My interests are in linear system algorithms, inverse matrix algorithms, wavelets, image denoising, image compression, cryptography, and steganography.
31
Scopus Publications
799
Scholar Citations
14
Scholar h-index
17
Scholar i10-index
Scopus Publications
An improved blind watermarking scheme for color image copyright protection using Hahn moments Nada I. Elbatawy, Abdelrahman A. Karawia, Mostafa M. El-Gayar, Yasser M. Fouda Scientific Reports, 2026 Ensuring copyright protection against illegal attacks and image processing operations while maintaining blind detection capabilities presents a significant challenge in color image watermarking. To address this issue, in this article, we propose a blind watermarking approach that integrates the Arnold transformation with watermark embedding in the transformed domain. Modified forms of Hahn discrete moments are introduced to effectively extract the key image features within this domain. The watermark is encrypted before being embedded into the magnitudes of the Hahn moments for each block using dither modulation, ensuring robustness against different types of attacks. Additionally, a reconstruction algorithm for color images based on Hahn moments is developed and employed during the watermark extraction phase. Experimental results confirm that the proposed scheme achieves high efficiency in terms of both imperceptibility and robustness. Extensive evaluations demonstrate its superior performance, with its PSNR and SSIM values reaching 64.693 dB and 0.9998, respectively. In the no-attack scenario, a perfect-quality watermark is extracted with BER = 0 and NCC = 1. Under various attacks, including filtering, noise, geometric, and robustness attacks, the proposed scheme continues to extract high-quality watermarks, achieving an average BER of 0.00001 and NCC of 0.9998, thereby outperforming the existing image watermarking techniques.
Privacy-Preserving Federated Learning: Adaptive Quantization and Layer-Specific Differential Privacy With Client Dropout Mitigation Ahmad G. Atia, Abdelrahman A. Karawia, Yasser M. Fouda, Mostafa M. El-Gayar Applied Computational Intelligence and Soft Computing, 2026 This paper presents an enhanced federated learning architecture that addresses key challenges in distributed machine learning through three novel contributions: (1) a theoretically grounded sensitivity analysis for differential privacy that formally derives the Δ parameter for deep learning models, (2) an adaptive quantization scheme that dynamically adjusts to model architecture and layer importance, and (3) a client dropout mitigation strategy using weighted aggregation and historical model averaging. We evaluate our framework on four benchmark datasets, demonstrating superior performance in a unified comparative analysis over FATE and PySyft frameworks. The system integrates AES, RSA, and TLS encryption with differential privacy in a novel framework that maintains model accuracy alongside strong privacy guarantees. We provide a comprehensive theoretical analysis of the sensitivity parameter Δ for convolutional neural networks, demonstrating its dependence on layer depth and gradient norms. Our adaptive quantization approach shows 15%–20% higher compression efficiency compared to uniform quantization while maintaining model accuracy. Experimental results on MNIST, CIFAR‐10, CIFAR‐100, and Fashion‐MNIST demonstrate the system’s effectiveness, achieving accuracies of 98.5%, 85.3%, 65.5%, and 92.1%, respectively, while maintaining ϵ‐differential privacy with ϵ values between 0.3 and 1.0, with formal (ε, δ)‐differential privacy guarantees tracked via the moments accountant method. The proposed client dropout handling method reduces accuracy degradation by up to 40% compared to standard federated averaging under 30% client dropout rates. Comparative analysis with FATE and PySyft shows our approach achieves 16−17% better communication efficiency while maintaining comparable privacy guarantees.
Advanced color image encryption using third-order differential equations and three-dimensional logistic map M. Abdul-Hameed, H. El-Metwally, S. Askar, A. M. Alshamrani, M. Abouhawwash, et al. Aip Advances, 2024 Image encryption stands out as a crucial technique employed to securely transmit images across the Internet. In this paper, we introduce a novel algorithm for encrypting color images. The algorithm is built upon the principles of differential equations, XOR operations, and chaotic maps. First, the plain image is three-dimensional pixel shuffled via a logistic map. Afterward, the differential equations are used as a mathematical tool for encrypting images. The third-order ordinary differential equations are used to encrypt the shuffled images. The color values of the plain image are considered coefficients for the independent variable X. Subsequently, an alternate matrix of the same size is generated using a three-dimensional logistic map, taking into account its color values as the exponents linked to the independent variable X. A set of third-order differential equations emerged, containing an equivalent number of elements as the color values present in the plain image. This set of differential equations is addressed in the following manner: combining XOR and integration three times with respect to the independent variable X for each set of obtained differential equations while treating the integration constant as zero. Ultimately, a set of ordinary equations involving the independent variable X is derived, where the coefficients of X represent color values for the cipher image. The results from experiments and the security analysis affirm the resilience of the proposed algorithm against established security attacks. It exhibits a substantial key space, heightened key sensitivity, and a strong encryption effect.
