Measure-independent characterization of contrast optimal visual cryptography schemes |
| |
Affiliation: | 1. Department of Computer Science, Open University of Madrid, Spain;2. School of Computer Science, Universidad Politécnica de Madrid, Spain;1. Shenyang Institute of Computing Technology, Chinese Academy of Sciences, Shenyang 110168, China;2. University of Chinese Academy of Sciences, Beijing 100039, China;1. Department of Information Engineering, Qilu University of Technology, 58 Sangyuan Road, Jinan 250100, China;2. School of Computer Science and Technology, Shandong University of Finance and Economics, 7366 2nd East Ring Road, Jinan 250014, China;3. School of Computing, Informatics, and Decision Systems Engineering, Arizona State University, P.O. Box 878809, Tempe, AZ 85287-8809, USA |
| |
Abstract: | Visual cryptography has been studied in two models and visual cryptography schemes have been evaluated using different contrast measures. Naor and Shamir introduced the deterministic model while Kafri and Keren introduced the random grid model. In the deterministic model, three different measures of contrast have been proposed, γns, γvv and γes, although only γns, has been thoroughly studied. Tight bounds on γns are known for several classes of schemes. In the random grid model the contrast is γrg.In this paper we focus the attention on the deterministic model and follow a measure-independent approach, which, by using the structural properties of the schemes, enables us to provide a characterization of optimal schemes that is independent of the specific measure used to assess the contrast. In particular we characterize and provide constructions of optimal schemes for the cases of (2, n)-threshold and (n, n)-threshold schemes. Then, we apply the measure-independent results to the three measures γns, γvv and γes, that have been used in the literature obtaining both new characterizations and constructions of optimal schemes as well as alternative proofs of known results.Finally we provide a connection between the deterministic and the random grid models showing that γes is the equivalent of γrg. This opens up a door between the two models which have been so far treated separately. |
| |
Keywords: | Secret sharing Visual cryptography Contrast optimal schemes |
本文献已被 ScienceDirect 等数据库收录! |
|