National Conference on Advances in Computer Science and Applications with International Journal of Computer Applications (NCACSA 2012) Proceedings published in International Journal of Computer Applications® (IJCA) 10 An Overview of Image Steganography using LSB Technique Jayeeta Majumder Sweta Mangal Department of Computer Science & Engineering Department of Computer Science & Engineering Haldia, West Bengal Haldia, West Bengal Haldia Institute of Technology Haldia Institute of Technology 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 steganographic techniques some are more complex than others and all of them have respective strong and weak points. This paper intends to give an overview of image steganography, its uses and techniques. For a more secure approach, this paper encrypts the message using secret key and then sends it to the receiver. The receiver then decrypts the message to get the original one. The rapid development of data transfer through internet made it easier to send the data accurate and faster to the destination. This paper deals with the algorithm based on hiding a large amount of data (image, audio, text) file into color BMP image. This project gives a brief idea about the image steganographic approach that make use of Least Significant Bit(LSB) algorithm for embedding the data into the bitmap image(.bmp) which is implemented through the JDK 1.5.0_07 environment. The Least Significant Bit (LSB) embedding technique suggests that data can be hidden in the least significant bits of the cover image and the human eye would be unable to notice the hidden image in the cover file. Keywords steganography, steganalysis, stego image, cover medium, LSB technique, 1. INTRODUCTION In the current trends of the world, the technologies have advanced so much that most of the individuals prefer using the internet as the primary medium o transfer data from one end to another across the world.Data security basically means protection of data from unauthorized users of hackers and providing high security to prevent data modification. This area of data security has gained more attention over the recent period of time due to the massive increase in data transfer rate over the internet. In order to improve the security features in data transfers over the internet, many techniques have been developed like: Cryptography Steganography etc. Steganography provides further security by hiding the cipher text into a seemingly invisible image or other formats. Steganography is a method of encryption that hides data among the bits of a cover file, such as a graphic or an audio file. The technique replaces unused or insignificant bits with the secret data. According to Johnson et al., (2001), “Steganography is the art of hoding and transmitting data through apparently innocuous carries to conceal the existence of data”. The level of visibility is decreased using many hiding techniques in „Image Modelling‟ like LSB „Manipulation‟, „Masking and Filtering‟. These techniques are performed by different steganographic algorithms like F5, LSB, JSteg etc. and the act of detecting the information hidden through these algorithms is called „Steganalysis‟. „Steganography‟ and „Cryptography‟ are closely related constructs. The hidden or embedded image, audio or video files act as carriers to send the private messages to the destination without any security breach. Steganography techniques can be implemented on various file formats such as audio („.mp3‟,‟.wmv‟, etc.), video („.mpeg‟,‟.dat‟, etc.) and images („.jpeg‟, „.bmp‟, etc.). However, the images are the most preferred file format for this technique. Fig:1 Graphical Version of the Steganographic System 2. STEGANOGRAPHY Steganography is the art and science of writing hidden messages in such a way that no one, apart from the sender and intended recipient, suspects the existence of the message, a form of security through obscurity. The word steganography is of Greek origin and means "concealed writing" from the Greek words steganos meaning "covered or protected", and graphein meaning "to write". Steganography literally means “covered languages”.