Enhanced RC6 permutation-diffusion operation for image encryption

The present scenario of the medical field is that sending the healthcare images through the internet is so far exposed to security threats. Hence, there is a need for an efficient and secure procedure to exchange healthcare images over the Internet. The Digital Image and Communication in Medicine (DICOM) provides security features for image header information but not for the pixel information. Hence to send the pixel information in a highly secured manner, the pixels need to be encrypted by using a suitable encryption algorithm. The number of pixel changing rate (NPCR) and the unified averaged changed intensity (UACI) are well-known encryption evaluation metrics to analyse the differential attack in image encryption. These two values are used to calculate the average number of pixel changes and intensity changes between two encrypted images before and after modifying any one pixel in a plaintext image respectively. If these two values are high, then the image encryption can resist the differential attacks. In this paper, a theoretical value of NPCR and UACI are computed for DICOM image encryption concerning different significant levels. An encryption algorithm with Gould transform, RC5, logistic map and DNA Diffusion is proposed for DICOM image to increase the NPCR, and UACI value and this method offered an efficient security strategy for DICOM pixel information. Finally, the computed theoretical value of NPCR and UACI are compared with the existing and proposed algorithm.

The widespread use of images, especially color images and rapid advancement of computer science, have led to an emphasis on securing these images and defending them against intruders. One of the most popular ways to protect images is to use encryption algorithms that convert data in a way that is not recognized by someone other than the intended user. The Advanced Encryption Standard algorithm (AES) is one of the most protected encryption algorithms. However, due to various types of theoretical and practical assaults, like a statistical attack, differential analysis, and brute force attack, its security is under attack.
 In this paper, a modified AES coined as (M-AES) is proposed to improve the efficiency of the AES algorithm by increasing the algorithm's security to make the algorithm more suitable for color image encryption, and make it more resistant to many attacks. The modification is conducted on ShiftRows transformation of the original AES algorithm. To test the efficiency of the proposed M-AES algorithm, several images are drawn from the Signal and Image Processing Institute's (SIPI) image dataset. Moreover, the Mean Square Error (MSE), Peak Signal-to-Noise Ratio (PSNR), Entropy (H), Correlation Coefficient (CC), visual evaluation of histogram, Number of Pixels Change Rate (NPCR) and Unified Average Changing Intensity (UACI) are used as an evaluation metric. The results show that proposed modification to the AES algorithm makes the algorithm more appropriate to image and surpasses the original AES. 
 The modification is conducted on ShiftRows step of the original AES algorithm. To test the efficiency of the proposed M-AES algorithm, several images are drawn from the signal and image processing institute's (SIPI) image dataset. Moreover, the mean square error (MSE), peak signal-to-noise ratio (PSNR), entropy (H), correlation coefficient (CC), visual evaluation of histogram, number of pixels change rate (NPCR) and unified average changing intensity (UACI) are used as an evaluation metrics. The results show that the suggested modification to AES makes it's more appropriate to the image and surpasses the original AES.

Medical images are regarded as important and sensitive data in the medical informatics systems. For transferring medical images over an insecure network, developing a secure encryption algorithm is necessary. Among the three main properties of security services (i.e., confidentiality, integrity, and availability), the confidentiality is the most essential feature for exchanging medical images among physicians. The Goldreich Goldwasser Halevi (GGH) algorithm can be a good choice for encrypting medical images as both the algorithm and sensitive data are represented by numeric matrices. Additionally, the GGH algorithm does not increase the size of the image and hence, its complexity will remain as simple as O(n2). However, one of the disadvantages of using the GGH algorithm is the Chosen Cipher Text attack. In our strategy, this shortcoming of GGH algorithm has been taken in to consideration and has been improved by applying the padding (i.e., snail tour XORing), before the GGH encryption process. For evaluating their performances, three measurement criteria are considered including (i) Number of Pixels Change Rate (NPCR), (ii) Unified Average Changing Intensity (UACI), and (iii) Avalanche effect. The results on three different sizes of images showed that padding GGH approach has improved UACI, NPCR, and Avalanche by almost 100%, 35%, and 45%, respectively, in comparison to the standard GGH algorithm. Also, the outcomes will make the padding GGH resist against the cipher text, the chosen cipher text, and the statistical attacks. Furthermore, increasing the avalanche effect of more than 50% is a promising achievement in comparison to the increased complexities of the proposed method in terms of encryption and decryption processes.

