system (Rodrigues et al,2006).have proposed new approach of **selective** or partial **encryption** of human face images based on discrete cosine transform and AES stream cipher use Variable Length Coding(VLC)method of the Huffman’s vector, they found that it can be cipher an **image** without disturbing the compression rate. (Panduranga et al.2013) describe **selective** **encryption** in two methods to secure only selected portion of medical and satellite images, the first way is very useful if the selected portion of **image** is known while the second **encryption** scheme is suitable when region of interest is found in **image**.(Rajinder et al,2013)makes security comparison between full and **selective** **image** **encryption** techniques using fidelity criteria such as correlation, entropy and histogram analysis, they found that **selective** methods provide great level of protection since they reduced the **encryption** process time. (Abeer et al. 2013)In this research, a novel **image** **encryption** method based on **3D** **chaotic** algorithm execute the diffusion and confusion operations. The experimental analysis show that the presented scheme provide high security level, they resistance to different types of attacks such as force attack, chosen-cipher text attacks and differential attack with **encryption** ratio equal to (6.25 %) and well-matched with compression process.

Show more
17 Read more

Key space size is the total number of different keys that can be used in the **encryption**. A good **encryption** scheme should be sensitive to the secret keys, and the key space should be large enough to make brute-force attacks infeasible. In this proposed algorithm, the initial conditions and parameters can be used as keys. The proposed **encryption** algorithm uses three different **chaotic** **map**, **chaotic** maps with different initial values. One **map** is for row scrambling, one **map** for column scrambling and another for XOR operation. Similarly two different PMMLCG sequences are used for row and column scrambling. So, this scheme provides a choice of using different keys. It provides a larger keys spaceof iterations to skip before the actual **encryption**/decryption starts.

Show more
where p(n ), X(n ), C(n), and (n−1) represent the current plain pixel, key stream element, output cipher-pixel and the previous cipher-pixel, respectively. Such diffusion algorithm can spread a slight difference in the plain **image** to large scale pixels in the ciphered **image** and thus differential attack may be practically useless. Additionally, to cipher the first pixel, c (−1) has to be set as a seed. In this project, **chaotic** logistic **map** is employed as the key stream generators.

[3]M.Y. Mohamed Parvees, J. Abdul Samath, I. Kaspar Raj and B. Parameswaran Bose, shows in their paper that A new color byte scrambling scheme is proposed in this paper for color **image** **encryption** using Logistic and Ikeda **map**. The **chaotic** sequences are generated using these **chaotic** maps and, according to the transformation of **chaotic** sequences, the position of **image** pixels and values is changed. The **encryption** of the **chaotic** **image** is done through confusion and diffusion. The confusion is obtained by changing the locations of pixels and the diffusion is obtained by changing the values of pixels. The logistic **map** is one-dimensional in this scheme that is simple and efficient and used to generate sequences of permutation to create confusion. To achieve diffusion, the two-dimensional Ikeda **map** is used to generate masking sequences. Finally, the result of the proposed algorithm is compared and validated by different cryptanalysis with existing results.

Show more
12 Read more

Due to the characteristics of easy-understanding and attractive presentation, multimedia contents such as **image** and audio, have been widely transmitted in Internet and mobile communications. people can obtain, use or process digital images more frequently. Since digital media such as **image**, audio, and video are easy to process, copy and transfer, the emergence of powerful tools raises a series of problems. It has become essential to secure information from leakages. Many peoplehas done research of this area and obtained many achievements [1].Some classic **encryption** techniques such asoptical transforms and **chaotic** maps have become a vital role in protecting images due to the increasing requirement for **image** storage and transmission[2-7].

Show more
Here we are considering that an **image** I = f(x, y) of size MXN consists of three primary color channels viz. RED, GREEN and BLUE. For simplicity, we assume the **image** size to be N X N. As presented in [1], the **image** **encryption** and decryption algorithms in this work are based on the Discrete Wavelet Transform, fractional Fourier transform and use **chaotic** logistic **map**, Tent **map** and Kaplan-Yorke **map**. These algorithms shall be further referred as Algorithm 1, Algorithm 2 and Algorithm 3 respectively throughout the paper. Each of these algorithms follows a similar sequence of operations but they differ in their implementation details. A general overview of the **encryption** and decryption process is as follows.

