Tri-layer stego for enhanced security - a keyless random approach

War between the good and evil in the internet ground is increasingly tougher as more and more refined evolution takes place in the digital arms and ammunitions. The intrusion of digital terrorists in the territory of original digital source is always very hard to combat. In this sensitive battle many patriotic weapons such as cryptography are defeated by the interlopers. As a consequence of this defeat, a black commando namely steganography has declared an effective encounter by hidden assault on the strangers. In this paper a novel tri-layer random stego technique has been proposed for enhanced security against any type of brute force. The proposed method consists of three stages. The first part involves embedding of data in binary image with pixel statistics conservation method. In the second level, the binary-stego image is embedded into a gray image employing Moore Space Filling Curve by adapting LSB technique. Finally, the gray stego image is infixed into a color image using Hilbert Space Filling Curve to produce the final color stego. Experimental results show that the proposed multi stage process remarkably improves the security level. The effectiveness of the proposed stego system has been estimated by computing bit error rate (BER), Mean square error (MSE), Peak Signal to Noise Ratio (PSNR) and Mean Structural Similarity index (MSSIM). This paper also illustrates how security has been enhanced using this algorithm.