A wrist-based photoplethysmography (PPG) tool offers a simple and non-invasive approach for applications in vital sign monitoring and healthcare. However, in a telecare network, these physiological signals ensure the authorisation demands for the domain of medical applications. Hence, this study proposes an intelligent method for PPG signal encryption and decryption. This method combines chaotic map and radial basis function network (RBFN) into symmetric cryptography with an adaptive scheme. The sine-power chaotic map is used as a key generator of 256 non-ordered numbers (key space) to set the private cipher codes. Two RBFNs are used to train an encryptor and a decryptor with the authorised cipher codes. Its substitution-based infosecurity scheme can change the numerical values of PPG raw data for each encrypted communication, and the decrypted PPG data are further applied for time- and frequency-domain analyses in clinical applications, such as heart and respiration rate analysis and arterial stiffness and upper extremity vascular disease evaluations. Through experimental results, the security levels are validated using the number of pixel change rate (NPCR), unified averaged changed intensity (UACI), and correlation analysis. The average NPCR, UACI, and correlation coefficient (CC) are 96.57%, 35.43%, and 0.005, respectively, between the plain PPG and the encrypted PPG data against hacker attacks. The larger-the-better of NPCR and UACI indexes and the smaller-the-better of CC index are obtained to evaluate the efficiency of the proposed cryptography method. The encrypted PPG also guarantees physiological signals of good quality in clinical applications. In addition, the performance of RBFN-based method is superior in adaptive learning capability than that of the traditional learning method in real-time applications.

Differential evolution (DE) is a powerful evolutionary algorithms, widely applied in different fields of science and engineering for solving the problem of optimization. Since image encryption has been viewed as an interesting research topic by many experts and innumerable methods to encrypt images have emerged, currently, the focus is on obtaining optimized images. The paper presents a novel image encryption scheme that uses intertwining logistic map (ILM), DNA encoding and DE optimization. The proposed approach is based on three phases: permutation involving ILM, diffusion engaging DNA and optimization using DE. Parameters like entropy, key sensitivity, secret key space, unified average change in intensity (UACI), correlation coefficient —vertical, horizontal and diagonal, and number of pixel change rate have been evaluated to test the efficiency of the proposed method. The paper also compares this performance with that of the genetic algorithms (GA), used previously for optimization. The significance of this approach is enhancing entropy, the essential characteristic of randomness, resisting against numerous statistical and differential attacks and generating good experimental results. The main contribution of this paper is to present the efficiency of DE in image optimization and exhibit how DE is better than GA.

In this paper, an efficient and low‐cost cryptographic system for highly secure image encryption is presented. The proposed image encryption structure is implemented based on the key processing (KP) stage, the processing of the input image (PII) stage, and the round function (KPPII‐RF). The key processing stage and the processing of the input image stage are used to increase key sensitivity and plain‐image sensitivity, respectively. The method is independent of the input image and the bit pattern of the main key, and no information is affected by the main key and the original image. In the proposed method, three parameters, the main key, the counter value, and the previously generated ciphertext, are utilized within the encryption process to produce each subsequent ciphertext. Because this method uses the previous ciphertext to generate the next ciphertext, it increases the confusion of the final result and provides better security against differential attacks. The most important innovations of this work include the simultaneous use of various techniques such as shuffling key bits by the key processing unit, shuffling pixels of the original image by the original image processing unit, utilizing a parameter known as a seed as a unique parameter for an image, and employing an appropriate round function to apply complexity to the data. The performance of the proposed structure is evaluated based on different security analyses. The information entropy values of the encrypted images based on the proposed scheme are higher than 7.995, while correlation values are very close to zero. Furthermore, the number of pixel change rate (NPCR) and unified average change intensity (UACI) for the proposed KPPII‐RF image encryption are higher than 99.5% and 33.3, respectively. The KPPII‐RF image encryption is verified for randomness through 16 NIST benchmark statistical tests from the NIST SP 800‐22 suite. The proposed structure provides an acceptable security level for image encryption.

