Vector-based Efficient Data Hiding in Encrypted Images via Multi-MSB Replacement

As an essential technique for data privacy protection, reversible data hiding in encrypted images (RDHEI) methods have drawn intensive research interest in recent years. In response to the increasing demand for protecting data privacy, novel methods that perform RDHEI are continually being developed. We propose two effective multi-MSB (most significant bit) replacement-based approaches that yield comparably high data embedding capacity, improve overall processing speed, and enhance reconstructed images' quality. Our first method, Efficient Multi-MSB Replacement-RDHEI (EMR-RDHEI), obtains higher data embedding rates (DERs, also known as payloads) and better visual quality in reconstructed images when compared with many other state-of-the-art methods. Our second method, Lossless Multi-MSB Replacement-RDHEI (LMR-RDHEI), can losslessly recover original images after an information embedding process is performed. To verify the accuracy of our methods, we compared them with other recent RDHEI techniques and performed extensive experiments using the widely accepted BOWS-2 dataset. Our experimental results showed that the DER of our EMR-RDHEI method ranged from 1.2087 bit per pixel (bpp) to 6.2682 bpp with an average of 3.2457 bpp. For the LMR-RDHEI method, the average DER was 2.5325 bpp, with a range between 0.2129 bpp and 6.0168 bpp. Our results demonstrate that these methods outperform many other state-of-the-art RDHEI algorithms. Additionally, the multi-MSB replacement-based approach provides a clean design and efficient vectorized implementation.Comment: 14 pages; journa

Privacy-preserving information hiding and its applications

The phenomenal advances in cloud computing technology have raised concerns about data privacy. Aided by the modern cryptographic techniques such as homomorphic encryption, it has become possible to carry out computations in the encrypted domain and process data without compromising information privacy. In this thesis, we study various classes of privacy-preserving information hiding schemes and their real-world applications for cyber security, cloud computing, Internet of things, etc. Data breach is recognised as one of the most dreadful cyber security threats in which private data is copied, transmitted, viewed, stolen or used by unauthorised parties. Although encryption can obfuscate private information against unauthorised viewing, it may not stop data from illegitimate exportation. Privacy-preserving Information hiding can serve as a potential solution to this issue in such a manner that a permission code is embedded into the encrypted data and can be detected when transmissions occur. Digital watermarking is a technique that has been used for a wide range of intriguing applications such as data authentication and ownership identification. However, some of the algorithms are proprietary intellectual properties and thus the availability to the general public is rather limited. A possible solution is to outsource the task of watermarking to an authorised cloud service provider, that has legitimate right to execute the algorithms as well as high computational capacity. Privacypreserving Information hiding is well suited to this scenario since it is operated in the encrypted domain and hence prevents private data from being collected by the cloud. Internet of things is a promising technology to healthcare industry. A common framework consists of wearable equipments for monitoring the health status of an individual, a local gateway device for aggregating the data, and a cloud server for storing and analysing the data. However, there are risks that an adversary may attempt to eavesdrop the wireless communication, attack the gateway device or even access to the cloud server. Hence, it is desirable to produce and encrypt the data simultaneously and incorporate secret sharing schemes to realise access control. Privacy-preserving secret sharing is a novel research for fulfilling this function. In summary, this thesis presents novel schemes and algorithms, including: • two privacy-preserving reversible information hiding schemes based upon symmetric cryptography using arithmetic of quadratic residues and lexicographic permutations, respectively. • two privacy-preserving reversible information hiding schemes based upon asymmetric cryptography using multiplicative and additive privacy homomorphisms, respectively. • four predictive models for assisting the removal of distortions inflicted by information hiding based respectively upon projection theorem, image gradient, total variation denoising, and Bayesian inference. • three privacy-preserving secret sharing algorithms with different levels of generality

Efficient and Robust Video Steganography Algorithms for Secure Data Communication

