Affiliations: Department of Information Engineering, and Computer
Science, Feng Chia University, Taiwan, R.O.C. ccc@cs.ccu.edu.tw | Department of Computer Science, and Information
Engineering, National Chiayi University, Taiwan, R.O.C. thchen@mail.ncyu.edu.tw,
llj95m@cs.ccu.edu.tw
Note: [] Address for correspondence: Department of Computer Science and Information Engineering, National Chiayi University,
Taiwan, R.O.C.
Abstract: Visual Cryptography (VC) has drawn much attention for providing the
service of secret communication. Basically, VC is the process of encoding a
secret into several meaningless shares and later decoding the secret by
superimposing all or some of the shares without any computation involved. VC
has been adopted to support some practical applications, such as image
authentication, visual authentication, image hiding, and digital watermarking.
Unfortunately, in many applications, VC has been shown to suffer from the
"cheating problem" in which the disclosed secret
image may be altered by malicious insiders who are called
"cheaters." While ubiquitous computing has been
well developed, it has recently occurred to people in both academia and
industry that research could benefit more from computational VC by introducing
light-weight computation costs in the decoding phase. In this paper, a simple
scheme is proposed to conquer the cheating problem by facilitating the
capability of share authentication. It is worthwhile to note that the proposed
scheme can identify for certain whether cheating attacks have occurred or not,
while other schemes that have the same objective frequently provide a vague
answer. In addition, the proposed scheme effectively addresses the two main
problems of VC, i.e., the inconvenience of meaningless share management and the
challenge of achieving difficult alignment.
Keywords: Visual cryptography, secret sharing, cheating problem
