X ML Streams Watermarking ( draft )

XML streams are online, continuous, distributed, high throughput sources of information. For streams carrying a significant intellectual and/or industrial value, proving ownership over pirated copies is a requirement for data producers. Watermarking is a known technique for hiding a copyright mark in a digital document, in a resilient manner. While such methods already exist for numerical streams, they do not meet the specific requirements of XML streams. In this paper, we introduce the l-détour algorithm, which allows for watermarking XML streams so that (i) the watermark embedding and detection processes are done online and use only a constant memory, (ii) the stream distortion is controlled, (iii) the type of the stream is preserved and finally (iv) the detection procedure does not require the original stream. We also evaluate, analytically and experimentally, the robustness of l-détour against attempts to remove the watermark.