Abstract:

DEM contains rich geo-spatial information and represents the true terrain. How to ensure the transmission security of secret DEM in network environment is a significant question in recent years. In this article, we use the three-dimension chaotic sequence to encrypt DEM files by scrambling its elevation value, pixel location and file header which break the value continuity and spatial continuity of elevations. When receivers get the scrambling DEM through the Internet, they can blind decrypt the data lossless by using secret key. The scrambling and recovering experiment based on ASCⅡ format DEM proves that the method can break the spatial characteristic and continuity of origin DEM with high security. Furthermore, user can recover the scrambling data back to origin lossless without original data. The features of the algorithm basically meet the application requirements of DEM data in secure transmission, encapsulation and storage.

Key words: DEM, scrambling, three-dimension chaotic sequence, confidential geographic data, security transmission