Cancelable biometric techniques play a vital role in the privacy and security of remote surveillance systems to keep the genuine users’ confidential data safe and away from intruders. This research presents an efficient cancelable biometric framework by exploiting an irreversible hybrid encryption technique that incorporates Deoxyribonucleic, Ribonucleic acid sequences (DNA and RNA), and the evolutionary optimization technique of the Genetic Algorithm (GA). So, these techniques are employed to create completely deformed templates from their original ones. Thus, our main contribution is offering a novel biometric security framework that achieves unique randomness characteristics using RNA and DNA sequences and the evolutionary GA-based encryption scheme. The proposed framework produces an entirely unrecognized biometric template by ciphering the main discriminative features of the biometric traits of the authorized clients. The proposed algorithm is first initialized by creating several encrypted biometric images of the original users by employing the logistic map function. Secondly, the initialized encrypted images are transformed into one vector of a binary array. Then, they are converted to their corresponding introns, exons, and consequently, their relevant codons are stored in the cloud database. Thirdly, these relevant codons are replaced by new ones after generating encrypted RNA lists. The utilized encryption key is extracted from the original biometric image after utilizing excessive permutations between its pixels. Then, the GA-based optimization technique is applied to select the most convenient biometric features. Finally, after employing the GA-based cross-over and mutation operations, the chosen features are used to generate the cancelable biometric traits. To validate the security efficacy of the proposed framework, different six biometric databases are used, which are Olivetti Research Laboratory (ORL) Faces (gray), CASIA v.5 Faces (color), UPOL Iris (gray), Indian Institute of Technology Delhi (IIT Delhi) Ear (color and gray), Fingerprint, and CASIA Palmprint (color and gray). The security performance of the proposed framework is compared to those of recent studies in this field, such as OSH (Optical Scanning Holography) and DRPE (Double Random Phase Encoding). The simulation results prove the superior performance of the proposed framework in terms of all tested evaluation metrics. The proposed framework provides high AROC (Area under the Receiver Operating Characteristic) that reaches 0.9990, low FAR (False Acceptance Rate) of 0.0015, more uniform histograms, high correlation values for genuine users, and complete hidden of biometric features. In addition, from a security perspective, the proposed framework accomplishes good entropy, UACI (unified average changing intensity), and NPCR (number of pixels change rate) values that reach 7.9960, 33.55%, and 99.65%, respectively.

The security of information and digital images has become a major issue during the last three decades. A large number of algorithms for data and image encryptions are reported in the literature. However, many of the proposed algorithms are not suitable in the fields of application, because they are cryptographically weak. In the present work, a novel algorithm for encoding digital images by using a circle map with 3 parameters has been proposed. In this article different images are used for testing the validity of the proposed algorithm. The algorithm has increased the strength of security of the image encryption against cipher-text-only, chosen-plaintext and chosen-cipher-text attacks. The analysis of cryptographic strength has also been performed to confirm the fact. The results of several experimental tests, such as, key space analysis, key sensitivity analysis and statistical analysis show that the proposed algorithm for image cryptosystems provides an efficient and secure way for image encryption. A comparison in terms of correlation between the initial and transformed images, number of pixels change rate (NPCR) and unified average changing intensity (UACI) is also done. Keywords: Circle map, Chaos, Lyapunov exponent, anti-differential attack, NPCR, UACI.

