In the second step of the **algorithm**, the concatenated images are regarded as one stream of bytes, **and** the **encryption** performed is both key dependent **and** data dependent. A single bit, call it fixBit, is chosen by a function based on the key. In this paper, this function adds some digits of the key **and** takes the remainder of dividing this sum by 8. A shuffle vector is constructed by listing the numbers of bytes which have the value of bit number fixBit equal to zero, followed by the numbers of bytes which have the value of bit number fixBit equal to one. This vector gives a mapping that specifies the new location of each byte in the array. This step is repeated for several iterations. Each iteration uses a different fixBit **and** applies the same steps to the new array that resulted from the preceding iteration. The number of iterations, k, is a small number chosen by a key-dependent function.

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Public-key **encryption** uses two distinct but mathematically related keys - public **and** private. The public key is the non- secret key that is available to anyone you choose (it is often made available through a digital certificate). The private key is kept in a secure location used only by the user. When data are sent they are protected with a secret-key **encryption** that was encrypted with the public key. The encrypted secret key is then transmitted to the recipient along with the encrypted data. The recipient will then use the private key to decrypt the secret key. The secret key will then be used to decrypt the message itself. This way the data can be sent over insecure communication channels [6].

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This paper aims at improving the level of security **and** secrecy provided by the digital color signal-based **image** **encryption**. The **image** **encryption** **and** decryption **algorithm** is designed **and** implemented to provide confidentiality **and** security in transmission of the **image** based data as well as in storage. This new proposed **encryption** **algorithm** can ensure the lossless of transmissions of images. The proposed **encryption** **algorithm** in this study has been tested on some images **and** showed good results.

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A novel optical **encryption** method is proposed in this paper to achieve 3-D **image** **encryption**. This proposed **encryption** **algorithm** combines the use of computational integral imaging (CII) **and** linear-complemented maximum- length cellular automata (LC-MLCA) to encrypt a 3D **image**. In the **encryption** process, the 2-D elemental **image** array (EIA) recorded by light rays of the 3-D **image** are mapped inversely through the lenslet array according the ray tracing theory. Next, the 2-D EIA is encrypted by LC-MLCA **algorithm**. When decrypting the encrypted **image**, the 2-D EIA is recovered by the LC-MLCA. Using the computational integral imaging reconstruction (CIIR) technique **and** a 3-D object is subsequently reconstructed on the output plane from the 2-D recovered EIA. Because the 2-D EIA is composed of a number of elemental images having their own perspectives of a 3-D **image**, even if the encrypted **image** is seriously harmed, the 3-D **image** can be successfully reconstructed only with partial data. To verify the usefulness of the proposed **algorithm**, we perform computational experiments **and** present the experimental results for various attacks. The experiments demonstrate that the proposed **encryption** method is valid **and** exhibits strong robustness **and** security.

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In selective **encryption** some content of the **image** is encrypted. It reduces the execution time because it encrypts only a part of the **image**. Consequently, selective **encryption** is sometimes called partial **encryption**. This **algorithm** provides security to the **image** **and** in the same time, some part of the **image** is visible. One of the use of this **algorithm** is in medical field, now a days the doctors are consulting the other doctors abroad, this **algorithm** can really help those. The medical **image** data is different from other visual data for multimedia applications. Since the lossy data cause some negative misdiagnosis.

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Visual cryptography technique for black **and** white images (Basic) introduced by Naor **and** Shamir [1]. Any visual secret information ( pictures, text, etc) is considered as **image** **and** **encryption** is performed using simple **algorithm** to generate n copies of shares depending on type of access structure schemes[2, 6].The simplest access structure is the 2 out of 2 scheme where the secret **image** is encrypted into 2 shares **and** both needed for a successful decryption. These shares are random dots without revealing the secret information.

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The proposed **algorithm** took Logistic map parameter μ **and** iterative initial value x0, **and** Hénon map initial value (x, y, z) as the original key, iteration time N. Each digit has 14 digital numbers, therefore, the key space is 10 14×6 =10 84 , the key space will be greater, **and** therefore, the **algorithm** has a strong resistance against attack of exhaustion as the key space will be greater. For example diffusion key space consists of 3 initial parameters (3-sub keys). The key space of each one is equal 256 bit **and** the attacker needs 3*2 256 operations to find the exact key. If the attacker employs 1000 million instructions per second of computer processing to guess the key by brute force attack, the computational load in years is:

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Abstract— This paper describes the results of efficient measuring methods whereby the **encryption** capability of four algorithms are evaluated. Specifically this work focuses on measuring the **encryption** quality, the memory requirement **and** the execution time of the **encryption** as an indicator to the usage of the software **and** the hardware. Also, the security analysis of these schemes is investigated from cryptographic viewpoint; statistical **and** differential attacks. A number of requirements are therefore identified upon which the algorithms are evaluated. The results of the efficient measuring methods show that each **algorithm** has its own strengths **and** weaknesses **and** no single **encryption** mechanism is able to get the maximum security with minimum execution time. The paper proposes that it may be possible to develop new algorithms providing adequate means of efficiency with acceptable security.

