Research Seminar: Key Issues of Secret Sharing Extension to Secret Image Sharing



  • Speaker: Professor Ching-Nung Yang (Dong Hwa University)
  • Topic: Key Issues of Secret Sharing Extension to Secret Image Sharing
  • Time: 10:00AM-11:00AM, March 15th, 2019
  • Venue: EE505
  • Chair: Dr Jimin Xiao


Audiences will learn how to secure multimedia (e.g., digital images) by secret image sharing (SIS). Recently, this SIS is an important research combining methods and techniques coming from cryptography and image processing. As we know, Shamir's polynomial based secret sharing (SS) is a well-known technology to share secrets into n shares. The secret can be recovered from any k shares; but (k-1) or fewer shares have no information about the secret. In fact, SIS has become a very important research and application topic. In the encyclopedia of image processing "Encyclopedia of Image Processing" (ISBN: 9781482244908), published in November 2018, there is a special chapter on secret image sharing. In this lecture, some key issues when extending SS to SIS will be explained and discussed in detail: (1)Random Secret vs. Meaningful Secret (Visual Image): random key can be used for SS, but the secret image in SIS should be meaningful. (2)Choice of Finite Field: image in SIS has 256 gray levels (0-255). (3)Where to Embed Secret? SS embeds secret into constant term, but SIS usually embeds the secret data into all coefficients (at this time, permutation of secret image is required). (4) Shadow Images: random in SS; and noise-like or meaningful (i.e., steganography) in SIS. This lecture also includes the latest technologies, algorithms, solutions and applications for SIS, e.g., SIS with authentication capability, SIS with progressive decryption, SIS with multiple decoding options, SIS with multiple secret images, and (t, s, k, n)-SIS and (t, k, n)-SIS with various threshold combinations. Finally, tips to research SIS will be given, so that everyone may have a deeper understanding to design and develop SIS.


Professor James C.N. Yang

Professor Ching-Nung Yang obtained his PhD degree in Electrical Engineering from National Cheng Kung University. His B.S. and M.S. degrees, both were awarded in Department of Telecommunication Engineering from National Chiao Tung University. Dr Yang served in National Dong Hwa University since 1999. His current title is Professor in Department of Computer Science and Information Engineering. He had been Visiting Professor to University of Missouri Kansas City, University of Milan, and University of Tokyo. He is currently a Fellow of IET (IEE) and an IEEE senior member. Professor Yang has done extensive researches on visual cryptography and secret image sharing, and is the chief scientist in both areas. In fact, a very important innovation of visual cryptography, the probabilistic visual cryptography, was firstly proposed by Professor Yang. His areas of interest include error correcting code, multimedia security, cryptography, and information security. He has authored two books and has published over 200 (including more than 100 SCI-indexed papers) professional research papers in the areas of information security and coding theory. In the meantime, he has served/is serving in international academic organizations. He serves as technical reviewers for over 40 major scientific journals in the areas of his expertise, and serves as editorial boards and editors of special issues for some journals. Also, he was invited as chairs, keynote speakers, and members of program committees for various international conferences. He is the recipient of the 2000, 2006, 2010, 2012, and 2014 Fine Advising Award in the Thesis of Master/PhD of Science awarded by Institute of Information & Computer Machinery.