Increasing the Capacity of the Cover Audio Signal by Using Multiple LSBs for Information Hiding

Steganography is an art and science of writing hidden messages in such a way that no one apart from the intended recipient knows the existence of the message. The maximum number of bits that can be used for LSB audio steganography without causing noticeable perceptual distortion to the host audio signal is 4 LSBs, if 16 bits per sample audio sequences are used. We propose 2 novel approaches of substitution technique of audio steganography that improves the capacity of cover audio for embedding additional data. Using these methods, message bits are embedded into multiple and variable LSBs. These methods utilizes up to 7 LSBs for embedding data. Results show that both these methods improve capacity of data hiding of cover audio by 35% to 70% as compared to the standard LSB algorithm with 4 LSBs used for data embedding. From subjective listening tests, it is seen that there is no noticeable difference between the cover audio signal and the stego audio signals obtained from the proposed methods. These novel approaches for increasing capacity show better results as compared to the existing approaches.