A secret sharing scheme allows a secret to be shared among a set of participants, P, such that only authorized subsets of P can recover the secret, but any unauthorized subset cannot recover the secret. In 1995, Naor and Shamir proposed a variant of secret sharing, called visual cryptography, where the shares given to participants are xeroxed onto transparencies. If X is an authorized subset of P, then the participants in X can visually recover the secret image by stacking their transparencies together without performing any computation. In this paper, we address the issue of cheating by dishonest participants, called cheaters, in visual cryptography. The experimental results demonstrate that cheating is possible when the cheaters form a coalition in order to deceive honest participants. We also propose two simple cheating prevention visual cryptographic schemes.
Keywordsvisual cryptography cheating secret sharing visual authentication
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- 1.Blakley G., Safeguarding Cryptographic Keys, Proc. AFIPS 1979 Natl. Conf. New York, Vol. 48 (1979) pp. 313–317.Google Scholar
- 5.Chang, C. C., Hwang, R. J. 1997Efficient cheater identification method for threshold schemesIEE Proc.-Comput. Digit. Technol.1442327Google Scholar
- 7.Naor, M., Pinkas, B. 1997Visual Authentication and IdentificationBurton, S. Kaliski,Jr. eds. Advances in Cryptology—Proceedings of Crypto 97Springer-VerlagNew York322336Lecture Notes in Computer Science, 1294Google Scholar
- 8.Naor, M., Shamir, A. 1995Visual cryptographySantis, Alfredo eds. Advances in Cryptology—Proceedings of Eurocypto 94Springer-VerlagNew York112Lecture Notes in Computer Science, 950Google Scholar
- 9.Ogata, W., Kurosawa, K. 1996Optimum secret sharing scheme secure against cheatingMaurer, Ueli M. eds. Advances in Cryptology—Proceedings of Eurocypto 96Springer-VerlagNew York200211Lecture Notes in Computer Science, 1070Google Scholar
- 12.G. J. Simmons, An introduction to shared secret and/or shared control schemes and their applications, Contemporary Cryptology, IEEE Press, Piscataway (1991) pp. 491–497.Google Scholar
- 14.Wang, C. C., Tai, S. C., Yu, C. S. 2000Repeating image watermarking technique by the visual cryptographyIEICE Trans. FundamentalsE83-A15891598Google Scholar