In this paper, a robust and efficient digital image watermarking algorithm using the fast Hadamard transform (FFIT) is proposed for the copyright protection of satellite 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 satellite image. The performance of the proposed algorithm is evaluated using a benchmarking tool called Stirmark. Results show that this algorithm is very robust and can survive up to 60% of all Stirmark attacks. These attacks were tested on a number of satellite test images of size 512/spl times/512/spl times/8 bit, 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.