Audio Steganography for Secure Communication

Abstract

Today’s large demand use of internet applications has created a need for the secure transmission of data. Various new methods are being developed to ensure the privacy and secrecy of the communication between two or more parties from interception and improper manipulation by eavesdropper. Cryptography being the main science for all implemented information security solutions. Steganography is an art and science of hiding secret data in such a way that its presence can’t be noticed. Apart from the intended recipient no one knows the existence of the secret data. All types of multimedia data formats such as image, video and audio use with Steganography. In this thesis two methods were introduced to improve the data hiding in standard CD audio and to make hidden message imperceptible by using object oriented programming architecture. It is based on Least Significant Bit (LSB) substitution and a much more accurate method called Injection. Both Steganographic algorithms work in different ways to embed secret text data into cover media. LSB audio data hiding method slightly reduces the audio quality according to the size of plaintext messages hiding. This issue can overcome by hiding fewer amounts of data. With this method Stego audio file size doesn’t change unusually and audio play time remains same. Injection method introduced for hiding any amount of text data, encrypted by using AES-128 algorithm by giving the users password privileges. This assures 100% perfect security if users can protect their information by using minimum 8 characters long passwords without revealing to a third party. Output audio size is increasing according to the capacity of texts hiding, but the audio quality and play time does not change and it remains 100% perfect as same as the original. Nobody can suspect the audio by listening. Both methods assure exactness of messages hided and extracted. All the results have evaluated by doing laboratory tests and sample survey. Laboratory tests targeted comparison of audio quality by visualizing waveforms, calculating SNR, THD & MF values before and after hiding message. And also evaluate the exactness of message before extraction and after. Both methods are giving 100% similar messages. Random sample survey conducted for evaluates the software quality, audio quality and message exactness by providing participants real time experience of the program. At the same time tested relevant participant’s knowledge and awareness about Steganography by providing a questionnaire.