An AES Double–Layer Based Message Security Scheme

Nowadays, the Achilles heel of any software system that deals with data communication and/or storage on a cloud is the security of information being handled. However, modern cryptographic methods were proven vulnerable to brute force and side channel attacks, and thus were dubbed insufficient to be used in a secure system. Security is effected by using the cryptographic methods in proactive contexts, one of which is the use of a cryptography/steganography hybrid multi-layer system. Cryptography would be responsible for the secrecy of data whereas steganography would be responsible for the secrecy of communication. In this work, we propose two possible hierarchies which are common in that they are both double-layered and that they employ AES-256 for the cryptographic layer. As for the steganographic layer, we propose using the least significant bit (LSB) embedding by means of color-plane cycling in bitmap images. The cycling follows a prime number sequence in one method and the Fibonacci sequence in the other. We compute the mean squared error (MSE) and the peak signal to noise ratio (PSNR) for both techniques for comparison and we show the superiority of the Fibonacci sequence. We also compare our results with the results reported in the literature for some of the most commonly used LSB steganographic methods in hybrid systems and show the superiority of our proposed message security scheme.