Images are the most used multimedia applications that are used for transferring data in this modern era. These transferred images may contain some confidential or private information like some financial associated information of any company. Therefore, the most important thing regarding the storage and communication of information is its security. The image encryption scheme is used for protecting visual information by using image transformation techniques that convert images into an incomprehensible manner.

In this modern age of information technology, multimedia data and information is being transferred at a very rapid speed. Most of the applications that are based on the Internet-of-Things require image transformation techniques for transferring information with the help of several sensor devices.

Therefore, if such applications are being used in the case of some information-sensitive sectors like healthcare, defense, or national security, we are required to encrypt such images while transferring information, so that it shouldn’t get mishandled or corrupted by any intruder. Because of the IoT devices’ resource constraint nature, we can’t implement the old traditional encryption techniques for this cause. However, cellular automata may be very beneficial in this case.

Cellular automata are considered a theory of automata that deals with discrete models of computation. It is also known as iterative arrays, tessellation structures, cellular structures, homogeneous structures, tessellation automata, and cellular spaces.

Image Encryption Scheme

An image encryption scheme can be defined as a technique for protecting the contents of an image. In this method, an image is converted into a noise-like encrypted image. This can be done by changing the values of pixels or by disrupting the positions of pixels in an image. An image encryption scheme uses a symmetric key; this secret key can be used for encrypting or decrypting the images.

The encryption scheme includes a total of three algorithms while encrypting an image for protection. In the first step, we generate the secret key that will be shared with the recipients. In the second step, we use that specified secret key for encrypting the image. In the third step, the recipient uses the provided secret key for decrypting the information. This can be considered as a very advanced technique for the secured transfer of data and information in this modern era. This technique guarantees the security of the information stored in the image in every possible aspect. Hence, cryptography is very useful in hiding the image content through encryption making the sensitive data unrecognizable to the intruder unless they decrypt it with the help of provided special decryption key.

Cellular Automata

A cellular automaton can be defined as multiple colored cells placed on a specified grid of shapes. Through this multiple discrete time steps in accordance with the rules set of neighboring cell’s states could be efficiently evolved. Cellular automata are mostly used for generating acoustic or visual content of multimedia. It is also used for creating random numbers that may be useful in cryptographic implementations.

The most common use of cellular automata is in modeling biological and physical systems as well as developing parallel computers. Fundamental laws of thermodynamics are obeyed by the reversible cellular automata; therefore, they can be very useful in stimulating the physical phenomena of fluid and gas dynamics. The best example of cellular automata can be given as our universe, as it consists of a large number of arrays of cells that store valuable numeric information in it. This huge array of cells include a giant 3-D geometric cellular automata in which every cell is surrounded by other 26 cells that are responsible for influencing its states.

Cellular automata are the best technique for cryptography of images because of their unpredicted, homogeneous, and parallel inherent properties. The software and hardware system could easily implement the algorithm of cellular automata. Fascinating complex behavior is being exhibited by the computational model of cellular automata.

Working of IESCA

Recently, researchers developed a new efficient and secured technique of image encryption with the help of 2-D Moore Cellular Automata, also known as MCA. This advanced technique is termed an efficient image encryption scheme using 2-D cellular automata or IESCA. This technique could be easily implemented in the hardware of any system. Cellular automata can be efficiently used for a quick generation of lots of chaotic and random sequences as compared to the pre-existing generators that generate random and chaotic sequences. A single bit of state value of each and every neighboring cell is used as a local transformation in this technique. Therefore, it results in very little consumption of resources and makes the implementation of cellular automata very easy and effective. 2-D Moore cellular automata result in the generation of an increased number of keyspaces as compared to the pre-existing image ciphering methods of cellular automata. The evaluations for the randomness regarding the ciphered images are done with the help of several statistical test suites like NIST and DIEHARD.

Several analyses of image encryption schemes using 2-D cellular automata are done regarding the performance and security of the technique results in enhanced resistance and robustness during any kind of security attack in the system. Hence, this is considered as the best mitigation technique to avoid the leakage of data and information to some intruders that may mishandle the sensitive information of the image. The efficiency of this cellular automaton image encryption scheme is very high as compared to the pre-existing techniques for encrypting images. The proposed image encryption scheme using 2-D cellular automata has achieved an improvement in its execution time of about 2.67% as compared to the old state-of-arts techniques. Along with this, the proposed image encryption scheme also achieved improvement in NCPR of about 5.02% and improvement in UACI value of about 7.69% as compared to the pre-existing state-of-art image encryption schemes. This technique is best because of its low cost, pretty fast encryption speed, a large number of security keys, and convenient realization.

References:

Main reference- Satyabrata Roy, Manu Shrivastava, Umashankar Rawat, Chirag Vinodkumar Pandey, Sanjeet Kumar Nayak,
IESCA: An efficient image encryption scheme using 2-D cellular automata,
Journal of Information Security and Applications

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