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Present era is marked by exponential growth in transfer of multimedia data through internet. Most of the Internet-of-Things(IoT) applications send images to cloud storages through internet. However, in sensitive applications such as healthcare, defense, etc., these images should be encrypted before transmission through insecure public channels to gateway fog nodes. Conventional encryption algorithms cannot be used there due to the resource constraint characters of IoT devices. Here, Cellular Automata (CA) based encryption algorithms can be used because of their inherent simplicity in implementation in hardware, without affecting the capability of generating highly random sequences. In this paper, a lightweight, robust and secure image encryption technique has been proposed using 2-D Von-Neumann Cellular Automata (VCA), called IEVCA, which is lossless, correlation immune and has all the essential properties of a good image cipher. Additionally, the proposed technique passes all the randomness tests of DIEHARD and NIST statistical test suites. Moreover, several security and performance analyses of the IEVCA proved its efficiency and resistance against security attacks. Experimental results of the IEVCA show its better performance when compared to the existing encryption techniques.

In the present era of Information Technology (IT), transfer of multimedia data is happening at a rapid pace. In many Internet-of-Things (IoT) based applications, sensor devices are sending information in the form of images. However, if the IoT applications are used in the information sensitive sectors like defense, healthcare, etc., the images must be encrypted before sending to the gateway fog nodes. Again, traditional encryption algorithms will not work in such scenarios due to the resource constraint nature of IoT devices. Here, Cellular Automata (CA) plays an important role. In this paper, a new secure and efficient image encryption technique is proposed using 2-D Moore Cellular Automata (MCA), called as IESCA which is lossless and easy to implement in hardware. Cellular Automata can generate random and chaotic sequence much faster than the existing chaotic sequence generators. It uses local transformations based on one bit state values of each of its neighbors. It makes CA implementation very easy and less resource consuming. Moreover, considering Moore convention has increased the key space more than the existing CA based image ciphering techniques. The randomness of the cipher images are evaluated using DIEHARD and NIST statistical test suites. Additionally, several security and performance analyses of the IESCA have proved its robustness and resistance against security attacks. Experimental results of the IESCA show its efficiency when compared to the existing encryption techniques. The proposed scheme has achieved 2.76% improvement in terms of execution time when compared with the state-of-the-arts. Moreover, the proposed scheme has achieved 5.02% improvement in terms of NPCR and 7.69% improvement in terms of UACI values when compared with the existing schemes.