1. Guided by

2. Problem Definition
 When ever we transmit the data(image) in the
network, any unauthenticated person can read our
data(image).
 In order to provide security to data(image) generally
sender will encrypt the data(image) and send it the
intended person and the receiver will decrypt the
encrypted data(image) and uses it

3. Background Introduction
 Extended Visual Cryptography schemes.
 The existing system does not provide a friendly
environment to encrypt or decrypt the data (images).
 Deals only with binary input share images.
 A larger pixel expansion value.
 It uses access structure or threshold access structure

4. Proposed System
 Proposed system Visual cryptography provides a
friendly environment to deal with images.
 Deal with Gray scale input images.
 A minimum pixel expansion.
 It uses general access structure.

5. Use case diagram

6. Administrator
Login login
Create
user Change
Delete password
user

7. Converting color image to binary
start j
If
value> no
Input image 122
yes
Img(I,J)=0
W=width(img) Img(I,J)=255
H=height(img)
Next J
for I=1 to W
Next I
for J=1 o H
Output
img
Value=Get
Brightness(P(I,J))
Stop

8. Share creation using halftone algorithm
If
Start Img(I,J)<
black
Let Img=input
image
temp(JX2,IX2)=black temp(JX2,IX2)=black
W=width(Img) temp(JX2,IX2H)=white temp(JX2,IX2H)=white
H=height(Img) temp(JX299,IX2)=white temp(JX299,IX2)=white
temp(JX299,IX2H)=black temp(JX299,IX2H)=black
Create
temp(width,height)
Output Next J
for I=0 to H-1
Img
Next I
For J0 to W-1 Stop

9. Algorithm2: Halftonig process
Input : The c x d dithering matrix D and a pixel with
gray-level g in input image I.
Output: The halftoned pattern at the position of the
pixel
For i=0 to c-1 do
For j=0 to d-1 to do
If g<=Dij then
print a black pixel at position (i,j);
Else
print a white pixel at position (i,j);

10. Algorithm 3: Embedding process
Input : The covering shares constructed in Section IV, the
corresponding VCS with pixel expansion and the
secret image .
Output: The embedded shares .
Step 1: Dividing the covering shares into blocks that contain
subpixels each.
Step 2: Choose embedding positions in each block in the
covering shares.
Step 3: For each black (respectively, white) pixel in,randomly
choose a share matrix (respectively).
Step 4: Embed the subpixels of each row of the share
matrix into the embedding positions chosen in
Step 2.

11. Embedding process
Start
for I=1 to w-1
Input
Img1,Img2 for J=1 to H-1
W1=width(Img1) width(Img2) Out(I,J)=Img1(I,J) or
H1=height(Img1)height(Img2) Img2(I,J)
If w1=w2 Output Next J
No
and process
H1=H2 fails
Next I
yes
Stop
W=W1=W2
H=H1=H2 Stop

12. Snap Shots

13. Work completed and future work

14. Conclusion