RST Invariant Fragile Watermarking for 2D Vector Map Authentication

2D vector maps are very important data in geographical information systems (GISs). It is considered to be content for which verification of integrity and authentication are urgently required. Using a marking technique and a rotation, scaling and translation (RST) invariant watermark generation method, we propose a scheme that detects and locates malicious attacks with high accuracy while providing the RST invariance property. In particular, we propose setting a unique mark on each feature, calculating the authentication watermark for each spatial feature group by folding the hash results of the differences of the log-radiuses, and embedding the watermark using a RST invariant watermarking method. While the watermark ensures both the sensitivity to malicious manipulations and the RST invariance property, the mark of each feature provides superior accuracy of tamper localization. Moreover, this algorithm is immune to feature rearrangement and vertex reversing operations. Theoretical analysis and experimental results are provided to demonstrate the effectiveness of our method.