Cryptography Reference
In-Depth Information
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(i)
(j)
(k)
(l)
(m)
(n)
(o)
(p)
FIGURE 3.18
Elementary blocks in E B : (a) s 0 B , (b) s 1 B , (c) s 2 B , (d) s 3 B , (e) s 4 B , (f) s 5 B , (g)
s 6 B , (h) s 7 B , (i) s 8 B , (j) s 9 B , (k) s 1 B , (l) s 1 B , (m) s 1 B , (n) s 1 B , (o) s 1 B , (p) s 1 B .
for 1 j and 1 k x where function ratote(p 1 p 2 :::p x ;k1) is dened
by formula (3.3).
Based upon the above denitions and formulae (3.5){(3.8), our visual
multi-secrets sharing scheme is formally presented in Algorithm 1.
Algorithm 1. Encoding x secret images into two circle shares
Input: x hw binary secret image P 1 ;P 2 ;:::;P x
Output: two circle shares A and B such that any single A or B leaks no
information about any one of the secret images, while A (i1) B recovers P i
for 1 i x in the human visual system where = 360 =x and A 0
1.
Create A and B as circle shares, which are decomposed into x chords
where each chord is composed by = h (w=x) chord-shaped blocks
referred to as a j and b j , 1 k x and 1 j , respectively and each
block contains 2x subpixels.
Generate E A and E B according to formulae (5) and (6), respectively.
2.
3.
for (each block j, 1 j ) do
3.1 f Determine j = ( 1 ; 2 ;:::; 2x ), a random permutation
of f1; 2;:::; 2xg
3.2
for (each chord k, 1 k x) do
f // all blocks in x chords of A and B adopt the
same permutation j
 
 
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