Sensor networks are ideal candidates for a wide range§of applications, such as monitoring of critical§infrastructures, data acquisition in hazardous§environments, and military operations. It is§necessary to guarantee the security and resilience of§sensor networks (as well as their applications) as§they become more and more popular. Despite many§security schemes have been proposed to protect§building blocks such as routing and key management,§some other building blocks (e.g., mobile sink and§time synchronization) are largely ignored. This book,§therefore, provides security building blocks for§sensor networks and develops a potential killer§application for sensor networks. The two proposed§security building blocks will help the sensor§networks tolerate mobile sink compromises and be§resilient against attacks on the time§synchronization, respectively. SVATS, a§sensor-network-based vehicle anti-theft system, is§designed to address the limitations of high cost,§high false-alarm rate and the easy disabling§drawbacks of the current vehicle theft tracking and§alarming systems. This system can detect vehicle§theft within seconds and track stolen vehicles as§well.