Cryptography Reference
In-Depth Information
FIGURE 15.4
Demonstration of steps in RAHA.
The steps stated in RAHA are also demonstrated in Figure 15.4.
Part II. Aim at the recovery of the original secret image.
Step 1. Collect at least t shadows among n shadows. Renumber t of them as
1, 2, ;t in order.
For g = 1; 2; ;
l m 2
t
m
, do a loop of the following steps:
Step 2. Chose the t feature value f j ;j = 1; 2; ;t forms the collected stego-
images.
Step 3. Let x j = f j , for j = 1; 2; ;t. Reconstruct q g (x)by using the pair
of (x j ;PV y (g j ) as follows:
q g (x) = P b=1 PV y (g)
Q j=1;j6=b xx j
x b x j modp
Step 4. Restore t pixels of the secret image from the t coecients in the
polynomial function q g (x) = (a 0 + a 1 x + + a t1 x t1 ).
b
15.4.2 Set-Up Authentication
In Thien and Lin's proposal [8], the size of shadows could be dramatically
reduced, with n shares being embedded into n different host images to avoid
 
 
Search WWH ::




Custom Search