Cryptography Reference
In-Depth Information
has been encoded as permute(s
1
A
;
1
) (permute(s
2
A
;
1
);permute(s
3
A
;
1
), re-
spectively), the same permutation
1
should be adopted for encoding b
1
to
preserve the superimposition result of s
1
A
s
B
(s
2
A
s
B
and s
3
A
s
B
, respec-
tively). Let us simply set
1
= f1; 2; 3; 4; 5; 6g. Therefore, b
1
is encoded as
permute(s
2
B
;
1
) (
) as show in Figure 3.12. It is easily seen that
a
1
b
1
= permute(s
1
A
;
1
) permute(s
2
B
;
1
)
= s
1
A
s
2
B
= =
a
1
b
1
= permute(s
2
A
;
1
) permute(s
2
B
;
1
)
= s
2
A
s
2
B
= =
a
1
b
1
= permute(s
3
A
;
1
) permute(s
2
B
;
1
)
= s
3
A
s
2
B
= =
(a)
(b)
(c)
FIGURE 3.11
Instances of the first three pixels of the three strips in (a) P
1
, (b) P
2
, and (c)
P
3
.
FIGURE 3.12
Encoding b
1
in B.
Therefore, the rst blocks in the rst chords of A B, A
120
B, and
A
240
B reconstruct (p
1
)
1
(), (p
2
)
1
(), and (p
3
)
1
(), respectively.
In summary, given a certain (p
1
;p
2
;p
3
)
j
in the first strips of (P
1
;P
2
;P
3
), b
j
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