LARGE DATA EMBEDDING; PROBLEM & SOLUTION

The objective of the study was to propose a high capacity data embedding system from DCT domain. The default quantization table is used for fixed mask projection quantization steps. Accordingly, DCT coefficient of the host image from low to higher frequency bands and embed bits from band to band with specially designed base vectors called Hadamard vectors. The embedding scheme procedure is described step wise. The proposed system can be used for data embedding and can be associated with another encryption method to make it safer. The proposed system is reported to be highly robust and secur

A new efficient block matching data hiding method based on scanning order selection in medical images

Digital technology and the widespread use of the Internet has increased the speeds at which digital data can be obtained and shared in daily life. In parallel to this, there are important concerns regarding the confidentiality of private data during data transmissions and the possibility that data might fall into the hands of third parties. Issues relating to data safety can also affect patients' medical images and other information relating to these images. In this study, we propose a new method based on block matching that can be used to hide the patient information in medical images. In this method, 8 scanning orders (6 of which are newly designed) are developed to provide high image quality. By diversifying the number of scanning orders, we aim to achieve the lowest number of bit changes. The performance of the developed method is measured using the number of bits subject to change, the peak signal-to-noise ratio and the mean structural similarity index measure image quality assessment metrics, and steganalysis attacks. The method we developed was found to be more effective in hiding data compared to the classical least significant bit method.https://doi.org/10.3906/elk-1506-18

Sayısal görüntülerde blok ve tarama sırası temelli yeni bir veri gizleme algoritması tasarımı

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Teknolojinin hızlı ilerleyişiyle sayısal veri elde etme oldukça kolay hale gelmiştir. Uçtan uca veri iletiminde ise ister istemez özel veya gizli veriler üçüncü şahısların eline geçebilmektedir. Rahatlıkla veri iletimi gerçekleştirebilmek için, veri gizleme gibi bazı ek önlemlerin alınması gerekmektedir. Gizli veri iletiminin kullanılabileceği yerlerden biri de sayısal görüntülerdir. Amacı veri gizleme olan steganografi bilimi ile istenilen bu gizliliği sağlamak mümkündür. Yapılan bu çalışmada, sayısal görüntülerde kullanılmak üzere blok eşleştirmeli ve tarama sırası seçimli tabanlı LSB tekniğini kullanan yeni bir veri gizleme algoritması geliştirilmiştir. Ana amacı görüntü üzerinde en az değişimi yapmak olan bu yeni algoritmada, görüntü ilk olarak 8×8 boyutunda bloklara ayrılmaktadır. Yaygın olarak kullanılan iki tarama sırasına ilave olarak, yeni tasarlanan altı çeşit tarama sırasıyla bu bloklardaki pikseller taranarak verinin gizleneceği en uygun yer belirlenmektedir. Değişimin en az yapılacağı bloklar ve bunu sağlayan tarama sırası seçilip veriler bu bloklara gizlenmektedir. Oluşan yeni görüntünün piksellerinde böylece en az değişimin yapılması sağlanmıştır. Geliştirilen algoritmanın başarımında ise MSE, PSNR, UQI, MSSIM, CQM, AD, SC, NCC ve NAE kalite ölçütleri kullanılıp yapılan hesaplamaların tamamında en iyi sonuçlar elde edilmiştir. Ayrıca görüntülerde gizli verinin olup/olmadığını ve eğer varsa ortaya çıkarılmasında kullanılan steganaliz ataklarına karşı testler yapılmış, geliştirilen algoritma bu ataklara karşı da başarılı olmuştur. Nihai olarak, algoritmanın kullanılabilmesi için bir yazılım gerçekleştirilmiş, yazılımla tıbbi görüntülerin incelenmesi, rapor hazırlanması ve veri gizlenmesi sağlanmıştır.With the rapid progress of the technology, obtaining of digital data has been become very simple. During data transmissions, special and secret data might fall into the hands of third parties. Data can be protected using some data hiding methods during their transmission through communication. Digital images are the one of the places where confidential data transmission can be used. It is possible to provide the desired privacy with steganography, which aims to hide data. In this study, a new algorithm is proposed that is based on block matching and scanning order selection using LSB to hide information in digital images. The fundamental aim of this study is ensuring as few bit changes as possible on the image, and so, firstly the cover image separated into different sub-blocks and each sub-block has a dimension of 8×8 pixels. To find the best block for secret data, the cover image scanned with eight different scanning orders where two of these scanning orders are commonly used and where six of these scanning orders are newly designed. After scanning progress, blocks are selected which need minimum changes and uses the most suitable one of eight scanning orders. Then the secret data can be hidden in these blocks. So that, the stego image which has secret data, includes minimum changes. The image quality of the stego images obtained via the proposed method has been measured with the MSE, PSNR, UQI, M−SSIM, CQM, AD, SC, NCC and NAE image quality metrics, and best results have been achieved. The results of steganalysis, which is the process used for identifying hidden data within stego images, have been verified the robustness of the stego images. Finally, a software is developed to hide data in medical image, to create report about medical image and to analyze medical image

Steganography-based secret and reliable communications: Improving steganographic capacity and imperceptibility

