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

Text books untuk mata kuliah pemrograman web

.HTML.And.Web.Design.Tips.And.Techniques.Jan.2002.ISBN.0072228253.pd

debreach: Selective Dictionary Compression to Prevent BREACH and CRIME

University of Minnesota M.S. thesis. July 2017. Major: Computer Science. Advisor: Peter Peterson. 1 computer file (PDF); vi, 81 pages.Compression side-channel attacks like CRIME and BREACH have made compression a liability even though it is a powerful tool for improving efficiency. We present debreach, a step towards a general and robust mitigation for these attacks. A modified DEFLATE compressor with output that is fully backwards-compatible with existing decompressors, debreach has the ability to mitigate compression side-channels by excluding from compression sensitive data (e.g., security tokens, emails) identified either by explicit byte ranges or through string matching. In terms of usability, security, and efficiency, we find that string matching is well-suited to the task of protecting security tokens, but we also find that existing approaches to token security work equally as well. On the other hand, we find explicit byte ranges are well-suited to protect arbitrary content, whereas existing approaches lack in either efficiency or generality. When compared to the widely-used and insecure zlib in realistic scenarios, explicit byte ranges reduce throughput in networked connections by 16-24% on popular website's data, though this still results in a 106-269% improvement over not compressing depending on the available bandwidth. While the reduction is significant, we show that debreach can still improve throughput on connections between 112-208 Mb/s. We end with a discussion of practical use cases for debreach along with suggestions for their implementation and potential improvements to the algorithm

Robust Text Steganography Algorithms for Secure Data Communications

In the era of information technology, a large amount of digital information is distributed over the Internet in the form of videos, images, text, and audio. The main purpose of widespread distribution enables users to share knowledge between one another. As a result, data transmission and information sharing are effected due to malicious activities. Different techniques exist to protect user authentication, data privacy, and copyrights. Two main techniques that improve security and data protection are Cryptography and Steganography. Cryptographic algorithms convert the secret message from plain text into cipher text. Then the message is sent over the communication channel. Steganography hides a secret message inside the carrier media. This proposal will investigate different Steganography algorithms and present novel algorithms employing text file as a carrier file. The proposed model hides secret data in the text file by applying various properties into file font format by inserting special symbols in the text file. In addition, the suggested model can be applied in both Unicode and ASCII code languages, regardless of the text file format. The proposed system achieves a high degree of the main Steganography attributes like hidden ratio, robustness, and transparency. In addition, this proposal provides guidance for other researchers in text Steganography algorithms

Digital audio watermarking for broadcast monitoring and content identification

Copyright legislation was prompted exactly 300 years ago by a desire to protect authors against exploitation of their work by others. With regard to modern content owners, Digital Rights Management (DRM) issues have become very important since the advent of the Internet. Piracy, or illegal copying, costs content owners billions of dollars every year. DRM is just one tool that can assist content owners in exercising their rights. Two categories of DRM technologies have evolved in digital signal processing recently, namely digital fingerprinting and digital watermarking. One area of Copyright that is consistently overlooked in DRM developments is 'Public Performance'. The research described in this thesis analysed the administration of public performance rights within the music industry in general, with specific focus on the collective rights and broadcasting sectors in Ireland. Limitations in the administration of artists' rights were identified. The impact of these limitations on the careers of developing artists was evaluated. A digital audio watermarking scheme is proposed that would meet the requirements of both the broadcast and collective rights sectors. The goal of the scheme is to embed a standard identifier within an audio signal via modification of its spectral properties in such a way that it would be robust and perceptually transparent. Modification of the audio signal spectrum was attempted in a variety of ways. A method based on a super-resolution frequency identification technique was found to be most effective. The watermarking scheme was evaluated for robustness and found to be extremely effective in recovering embedded watermarks in music signals using a semi-blind decoding process. The final digital audio watermarking algorithm proposed facilitates the development of other applications in the domain of broadcast monitoring for the purposes of equitable royalty distribution along with additional applications and extension to other domains

Aesthetic Programming

Aesthetic Programming explores the technical as well as cultural imaginaries of programming from its insides. It follows the principle that the growing importance of software requires a new kind of cultural thinking — and curriculum — that can account for, and with which to better understand the politics and aesthetics of algorithmic procedures, data processing and abstraction. It takes a particular interest in power relations that are relatively under-acknowledged in technical subjects, concerning class and capitalism, gender and sexuality, as well as race and the legacies of colonialism. This is not only related to the politics of representation but also nonrepresentation: how power differentials are implicit in code in terms of binary logic, hierarchies, naming of the attributes, and how particular worldviews are reinforced and perpetuated through computation. Using p5.js, it introduces and demonstrates the reflexive practice of aesthetic programming, engaging with learning to program as a way to understand and question existing technological objects and paradigms, and to explore the potential for reprogramming wider eco-socio-technical systems. The book itself follows this approach, and is offered as a computational object open to modification and reversioning

On the use of NAND flash memory in high-performance relational databases

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.Includes bibliographical references (p. 47-49).High-density NAND flash storage has become relatively inexpensive due to the popularity of various consumer electronics. Recently, several manufacturers have released IDE-compatible NAND flash-based drives in sizes up to 64 GB at reasonable (sub-$1000) prices. Because flash is significantly more durable than mechanical hard drives and requires considerably less energy, there is some speculation that large data centers will adopt these devices. As database workloads make up a substantial fraction of the processing done by data centers, it is interesting to ask how switching to flash-based storage will affect the performance of database systems. We evaluate this question using IDE-based flash drives from two major manufacturers. We measure their read and write performance and find that flash has excellent random read performance, acceptable sequential read performance, and quite poor write performance compared to conventional IDE disks. We then consider how standard database algorithms are affected by these performance characteristics and find that the fast random read capability dramatically improves the performance of secondary indexes and index-based join algorithms. We next investigate using logstructured filesystems to mitigate the poor write performance of flash and find an 8.2x improvement in random write performance, but at the cost of a 3.7x decrease in random read performance. Finally, we study techniques for exploiting the inherent parallelism of multiple-chip flash devices, and we find that adaptive coding strategies can yield a 2x performance improvement over static ones. We conclude that in many cases flash disk performance is still worse than on traditional drives and that current flash technology may not yet be mature enough for widespread database adoption if performance is a dominant factor. Finally, we briefly speculate how this landscape may change based on expected performance of next-generation flash memories.by Daniel Myers.S.M

A Novel Approach of Steganography using Bit plane Slicing and Catalan-Lucas Number Sequence

This paper represents a novel approach of steganography using ModifiedSteganographic algorithm with Catalan-Lucas Series. In this algorithm,Catalan Lucas number sequence represents each RBG component of the image by 16 bits instead of 8 bits. By applying Bit Plane Slicing technique, the cover image is sliced into 48 virtual planes and the message to be hidden is also sliced into 16 virtual planes. These 16 planes of the secret message are hidden into some of the 48 virtual planes of the cover image using the proposed algorithm. This process generates three keys at the sender which are required to extract the message from the stego image at the receiver. This method provides high data security and hiding capacity. The experimental results and the PSNR values are also discussed with the advantages from the security perspective

Data Hiding and Its Applications

Data hiding techniques have been widely used to provide copyright protection, data integrity, covert communication, non-repudiation, and authentication, among other applications. In the context of the increased dissemination and distribution of multimedia content over the internet, data hiding methods, such as digital watermarking and steganography, are becoming increasingly relevant in providing multimedia security. The goal of this book is to focus on the improvement of data hiding algorithms and their different applications (both traditional and emerging), bringing together researchers and practitioners from different research fields, including data hiding, signal processing, cryptography, and information theory, among others