In this paper, a robust and efficient digital image watermarking algorithm using the fast Hadamard transform (FHT) is proposed for the copyright protection of digital images. This algorithm can embed or hide an entire image or pattern as a watermark such as a company's logo or trademark directly into the original image. The performance of the proposed algorithm is evaluated using Stirmark 3.1 that consists of 90 different types of image attacks. Results show that this algorithm is very robust and can survive most of the Stirmark attacks. These attacks were tested on a number of test images of size 512/spl times/512/spl times/8 bits, embedded with a watermark image of size 64/spl times/64/spl times/8 bits. The simplicity of the fast Hadamard transform also offers a significant advantage in shorter processing time and ease of hardware implementation than other orthogonal transforms, such as the discrete cosine transform and wavelet transform.