An image steganography algorithm via a compression and chaotic maps M. Abdelhakm, A. Salah, S. Askar, M. Abouhawwash, A. A. Karawia Aip Advances, 2024 Steganography is widely recognized as an effective method for protecting information via digital media. This paper presents an innovative image steganography algorithm incorporating image compression, chaotic maps, and the least significant bit. The process begins with the compression of a confidential medical image using Huffman encoding. The compressed image then undergoes shuffling, facilitated by the chaotic logistic map. The bits from the shuffled image are discreetly embedded into randomly selected pixels of the cover image, guided by the chaotic piecewise smooth map. The resulting stego image is generated. Statistical analyses are applied to both the cover and stego images for evaluation. The proposed algorithm is compared against state-of-the-art algorithms, and the results demonstrate its superiority over existing methods.
An Image-Encipherment Algorithm Using a Combination of a One-Dimensional Chaotic Map and a Three-Dimensional Piecewise Chaotic Map Sameh Askar, Ahmad Alshamrani, Aesha Elghandour, Abdelrahman Karawia Mathematics, 2023 One-dimensional and three-dimensional piecewise chaotic maps are used to propose an image-encipher technique in this article. First, the logistic map is used to construct the pseudo-random sequence. After that, this sequence is used to scramble the plain image. Next, the three-dimensional piecewise chaotic map has produced a mask of the chaotic sequence. After doing some preprocessing steps on the mask, a bit-wise XOR operation with the mask is applied to the shuffled image. The suggested algorithm is used to encipher and decipher a different range of images. To check the algorithm security and efficiency, the algorithm performance was calculated using multiple statistical tests and compared to several recent algorithms. Furthermore, numerical simulations and experimental data are also used to validate the proposed algorithm’s resistance to various attacks.
Medical image steganographic algorithm via modified LSB method and chaotic map A. A. Karawia Iet Image Processing, 2021 Many methods of hiding information in an image are existing now. The least significant bit is the famous method used in steganographic algorithms. Medical image steganography is a technique used to make the transmission of these images secure so that the decision of the Specialist physician based on these images is not affected. In this paper, medical image steganographic algorithm using modified least significant bit and chaotic map is proposed. The main problem is that the selection of embedding pixels within the host image is not protected enough in most existing methods. So, the author used two-dimensional piecewise smooth chaotic map to select the positions of these pixels randomly. On the other hand, all bits in the secret medical image are transmitted without losing any bit. To do that, the secret medical image is encrypted using one-dimensional piecewise chaotic map (Tent map). Then, the steganographic algorithm is used to hide the bits of the encrypted secret medical image. The bits of each embedded pixel are shuffled before the embedding pro-cess randomly. After that, the stego image is created. The host image and stego image are analysed with the peak signal-to-noise ratio, the mean square error, histogram test, image quality measure and relative entropy test. The stego image displays acceptable result when comparing with the host image. Also, the chi-square attack test is performed and the stego image can resist it. The proposed algorithm can assist the sending of medical images via communication media.
Cryptographic algorithm using newton-raphson method and general bischi-naimzadah duopoly system Abdelrahman Karawia Entropy, 2021 Image encryption is an excellent method for the protection of image content. Most authors used the permutation-substitution model to encrypt/decrypt the image. Chaos-based image encryption methods are used in this model to shuffle the rows/columns and change the pixel values. In parallel, authors proposed permutation using non-chaotic methods and have displayed good results in comparison to chaos-based methods. In the current article, a new image encryption algorithm is designed using combination of Newton-Raphson’s method (non-chaotic) and general Bischi-Naimzadah duopoly system as a hyperchaotic two-dimensional map. The plain image is first shuffled by using Newton-Raphson’s method. Next, a secret matrix with the same size of the plain image is created using general Bischi-Naimzadah duopoly system. Finally, the XOR between the secret matrix and the shuffled image is calculated and then the cipher image is obtained. Several security experiments are executed to measure the efficiency of the proposed algorithm, such as key space analysis, correlation coefficients analysis, histogram analysis, entropy analysis, differential attacks analysis, key sensitivity analysis, robustness analysis, chosen plaintext attack analysis, computational analysis, and NIST statistical Tests. Compared to many recent algorithms, the proposed algorithm has good security efficiency.