Show more
Compared to the method of shuffling the method of substitution is more efficient and more secure as it involves changing the pixel values. Even such shuffling when applied as a one and only **encryption** technique leads to weaker encrypted **image**. Thereby in order to improve the security shuffling and the substitution are combined by some researchers [3, 4].In this paper we use **image** **encryption** based on DNA Subsequence Operation along with the use of **chaotic** **map** and **image** fusion.

An important step in any digital **chaotic** **encryption** is the selection of the **map**. **Chaotic** maps have different behavior regarding com- plexity, **chaotic** properties cycle length, **chaotic** interval, periodic windows, etc., sensitivity to initial conditions and reaction to tra- jectory perturbations, etc., that influence the structure or behavior of the **chaotic** **encryption** system. In fact, some systems have been broken for not considering the weaknesses of the chosen **chaotic** **map** and efficiency, it is desirable to provide some independency between the cryptosystem and the **chaotic** **map** under consideration. This independency means that, a full knowledge of the selected **chaotic** **map** is not needed to fulfill the security and efficiency re- quirements of a good cryptosystem.

Show more
A second example where compression of encrypted vi- sual data is desirable is data transmission over heterogeneous networks, for example, a transition from wired to wireless networks with corresponding decreasing bandwidth. Con- sider the transmission of uncompressed encrypted visual data in such an environment as occurring in telemedicine or teleradiology, for example, when changing from the wired network part to the wireless one, the data rate of the visual material has to be reduced to cope with the lower bandwidth available. Employing a classical **encryption** scheme, the data has to be decrypted, compressed, and re-encrypted similar to the surveillance scenario described before. In the network scenario, these operations put significant computation load onto the network node in charge for the rate adaptation and the key material needs to be provided to that network node, which is demanding in terms of key management. A solution where the encrypted material may be compressed directly is much more eﬃcient of course. The classical approach to tackle this second scenario is to apply format compliant en-

Show more
16 Read more

Chaos is characterized by ergodicity, sensitive dependence on initial conditions and random-like behaviors, which is an aperiodic dynamics process, seeming disorderly and unsystematic; actually it contains order[15]. Introducing chaos theory into the field of **image** **encryption** and information security is an important frontier subject of e nonlinear science and information science.The chaos theory was used in applications to cryptology from the 1980s.And a number of chaos based **image** **encryption** scheme have been developed in recent years which we discuss in brief in this paragraph.In 1992,Bourbakis and Alexopoulos [9] have proposed an **image** **encryption** scheme which utilizes the SCAN language to encrypt and compress an **image** simultaneously. Wu Yue [10] demonstrated the construction of a symmetric block **encryption** technique based on two-dimensional standard baker map.Since 2010, Liu Huibin et al. have proposed a number of different **encryption** schemes based on one or more **chaotic** maps[9-13].Recent cryptanalytic results[14-16] have shown that these schemes proposed in contain security defects.

Show more
10 Read more

tems have become a good password system [4]. Recently some researchers such as [5,6], they used two **chaotic** maps to encrypt the **image** to enhance the security. Simi- larly, Ashtiyani et al. [7] also employed **chaotic** maps and other method to encrypt the images. Ahmad [8] in- troduced a new method using two logistic **chaotic** maps and a large enough external secret keys for **image** en- cryption. This method exhibits a high security, but they did not proof this method is robust or not to common signal processing attacks. The scheme proposed in this paper is based on two **chaotic** maps which can overcome the periodicity of Arnold **map** and is more security; be- sides, it is robust to the common signal attacks. The re- searchers in [9,10], proved that logistic **map**, that was widely used in the **encryption** domain, is not enough ran- dom and uniform. Then, they propose to use other cha- otic maps like Piece Wise Linear **Chaotic** **Map** (PWLCM). In [11] and [12] presents a chaos-based cryptosystem for secure transmitted images abased on a 2D **chaotic** **map** which is used to shuffle the **image** pixel positions, ac- companied with substitution (confusion) and permutation (diffusion) operations on every block. A multiple rounds, are combined using two perturbed **chaotic** PWLCM maps. Indeed, to obtain better dynamical statistical properties and to avoid the dynamical degradation caused by the digital **chaotic** system working in a finite state, a pertur- bation technique is used.

