Publisher Summary This chapter analyzes the security requirements and architectures in a multimedia communication system (placement of security functions, link-by-link security architecture, point-to-point security architecture, end-to-end media security architecture), discusses the motivations behind format-compliant content protection, and describes the approaches to achieve format-compliant content protection.. There are two approaches for format-compliant content encryption: joint encryption and compression, and format-compliant selective encryption/scrambling. A joint approach leads to an improved system performance in terms of speed and flexibility that allows many requirements of multimedia applications to be addressed. This joint approach results in an encrypted compressed bit stream–– that is, compliant with the compression format. In format-compliant selective encryption/scrambling framework, encryption operations are executed on the compressed bitstream, and full bit-level compliance to the compression syntax is maintained. The chapter examines format-agnostic content protection and semi-format-compliant content protection and also elaborates the types of these approaches. It summarizes that format-compliant content protection can maintain the end-to-end security, ease of deployment, backward compatibility to legacy systems, and QoS performance of multimedia applications, at the cost of sacrificing certain content adaptation functionality and granularity, depending on where and how the security functions are implemented.