Encryption of geographic information 3D point cloud data by integrating improved QR and diffraction holography

Abstract With the widespread application of geographic information systems in surveying, remote sensing, and urban modeling, massive amounts of 2D images and 3D point cloud data are exposed to high security risks during transmission and sharing. How to improve encryption efficiency and robustness while ensuring information integrity has become a key issue that urgently needs to be addressed in the geographic data security. The research proposes a three-dimensional point cloud data encryption method that integrates improved quick response codes and diffraction holography. The quick response code and phase retrieval algorithm are combined to achieve integrated embedding of image texture, geographic coordinates, and user information. To address the large volume and phase loss in point cloud data, a holographic encryption model based on stripe interference and biphasic decomposition is constructed, and quick encryption is achieved using a lightweight key stream generated by a chaotic system. The key sensitivity test showed that when the disturbance amplitude reached 10 –5 , the peak signal-to-noise ratio dropped to about 5–7 dB, and the corresponding tolerance threshold was only 10 –5 , highlighting the high dependence of decryption on key synchronization. In the random testing conducted by the National Institute of Standards and Technology, the proposed method achieved a pass rate of 100% for both odd and even index sequences. In the efficiency evaluation, the 2D and 3D throughput rates on the two datasets reached 119.4 MPix/s and 947.8 kPts/s, respectively, with an average running time controlled within 1 s, demonstrating high practical value. The overall results indicate that this method can achieve a good balance between security, efficiency, and robustness, providing feasible solutions for the secure storage and transmission of multidimensional geographic information, and offering new technical ideas for data protection in complex geographic information application scenarios.