Journal of Xidian University

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Improved (k, n) tagged visual cryptography scheme

GUO Songge1;LV Donghui 1;REN Yanli1,2,3   

  1. (1.School of Communication and Information Engineering, Shanghai Univ., Shanghai 200444, China;
    2. Shanghai Institute of Advanced Communication and Data Science, Shanghai 200444, China;
    3. Key Lab. of Scalable Computing and Systems, Shanghai Jiaotong Univ., Shanghai 200240, China)
  • Received:2017-08-12 Online:2018-10-20 Published:2018-09-25

Abstract:

Decrypted images of the existing tagged visual cryptography has a poor visual quality and the problems of pixel expansion and design of encryption matrices. So this paper exploits the properties of (2, 2) random grid-based visual cryptography to modify the embedding method and location of the tagged images, and improves the visual quality of decrypted images by reducing the impact of the tagged information on secret information. The scheme uses a random grid to avoid pixel expansion and design of encryption matrices, and it can flexibly adjust the visual quality of decrypted images. Compared with the existing schemes, the secret images recovered in this scheme have a better visual quality when the same proportion of tagged information is embedded in shares.

Key words: encryption, image processing, tagged visual cryptography, random grid