Vector Map Encryption Method Based on Secret Sharing

Vector map data is of great value and widely used in different fields. The issues for its data security have become increasingly urgent in the modern information age. Encryption technology converts the plaintext data into ciphertexts, making the data unreadable to unauthorized users, thus, plays a vital role in safeguarding sensitive information in various scenarios. Although several encryption algorithms for vector maps have been developed, most of the existing methods lack some very important security related properties, such as the disaster tolerance property, probabilistic property, diffusion property and the robustness to data RST (Rotation, Scaling and Translation) transformations, which greatly affects the security of the encryption algorithms. In this paper, a novel vector map encryption algorithm based on k,n-threshold secret sharing is proposed, which encrypts one map into n map shares and reconstructs the plaintext map by collecting at least k shares, thus improving the algorithm’s security and achieving the disaster tolerance property. Moreover, random numbers and cipher-feedback mode are cooperated into the encryption process in the proposed method to achieve probabilistic and diffusion properties. In addition, quantized polar coordinate is defined and original map coordinates are transformed into quantized polar coordinates before encryption and decryption process to achieve robustness to data RST transformations. Experiments on map data of different types (including points, polylines, and polygons) demonstrate the effectiveness and superiority of the proposed method.