Marsland Press Journal of American Science 2009:5(2) 36-42 36 Implementation of Improved Steganographic Technique for 24-bit Bitmap Images in Communication Mamta Juneja, Parvinder Sandhu Department of Computer Science and Engineering, Rayat and Bahra Institute of Engineering and Biotechnology, V.P.O Sahauran, Tehsil Kharar, Distt. Mohali, Punjab- 140104, INDIA 91-098786-77624 er_mamta@yahoo.com Abstract Steganography is the process of hiding one file inside another such that others can neither identify the meaning of the embedded object, nor even recognize its existence. Current trends favor using digital image files as the cover file to hide another digital file that contains the secret message or information. One of the most common methods of implementation is Least Significant Bit Insertion, in which the least significant bit of every byte is altered to form the bit-string representing the embedded file. Altering the LSB will only cause minor changes in color, and thus is usually not noticeable to the human eye. While this technique works well for 24-bit color image files, steganography has not been as successful when using an 8-bit color image file, due to limitations in color variations and the use of a colormap. This paper presents the results of research investigating the combination of image compression and steganography. The technique developed starts with a 24-bit color bitmap file, and then compresses the file by organizing and optimizing an 8-bit colormap. After the process of compression, a text message is hidden in the final, compressed image. Results indicate that the final technique has potential of being useful in the steganographic world. [Journal of American Science 2009:5(2) 36-42] ( ISSN: 1545-1003) Keywords: Bitmap, Colormap, Compression, LSB Based Insertion, Steganography Introduction Staganography is an ancient technology that has applications even in today’s modern society. A Greek word meaning “covered writing,” steganography has taken many forms since its origin in ancient Greece. During the war between Sparta and Xerxes, Dermeratus wanted to warn Sparta of Xerxes’ pending invasion. To do this, he scraped the wax off one of the wooden tablets they used to send messages and carved a message on the underlying wood. Covering it with wax again, the tablet appeared to be unused and thereby slipped past the sentries’ inspection. However, this would not be the last time steganography would be used in times of war. In World War II, the Germans utilized this technology. Unlike the Greeks, these messages were not physically hidden; rather they used a method termed “null ciphering.” Null ciphering is a process of encoding a message in plain sight. For example, the second letter of each word in an innocent message could be extracted to reveal a hidden message. Although its roots lay in ancient Greece, steganography has continually been used with great success throughout history. Today steganography is being incorporated into digital technology. The techniques have been used to create the watermarks that are in our nation’s currency, as well as encode music information in the ever-popular mp3 music file. Copyrights can be included in files, and fingerprints can be used to identify the people who break copyright agreements [5] [6] and [8].However, this technology is not always used for good intentions; terrorists and criminals can also use it to convey information. According to various officials and experts, terrorist groups are “hiding maps and photographs of terrorist targets and posting instructions for terrorist activities on sports chat rooms, pornographic bulletin boards, and other Web sites”[1]. This aspect of steganography is what sparked the research into this vast field [3] and [4]. Education and understanding are the first steps toward