Abstract
This chapter discusses the notion of secret sharing. The scope of secret sharing was extended to new areas of security in the 1990s. With the evolution of encryption techniques, secret sharing began to be adapted for multimedia data, notably for images. Naor and Shamir proposed an adaption of the concept of secret sharing for the domain of 2D imaging. The chapter provides a description of visual cryptography, one of the earliest approaches to visual secret sharing. It then presents secret image sharing methods based on polynomial approaches, ensuring that the reconstructed secret image will be of the best possible quality. The chapter also describes the principle of secret 3D object sharing and presents methods for secret 3D object sharing based on binary shares. Social networks are immensely popular, with over two billion active users worldwide. The chapter aims to address specific problem by describing a hybrid photo sharing method for social networks.