Thesis Abstract

Steganography is the art of hiding the fact that communication is taking place, by hiding information in other information. Many different carrier file formats can be used, but digital images are the most popular because of their frequency on the internet. For hiding secret information in images, there exists a large variety of steganography techniques some are more complex than others and all of them have respective strong and weak points. Different applications may require absolute invisibility of the secret information, while others require a large secret message to be hidden. This project report intends to give an overview of image steganography, its uses and techniques. It also attempts to identify the requirements of a good steganography algorithm and briefly recommended on which stenographic technique are more suitable for which applications.

Thesis Overview

Introduction

1.1  Background to the study

Currently, the digital information revolution has brought significant changes in our society and daily routines. In line with the revolution, Internet and wireless network offer ubiquitous channels to deliver and exchange information.  Therefore, public information exchange is secured by using an encryption method where a secret data can be encrypted to prevent the content  from  being  intercepted.  However,  with  the technological  advancement  of  information  security,  most  Internet  users  are not  aware that  sending  encrypted  messages  will  draw  unnecessary  attention  to  malicious  black hats such as crackers and hackers. This is because the encrypted data appears as a string of gibberish data that might arouse suspicion. Moreover, there is a possibility of illegal exploitation attempts to the vulnerability of the encrypted messages due to curiosity and inquisitiveness of a hacker. As a result, the secret data which has been encrypted could be  illegally  intercepted,  unauthorized  tampered  or  even  damaged  during  data transmission.

In order to alleviate the issue mentioned above, steganography is introduced as an alternative design to conceal a secret data into an unsuspicious cover-object so that it can  be  sent  stealthily  through  a  public  communication  channel  without  drawing  any unnecessary attention of the black hats.

Steganography is derived from the findings of Johannes Trithemus (1462-1516) entitled  Steganographia  which  comes  from  the  Greek  words  (στεγανÏŒ-ς,  γραυ-ειν), steganos literally means “covered”; and graphia means “writing”. Eventually the entire

definition is defined as covered writing (Petitcolas et al., 1999).

 1.2 Statements of the problem

Over the years, numerous steganography techniques that embed secret data into cover-objects such as image, audio, video  etc. have been invented and implemented. However, in  the  current  image-based  steganography  technology,  there  are  several

problems arise due to              

i.       Distortion produced in a stego-image after embedding a secret data.

There are certain existing schemes such as Hide and Seek 4.1 and Hide in the Picture 2.1 result in a distorted stego-image after embedding a secret data. Due to  this  factor,  the  stego-image  produced  is  able  to  raise  suspicion  and  can  be clearly  distinguished  by  an  attacker.  Thus,  researches  on  alleviating  the distortion problem in the stego-image need to be carried out.

ii.     There  is  a  rest