Show more
Abstrak. Imej digunakan dalam pelbagai bidang seperti perubatan, ketenteraan, sains, kejuruteraan, kesenian, hiburan, pengiklanan, pendidikan dan latihan. Dengan bertambahnya penggunaan teknik digital bagi penghantaran dan penyimpanan imej, isu asas untuk melindungi kerahsiaan, keutuhan dan kesahihan imej perlu dititikberatkan. Kertas-kerja ini membincangkan algoritma alternatif penyulitan kekunci simetri, iaitu Secure **Image** **Encryption** (SIP), bagi melindungi keselamatan imej, Algoritma ini direka bentuk berdasarkan teknik chaos. SIP mengolah piksel, bukannya bit sebagaimana yang dilakukan oleh algoritma penyulitan yang popular seperti Triple-DES dan IDEA. Pada umumnya, SIP terdiri dari pada tiga komponen: (1) fungsi transformasi mendatar-menegak (HVT); (2) fungsi anjakan (S), dan (3) fungsi skala kelabu (GS). Fungsi HVT adalah berdasarkan pemetaan chaos yang digunakan dalam algoritma pemetaan Baker. Fungsi GS pula melanjutkan algoritma ini ke tiga-dimensi dengan dimensi ketiga merujuk kepada aras skala kelabu piksel. Algoritma ini menyokong dua mod operasi, iaitu Electronic Code Book (ECB) dan Cipher Block Chaining (CBC). Analisis yang dilakukan terhadap SIP menunjukkan aras keselamatan masih memuaskan walaupun kekunci yang digunakan terdiri daripada kekunci lemah jika digunakan dalam algoritma pemetaan Baker.

Show more
12 Read more

In 1950s, Shannon clearly states that cryptographic chaos can be archived due to its central crease mechanism and its stretching [2]. The need for **encryption** turns out to be an urgent need and the chaos theory grows until it is approved by the cryptographers of the time until the 1980s. Shannon confirms that the fulfillment of chaos overcame the chaos and proposes the figure the first fundamental chaos and coincidence of chaos in the 1980s and it was clearly seen in 1990 as well. The first figure based on chaos was suggested in 1990 and chaos entered the scene. In fact, many books related to chaos have been published. (Baplista 1998) 1996 extended the **chaotic** **encryption**. Although the origins of the system of standard chaos are based on continuous systems and distinctive features since 2000, the chaos emerged as a protected statement as an application in **Chaotic** cryptography in **chaotic** cryptography was carried out in 2006 by Alvarez and Li, where some consequences of the non-static or dynamic fall of a **chaotic** **map** are exposed within the core of cryptography. Undoubtedly, the researchers focused on this study to evaluate the **chaotic** **encryption** technique. The **chaotic** **encryption** techniques are similar, but here the activation was carried out only by chaos. The algorithm based on the **chaotic** key (CKBA) as an **encryption** method generates a bit sequence key using a **chaotic** system proposed by (Yen and Guo) [5], the binary sequence is generated and, consequently, the key pixel of the selected **image** arranged. There are certain techniques that encrypt part of the **image** or audio and not all the content [6, 7].

Show more
13 Read more

In recent years, the security of digital images has attracted much attention in computer communication and network engineering [1,2]. Since Mathews, a British scholar, first proposed the "**chaotic** cipher" in 1989, many scholars had studied the close relationship between chaos and cryptography, such as Logistic [3], Arnold cat [4,5], Chebyshev and Henon mapping, and others algorithms, which based on some mathematical transformations[6-11]. Jessica Fridrich, the first person, whom applied chaos theory to **image** **encryption**, in 1997 [3]. In 2005, Z Guan and fellows proposed a new **encryption** algorithm based on Arnold cat mapping [4,5]. In 2009, Xiao D and fellows analysis and improvement it[5]. In the same year, Cahit Cokal and et al analyzed the security of this algorithm [4]. In 2008, R Rhouma and B Safya first applied Logistic mapping to hyperchaotic systems [2,3]. In 2009, K Wong pointed out that an existing **image** **encryption** system based on chaos includes two stages: substitution and diffusion. The multi-dimensional **chaotic** mapping usually uses the **image** pixel arrangement in the alternative phase, and the one-dimensional (1D) **chaotic** mapping is used for the purpose of diffusion, and an efficient **chaotic** **image** **encryption** and diffusion method is proposed [6]. In 2010, Narendra Singh and Aloka Sinha proposed Chaos based multiple **image** encryptions using multiple canonical transforms [7]. In the same year, Lang J and others proposed **image** **encryption** based on the multiple-parameter discrete fractional Fourier transform and chaos function [8], and so on. The results on chaos have also obtained. That is, the translation-type **chaotic** systems were proposed [12,13] by Liu in 2016.

