Render Sequence Encoding
for Document Protection
Baoshi Zhu, Jiankang Wu, and Mohan S. Kankanhalli ,Member
IEEE Transactions on Mutimedia
Reporter:李衍緯
Outline
Introduction
 Basic Idea of RSE
 Encoding Algorithm
 Decoding Algorithm
 Information Carrying Capacity
 Robustness
 Tamper Detection With RSE
 Conclusion

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Introduction
RSE of
electronic document
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A.Basic Idea of RSE
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B. Encoding Algorithm
Definition 2.1：
The permutation <3,4,1,5,2> has five inversion
(3,1),(3,2),(4,1),(4,2),(5,2)

Definition 2.2：
The inversion sequence for permutation <3,4,1,5,2> is <2,3,0,0,0>

Theorem 2.1：
The inversion sequence <a1,a2,…,an> of the permutation < i1,i2,…,in >
satisfies this condition

0  a1  n  1,0  a2  n  2,...,0  an1  1, an  0
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Algorithm2.1 ：(Encoding Algorithm)
For any integer X ：
1) Choose an appropriate number n such that n!>X
2) Calculate a1=X/(n-1)! X1=X-a1*(n-1)! ,... ,ak=XkXk=Xk-1-ak-1*(n-k)! ,..., an-1=Xn-2 Xn-1=Xn1/(n-1)!
2-an-1*(n-1)! , an=Xn-1 。
3) Sequence <a1,a2,…,an> is the inversion sequence
identified by data X.

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Payload =GNU, Length=11
Normal notation <11,1,5,2,9,6,7,10,8,3,4>
Inversion sequence <1,2,7,7,1,2,2,3,1,1,0>
TOTAL number of “e”
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
A permutation can be uniquely identified using
its inversion sequence.

The encoding algorithm can uniquely map the
payload data to an inversion sequence.
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C. Decoding Algorithm

permutation target and the permutation length can
be made public, transferred though auxiliary
channels, or pre-agreed between the encoder and
decoder.

Permutation used must not contain repeatable subpermutation.
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Permutation target =“e”
Render sequence
Length=11
<S1,S2,…Sn>=<11,1,5,2,9,6,7,10,8,3,4,22,12,16,13,20,17,18,21,19,14,15,32,23,24
,31,27,28,31,29,25,26,43,33,37,34,41,38,39,42,40,35,36,44,45,46>
S’k=Sk+1-Sk
<S’1',S’2,…S’n>=
MAX =11,
Length=11
<10,-4,3,-7,3,-1,-3,2,5,-1,-18,
10,-4,3,-7,3,-1,-3,2,5,-1,-18,
Render sequence
n
X   ai  (n  1)!
10,-4,3,-7,3,-1,-3,2,5,-1,-18,
i 1
=<11,1,5,2,9,6,7,10,8,3,4>
10,-4,3,-7,3,-1,-3,2,5,-1,-18,
After calculate , X=4673109
-1,-1>
By ASCII code X=GNU
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D. Information Carrying Capacity
Nbits  log2 n!
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Document
Printer
PostScript
Robustness
Encoding
document
PDF
PDF
PCL
PostScript
PCLXL
Successful
EPS
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F. Tamper Detection With RSE
Render sequence =
11
<11,1,5,2,9,6,7,10,8,3,4,
22,12,16,13,20,17,18,21,19,14,15,
11
32,23,24,31,27,28,31,29,25,26,
10
43,33,37,34,41,38,39,42,40,35,36,
11
44,45,46>
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Conclusion
Advantage:
1.
Large information-carry capacity.
2.
Robustness.
3.
Difficult to forge the document.
4.
Easy to operate. (Compare with Digital signature.)
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