Cryptography Reference
In-Depth Information
this phase.
8
<
T = c
7
c
6
c
5
c
4
c
3
c
2
f
5
f
4
k d
7
d
6
d
5
d
4
d
3
d
2
f
3
f
2
k g
7
g
6
g
5
g
4
g
3
g
2
f
1
k h
7
h
6
h
5
h
4
h
3
h
2
f
0
P = T mod 2
t
P = fp
i
j i 2f1; 2;:::tg;p
i
2f0; 1gg
;
:
(16.17)
FIGURE 16.22
Hiding the check bits p
1
,p
2
.
16.4.2 Reconstruction and Verifying Phase
This section describes the proposed secret recovery scheme and authentication
scheme. Recall that after performing the secret sharing process for a group of
n participants, each participant obtains one stego-image SI
0
j
. The proposed
process for stego-image authentication and secret image recovery is summa-
rized in the following paragraphs.
Input:
The random number generator used to generate integers
a
1
;a
2
;:::;a
k1
in Equation 16.16, the secret key t used for gen-
erating the check bits (e.g., t = 2), and a set of at least k stego-
images SI
0
j
, say m ones, with k m n , j = 1, 2, ..., m.
Output:
A report of failure of secret reconstruction, or the recovered secret
image GI
0
if all the stego-images are authenticated as genuine.
Step 1:
Use the random number generator to generate a
1
;a
2
;:::;a
k1
in
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