Female facial beauty analysis for assesment of facial attractivness Proceedings of the 2013 2nd International Conference on Information Management in the Knowledge Economy Imke 2013, 2013
An improved blind watermarking scheme for color image copyright protection using Hahn moments NI Elbatawy, AA Karawia, MM El-Gayar, YM Fouda Scientific Reports 16 (1), 13027 , 2026 2026
Enhanced Image Encryption Scheme Utilizing Charlier Moments and Modified Chaotic Mapping SA Elanany, AA Karawia, YM Fouda International Journal of Wireless and Microwave Technologies 15, 1-17 , 2025 2025 Citations: 1
Advanced color image encryption using third-order differential equations and three-dimensional logistic map M Abdul-Hameed, H El-Metwally, S Askar, AM Alshamrani, ... AIP Advances 14 (7) , 2024 2024 Citations: 2
An image steganography algorithm via a compression and chaotic maps M Abdelhakm, A Salah, S Askar, M Abouhawwash, AA Karawia AIP Advances 14 (4) , 2024 2024 Citations: 2
An image-encipherment algorithm using a combination of a one-dimensional chaotic map and a three-dimensional piecewise chaotic map S Askar, A Alshamrani, A Elghandour, A Karawia Mathematics 11 (2), 352 , 2023 2023 Citations: 4
Image encryption via a 2-d logistic-baker map and fractional discrete meixner moments AA Karawia, YM Fouda 2022 Citations: 1
A Breakdown Free Numerical Algorithm for Inverting General Tridiagonal Matrices M El-Mikkawy, A Karawia arXiv preprint arXiv:2208.12843 , 2022 2022 Citations: 1
A Hybrid Numerical Algorithm for Evaluating n-th Order Tridiagonal Determinants M El-Mikkawy, AR Karawia arXiv preprint arXiv:2207.11157 , 2022 2022
A new cryptographic algorithm via a two-dimensional chaotic map A Elghandour, A Salah, A Karawia Ain Shams Engineering Journal 13 (1), 101489 , 2022 2022 Citations: 53
Medical image steganographic algorithm via modified LSB method and chaotic map AA Karawia IET Image Processing 15 (11), 2580-2590 , 2021 2021 Citations: 22
New encryption algorithm using bit-level permutation and non-invertible chaotic map AA Karawia, YA Elmasry IEEE Access 9, 101357-101368 , 2021 2021 Citations: 29
An image encryption algorithm based on bisection method and one-dimensional piecewise chaotic map AN Elghandour, AM Salah, YA Elmasry, AA Karawia IEEE Access 9, 43411-43421 , 2021 2021 Citations: 39
Cryptographic algorithm using newton-raphson method and general bischi-naimzadah duopoly system A Karawia Entropy 23 (1), 57 , 2020 2020 Citations: 5
Image encryption based on fisher‐yates shuffling and three dimensional chaotic economic map A Karawia IET Image Processing 13 (12), 2086-2097 , 2019 2019 Citations: 31
An algorithm of image encryption using logistic and two-dimensional chaotic economic maps SS Askar, AA Karawia, A Al-Khedhairi, FS Al-Ammar Entropy 21 (1), 44 , 2019 2019 Citations: 89
Encryption algorithm of multiple-image using mixed image elements and two dimensional chaotic economic map AA Karawia Entropy 20 (10), 801 , 2018 2018 Citations: 49
Cryptographic algorithm based on pixel shuffling and dynamical chaotic economic map SS Askar, AA Karawia, FS Alammar IET Image Processing 12 (1), 158-167 , 2018 2018 Citations: 45
A New Recursive Algorithm For Inverting A General Comrade Matrix AA Karawia ARS COMBINATORIA 130, 205-213 , 2017 2017
On solving comrade linear systems via transformations A Karawia, S Askar British Journal of Mathematics & Computer Science 18 (1), 1-8 , 2016 2016 Citations: 2
On the inverse of general cyclic heptadiagonal matrices AA Karawia ARS COMBINATORIA 125, 161-171 , 2016 2016 Citations: 1
