# Visual Cryptography Scheme to Predict Phishing Sites

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**Abstract**

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

**I.Introduction **

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.

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