Over the last two decades, the science of secretly embedding and communicating data has gained tremendous significance due to the technological advancement in communication and digital content. Steganography is the art of concealing secret data in a particular interactive media transporter such as text, audio, image, and video data in order to build a covert communication between authorized parties. Nowadays, video steganography techniques are important in many video-sharing and social networking applications such as Livestreaming, YouTube, Twitter, and Facebook because of noteworthy developments in advanced video over the Internet. The performance of any steganography method, ultimately, relies on the imperceptibility, hiding capacity, and robustness against attacks. Although many video steganography methods exist, several of them lack the preprocessing stages. In addition, less security, low embedding capacity, less imperceptibility, and less robustness against attacks are other issues that affect these algorithms. This dissertation investigates and analyzes cutting edge video steganography techniques in both compressed and raw domains. Moreover, it provides solutions for the aforementioned problems by proposing new and effective methods for digital video steganography. The key objectives of this research are to develop: 1) a highly secure video steganography algorithm based on error correcting codes (ECC); 2) an increased payload video steganography algorithm in the discrete wavelet domain based on ECC; 3) a novel video steganography algorithm based on Kanade-Lucas-Tomasi (KLT) tracking and ECC; 4) a robust video steganography algorithm in the wavelet domain based on KLT tracking and ECC; 5) a new video steganography algorithm based on the multiple object tracking (MOT) and ECC; and 6) a robust and secure video steganography algorithm in the discrete wavelet and discrete cosine transformations based on MOT and ECC. The experimental results from our research demonstrate that our proposed algorithms achieve higher embedding capacity as well as better imperceptibility of stego videos. Furthermore, the preprocessing stages increase the security and robustness of the proposed algorithms against attacks when compared to state-of-the-art steganographic methods

Enhancing The Performance Of Digital Image Data Hiding Using Reduced Difference Expansion Technique And Constant Base Point