Security and privacy of patients’ information remains a major issue of concern among health practitioners. Therefore, measures must be put in place to ensure that unauthorized individual do not have access to this information. However, the adoption of digital alternative of retrieving and documenting medical information has further opened it up to more attacks. This article presents a modified blowfish algorithm for securing textual and graphical medical information. The F-function used in generating round sub-keys was strengthened so as to produce a strong key that could resist differential attacks. Number of Pixel Change Rate (NPCR) and Unified Average Changing Intensity (UACI) of 98.85% and 33.65% revealed that the modified algorithm is sensitive to changes in its key and also resistive to differential attacks. Furthermore, the modified algorithm demonstrated a better encryption and decryption time than the existing blowfish algorithm.

Secure image transmission is one of the most challenging problems in the age of communication technology. Millions of people use and transfer images for either personal or commercial purposes over the internet. One way of achieving secure image transmission over the network is encryption techniques that convert the original image into a non-understandable or scrambled form, called a cipher image, so that even if the attacker gets access to the cipher they would not be able to retrieve the original image. In this study, chaos-based image encryption and block cipher techniques are implemented and analyzed for image encryption. Arnold cat map in combination with a logistic map are used as native chaotic and hybrid chaotic approaches respectively whereas advanced encryption standard (AES) is used as a block cipher approach. The chaotic and AES methods are applied to encrypt images and are subjected to measures of different performance parameters such as peak signal to noise ratio (PSNR), number of pixels change rate (NPCR), unified average changing intensity (UACI), and histogram and computation time analysis to measure the strength of each algorithm. The results show that the hybrid chaotic map has better NPCR and UACI values which makes it more robust to differential attacks or chosen plain text attacks. The Arnold cat map is computationally efficient in comparison to the other two approaches. However, AES has a lower PSNR value (7.53 to 11.93) and has more variation between histograms of original and cipher images, thereby indicating that it is more resistant to statistical attacks than the other two approaches.

Nowadays, Satellite remote sensing and especially earth observation satellites require improvement when implementing an algorithm using reconfigurable hardware in terms of efficiency, performance, and security level. Furthermore, the transmission of the computed data from the earth observation satellite to the ground station is subject to potential attacks, and data can be corrupted during transmission. The land surface Temperature algorithm is an essential factor that can be extracted from the earth observation satellite. In this paper, we proposed a secure land surface temperature implementation by combining the advanced encryption algorithm and Hamming code implemented on radiation-tolerant Virtex-4QV field programmable gate array (FPGA). The iterative looping technique was used to implement the Advanced Encryption Standard (AES) algorithm with the aim of achieving high throughput and high security levels. The results showed that the proposed hardware implementation consumes 3319 Slices and 2 BRAMs while achieving higher throughput of 1854.82 Mbps. Moreover, we have evaluated the efficiency of the suggested cryptosystem by exploiting security measurement analysis such as Histogram, correlation coefficient, entropy, number of pixels change rate (NPCR), and unified averaged changed intensity (UACI). The proposed cryptosystem results prove the efficiency in terms of hardware consumed and high-security level. This implementation may be utilized, proposed, and even configurable for any earth observation satellites, including nano- and pico-CubeSats since we employed radiation-tolerant FPGA.

Concealing sensitive information inside multimedia is very interesting in secure communication due to its wide application. This study discusses the different difficulties involved in embedding the ciphertext inside video frame without affecting the imperceptibility and the strength resistance against different cyberattacks. The main goal of this study is to suggest a novel technique to conceal encrypted data inside video frames securely. This is done by combining the Laplacian of Gaussian (LoG) edge detection algorithm and Chacha20 encryption algorithm. LoG facilitates to detect the suitable location inside video frame for concealing data. While ChaCha20 is used to encrypt data before embedding them inside these locations, which augmenting data security. The proposed method involves sequence of steps involving detecting edges inside video frames, determining the suitable edges for concealing data, encrypting data by XORing it with the encryption key which is generated using ChaCha20 algorithm, embedding the encrypted data inside the determined edges, and then reconstruct the video frame to rebuild the video that involves the concealed encrypted data and keeping the lowest level of visual distortion. The experimental results showed that combining these two approaches provide fast, robust, and secure method, which can be seen by evaluating the system using mean square error, peak signal-to-noise ratio, correlation, number of pixels change rate, unified average changing intensity, and entropy, these evaluation metrics provide excellent results. This study suggests a strong and novel method to embed the encrypted data inside video frames which can be employed in secure communication, copyright protection, and data authentication. Merging LoG and ChaCha20 algorithms produce perfect results in both security and visual perception quality, that provides a means for farther achievement in secure data embedding techniques.

