Steganography is classified as the art of hiding information. In a digital context, this refers to our ability to hide secret messages within innocent digital cover data. The digital domain offers many opportunities for possible cover mediums, such as cloud based hiding (saving secret information within the internet and its structure), image based hiding, video and audio based hiding, text based documents as well as the potential of hiding within any set of compressed data. This dissertation focuses on the image based domain and investigates currently available image based steganographic techniques. After a review of the history of the field, and a detailed survey of currently available JPEG based steganographic systems, the thesis focuses on the systems currently considered to be secure and introduces mechanisms that have been developed to detect them. The dissertation presents a newly developed system that is designed to counter act the current weakness in the YASS JPEG based steganographic system. By introducing two new levels of randomization to the embedding process, the proposed system offers security benefits over YASS. The introduction of randomization to the B‐block sizes as well as the E‐block sizes used in the embedding process aids in increasing security and the potential for new, larger E‐block sizes also aids in providing an increased set of candidate coefficients to be used for embedding. The dissertation also introduces a new embedding scheme which focuses on hiding in medium frequency coefficients. By hiding in these medium frequency coefficients, we allow for more aggressive embedding without risking more visual distortion but trade this off with a risk of higher error rates due to compression losses. Finally, the dissertation presents simulation aimed at testing the proposed system performance compared to other JPEG based steganographic systems with similar embedding properties. We show that the new system achieves an embedding capacity of 1.6, which represents round a 7 times improvement over YASS. We also show that the new system, although introducing more bits in error per B‐block, successfully allows for the embedding of up to 2 bits per B‐block more than YASS at a similar error rate per B‐block. We conclude the results by demonstrating the new systems ability to resist detection both through human observation, via a survey, as well as resist computer aided analysis. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2010.

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The RSA data encryption algorithm was developed by Ronald Rivest, Adi Shamir and Leonard Adelman in 1978 and is considered a de facto standard for public-key encryption. This computer science thesis demonstrates the author's ability to engineer a software system based on the RSA algorithm. This adaptation of the RSA encryption process was devised to be used on any type of data file, binary as well as text. In the process of developing this computer system, software tools were constructed that allow the exploration of the components of the RSA encryption algorithm. The RSA algorithm was further interpolated as a method of providing software licensing, that is, a manner in which authorization to execute a particular piece of software can be determined at execution time. This document summarizes the RSA encryption process and describes the tools utilized to construct a computer system based on this algorithm. / Department of Computer Science

Encryption is increasingly being used as deterrence for software piracy and vulnerability exploitation. Unencrypted or insecure programs can be the subject of intensive scrutiny by attackers in an attempt to disable protective features or to find buffer overflows as an avenue of attack of other systems. The application of encrypted programs, however, leads to other security concerns as users are no longer able to distinguish between malicious and benign behavior due to the secretive nature of encryption. Furthermore, should an attacker gain access to the software update process then malicious updates or modifications can be made to the system without the knowledge of the users. Therefore, system administrators running encrypted software now have a need for techniques that would allow such encrypted software to execute properly while minimizing the possibility of the system being compromised. The goal of this research is to develop a methodology that can enable users to trust encrypted software to allow their execution.

Thesis (PhDElectronicEngineering)--University of South Australia, 2005.

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 103-110). Also available on the World Wide Web.

Thesis (M.S.)--Rochester Institute of Technology, 2007. / Typescript. Includes bibliographical references (p. 64-66).

Thesis (Ph. D.)--Ohio University, November, 2003. / Title from PDF t.p. Includes bibliographical references (leaves 84-85).

Thesis (Ph.D.)--University of Wollongong, 2004. / Typescript. Includes bibliographical references: leaf 195-202.

Thesis (M. Eng. (Computer Engineering)) -- Universiteit van Pretoria, 2005. / Includes bibliographical references.