Use Digital Watermarking to Protect GIS Data by Chinese Remaindering
基于中国剩余定理的GIS数字水印算法

Along with the popularization of Internet and the development of multimedia techniques, internet has become a main way for information communication. People can get a lot of information through the Internet, such as text, image, graphics, audio and video etc. Unfortunately however: internet and multimedia also afford virtually unprecedented opportunities to pirate copyrighted material. This risk is same to the distribution of GIS data through internet. As a result, digital Watermarking has been presented as an efficiently solution to copyright protection. Dozens of schemes and algorithms have been proposed, but most of those are for multimedia data. In this paper, a new watermarking method is proposed for the protection of GIS data. This approach applies the Chinese Remaindering to construct embedding watermarking in GIS data. The influence of embedding process on GIS data would ignore under the lower measurement precision. It can be used as tamper proof and authentication of GIS data .This algorithm accord with Asmuth-Bloom system, so we can extract watermarking use only a part of GIS data. The extraction process doesn't need the original watermarking, because the embedding procedure is based on the states that a positive integer is uniquely specified by its remainder modulo relatively prime integers. The algorithm bases on the coordinate of the points, so it can be widely used in GIS data protection such as relation database, as well as triangular mesh. The results show that the algorithm can work well. Finally, some open problem is discussed.