High-Capacity Steganography Using MRF-Synthesized Cover Images

Steganography [6][13] refers to embedding information or secret message into media. This paper presents a simple and secure high-capacity steganographic algorithm for information hiding [15]. We synthesize a cover-image texture with four gray levels 32, 96, 160, and 224 of user-selected size based on a Markov Random Field (MRF) model [3]. On the other hand, each byte of the secret information (secret message, image, etc.) is first encrypted based on an exponential modular arithmetic which is then partitioned into two 4-bit words. Each 4-bit word represented as an integer value in [0, 15] is inserted into a pixel in the selected cover-image to form a stego-image. The embedding capacity for an m by n cover-image could be as high as (m × n)/2, an experiment is illustrated for the proposed methodology. Keyword: Cover-Image, Encryption, Markov Random Field, Stego-Image.