Steganographic method for secure communications

Cryptographic methods secure an important message by encrypting it to an unrecognized form of data which may arouse the interest of cryptanalysis for part of the recipients. Steganographic methods hide the encrypted message in cover carriers so that it cannot be seen while it is transmitted on public communication channels such as computer network. Many steganographic methods embed a large amount of the secret information in the first k LSBs of the pixels of the cover images. Because of the imperfect sensibility of the human visual system, the existence of the embedded secret information can be imperceptible. Unfortunately, the hidden secret information may be discovered by the common-cover-carrier attack if it has not been appropriately disposed. In this paper, an LSB-based steganographic method is proposed to resolve this problem. By using variable-size insertion and redundant Gaussian noise adding, the stego-images created with the proposed method can survive both the human visual system and the common-cover-carrier attack. Moreover, many cryptographic protocols are involved in the proposed method to resolve the problems of security and key management that may be encountered in other steganographic methods. The proposed method is hence suitable for secure communications.