Focuses on protecting data security and privacy when participants communicate with each other in the Internet of Things (IoT). Technically, the authors categorize and introduce a collection of secure and privacy-preserving data communication schemes/protocols in three traditional scenarios of IoT: wireless sensor networks, smart grid and vehicular ad-hoc networks recently. They present three advantages which will appeal to readers. Firstly, they broadens reader's horizon in IoT by touching on three interesting and complementary topics: data aggregation, privacy protection, and key agreement and management. Secondly, various cryptographic schemes/protocols used to protect data confidentiality and integrity are presented. Finally, the authors illustrate how to design practical systems to implement the algorithms in the context of IoT communication.;Secure data aggregation in wireless sensor network -- (Problems, models and goals -- Cryptographic-based data aggregation schemes -- Non cryptographic-based data aggregation schemes) -- Privacy-preserving meter reading transmission in smart grid -- (Cryptographic-based privacy-preserving schemes -- Perturbation-based privacy-preserving schemes) -- Key agreement and management in vehicular ad-hoc network -- (Cryptographic-based secure and privacy-preserving schemes -- Non cryptographic-based secure and privacy-preserving schemes).