A steganographic scheme for colour image authentication (SSCIA)

This paper deals with a novel steganographic technique which demonstrates the colour image authentication technique in frequency domain based on the Discrete Fourier Transform (DFT). The DFT is applied on sub-image block called mask of size 2 × 2 for frequency components of corresponding spatial component. This transforms process done from beginning to end mask in row major order of the carrier image. Image authentication is done by hiding secrete message/image into the transformed frequency components of carrier image. Four secrete message/image bits are fabricated within the transformed real frequency component of each carrier image byte except the LSB of first frequency component of each mask. After embedding, a delicate re-adjust phase is incorporated in all the frequency component of each mask, to keep the quantum value positive and non fractional in spatial domain. Robustness is achieved by hiding an authenticating or secretes message/image in the frequency component with positive and negatives both quantum values and invisibility is satisfied in spatial domain using delicate re-adjust phase. Inverse DFT (IDFT) is performed after embedding to transform embedded image in frequency domain to spatial domain. This novel technique is also applicable for secrete data transmission through carrier colour image by hiding secrete data. Experimental results conform that the proposed algorithm performs better than discrete cosine transformation (DCT), Quaternion Fourier Transformation (QFT) and Spatio Chromatic DFT (SCDFT) based schemes.