245 Copyright © 2014, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. Chapter 13 DOI: 10.4018/978-1-4666-6158-5.ch013 Transform Domain Techniques for Image Steganography ABSTRACT Recent advancement of multimedia technology has posed serious challenges to copyright protection, ownership, and integrity of digital data. This has made information security techniques a vital issue. Cryptography, Steganography, and Watermarking are three major techniques for securing information and ensuring copyright ownership. This chapter presents an overview of transform domain techniques for image steganography. The authors discuss the characteristics and applications of image steganogra- phy and briefy review Discrete Cosine and Wavelet transform-based image steganography techniques. They also discuss the various metrics that have been used to assess the performance of steganography techniques and shed light on the future of steganography. INTRODUCTION Steganography techniques were invented as a quest of human desire for communicating secret information. The term steganography refers to covered communication. Secret communication plays an important role in diplomacy and wars. Hence devising ways for secret communication has ever been fascinating. Codes and ciphers, invisible inks, wax coated wooden tablets, physical objects have been used thousands of years ago to com- municate secret information. The oldest example of steganography is traced back to around 400 BC in the Greek history. The word steganography has been derived from the Greek words steganos (covered or secret) and graphein (writing) which literally means “covered writing”. In the “Histories of Herodotus” (1996), Herodotus reports an inter- esting story of Greek ruler Histiaeus. In order to inform his friends that it was time to begin a revolt against Mededs and Persians he tattooed a message on the shaved head of a slave. He waited till his hair grew back, and then sent him. The message reached to the intended recipients and the revolt was successful. Of course it took longer time, unlike emails, to grow hair back and to travel to the destination. Since then revolutionary changes have been occurred in the world of communica- tion. We are now living in the digital era leading to enormous amount of digital content of various modalities. This has added new dimensions and brought new challenges to information security. Siddharth Singh University of Allahabad, India Tanveer J. Siddiqui University of Allahabad, India