Steganography: a class of secure and robust algorithms

This research work presents a new class of non-blind information hiding algorithms that are stego-secure and robust. They are based on some finite domains iterations having the Devaney's topological chaos property. Thanks to a complete formalization of the approach we prove security against watermark-only attacks of a large class of steganographic algorithms. Finally a complete study of robustness is given in frequency DWT and DCT domains.Comment: Published in The Computer Journal special issue about steganograph

Imperceptible and secure image watermarking using DCT and random spread technique

Watermarking is a copyright protection technique, while cryptography is a message encoding technique. Imperceptibility, robustness, and safety are aspects that are often investigated in watermarking. Cryptography can be implemented to increase watermark security. Beaufort cipher is the algorithm proposed in this research to encrypt watermark. The new idea proposed in this research is the utilization of Beaufort key for watermark encryption process as well as for spread watermark when inserted as PN Sequence substitute with the aim to improve imperceptibility and security aspects. Where PN Sequence is widely used in spread spectrum watermarking technique. Based on the experimental results and testing of the proposed method proved that imperceptibility and watermark security are increased. Improved imperceptibility measured by PSNR rose by about 5dB and so did the MSE score better. Robustness aspect is also maintained which has been proven by the excellent value of NCC

Hybrid chaotic map with L-shaped fractal Tromino for image encryption and decryption

Insecure communication in digital image security and image storing are considered as important challenges. Moreover, the existing approaches face problems related to improper security at the time of image encryption and decryption. In this research work, a wavelet environment is obtained by transforming the cover image utilizing integer wavelet transform (IWT) and hybrid discrete cosine transform (DCT) to completely prevent false errors. Then the proposed hybrid chaotic map with L-shaped fractal Tromino offers better security to maintain image secrecy by means of encryption and decryption. The proposed work uses fractal encryption with the combination of L-shaped Tromino theorem for enhancement of information hiding. The regions of L-shaped fractal Tromino are sensitive to variations, thus are embedded in the watermark based on a visual watermarking technique known as reversible watermarking. The experimental results showed that the proposed method obtained peak signal-to-noise ratio (PSNR) value of 56.82dB which is comparatively higher than the existing methods that are, Beddington, free, and Lawton (BFL) map with PSNR value of 8.10 dB, permutation substitution, and Boolean operation with PSNR value of 21.19 dB and deoxyribonucleic acid (DNA) level permutation-based logistic map with PSNR value of 21.27 dB

A Non-Blind Image Watermarking Method for Copyright Protection

   في هذا البحث ، تم تقديم طريقة العلامة المائية غير العمياء لحماية حقوق النشر الخاصة بالصور الرقمية الملونة. تعتمد هذه الطريقة على مجموعة من التحويلات الرقمية (DWT ، DCT) في مجال التردد. تعتمد عملية التضمين في هذه الطريقة على تقسيم الصورة المضيفة إلى كتل غير متراكبة 16 × 16 واستخدام مقياس إنتروبيا الحافة لاختيار الكتل المناسبة لعملية التضمين لزيادة عدم الإدراك في النظام المقترح. أما بالنسبة لعملية الاستخراج ، فهي تتم بطريقة تتطلب وجود الصورة الأصلية ولكنها تتبع نفس بروتوكول التضمين لاستخراج العلامة المائية المشفرة المضمنة . و لرفع مستوى الأمان ، تم تطبيق طريقة تشفير هجينة باستخدام الخريطة الفوضوية وترميز الحمض النووي لتشفير العلامة المائية قبل تضمينها. تظهر النتائج التجريبية أن الاختلافات بين الصورة ذات العلامة المائية والصورة الأصلية لا يمكن تمييزها. الطريقة المقترحة قاومت بشكل فعال هجمات معالجة الصور الشائعة.    In this paper, a non-blind watermarking method for protecting the copyright of digital color images is introduced. This method based on the combination of digital transforms (DWT, DCT) in the frequency domain. The embedding process in this method depends on the partition of the host image into 16×16 non-overlapped blocks and the use of edge entropy metric to choose the appropriate blocks for the insertion process for the purpose of increasing the imperceptibility of the proposed system. As for the extraction process, it is carried out in a way that requires the presence of the original image but rather follows the same embedding protocol to extract the embedded encrypted watermark. To raise the security level, a hybrid encryption method using the chaotic map and DNA coding has been applied for encrypting the watermark before embedding it. Experimental results demonstrate that the differences between the watermarked image and the original image are indistinguishable. The proposed method is effectively resisted common image processing attacks

Research on digital image watermark encryption based on hyperchaos

The digital watermarking technique embeds meaningful information into one or more watermark images hidden in one image, in which it is known as a secret carrier. It is difficult for a hacker to extract or remove any hidden watermark from an image, and especially to crack so called digital watermark. The combination of digital watermarking technique and traditional image encryption technique is able to greatly improve anti-hacking capability, which suggests it is a good method for keeping the integrity of the original image. The research works contained in this thesis include: (1)A literature review the hyperchaotic watermarking technique is relatively more advantageous, and becomes the main subject in this programme. (2)The theoretical foundation of watermarking technologies, including the human visual system (HVS), the colour space transform, discrete wavelet transform (DWT), the main watermark embedding algorithms, and the mainstream methods for improving watermark robustness and for evaluating watermark embedding performance. (3) The devised hyperchaotic scrambling technique it has been applied to colour image watermark that helps to improve the image encryption and anti-cracking capabilities. The experiments in this research prove the robustness and some other advantages of the invented technique. This thesis focuses on combining the chaotic scrambling and wavelet watermark embedding to achieve a hyperchaotic digital watermark to encrypt digital products, with the human visual system (HVS) and other factors taken into account. This research is of significant importance and has industrial application value