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Unlike encryption, steganography hides the very existence of secret information rather than hiding its meaning only. Image based steganography is the most common system used since digital images are widely used over the Internet and Web. However, the capacity is mostly limited and restricted by the size of cover images. In addition, there is a tradeoff between both steganographic capacity and stego image quality. Therefore, increasing steganographic capacity and enhancing stego image quality are still challenges, and this is exactly our research main aim. Related to this, we also investigate hiding secret information in communication protocols, namely Simple Object Access Protocol (SOAP) message, rather than in conventional digital files. To get a high steganographic capacity, two novel steganography methods were proposed. The first method was based on using 16x16 non-overlapping blocks and quantisation table for Joint Photographic Experts Group (JPEG) compression instead of 8x8. Then, the quality of JPEG stego images was enhanced by using optimised quantisation tables instead of the default tables. The second method, the hybrid method, was based on using optimised quantisation tables and two hiding techniques: JSteg along with our first proposed method. To increase the steganographic capacity, the impact of hiding data within image chrominance was investigated and explained. Since peak signal-to-noise ratio (PSNR) is extensively used as a quality measure of stego images, the reliability of PSNR for stego images was also evaluated in the work described in this thesis. Finally, to eliminate any detectable traces that traditional steganography may leave in stego files, a novel and undetectable steganography method based on SOAP messages was proposed. All methods proposed have been empirically validated as to indicate their utility and value. The results revealed that our methods and suggestions improved the main aspects of image steganography. Nevertheless, PSNR was found not to be a reliable quality evaluation measure to be used with stego image. On the other hand, information hiding in SOAP messages represented a distinctive way for undetectable and secret communication.The Ministry of Higher Education in Syria and the University of Alepp

Steganography-based secret and reliable communications : improving steganographic capacity and imperceptibility

Unlike encryption, steganography hides the very existence of secret information rather than hiding its meaning only. Image based steganography is the most common system used since digital images are widely used over the Internet and Web. However, the capacity is mostly limited and restricted by the size of cover images. In addition, there is a tradeoff between both steganographic capacity and stego image quality. Therefore, increasing steganographic capacity and enhancing stego image quality are still challenges, and this is exactly our research main aim. Related to this, we also investigate hiding secret information in communication protocols, namely Simple Object Access Protocol (SOAP) message, rather than in conventional digital files. To get a high steganographic capacity, two novel steganography methods were proposed. The first method was based on using 16x16 non-overlapping blocks and quantisation table for Joint Photographic Experts Group (JPEG) compression instead of 8x8. Then, the quality of JPEG stego images was enhanced by using optimised quantisation tables instead of the default tables. The second method, the hybrid method, was based on using optimised quantisation tables and two hiding techniques: JSteg along with our first proposed method. To increase the steganographic capacity, the impact of hiding data within image chrominance was investigated and explained. Since peak signal-to-noise ratio (PSNR) is extensively used as a quality measure of stego images, the reliability of PSNR for stego images was also evaluated in the work described in this thesis. Finally, to eliminate any detectable traces that traditional steganography may leave in stego files, a novel and undetectable steganography method based on SOAP messages was proposed. All methods proposed have been empirically validated as to indicate their utility and value. The results revealed that our methods and suggestions improved the main aspects of image steganography. Nevertheless, PSNR was found not to be a reliable quality evaluation measure to be used with stego image. On the other hand, information hiding in SOAP messages represented a distinctive way for undetectable and secret communication.EThOS - Electronic Theses Online ServiceMinistry of Higher Education in SyriaUniversity of AleppoGBUnited Kingdo

Steganography-based secret and reliable communications : improving steganographic capacity and imperceptibility

Unlike encryption, steganography hides the very existence of secret information rather than hiding its meaning only. Image based steganography is the most common system used since digital images are widely used over the Internet and Web. However, the capacity is mostly limited and restricted by the size of cover images. In addition, there is a tradeoff between both steganographic capacity and stego image quality. Therefore, increasing steganographic capacity and enhancing stego image quality are still challenges, and this is exactly our research main aim. Related to this, we also investigate hiding secret information in communication protocols, namely Simple Object Access Protocol (SOAP) message, rather than in conventional digital files. To get a high steganographic capacity, two novel steganography methods were proposed. The first method was based on using 16x16 non-overlapping blocks and quantisation table for Joint Photographic Experts Group (JPEG) compression instead of 8x8. Then, the quality of JPEG stego images was enhanced by using optimised quantisation tables instead of the default tables. The second method, the hybrid method, was based on using optimised quantisation tables and two hiding techniques: JSteg along with our first proposed method. To increase the steganographic capacity, the impact of hiding data within image chrominance was investigated and explained. Since peak signal-to-noise ratio (PSNR) is extensively used as a quality measure of stego images, the reliability of PSNR for stego images was also evaluated in the work described in this thesis. Finally, to eliminate any detectable traces that traditional steganography may leave in stego files, a novel and undetectable steganography method based on SOAP messages was proposed. All methods proposed have been empirically validated as to indicate their utility and value. The results revealed that our methods and suggestions improved the main aspects of image steganography. Nevertheless, PSNR was found not to be a reliable quality evaluation measure to be used with stego image. On the other hand, information hiding in SOAP messages represented a distinctive way for undetectable and secret communication.EThOS - Electronic Theses Online ServiceMinistry of Higher Education in SyriaUniversity of AleppoGBUnited Kingdo