A method for providing digital image authenticity

A method for providing digital image authenticity by embedding a digital 'watermark' into the image is proposed. The watermark signal is inserted into the image using the block-based discrete cosine transform (DCT) domain. The appropriate spectral components are modified in such way to preserve the visually intact image content, being resistive to common image processing procedures such as brightness modification, noise removal, image cropping and image compression using the JPEG algorithm.