A High capacity Double-Layer Gray Code Based Security Scheme for Secure Data Embedding

With the recent amelioration in digital communication and cloud storage, security remains a concern. Even though cryptographic algorithms have been readily used, they have been proved to be vulnerable to brute force and side channels attacks. Hence an additional security layer must be integrated to overcome the suspicion introduced by cryptography which is only concerned with the secrecy of the transmitted data. Adjacently, steganography tackles the secrecy of communication in the first place and hence a hybrid double layer security scheme that integrates both systems safeguards the data in terms of secrecy and imperceptibility. In this paper, we propose a double layer blind reversible security scheme which deploys Blowfish encryption as a cryptographic layer followed by a least significant bit image steganographic layer which spreads the encrypted secret data required to be transmitted over the pixels of an image cover medium. Our scheme also spreads the data again over the color channels of the pixels selected for embedding according to a gray code sequence. In order to judge the performance of our proposed scheme, the values of peak signal to noise ratio, mean squared error and structural similarity index have been computed and compared to other least significant bit schemes in the literature. The proposed scheme has been proved superior in terms of capacity, imperceptibility and computational complexity.