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Umaparvathi **and** Varughese in [9] presented a comparison of the most commonly used symmetric **encryption** algorithms AES (Rijndael), DES, 3DES **and** Blowfish in terms of power consumption. A comparison had been conducted for those **encryption** algorithms using different data types like text, **image**, audio **and** video. The various **encryption** algorithms had been implemented in Java. In the experiments, the software encrypts different file formats with file sizes (4MB - 11MB). The performance metrics like **encryption** time, decryption time **and** throughput had been collected. The presented simulation results showed that AES has a better performance than other common **encryption** algorithms used. Since AES had not showed any known security weak points in the presented study, this makes it an excellent candidate. 3DES showed poor performance results since it requires more processing power. Since the battery power is one of the major limitations in MANET nodes, the AES **encryption** **algorithm** is the best choice.

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Abstract- The advent of wireless communications, both inside **and** outside the home-office environment has led to an increased demand for effective **encryption** systems. The beauty of **encryption** technology comes out in more pronounced way when there is no absolute relation between cipher **and** original data **and** it is possible to rebuild the original **image** in much easier way. As chaotic systems are known to be more random **and** non-predictable, they can be made utilized in achieving the **encryption**. The transposition technology of **encryption** systems requires scrambleness behaviour in order to achieve the **encryption** of the data. This scrambleness behaviour can be derived from the randomness property of chaos which can be better utilized in the techniques like transposition system. In wireless communication systems, bandwidth utilization is an important criterion. In order to use **encryption** system in wireless communication; key space plays an important role for the efficient utilization of the bandwidth. In this paper we present a chaos based **encryption** **algorithm** for images. This **algorithm** is based on pixel scrambling where in the randomness of the chaos is made utilized to scramble the position of the data. The position of the data is scrambled in the order of randomness of the elements obtained from the chaotic map **and** again rearranged back to their original position in decryption process. The same **algorithm** is tested with two different maps **and** performance analysis is done to select best suited map for **encryption**.

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We propose a new non-chaos based **image** **encryption** scheme using a key of 128-bit size. In the **algorithm**, **image** is partitioned into several key based dynamic blocks **and** each block is passed through the eight rounds of diffusion as well as substitution process. In diffusion process, sequences of block pixels are rearranged within itself by a zigzag approach whereas block pixels are replaced with another by using difference transformation in substitution process. We have carried out an extensive security **and** performance analysis of the proposed **image** **encryption** technique using various statistical analysis, key sensitivity analysis, differential analysis, key space analysis, speed performance, etc. Based on the results of our analysis, we conclude that the proposed **image** **encryption** technique is perfectly suitable for the secure **image** storing **and** transmission.

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Many **image** in recent years are transmitted via internet **and** stored on it. Maintain the confidentiality of these data has become a major issue. So that **encryption** algorithms permit only authorized users to access data which is a proper solution to this problem.This paper presents a novel scheme for **image** **encryption**. At first, a two dimensional logistic mapping is applied to permutation relations between **image** pixels. We used a fractal **image** as an **encryption** key. Given that the chaotic mapping properties such as extreme sensitivity to initial values, random behavior, non-periodic, certainty **and** so on, we used theses mappings in order to select fractal key for **encryption**. Experimental results show that proposed **algorithm** to encrypt **image** has many features. Due to features such as large space key, low relations between the pixels of encrypted **image**, high sensitivity to key **and** high security, it can effectively protect the encrypted **image** security.

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Step iii. Then uniform scrambling is applied onto the **image** IW’’ where the pixels in the same block of original **image** is distributed into all the blocks of scrambled **image** **and** the every block has one pixel at least, without regarding to the order of the pixels appearance, accordingly all the pixels in the same block of scrambled **image** come from different blocks of original **image**. Figure below shows that all the pixels in the first block of the original **image** are distributed into all the blocks of the scrambled **image**. Thus, the ideal block numbers is N for an original **image** of size NxN. After scrambling, the resultant would be a new **image** IW’’’.

