Hiding confidential signature into digital images via frequency domain

We describe a technique for hiding a confidential signature into a digital image, also referred to as digital watermarking. The embedded signature, or watermark, is usually a recognizable pattern like a company logo. Our technique is applied to the frequency domain of the image, obtained by a two dimensional Fourier transform. The watermark is embedded into the magnitude coefficients. This technique does not require the original image to recover the embedded signature.