SLP Header

Visual Cryptography Scheme to Predict Phishing Sites

IJCSEC Front Page

Phishing is an attempt by an individual or a group to thieve personal confidential information such as passwords, credit card information etc from unsuspecting victims for identity theft, financial gain and other fraudulent activities. In this paper we have proposed a new approach named as "A Novel Antiphishing framework based on visual cryptography" to solve the problem of phishing. Here an image based authentication using Visual Cryptography (vc) is used. The use of visual cryptography is explored to preserve the privacy of image captcha by decomposing the original image captcha into two shares that are stored in separate database servers such that the original image captcha can be revealed only when both are simultaneously available; the individual sheet images do not reveal the identity of the original image captcha. Once the original image captcha is revealed to the user it can be used as the password.
Keywords:Vc, Passwords, Privacy
VISUAL cryptography (VC), which was proposed by Naor and Shamir, allows the encryption of secret information in image form [1]. Following their work, much research was done on visual secret sharing schemes (VSSs) [2]. From the point of view of access structures, the existing VC schemes (VCSs) can be divided into two categories: threshold access structure (also known as k-out-of-n VCSs or (k, n)-VCSs) [3]– [5] and general access structure (GAS) [6]–[12]. Naor and Shamir focused on how to generate n shares such that the secret image is revealed by at least k shares (2 ≤ k ≤ n).mobile devices have mobile databases in order to achieve stable data processing.
Ateniese et al. (hereinafter Ateniese) [6] proposed the GAS concept and also developed a VC-based solution for some GASs. Using the GAS enables dealers to define reasonable combinations of shares as decryption conditions rather than to specify the number of shares.
For example, if there are four participants (one president, one vice president, and two managers) sharing a secret, the president may expect to decrypt the secret with any single colleague who holds one of the other shares, whereas the vice president is allowed to obtain the secret only with two managers. The two managers are restricted from accessing the secret. Given these flexibilities, we also can set the number of shares as the decrypting condition. Clearly, (n, n)- and (k, n)-VCSs are special cases of the GAS. The pixel-expansion problem is a major drawback with most VCSs that use the VC-based approach. The pixelexpansion problem affects the practicability of a VC scheme because it increases the storage and/or transmission costs. Moreover, the pixel-expansion problem usually introduces the side effect that the recovered secret images have less contrast. The contrast of the recovered images decreases in proportion to 1/m, whereas the shares are expanded by a factor of m times.. As a result, the decrease in contrast limits the application of these VC schemes. To address the pixel expansion problem, Adhikari et al. also proposed construction methods for VCSs for GASs; their approach aims to reduce the pixel expansion factor for (k, n)-VCSs [10]. Hsu et al. (hereinafter Hsu) used the probability concept to construct a VCS for GAS [7], [8]. However, Hsu’s method does not guarantee enough blackness in some access structures, such that recovered images cannot be recognized by the naked eyes. Liu et al. proposed a deterministic construction method for GASs to balance the drawbacks of display quality and pixel expansion [9]. The developer should use a particular library that is provided by the vender of mobile database or modify existing mobile applications for synchronization process. Because of these flexible restrictions, the extensibility, adaptability and flexibility of mobile business systems are markedly decrease. This problem must be solved in order to build efficient mobile business systems because upcoming mobile environments will have heterogeneous characteristics in which diverse mobile devices, mobile databases, and RDBMS exist. This paper suggests new SAMD (Synchronization Algorithms based on Message Digest) in order to resolve the problems mentioned above. SAMD resolves synchronization problems using only standard SQL queries as certified by the ISO (International Organization for Standardization). This is followed by a possible synchronization of any data combination regardless of the kind of server-side database or mobile database. The SAMD therefore would provide extensibility, adaptability and flexibility.


