Steganographic Scheme based on Message-Cover matching

Steganography is one of the techniques that enter into the field of information   security, it is the art of dissimulating data into digital files in an imperceptible way that does not arise the suspicion. In this paper, a steganographic method based on the Faber-Schauder discrete wavelet transform is proposed. The embedding of the secret data is performed in Least Significant Bit (LSB) of the integer part of the wavelet coefficients. The secret message is decomposed into pairs of bits, then each pair is transformed into another pair based on a permutation that allows to obtain the most matches possible between the message and the LSB of the coefficients. To assess the performance of the proposed method, experiments were carried out on a large set of images, and a comparison to prior works is accomplished. Results show a good level of imperceptibility and a good trade-off imperceptibility-capacity compared to literature

A Review on Steganography Techniques

Steganography is the science of hiding a secret message in cover media, without any perceptual distortion of the cover media. Using steganography, information can be hidden in the carrier items such as images, videos, sounds files, text files, while performing data transmission. In image steganography field, it is a major concern of the researchers how to improve the capacity of hidden data into host image without causing any statistically significant modification. Therefore, this paper presents most of the recent works that have been conducted on image steganography field and analyzes them to clarify the strength and weakness points in each work separately in order to be taken in consideration for future works in such field.   

New Framework for Code-Mapping-based Reversible Data Hiding in JPEG Images

Code mapping (CM) is an efficient technique of reversible data hiding (RDH) in JPEG images, which embeds data by constructing the mapping relationship between used codes and unused codes in JPEG bitstream. In this paper, we present a new framework to design the CM-based RDH method. Firstly, to suppress the file size expansion and improve the applicability, a new code mapping strategy is proposed. Based on the proposed strategy, the mapped codes are redefined by customizing a new Huffman table thoroughly rather than selected from the unused codes in the original Huffman table. Afterwards, the key issue of designing the CM-based RDH method, i.e., constructing the code mapping, is converted into solving a combinatorial optimization problem. As a realization, a novel CM-based RDH method is introduced by employing the genetic algorithm (GA). Experimental results show that the efficacy of the proposed method with high embedding capacity and no signal distortion while suppressing file size expansion

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)

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