Graph Steganography Based on Multimedia Cover to Improve Security and Capacity

Information is important asset, so it takes effort to maintain the confidentiality, integrity, and availability of information. Cryptography and steganography methods can be combined to improve information security. Steganography is divided into two types, Noisy Steganography and Noiseless Steganography. Noisy steganography has some disadvantages that can cause noise and the process of concealment that requires a container, while Noiseless Steganography (Nostega) will not produce noise and not require a container. One of the nostega paradigms is Graph Steganography (Graphstega). Graphstega is a technique that inserts messages as plotted data on a graph. This paper proposes a method that produces a graphstega encoding method that reduce the plot ratio gap, enhances data security by encrypting data, improve reality data with combination of excel cover, increasing message capacity without overlapping plots using (data splitting techniques, setting graphstega image resolution, setting font size on the graph plot), and implementing graphstega on text cover, digital image, and image hardcopy. The result of proposed graphstega method shows that it can improve data security, the value of the plot looks more realistic, reduce the plot ratio gap, increase message capacity, and can be implemented in text cover, image cover, and image hardcopy so the message distribution increases.