Abstract: Information security is a major issue in the field of communication systems to avert an intruder who attack the network or steal the information. Researchers are still active in designing various cryptographic algorithms to support resource constrained computing systems. Modern wireless communication channel streams multimedia information like high-quality videos, color still images, audios and requires high-speed microprocessor for fast processing and secure transmission over insecure channels. Consequently, design of high-speed processing security algorithm emerged to give solutions to Wireless Multimedia Sensor Network. Hence, this study discusses a fast image encryption by AES modified with reversible cellular automata based S-Box.