ABSTRACT
This chapter presents the categorization of visual cryptography (VC) and details the mathematics and technology behind the development of computation-based VC schemes. It shows that there are four types of VC approaches in the category of computation-based VC which are XOR-based VC, XOR-based multiple secret sharing, verifiable visual cryptography and multitone visual cryptography. The computation-based VC approach eliminates many unnecessary encryption constraints of VC such as contrast loss of the recovered secret at receiver end, binary image as secret and limitations of share and secret images. The chapter explores the efficient hybrid VC algorithms as per the requirements and the MATLAB code for the implementation of the approaches. It discusses one of the development methods for XOR-based VC approach for binary images. A XOR-based method can handle perfect recovery of the secrets. The chapter describers a secret sharing method for multitone secrets.