Show more
The proposed algorithm for **image** **encryption** uses Tinkerbell **chaotic** maps and magic square. Fig. 1 shows the **encryption** process. It mainly consists of a secret key, 2D Tinkerbell **map** generation, row shifting, pixel modification, magic square generation and pixel shuffling. The proposed Tinkerbell **map** based algorithm uses a 128 bits long secret key. It can be a 16 character length hexadecimal key. It is further divided as 16 sub keys of 8 bits length.

Development of society leads towards the importance of data used, so huge amounts of digital visual data is stored on various media and exchange over various sorts of networks now a day .**Image** have enough importance in our life, so it used in digital form and increasing importance due to improvements of performance in computer speed, media storage and network bandwidth. So the vulnerability of this form of information to be attacked such as modification and fabrication is higher as compared to paper based **image**.

Guam et al. used a 2D Cat **map** and Chen's **chaotic** system for pixel position permutation and pixel value masking, in 2005 respectively [1]. Giesl [10] proposed an **image** **encryption** system using strange attractor in 2009. Today, because of the properties of **chaotic** systems, such as sensitivity to initial conditions and control parameters, pseudo randomness and ergodicity, chaos becomes popular in **image** **encryption** (Lian et al.

18 Read more

In the suggested algorithm in [6], each pixel is substituted for another pixel, which is determined as follows. First, the original pixel is divided into two parts. In the following, a s-box, which is based on Logistic **map**, is utilized to generate a random number per half. These numbers are employed as the coordinates of the latter pixel. In the proposed algorithm by Zheng and et al. [7], a circular s-box, which contains a header, is employed. Each pixel is substituted by an element of the s-box, considering the pixel value and the element of the s-box which is pointed by the header. In the following, each pixel is enciphered using the outcome of the s-box and previous encrypted pixel. Ref. [8] has investigated the disadvantages of substitution-based **encryption** algorithms. Then, it has proposed an algorithm which utilized a three-dimensional matrix for permutation.

Show more
Use several rounds of operation for block ciphers. The basic properties of **chaotic** systems are the deterministicity, the sensitivity to initial conditions and parameters and the ergodicity. Deterministicity means that **chaotic** systems have some determining mathematical equations ruling their behavior. The sensitivity to initial conditions means that when a **chaotic** **map** is iteratively applied to two initially close points, the iterations quickly diverge, and become uncorrelated in the long term. Sensitivity to parameters causes the properties of the **map** to change quickly, when slightly disturbing the parameters, on which the **map** depends. Hence, a **chaotic** system can be used as a pseudo-random number generator. The ergodicity property of a **chaotic** **map** means that if the state space is partitioned into a finite number of regions, no matter how many, any orbit of the **map** will pass through all these regions.

Show more
13 Read more

It can be found from the definition and characteristics of the **chaotic** system that the **chaotic** system is very sensitive to the initial value. In a cryptographic system, if the subtle changes in the key can lead to obvious changes in the **encryption** results, the **encryption** algo- rithm or the cryptographic system has a better **encryption** effect, that is, the high sensitivity to the existence of the key. Therefore, with the sensitivity of the **chaotic** system to the initial value, an **encryption** system based on **chaotic** systems can be constructed. At present, the **encryption** technology based on chaos is mainly divided into two types. The first type is a secure communication **encryption** system based on **chaotic** synchronization technology. The second type is a digital **encryption** system based on the **chaotic** system to create a stream **encryption** key or the homogeneous group key. Due to the orbital hybrid type and initial value sensitivity characteristics of **chaotic** systems, the hybrid characteristics of the **chaotic** system can be applied to the confusing processing in the encryp- tion process, and the **chaotic** characteristics of the **chaotic** system corresponded to the pseudorandomness and key- sensitive demand required by the **encryption** system. At present, most **chaotic** mapping applications in **encryption** technology use the mapping reference algorithm which is more commonly used in traditional cryptography.

Show more
10 Read more