The last few decades have been marked by a rapid growth and significant enhancement of the internet infrastructures, i.e., the internet has become a broad network enabling many enterprises around the world to interact while sharing multimedia data. Nevertheless, this technology has brought many challenges related to securing private and sensitive information which has led to the application of cryptography technique as a mean for securing data by encrypting them. However, since the encrypted data can be seen by active and sophisticated intruders during the transmission, this may lead to its suspicion which can result in unauthorized access. Thereby, data hiding (which is also called information hiding) is another technique for securing commutation via the public network. Data hiding is one of the best and most challenging fields dealing with securing organizational sensitive information due to many factors such as identity theft, information phishing, user privacy, network policy violation, contents and copyright protection. It is performed by utilizing some carriers to conceal private information which is further extracted later to verify and validate the genuineness. Digital steganography has been recognized among the recent and most popular data hiding techniques. Steganography is the practice of concealing confidential information in the codes that make up the digital files. Such digital files can be an image, audio, video, and text. Different from cryptography, however, steganography provides security by disguising the presence of communication. It originates from the concept that if the communication is visible, the suspicion or attack is obvious. Hence, the main goal is to always disguise the presence of the hidden confidential data. Recently, various data iv hiding methods based on digital image steganography have been already suggested by several researchers around the globe. The main goal was to improve the security, embedding capacity and the quality of the stego image. However, research have shown that there is still a challenge to achieve a good visual quality of the stego media while preserving a good embedding capacity. In this direction, this study aims at proposing a new data hiding approach that enhances the quality of the stego image and the embedding capacity. That is, the suggested approach enhances the existing data hiding methods by utilizing pixel block, constant base point for each pixel block and the reduced difference expansion scheme (RDE-scheme) for grayscale digital images. Accordingly, the suggested enhancement is detailed as follows. First, the existing reduced difference expansion scheme (RDE-scheme) for reducing the difference values is enhanced in order to get possible small values to be used while concealing the secret data into the cover image. The main objective behind this enhancement is to allow data to be concealed while preserving the quality of the stego image. Notice that the suggested RDE-scheme does not only enhance the quality but also it solves the problem of underflow and overflow. The underflow is encountered when the pixel value in the stego image is below 0 (Pixel value < 0) while the overflow occurs when it is greater than 255 (Pixel value > 255). Second, the new constant base point for each pixel block is chosen differently for the sake of increasing the visual quality of the stego image. Third, we have adjusted the size of the pixel block which achieves a high embedding capacity while distorting the cover media from quad of quad (4 × 4 ) to quad, block of size 2 by 2 (2 × 2). Besides, the effect of varying the size of the secret data with respect to the quality of the stego image is also investigated throughout this study. Overall, based on the experimental results, good visual quality of the stego image which is evaluated by measuring the peak signal-to-noise ratio (PSNR) and good embedding capacity (measured in bits) are yielded compared to the previous approach, i.e., the proposed method is effective in terms of maintaining both visual quality of the stego image and the embedding capacity. Index terms— Data hiding, information security, reduced difference expansion, digital steganography, cover image, stego image, confidential data =================================================================================================== Beberapa dekade terakhir internet telah menjadi jaringan luas yang memungkinkan banyak perusahaan di seluruh dunia untuk berinteraksi sambil berbagi data multimedia. Ini merupakan tanda bahwa infrastruktur internet telah tumbuh dan berkembang secara signifikan. Namun, teknologi ini memiliki banyak tantangan dalam hal pengamanan informasi yang bersifat sensitif dan pribadi sehingga mendorong penerapan teknik kriptografi untuk mengamankan data dengan cara mengenkripsinya. Teknik kriptografi memiliki kekurangan yaitu hasil enkripsi dapat dilihat oleh penyusup (intruders) selama transmisi sehingga menyebabkan kecurigaan yang berakibat pada tindakan akses yang bersifat ilegal. Untuk mengurangi hal ini, data hiding dapat dimanfaatkan untuk mengamankan informasi tersebut. Data hiding adalah salah satu teknik terbaik untuk mendapatkan data tetapi memiliki banyak tantangan permasalahan seperti pencurian identitas, phising, pelanggaran kebijakan jaringan dan hak cipta. Untuk mendapatkan kemanan data, data hiding memanfaatkan beberapa media untuk menyembunyikan informasi dan dapat diekstrak untuk memverifikasi keasliannya. Salah satu teknik data hiding yang paling terkenal adalah steganografi digital. Teknik ini menyembunyikan informasi rahasia kedalam file digital seperti citra digital, audio, video dan teks. Berbeda dengan kriptografi, steganografi memberikan keamanan informasi dengan menyamarkannya dalam file digital. Penyebab digunakannya tindakan ini adalah jika komunikasi terlihat maka akan mengundang kecurigaan yang mengakibatkan terjadi serangan seperti yang dijelaskan sebelumnya. Oleh karena itu, tujuan utama dari teknik ini adalah menyamarkan informasi rahasia dengan vi menyembunyikannya kedalam file yang digunakan. Akhir-akhir ini, beberapa teknik data hiding dengan menggunakan citra digital telah banyak dikembangkan oleh beberapa peneliti di seluruh dunia. Tujuan utama mereka adalah untuk meningkatkan keamanan, kapasitas penyisipan dan kualitas dari citra stego. Sampai saat ini, banyak penelitian yang menunjukkan bahwa masih menjadi tantangan untuk mendapatkan kualitas media stego yang baik dengan kapasitas penyisipan yang tinggi. Dengan maksud yang sama, penelitian ini mengusulkan konsep pendekatan baru dalam hal data hiding yang dapat meningkatkan kualitas dan kapasitas dari citra stego. Pendekatan tersebut dilakukan dengan cara meningkatkan metode data hiding yang sudah ada dengan memanfaatkan blok piksel, penentuan base point yang konsisten untuk masing-masing blok dan mereduksi difference expansion untuk citra abu-abu. Rincian dari pendekatan tersebut adalah sebagai berikut. Pertama, skema reduksi difference expansion (RDE) ditingkatkan untuk mendapatkan nilai terkecil yang akan digunakan dalam penyembunyian data kedalam citra carrier. Tujuannya adalah memungkinkan data dapat disisipkan dengan tetap menjaga kualitas citra stego tetap baik. Perlu diketahui bahwa usulan skema RDE tidak hanya meningkatkan kualitas tetapi juga menyelesaikan masalah overflow dan underflow. Underfow merupakan kondisi piksel dalam citra stego bernilai kurang dari 0 sedangkan overflow terjadi ketika nilai piksel melebihi 255. Kedua, base-point yang bersifat konstan untuk masing-masing blok piksel akan dipilih secara berbeda untuk dapat meningkatkan kualitas visual dari citra stego. Ketiga, kami mengatur ukuran blok dari quad of quad (4x4) yang memiliki kualitas citra stego kurang baik menjadi 2x2. Hal lain yang kami lakukan adalah mengetahui efek dari besar ukuran data yang digunakan dalam proses penyisipan. Secara keseluruhan, berdasarkan hasil eksperimen, usulan pendekatan ini memiliki kemampuan yang lebih baik dibandingkan dengan penelitian sebelumnya yang ditandai dengan kapasitas penyisipan yang lebih tinggi dan kualitas visual citra stego yang baik yang diukur menggunakan metode signal-to-noise ratio (PSNR)

