International Journal of Computer Applications (0975 – 8887) Volume 178 – No. 50, September 2019 30 Hiding Confidential File using Audio Steganography Md. Rasedur Rahman Department of CSE, Jahangirnagar University, Bangladesh Partha Chakraborty Department of CSE, Comilla University, Bangladesh Md. Zahidur Rahman Department of CSE, Comilla University, Bangladesh Md. Golam Moazzam Department of CSE, Jahangirnagar University, Bangladesh ABSTRACT Steganography is the art of hiding information in ways that prevent the detection of hidden messages. It includes a vast array of secret communications methods that conceal the message’s very existence. These methods include invisible inks, microdots, character arrangement, digital signatures, covert channels, and spread spectrum communications. In this research we have proposed a simple and effective way to hide data in audio file with 256 bit AES encryption based on Least Significant Bits technique. This approach can hide not only text message but also any type of files currently used e.g. .jpg, .pdf, .mp3, mpeg4 etc in a wav audio file. Keywords Cryptography, Decryption, Encryption, LSB, Secret key, Steganography, Stego-image 1. INTRODUCTION A Hiding data and communications have existed since there is a need to communicate secretly with others. Steganography techniques are used to address digital copyrights management, protect information, and conceal secrets [1]. It is the art and science of hiding information into picture or other media in such a way that no-one apart from the sender and intended recipient even realizes there is a hidden information [2], [3]. This includes the concealment of digital information within computer files. Generally, a steganographic message will appear to be something else, may be picture, video, sound file, even the radio communication. This apparent message is the cover text. For instance, a message may be hidden by using invisible ink between the visible lines of innocuous documents. The hidden information is called stego-message which may be open message, but may be encrypted one as well. Data hiding [4] in the image has become an important technique for image authentication. Ownership verification and authentication is the major task for military people, research institute and scientist. It refers to the nearly invisible embedding of information within a host data set as message, image, and video. In steganographic [5], [6] applications, the hidden data may be secrete message or secrete hologram or secrete video whose mere presence within the host data set should be undetectable; The goal of steganography is to hide the message in the source image by some key techniques and cryptography is a process to hide the message content. To hide a message inside an image without changing its visible properties [7] the source image may be altered. The most common methods to make these alteration involves the usage of the least-significant bit (LSB) developed by masking, filtering and transformations on the source image [8]. This paper focuses on the technique to secure data or message with authenticity and integrity. The entire work has been done in WPF C#. In this work, the secret message is encrypted before the actual embedding process starts. It uses a simple encryption technique and a secret key and hence it will almost be impossible for the intruder to unhide the actual secret message from the embedded cover file without knowing secret key. Only receiver and sender know the secret key. N- bit LSB substitution technique is used as embedding and extraction method. 2. LITERATURE REVIEW Sealed Information security and image authentication has become very important to protect digital image document from unauthorized access. Data is the backbone of today’s communication. To ensure that data is secured and does not go to unintended destination, the concept of data hiding came up to protect a piece of information. Many researchers’ have explored their innovative idea to implement steganography. The most famous method of traditional steganography technique around 440 B.C. is marking the document with invisible secret ink, like the juice of a lemon to hide information [9], [10]. Another method is to mark selected characters within a document by pinholes and to generate a pattern or signature [11]. Warkentin proposed an algorithm to hide data inside the audio visual files. Secret message will be hidden in a carrier file [12]. On the other hand, El-Emam [13], has proposed another algorithm to hide a huge amount of data that can be audio, image and text file inside of a color bitmap image where has maintained high security. He has filtered and segmented of image file instead of bits replacement is used on the appropriate pixels. Moreover, another researcher Chen has given concept to hide data inside of image edge portions that is modified method of El-Emam [14]. Rosziati Ibrahim and Teoh Suk Kuan [15] proposed an algorithm to hide message inside image. In the system data has been taken from input box as a text then converted it to binary codes. After converting, binary code is compressed as a file and then hide inside of Image. This steganography technique is used as an Image Steganography. 3. PROPOSED APPROACH Least Significant Bit (LSB) method is good for audio steganography. LSB-Steganography is a steganography technique in which we hide messages inside an image by replacing least significant bit of career with the bits of message to be hidden. Fig. 1 shows the working logic of LSB method for audio steganography.