Advanced techniques for covert communication

Abstract

The technique of covert communication addresses the issues relating to optimality of undetectable and secured communication of confidential sensitive information over an insecure public communication channels. Advancement in digital communication and networking has posed a serious threat to secure data transmission. It is the confidential information that flows via network fuels the engine of global economy. In order to ensure secure data communication and highly sensitive confidential information does not reach unauthorized destination, the concept of covert communication has attracted many researchers to come up with innovative and creative solutions to secure confidential information from falling into hands of unauthorized intruders. newline newlineSteganography is an art and also a science of embedding secret sensitive information into a host data set in such a manner that its existence cannot be identified. Here emphasis is given to Reversible Data Hiding techniques. Reversible Data Hiding can be considered as a special form of information embedding technique, which facilitates greater possibility of applications to link two different sets of information in such a manner that cover mediums can be retrieved in a lossless fashion after the embedded messages are extracted. Reversible data hiding employs the use of redundancy in carrier medium. These techniques play a major role in medical imaging, military applications and remote sensing, which demands lossless restoration of carrier medium information after the embedded confidential information is retrieved, while protecting the confidentiality of payload information. newlineLossless data hiding scheme proposed in this thesis for color cover images exploits least computational complexity by using histogram shifting technique to embed sensitive information bits in confused host image blocks. Confusion in cover image is a result of quad tree decomposition. newline