Nghiên cứu một số kỹ thuật phát hiện ảnh giấu tin

ĐẠI HỌC QUỐC GIA HÀ NỘI
TRƯỜNG ĐẠI HỌC CÔNG NGHỆ



HỒ THỊ HƯƠNG THƠM


NGHIÊN CỨU MỘT SỐ KỸ THUẬT
PHÁT HIỆN ẢNH GIẤU TIN




LUẬN ÁN TIẾN SỸ CÔNG NGHỆ THÔNG TIN






HÀ NỘI - 2012
2

ĐẠI HỌC QUỐC GIA HÀ NỘI
TRƯỜNG ĐẠI HỌC CÔNG NGHỆ


HỒ THỊ HƯƠNG THƠM

NGHIÊN CỨU MỘT SỐ KỸ THUẬT
PHÁT HIỆN ẢNH GIẤU TIN


Chuyên ngành: Hệ thống thông tin
Mã số: 62 48 05 01


LUẬN ÁN TIẾN SỸ CÔNG NGHỆ THÔNG TIN

NGƯỜI HƯỚNG DẪN KHOA HỌC:
1. TS. Hồ Văn Canh
2. PGS. TS. Trịnh Nhật Tiến


HÀ NỘI - 2012
6

MỤC LỤC
LỜI CAM ĐOAN 1
LỜI CẢM ƠN 4
MỤC LỤC 6
DANH MỤC CÁC KÝ HIỆU VÀ TỪ VIẾT TẮT 9
DANH MỤC CÁC BẢNG 10
DANH MỤC CÁC HÌNH VẼ 12
PHẦN MỞ ĐẦU 14
CHƯƠNG 1. GIẤU TIN TRONG ẢNH, PHÁT HIỆN ẢNH CÓ GIẤU TIN VÀ CÁC
NGHIÊN CỨU LIÊN QUAN 21
1.1. GIU TIN TRONG  21
 21

 23
 27
N NH GI 29
 29
 29
 31
 32
 35
C NGHI 37
 37
 39
 41
KT LU 41
CHƯƠNG 2. KỸ THUẬT PHÁT HIỆN MÙ CHO ẢNH GIẤU TIN TRÊN LSB 42
2.1. K THUA MI 42
 42
 42
 44

2

1
2
) 48
 48
 48
2. 52
 52
7

 53
 62
 63
   66
2.2. K THUA MIN TN S 70
  70
 71
2.3. T QU TH NGHIM 72
 72
 72
 76
 77
 77
 79
KT LUG 2 79
CHƯƠNG 3. MỘT SỐ KỸ THUẬT PHÁT HIỆN CÓ RÀNG BUỘC 80
N U TIN S DNG K THUT GIU HKC 80
 80
 81
 81
 83
 86
  89
 89
 91
N U TIN S DNG K THUT GIU DIH 92
 92
 93
 thut giu DIH 93
u 95

 99
 99
 101
N U TIN S DNG K THUT GIU IWH 101
 101
8

 104
 thut giu IWH 104
 105
 109
 109
3.3.3.2.  110
N U TIN S DNG K THUT GIU RVH 111
 111
 114
 114
 117
t qu th nghim 124
3.4.3.1. Th nghim 124
3.4.3.2. Nh 126
KT LUG 3 127
KẾT LUẬN CHUNG 128
DANH MỤC CÁC CÔNG TRÌNH CÔNG BỐ CỦA TÁC GIẢ 133
TÀI LIỆU THAM KHẢO 134
PHỤ LỤC – CHƯƠNG TRÌNH ĐỀ MÔ GIẤU TIN TRONG ẢNH VÀ PHÁT HIỆN
ẢNH CÓ GIẤU TIN 145

9

DANH MỤC CÁC KÝ HIỆU VÀ TỪ VIẾT TẮT
DCT Discrete Cosine Transform
DFT Discrete Fourier Transform
DWT Discrete Wavelet Transform
DIH Difference Image Histogram
FIR Finite Impulse Response
HVS Human Visual System
HKC tin Hwang, J. Kim Choi
IWT Integer Wavelet Transform
IDCT Inverse Discrete Cosine Transform
IDWT Inverse Discrete wavelet transform
i.i.d Independent and Identically Distributed
JPEG Joint Photographic Experts Group
LLRT Logarithm Likelihood Ratio Test
LSB Least Significant Bit
MBNS Multiple-Base Notational System
MOS Mean Opinion Score
MSB Most Significant Bit
MSE Mean Squared Error
NSAS 
Pdf Probability Density Function
PNG Portable Network Graphics
PMF Probability Mass Function
PR Pseudo Random
PSNR Peak Signal To Noise Ratio
PoV Pair of Value
QIM Quantization Index Modulation
RS Regular /Singular
RVH Reversible Vertical Horizontal Technique
RCM Reversible Contrast Mapping

