Security and smart spaces are among the most significant topics in IoT nowadays. The implementation of secured smart spaces is at the heart of this concept, and its development is a key issue in the next generation IoT. This book addresses major security aspects and challenges in realizing smart spaces and sensing platforms in critical Cloud and IoT applications. The book focuses on both the design and implementation aspects of security models and strategies in smart that are enabled by wireless sensor networks and RFID systems. It mainly examines seamless data access approaches and encryption and decryption aspects in reliable IoT systems.