Covered CDMA multi-user writing on spatially divided image

The dark cousin of cryptography is the modern messiah to deliver secret communications against the stern menace from hackers. Hence, providing data security in information systems using steganography has become an important subject. In this article, an effective multi-user Code Division Multiple Access (CDMA) based stego technique has been proposed to improve the security level of the secret nexus. In this technique the four parts of secret message to be hidden have been obtained from four different users and they are embedded in the four quadrants of stego cover in different sequence which is decided by the chief of the secret group. In order to validate the efficiency of the proposed technique, Mean Square Error (MSE,) Peak Signal to Noise Ratio (PSNR) and Mean Structural SIMilarity Index (MSSIM) before and after embedding secret message in stego cover have been estimated for various message lengths.