  1. M. Naor and A. Shamir, “Visual cryptography,” in Advances in Cryptology, vol. 950. New York, NY, USA: Springer-Verlag, 1995, pp. 1–12.
  2. J. Weir and W. Yan, “A comprehensive study of visual cryptography,” in Transactions on Data Hiding and Multimedia Security V (LNCS), vol. 6010. New York, NY, USA: Springer-Verlag, 2010, pp. 70–105.
  3. C. N. Yang, “New visual secret sharing schemes using probabilistic method,” Pattern Recognit. Lett., vol. 25, no. 4, pp. 481–494, 2004.
  4. R. Ito, H. Kuwakado, and H. Tanaka, “Image size invariant visual cryptography,” IEICE Trans. Fundam., vol. E82-A, no. 10, pp. 2172–2177, 1999.
  5. P. L. Chiu and K. H. Lee, “A simulated annealing algorithm for general threshold visual cryptography schemes,” IEEE Trans. Inf. Forensics Security, vol. 6, no. 3, pp. 992–1001, Sep. 2011.
  6. G. Ateniese, C. Blundo, A. D. Santis, and D. R. Stinson, “Visual cryptography for general access structures,” Inf. Comput., vol. 129, no. 2, pp. 86–106, 1996.
  7. C. S. Hsu and Y. C. Hou, “Goal-programming-assisted visual cryptography method with unexpanded shadow images for general access structures,” Opt. Eng., vol. 45, no. 9, pp. 097001-1–097001-10, 2006.
  8. C. S. Hsu, S. F. Tu, and Y. C. Hou, “An optimization model for visual cryptography schemes with unexpanded shares,” in Foundations of Intelligent Systems (LNAI), vol. 4203. New York, NY, USA: Springer- Verlag, 2006, pp. 58– 67.
  9. F. Liu, C. Wu, and X. Lin, “Step construction of visual cryptography schemes,” IEEE Trans. Inf. Forensics Security, vol. 5, no. 1, pp. 27–38, Mar. 2010.
  10. A. Adhikari, T. K. Dutta, and B. Roy, “A new black and white visual cryptographic scheme for general access structures,” in Progress in Cryptology (LNCS), vol. 3348. New York, NY, USA: Springer-Verlag, 2004, pp. 399–413.
  11. L. A. MacPherson, “Grey level visual cryptography for general access structures,” M.S. thesis, School of Comput. Sci., Univ. Waterloo, Waterloo, ON, Canada, 2002.
  12. K. H. Lee and P. L. Chiu, “An extended visual cryptography algorithm for general access structures,” IEEE Trans. Inf. Forensics Security, vol. 7, no. 1, pp. 219–229, Feb. 2012.
  13. F. Liu, C. K. Wu, and X. J. Lin, “A new definition of the contrast of visual cryptography scheme,” Inf. Process. Lett., vol. 110, no. 7, pp. 241–246, 2010.
  14. C. Blundo and A. De Santis, “Visual cryptography schemes with perfect reconstruction of black pixels,” Comput. Graph., vol. 22, no. 4, pp. 449–455, 1998.
  15. T. Hofmeister, M. Krause, and H. U. Simon, “Contrastoptimal k out of n secret sharing schemes in visual cryptography,” Theoretical Comput. Sci., vol. 240, no. 2, pp. 471–485, 2000.
  16. H. Koga, “A general formula of the (t, n)-threshold visual secret sharing scheme,” in Advances in Cryptology, Asiacrypt. New York, NY, USA: Springer-Verlag, 2002, pp. 328–345.
  17. Y. W. Chow, W. Susilo, and D. S.Wong, “Enhancing the perceived visual quality of a size invariant visual cryptography scheme,” in Information and Communications Security (LNCS), vol. 7618. New York, NY, USA: Springer- Verlag, 2012, pp. 10–21.
  18. H. B. Zhang, X. F. Wang, W. H. Cao, and Y. P. Huang, “Visual cryptography for general access structure using pixelblock aware encoding,” J. Comput., vol. 3, no. 12, pp. 68–75, 2008.