SS Spread Spectrum
SSIS Spread Spectrum Image Steganography
10

DANH MỤC CÁC BẢNG

Bng 1.1. Bi tng trong tp  38
B t
0
ng v x
0
theo bng lp sn trong [108] 47
Bi nh theo t
0
p 
0_1
, 
LSB_30
, 
LSB_50
, 
LSB_70
, 
LSB_100
48
B 
1
2
ng v  theo bng lp sn trong [108] 51
Bng 2.4. Kt qu i nh ng v 

1
2
trong bng 2.3 51
Bi 
0_1
, 
LSB_
30
, 
LSB_
50
, 
LSB_
70
, 
LSB_
100
bng

k thu lch
chu
1
2
52
Bng 2.6: Kt qu th nghi 59
Bng 2.7: Kt qu th nghi 61
Bng 2.8: Kt qu th nghic lng  61
Bng 2.9. Bng thn sut xut hin c n ting Anh 64
Bng 2.10. Th nghi ch |c
i

j
 s
i
j
| ca nh gc 65
B sai lch gia tn sut ca nh kinh c l 67
Bng 2.12. Kt qu c lng xp x i tp 10 nh 69
Bng 2.13. Kt qu c lng xp x theo (p 10 nh chun 69
Bng 2.14. Kt qu i p 
0
, 
LSB_
30
, 
LSB_
50
,

LSB_
70
, 
LSB_
100
bng mt s k thun u tin 73
Bng 2.15. Kt qu  p nh  gm 10440 nh (
0


LSB_
30

, 
LSB_
50
, 
LSB_
70
, 
LSB_
100
) 73
Bng 2.16. Kt qu  p nh  gm 4176 nh (tp 
0
,

LSB_
100
) 74
Bng 2.17. Kt qu c lp 
0
, 
LSB
_30
, 
LSB
_50
, 
LSB
_70
, 
LSB

_100
75
Bng 2.18. Kt qu thi gian thc hip 
0
(2088 nh) 75
Bng 2.19: T l i nh ca k thu l 
n
2
[71] vp nh 
0
,

25
, 
50
, 
100
78
Bng 2.20. Kt qu  p nh  78
Bng 2.21. Thi gian thc hip J
0
78
Bng 3.1. Bng kt qu p 
0

HKC_2500
89
11

Bng 3.2. Kt qu  p nh  gm 4176 nh (

0


HKC_2500
) 90
Bng 3.3. Kt qu c lp 
0

HKC_2500
90
Bng 3.4. Bng kt qu i bng ba k thun: c
Lin ci ti thu xut mp 
HKC_R100
91
Bng 3.5. Kt qu  p nh U gm 4176 nh (
0


HKC_R100
) 91
Bng 3.6. S dng k thun t i p

DIH_7168
94
Bng 3.7. c lu cho nh Lena.bmp tru tin s dng
DIH bng k thut c l 94
Bng 3.8. Bng kt qu i u tin bp 
0

DIH_6000

99
Bng 3.9. Kt qu c lp 
0

DIH_6000
100
Bng 3.10. Kim tra nh Lena.bmp tru tin s dng IWH bng k thut
n LSB c s wavelet. 104
Bng 3.11. Kt qu th nghim c l 109
Bng 3.12. Bng kt qu i u tin bp 
0

IWH_6000
109
Bng 3.13. Kt qu c lp 
0

IWH_6000
109
Bng 3.14. Kim tra p 
RVH_7168
b thun t
min LSB 116
Bng 3.15. c lu cho tp 
RVH_7168
bng k thu 
kh 116
Bng 3.16. T l i nh (gu tin) vi mt s  ngng T 126
Bng 3.17. Kt qu c lp 
0


RVH_7500
126










12

DANH MỤC CÁC HÌNH VẼ
  u tin trong nh [84]. 21
  nh. 22
a gia nh c- bit [84]. 24
 n u tin [84] 29
 m t: a) ca tp p, b) ca tp p sau khi lc bng FIR . 34
nh th nghim cho k thu l  59
p 10 nh chun ly v t [107] 68
 tn su s cosine: a) nh cover, b) nh stego [94] 71
 tn sut: (a) nh gc, (b) nh giu tin bng HKC 81
m Peak: (a) trc khi giu tin, (b) sau khi giu tin 82
 tn sut ca: (a) nh gc, (b) nh giu tin bng HKC 83
n ginh nh  128 x 56
m  nh Lena (gc), (d) khi dch chuyn,
(e) sau khi giu tin 93

p nh th nghim 95
 tn sut h s a nh trc khi giu tin bng DIH: a)
Airplane.bmp, b) Beer.bmp, c) Elaine.bmp, d) House.bmp, e) Lena.bmp,
f) Peppers.bmp, g) Sailboat.bmp, h) Tiffany.bmp 96
 tn sut h s a nh sau khi giu tin bng DIH: a)
Airplane.bmp, b) Beer.bmp, c) Elaine.bmp, d) House.bmp, e) Lena.bmp,
f) Peppers.bmp, g) Sailboat.bmp, h) Tiffany.bmp 96
t qu c l p nh 
0
p

