This chapter discusses the motivation for security mechanisms in Wireless Video Sensor Networks (WVSNs). It provides overview of the general design challenges in WVSNs. The chapter discusses various security issues and their solutions in the context of WVSN. It presents the technical background of digital video watermarking. The chapter reviews the security mechanisms for WvsNs based on digital watermarking. A wireless communication channel is available to any entity that tunes its radio interface to the frequency of the channel for transmission or reception. The WVSNs have a number of requirements that are unique to its architecture such as high bandwidth for video streaming, low-complexity video encoding techniques, application-specific quality of service demands, and resource constraints. Video encoding is often a complex and processing intensive operation due to which considerable energy drain can occur at resource-limited sensor nodes. Different WVSN applications may have different requirements in terms of bandwidth, processing, and compression, among others.