Abstract: Steganography is the powerful tool for hiding information inside useful cover medium in ways such that the hidden message is undetectable. In Greek language, stego means covered or secret and graphy means to write. Hence, steganography means covered writing. Transform domain steganography is one of the techniques used for hidden exchange of information in frequency domain and it can be defined as the study of invisible communication that deals with the ways of hiding the existence of the communicated message. In this way, if successfully achieved, the message does not get attention of attackers and eavesdroppers. In steganography, information can be hidden in different cover carriers. Cover media can be a text, image, audio or video files.

Keywords: DCT, DWT, SVD, PSNR, MSE, Stego-image.