In today's communication world, data sharing and transfer is increasing exponentially. The threat of an attacker accessing secret information has been an ever existing concern for the data communication experts. Cryptography and steganography are the most widely used techniques to overcome this threat. Steganography is the art of hiding the existence of the communication message before sending it to the receiver. In this paper it is proposed to use Discrete Fractional Fourier transform (DFrFT) as basic tool in image processing for data hiding technique called steganography. A comparative study of steganography in spatial domain and frequency domain based on Discrete Fourier transform (DFT), Discrete cosine transform (DCT), Discrete Fractional Fourier transform (DFrFT) is made. Peak signal to noise ratio (PSNR) and Mean square error (MSE) of cover image and stego image are used as performance index and it is found that among three frequency domain methods DFrFT based steganography gives better results in terms of PSNR and MSE and also provide more security for communication. MATLAB platform is used for simulation, results show that the proposed technique provides more security, better PSNR and lower MSE of cover image and stego image.

Steganography Cryptography Discrete Fourier transform Discrete cosine transform Discrete fractional Fourier transform.