LSB modification based Audio Steganography using Trusted Third Party Key Indexing method

In the present scenario of extensive mediums for communication technologies, it has always been a challenging task to ensure the confidentiality of the sensitive information that is transmitted over a secured channel. Amongst various reliable and efficient techniques to secretly exchange information, Audio Steganography is considered very promising. LSB technique for Audio Steganography is very efficient that embeds the secret message with an audio file by replacing LSBs of that audio. In this paper Random Key Indexing method is proposed to replace the LSBs of the carrier audio with secret message. The bit replacement is guided by primary key that is provided by TTP (Trusted Third Party) and secondary key that will be generated at encoder end during embedding process and is supplied to the decoder end. The proposed method also uses message retrieval code that adds another layer of protection to the process. The method is successfully tested on various 32 bit & 16 bit stereo wave files with different payloads. The SNR_dB values comes out be in the range 139 dB to 142 dB for 32 bit and 67 dB to 85 dB for 16 bit stereo files. The Bit Error Rate (BER) comes out be in the range 0.23 to 0.32 percent for 32 bit and 0.018 to 0.028 percent for 16 bit files.