Although semi-blind and blind watermarking schemes based on Discrete Cosine Transform (DCT) or Discrete Wavelet Transform (DWT) are robust to a number of attacks, they fail in the presence of geometric attacks such as rotation, scaling, and translation. The Discrete Fourier Transform (DFT) of a real image is conjugate symmetric, resulting in a symmetric DFT spectrum. Because of this property, t...

This paper gives a general introduction to the digital watermarking procedures and their security aspects. The first issue is to clarify unifying and differentiating properties of steganography and watermarking. Then the most important aspects of digital watermarking are reviewed by studying application, requirement and design problems. We put emphasis on the importance of digital watermark as ...

Steganography is the study of data hiding for the purpose of covert communication. A secret message is inserted into a cover file so that the very existence of the message is not apparent. Most current steganography algorithms insert data in the spatial or transform domains; common transforms include the discrete cosine transform, the discrete Fourier transform, and discrete wavelet transform. ...