gesture. The secure channel protects the mappings between original password symbols and associated random symbols. Unlike previous LRP system users, Shadow Key users do not need to remember anything except their passwords. Leakage Resilient Password Systems is designed for professionals working in the security industry. Advanced-level students studying computer science and electrical engineering will find this brief full of useful material.

As a fast-evolving new area, RFID security and privacy has quickly grown from a hungry infant to an energetic teenager during recent years. Much of the exciting development in this area is summarized in this book with rigorous analyses and insightful comments. In particular, a systematic overview on RFID security and privacy is provided at both the physical and network level. At the physical level, RFID security means that RFID devices should be identified with assurance in the presence of attacks, while RFID privacy requires that RFID devices should be identified without disclosure of any valuable information about the devices. At the network level, RFID security means that RFID information should be shared with authorized parties only, while RFID privacy further requires that RFID information should be shared without disclosure of valuable RFID information to any honest-but-curious server which coordinates information sharing. Not only does this book summarize the past, but it also provides new research results, especially at the network level. Several future directions are envisioned to be promising for advancing the research in this area.