ABSTRACTRecently, in chaotic cryptography several new techniques have been suggested to develop efficient and secure image encryption algorithm for communication of image over insecure/public channels. Some of these techniques are computationally less complex but fails to provide sufficient security, and some techniques are though highly secured but increases computational overhead for encryption and decryption. This paper presents an efficient bit-plane encryption algorithm using chaotic, quadratic, and cubic maps. The proposed algorithm is based on the confusion, diffusion, and pixel randomisation processes. The encryption security of this technique for different bit-plane has been tested through key space analysis, statistical analysis, entropy analysis, and sensitivity analysis for real time image encryption and transmission. The presented algorithm shows the strength of security in terms of information entropy, peak signal-to-noise ratio (PSNR), number of pixels change rate (NPCR), unified average changing intensity (UACI), and correlation coefficient with the number of encrypted bit planes. It is clear that the strength of security increases with the number of encrypted bit planes, but the presented results demand that the level of security reached to the requirements (expected theoretically according to [C. Fu, et al., Optic Express, 20, 2363–78, Jan. 2012]) after encryption of four to six bit planes with reasonable small encryption/decryption time. This features proved the novelty of the proposed work. The algorithm is tested by the random and pseudo-random sequence of test standard SP 8000-22 released by National Institute of Standard and Technology Commission (NIST).

Recently, there is an increasing demand for efficient and secure transreception of medical images in telemedicine applications. Though a fixed spectrum is allocated to each user, most of the time it remains unused by the concerned user. Cognitive Radio (CR) is a technology that utilizes the unused spectrum efficiently by adopting spectrum sensing concept. This paper proposes an efficient and secure transmission of medical images by adopting CR technology and image encryption technique. Firstly, the novel medical image encryption algorithm is proposed to encrypt the DICOM (Digital Imaging and Communications in Medicine) image effectively. Then, the spectrum sensing technique is carried out via Universal Software Radio Peripheral (USRP) to sense the unused frequency band to transmit the encrypted bio signal. The proposed encryption algorithm combines DNA (Deoxyribo Nucleic Acid) sequence operation and chaotic maps to successfully encrypt the DICOM image pixels. Experimental results are done and various analysis such as Unified Average Changing Intensity (UACI), Number of Pixel Changing Rate (NPCR), entropy estimation and chi-square tests are carried out to validate the sternness of the encryption algorithm.

The majority of imaging techniques use symmetric and asymmetric cryptography algorithms to encrypt digital media. Most of the research works contributed in the literature focus primarily on the Advanced Encryption Standard (AES) algorithm for encryption and decryption. This paper propose an analysis for performing image encryption and decryption by hybridization of Elliptic Curve Cryptography (ECC) with Hill Cipher (HC), ECC with Advanced Encryption Standard (AES) and ElGamal with Double Playfair Cipher (DPC). This analysis is based on the following parameters: (i) Encryption and decryption time, (ii) entropy of encrypted image, (iii) loss in intensity of the decrypted image, (iv) Peak Signal to Noise Ratio (PSNR), (v) Number of Pixels Change Rate (NPCR), and (vi) Unified Average Changing Intensity (UACI). The hybrid process involves the speed and ease of implementation from symmetric algorithms, as well as improved security from asymmetric algorithms. ECC and ElGamal cryptosystems provide asymmetric key cryptography, while HC, AES, and DPC are symmetric key algorithms. ECC with AES are perfect for remote or private communications with smaller image sizes based on the amount of time needed for encryption and decryption. The metric measurement with test cases finds that ECC and HC have a good overall solution for image encryption.