International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 09 Issue: 06 | June 2022 www.irjet.net p-ISSN: 2395-0072 © 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 827 Chaos Based Image Encryption Techniques: A Review Bhavana Sharma 1 , Jaspreet Singh 2 1 Assistant Professor, Dept. of CSE, The North Cap University, Gurugram, Haryana, India 2 Student, Dept. of CSE, The North Cap University, Gurugram, Haryana, India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - Digital images are a common part of multimedia communication, and in the current scenario they are frequently used to transmit data. Therefore, their security is a major concern for them. Chaos maps are good for encrypting images because they are chaotic, ergodic, and highly sensitive to initial conditions. Many of the past proposed image encryption methods relied on low- dimensional chaotic maps, which are the least secure and have limited resistance to brute force and statistical attacks. In attempt to overcome this difficulty, researchers have created a variety of high-dimensional chaotic maps. This review article gives a scientific evaluation of a variety of studies conducted over the recent years that have employed chaotic in various forms to process digital images in the encryption. Key Words: Image Encryption, Chaotic Systems, Logistics Map, Performance Metrics, Arnold Map, Cryptography 1. INTRODUCTION The security of images has become a big problem because we are exchanging more information through the internet [1]. To protect confidential photographs from unauthorized users, many encryption techniques have been developed in recent years [2]. Cryptography is a science and method of keeping data safe from prying eyes by storing and transferring it in an unreadable format for attackers [3]. In reality, cryptographic methods are supposed to be tough to crack. As a result, encryption is critical to the security of digital content [4]. Due to the quantity and redundancy of image data, current encryption algorithms are not suitable for encrypting image data, and hence cannot guarantee the data’s security and confidentiality [5]. Over the last few decades, various approaches for encrypting image data have also been presented, with chaotic-based encryption being the most powerful and widely used due to its erratic and uncertain character [6]. 1.1 OVERVIEW OF CHAOTIC MAP THEORY For chaotic-based picture encryption, one-dimensional and multi-dimensional chaotic maps are utilised. The use of multi-Dimension chaotic maps improves the security of picture encryption by virtue of its complicated structure and the inclusion of numerous parameters, but also increases the difficulty of implementing the method [7]. Matthews employed chaotic to encrypt data for the first time in the late 1980s, while Habutsu et al. published the first chaotic block cypher algorithm in 1991. In 1998, Baptista published a chaotic encryption scheme. In addition, Friedrich stated that to achieve a high level of security, the picture encryption method should be repeated in two steps: diffusion and permutation [8]. The permutation stage is required to minimise the high correlation between adjacent pixels. Permutation methods are divided into two categories: pixel and bit level. The diffusion phase is responsible for modifying pixel values in order to develop an oscillatory behavior and avoid the attack [9]. Almost all proposals for chaotic-based picture encryption are inspired by two factors: I the potential for reduces the computational effort when compared to standard encryption; and (ii) purported security issues when classical cyphers are applied on images [10]. 1.2 IMAGE ENCRYPTION USING A CHAOTIC SYSTEM Non-chaos techniques and chaos-based or are two types of picture encryption. In chaos-based approaches, initial conditions are extremely important. If we modify something in the starting situation, the entire outcome will change [11], [12], [13], [14], [15], [16]. Healthcare, military, online communication, photo messaging applications for smart phones, multimedia systems, images used in healthcare, Tele-medicine, and government papers are just few of the applications of the encryption concept based on chaos [14]. Diffusion and Confusion are the two phases of a chaos- based encryption method. The chaos-based picture encryption technique is depicted in block diagram in Figure 1. The phase of confusion occurs when the position of pixels is scrambled without changing their value. The purpose of a diffusion phase is to alter the estimation of each pixel in the image [11], [17]. Figure 2 illustrates the connection between chaotic map theory and cryptography.