An encryption algorithm for vector maps based on the Gaussian random and Haar transform

Security of vector maps is of importance in the community of geographic information sciences. Although some encryption techniques can protect vector maps from piracy, they need to decrypt the entire map in order to extract parts of the data, which obviously brings inconvenience to the users. To solve the problem, an encryption algorithm for vector maps based on Gaussian random and Haar transform is proposed in this paper. First, all vertices are randomized via the Gaussian random method to get the shuffled vector map coordinates. Then, the average coefficient and the differential coefficient generated by the Haar transform are encrypted. Lastly, the encrypted map data is obtained through performing the inverse Haar transformation. Experiments show that (1) the proposed algorithm guarantees authorized users can decrypt any parts (layers) of encrypted vector maps; and (2) the algorithm outperforms other existing encryption methods in security and efficiency.