Data Hiding in Digital Video

With the rapid development of digital multimedia technologies, an old method which is called steganography has been sought to be a solution for data hiding applications such as digital watermarking and covert communication. Steganography is the art of secret communication using a cover signal, e.g., video, audio, image etc., whereas the counter-technique, detecting the existence of such as a channel through a statistically trained classifier, is called steganalysis. The state-of-the art data hiding algorithms utilize features; such as Discrete Cosine Transform (DCT) coefficients, pixel values, motion vectors etc., of the cover signal to convey the message to the receiver side. The goal of embedding algorithm is to maximize the number of bits sent to the decoder side (embedding capacity) with maximum robustness against attacks while keeping the perceptual and statistical distortions (security) low. Data Hiding schemes are characterized by these three conflicting requirements: security against steganalysis, robustness against channel associated and/or intentional distortions, and the capacity in terms of the embedded payload. Depending upon the application it is the designer\u27s task to find an optimum solution amongst them. The goal of this thesis is to develop a novel data hiding scheme to establish a covert channel satisfying statistical and perceptual invisibility with moderate rate capacity and robustness to combat steganalysis based detection. The idea behind the proposed method is the alteration of Video Object (VO) trajectory coordinates to convey the message to the receiver side by perturbing the centroid coordinates of the VO. Firstly, the VO is selected by the user and tracked through the frames by using a simple region based search strategy and morphological operations. After the trajectory coordinates are obtained, the perturbation of the coordinates implemented through the usage of a non-linear embedding function, such as a polar quantizer where both the magnitude and phase of the motion is used. However, the perturbations made to the motion magnitude and phase were kept small to preserve the semantic meaning of the object motion trajectory. The proposed method is well suited to the video sequences in which VOs have smooth motion trajectories. Examples of these types could be found in sports videos in which the ball is the focus of attention and exhibits various motion types, e.g., rolling on the ground, flying in the air, being possessed by a player, etc. Different sports video sequences have been tested by using the proposed method. Through the experimental results, it is shown that the proposed method achieved the goal of both statistical and perceptual invisibility with moderate rate embedding capacity under AWGN channel with varying noise variances. This achievement is important as the first step for both active and passive steganalysis is the detection of the existence of covert channel. This work has multiple contributions in the field of data hiding. Firstly, it is the first example of a data hiding method in which the trajectory of a VO is used. Secondly, this work has contributed towards improving steganographic security by providing new features: the coordinate location and semantic meaning of the object

Entropy in Image Analysis II

Image analysis is a fundamental task for any application where extracting information from images is required. The analysis requires highly sophisticated numerical and analytical methods, particularly for those applications in medicine, security, and other fields where the results of the processing consist of data of vital importance. This fact is evident from all the articles composing the Special Issue "Entropy in Image Analysis II", in which the authors used widely tested methods to verify their results. In the process of reading the present volume, the reader will appreciate the richness of their methods and applications, in particular for medical imaging and image security, and a remarkable cross-fertilization among the proposed research areas