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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