Cloud computing is revolutionizing the cyberspace by enabling convenient, on-demand network access to a large shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released [1]. While cloud computing is gaining popularity, diverse security, privacy and trust issues are emerging, which hinders the rapid adoption of this new computing paradigm. However, the development of defense solutions is lagging behind. To identify the limitations of existing solutions and to envision the future research directions are essential for ensuring a secure and trustworthy cloud environment. This chapter introduces important concepts, models, key technologies, and unique characteristics of cloud computing, which helps readers better understand the fundamental reasons for current security, privacy, and trust issues in cloud computing. Furthermore, critical security, privacy and trust challenges, and the corresponding state-of-the-art solutions are categorized and discussed in detail, followed by future research directions, which concludes this chapter