MOST CITED SCHOLAR PUBLICATIONS
Inversion of general tridiagonal matrices M El-Mikkawy, A Karawia Applied Mathematics Letters 19 (8), 712-720 , 2006 2006 Citations: 135
An algorithm of image encryption using logistic and two-dimensional chaotic economic maps SS Askar, AA Karawia, A Al-Khedhairi, FS Al-Ammar Entropy 21 (1), 44 , 2019 2019 Citations: 89
Image encryption algorithm based on chaotic economic model SS Askar, AA Karawia, A Alshamrani Mathematical Problems in Engineering 2015 (1), 341729 , 2015 2015 Citations: 63
A new cryptographic algorithm via a two-dimensional chaotic map A Elghandour, A Salah, A Karawia Ain Shams Engineering Journal 13 (1), 101489 , 2022 2022 Citations: 53
A computational algorithm for solving periodic penta-diagonal linear systems AA Karawia Applied mathematics and computation 174 (1), 613-618 , 2006 2006 Citations: 51
Encryption algorithm of multiple-image using mixed image elements and two dimensional chaotic economic map AA Karawia Entropy 20 (10), 801 , 2018 2018 Citations: 49
Cryptographic algorithm based on pixel shuffling and dynamical chaotic economic map SS Askar, AA Karawia, FS Alammar IET Image Processing 12 (1), 158-167 , 2018 2018 Citations: 45
An image encryption algorithm based on bisection method and one-dimensional piecewise chaotic map AN Elghandour, AM Salah, YA Elmasry, AA Karawia IEEE Access 9, 43411-43421 , 2021 2021 Citations: 39
The use of the Sherman–Morrison–Woodbury formula to solve cyclic block tri-diagonal and cyclic block penta-diagonal linear systems of equations M Batista, ARAI Karawia Applied Mathematics and Computation 210 (2), 558-563 , 2009 2009 Citations: 35
On solving pentadiagonal linear systems via transformations SS Askar, AA Karawia Mathematical Problems in Engineering 2015 (1), 232456 , 2015 2015 Citations: 32
Image encryption based on fisher‐yates shuffling and three dimensional chaotic economic map A Karawia IET Image Processing 13 (12), 2086-2097 , 2019 2019 Citations: 31
New encryption algorithm using bit-level permutation and non-invertible chaotic map AA Karawia, YA Elmasry IEEE Access 9, 101357-101368 , 2021 2021 Citations: 29
Medical image steganographic algorithm via modified LSB method and chaotic map AA Karawia IET Image Processing 15 (11), 2580-2590 , 2021 2021 Citations: 22
Two algorithms for solving comrade linear systems AA Karawia Applied mathematics and computation 189 (1), 291-297 , 2007 2007 Citations: 14
Symbolic algorithm for solving comrade linear systems based on a modified Stair-Diagonal Approach AA Karawia Applied Mathematics Letters 26 (9), 913-918 , 2013 2013 Citations: 12
On solving a general bordered tridiagonal linear system AA Karawia, QM Rizvi International Journal of Mathematical Sciences 33 (2) , 2013 2013 Citations: 11
Female facial beauty analysis for assesment of facial attractivness QM Rizvi, AA Karawia, S Kumar 2013 2nd international conference on information management in the knowledge … , 2013 2013 Citations: 10
New double periodic and solitary wave solutions to the modified Kawahara equation A Elgarayhi, AA Karawia International Journal of Nonlinear Science 7 (4), 414-419 , 2009 2009 Citations: 8
Two algorithms for solving general backward pentadiagonal linear systems AA Karawia International Journal of Computer Mathematics 87 (12), 2823-2830 , 2010 2010 Citations: 7
Cryptographic algorithm using newton-raphson method and general bischi-naimzadah duopoly system A Karawia Entropy 23 (1), 57 , 2020 2020 Citations: 5