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et al used Discrete Wavelet Transform for encrypted images [6]. Younes **and** Jantan introduced the concept of the block- based transformation encrypted **image** **algorithm** [7]. Mao et al used a new scheme of chaotic Baker maps **image** **encryption** [8]. Wu et al studied **and** used the concept of Sadouka matrix in encrypted **image** [9]. Jayant **and** Roy proposed the method of break correlation among neighboring pixels [10]. Alghamdi **and** Hanif Ullah used chaotic function for iris **encryption** **image** [11]. Jolfaei **and** Mirghadri Surveyed **and** studied the Salsa20 scheme for **image** **encryption** [12] .Ye **and** Zhou proposed the concept of chaos-based **image** **encryption** scheme [13]. Dey introduced mixed **and** Vernam permutation **algorithm** [14]. Landge et al proposed the method of 64-bits blowfish [15]. Al-Husainy proposed **algorithm** which mixed boolean operations **and** **image** hiding [16]. Shreef **and** Hoomod used the interpolating functions technique to encrypt **image** [17]. Ye proposed an **algorithm** based on chaos **and** diffusion mechanism with permutation [18]. Al-Rammahi et al introduced an encrypted **algorithm** based on the analysis of singular value decomposition [19]. Lin **and** fuh introduced Barcode **Image** Decoding in two dimensions [20].

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The proposed **image** **encryption** **algorithm** has two major steps. Firstly, the correlation among the adjacent pixels is disturbed completely as the **image** data have strong correlations among adjacent pixels. For **image** security **and** secrecy, one has to disturb this correlation. To achieve this, a block **and** stream based **image** shuffling scheme is proposed using the three chaotic maps mentioned above. Then the pixel values of the shuffled **image** are modified by employing Henon map. **Encryption** is done in two stages confusion **and** diffusion.

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x Tunability: It could be very desirable to dynamically define the encrypted part **and** the **encryption** parameters with respect to different applications **and** requirements. Static definition of encrypted part **and** encrypted parameters limits the usability of the scheme to a restricted set of applications. Tunability factor can have one of the values ‘yes’ or ‘no’.

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The Internet as a whole does not use secure links, thus information in transit may be vulnerable to interruption as well. The important of reducing a chance of the information being detected during the transmission is being an issue in the real world now days. The Digital watermarking method provides for the quick **and** inexpensive distribution of digital information over the Internet. This method provides new ways of ensuring the sufficient protection of copyright holders in the intellectual property dispersion process. The property of digital watermarking images allows insertion of additional data in the **image** without altering the value of the **image**. This message is hidden in unused visual space in the **image** **and** stays below the human visible threshold for the **image**. Both seek to embed information inside a cover message with little or no degradation of the cover-object. In this paper investigate the following relevant concepts **and** terminology, history of watermarks **and** the properties of a watermarking system as well as a type of watermarking **and** applications. We are proposing edge detection using Gabor Filters. In this paper we are proposed least significant bit (LSB) substitution method to encrypt the message in the watermark **image** file. The benefits of the LSB are its simplicity to embed the bits of the message directly into the LSB plane of cover-**image** **and** many techniques using these methods. The LSB does not result in a human perceptible difference because the amplitude of the change is little therefore the human eye the resulting stego **image** will look identical to the cover **image** **and** this allows high perceptual transparency of the LSB. The spatial domain technique LSB substitution it would be able to use a pseudo-random number generator to determine the pixels to be used for embedding based on a given key. We are using DCT transform watermark algorithms based on robustness. The watermarking robustness have been calculated by the Peak Signal to Noise Ratio (PSNR) **and** Normalized cross correlation (NC) is used to quantify by the similarity between the real watermark **and** after extracting watermark.

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Although Cloud computing keeps growing, its users are aware **and** cite security guaran- tees as their main concern when adopting such services (Columbus, 2017a; Meeker, 2017). These concerns are not without a cause; in recent years, several cases of privacy breaches have surfaced. Some of these are intended company policies, such as using data assumed private for advertising purposes (Rushe, 2013); other breaches may also be the result of government-ordered surveillance programs (Cook, 2016; Greenwald **and** MacAskill, 2013). These kind of leaks aﬀect not only companies, but also individual users (Hough, 2010; Lewis, 2014; Turner, 2016). Particularly sensitive information, like health records, have also been the subject of several attacks (HCA News, 2018; O’Hara, 2017; Roston, 2017); with the recent growth in personal health apps usage (Khalaf, 2014; Meeker, 2017), the need for data security increases. In light of these concerns **and** news, Cloud services present themselves as a double-edged sword for its users: how to leverage the advantages of the Cloud without compromising privacy **and** security?

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