Objectives  Security of vector spatial data is of importance in the community of geographic information sciences. It is necessary to encrypt the vector spatial data based on the consideration of data security. The existing method is to encrypt the entire data file, which affects the view of attribute data and destroys vector spatial data structure.

  Methods  A coordinate encryption method which does not change the structure of vector spatial data file is proposed, which not only protects the security of data, but also has no impact on the normal use of data. Firstly, vector spatial data are encrypted in Haar transform domain by the secret key. The secret key used to encrypt the coordinate data is generated combined Hash key with Gaussian random number. The average coefficient and the differential coefficient are obtained from Haar transformation of the vertex sequence of vector spatial data and are encrypted by the secret key. After that, the encrypted coordinates are obtained by Haar inverse transformation of data. Finally, the Gaussian random number is utilized to scramble the vertex sequence in order to get the encrypted disordered vector spatial data.

  Results  The experimental results show that: (1)The structure and attribute data of the vector spatial data file are completely unchanged after encryption, only the coordinates are encrypted, and efficiency is improved. (2) The algorithm can effectively decrypt and restore the original vector spatial data, with high security.

  Conclusions  The proposed method can not change the structure of vector spatial data, and the efficiency of encryption is improved.