Digital watermarking is a process that embeds an imperceptible signature or watermark in a digital file containing audio, image, text or video data. The watermark is later used to authenticate the data file and for tamper detection. It is particularly valuable in the use and exchange of digital media such as audio and video on emerging handheld devices. However, watermarking is computationally expensive and adds to the drain of the available energy in handheld devices. We present an approach in which we partition the watermarking embedding and extraction algorithms and migrate some tasks to a proxy server. This leads to a lower energy consumption on the handheld without compromising the security of the watermarking process. Our results show that executing watermarking partitioned between the proxy and the handheld reduces the total energy consumed by 80% over running it only on the handheld and improves performance by over two orders of magnitude. Categories and Subject Descriptors K....