DIH_6000
100
 tn su s wavelet: (a) Bi nh gu, (b) Biu
 ng mt ct tn sut h s  Z [99]. 102
 tn sut h s wavelen cao ca: (a) nh Lena
gnh giu tin v u: (b) T = 3, (c) T = -3, (d) T = 5,
(e) T = -6, (f) T = 8. 103
13

 tn sut h s n cao cnh gc: a)
Airplane.bmp, b) Beer.bmp, c) Elaine.bmp, d) House.bmp, e) Lena.bmp,
f) Peppers.bmp, g) Sailboat.bmp, h) Tiffany.bmp 105
 tn sut h s n cao: (a) ca nh Lena
gu tin v u: (b) T = 2, (c) T = 4, (d)
T = 6. 106
 nghim c lp nh: a) tp 
0
p


IWH_6000
110
 111
nh Baboon 115
 Bi tn sut ca: (a) nh cover_Baboon, (b) nh stego_Baboon 115
t: (a) chn, (b) l ca nh cover_Baboon. Bmp . 117
t: (a) chn,(b) l ca nh stego_Baboon. Bmp 118
  c |P
LSB
(0)  P
LSB
(1)| cm 
n trong tp:a) 
0
, b) 
RVH_R
25
, c) 
RVH_R
50
, d) 
RVH_R
75
, e) 
RVH_R
100
125


14

PHẦN MỞ ĐẦU
1. Tính cấp thiết của luận án
   Steganography
1
         
 quan  . 
 
[76] (485-    

 
  
n. Ha Elder (23-





steganos graphia bản viết  [27].
T

   

  
ctin 
 ) rong
   Jessica Fridrich [32].


 

1
Steganography 
15






Hình 1. Kỹ thuật giấu tin công bố trong giai đoạn 1992 – 2007[32]
 hay trong 
.   

Internet hi 
(2).

Hình 2. Tỉ lệ phương tiện được lựa chọn để giấu tin năm 2008 [32]
 
? Theo [18, 27]
 
16

1/.  trong   
.
 (undistinguishable)  
 .
        apacity) trong
 1/ v yu c 2/ nu trn. Ngo ra, vi gi
thng tin trong  c em l kh nng ti ki b nh v th gian truy tin

 k.       8        
 595350 pixel

b 
  
 
 (difference image).
 
   thay
 bit LSB 
 [16, 17, 19, 50, 51, 53 - 55, 65, 67, 69, 75, 77, 91, 100]. 

    SS (Spread Spectrum) [3, 4,
26, 60],              QIM
(Quantization Index Modulation) [5, 23, 42, 65, 79], hay   
khBNS [101], RCM [25], RVH [45
 trong M  , T
nhng v n c v s ph tri  k thu M ,

17

image steganalysis
2

   .
hai 
,  l: T
; T 





an ninh I   
t
.
  : 
t  (blind steganalysis) 
;  
 
  constraint steganalysis).

 :
-  LSB  
gian  31, 38, 84, 95, 102 
[71
83 59, 81, 82
 66].
-  cho 
     
OutGuess), [33] 46] (t

2
image steganalysis 
18

HKC), [24] (
tin MBNS).
 
 
 . 


    an ninh,  hay 
 
 .
2. Mục tiêu và phạm vi nghiên cứu
  

- 
LSB 

 
so 
-  
 
tin
 

 .
MAP 




19

3. Những đóng góp của luận án
 

 


-  ba    LSB  
  : n      , p 

2
 (
1
2
),  p .
- 

- tin 
  
 
:
- K    wavelet.
- K   .
- KHKC 
- K .
T 
 
                
Washington [103], 
 
4. Tổ chức luận án
ba      
Chương 1 
 n 

(PrecisionRecall),  (F-measure) 


20

Chương 2      
LSB , 
1
2
,  
 .
 
   
2
A. Westfeld [15], LLRT K. Sullivan [80]
: RS  [31], DI 
X. Ping [102]  .
Chương 3   k  cho 
 . C 

kết luận chung phụ lục.
Phụ lục    


21

Chương 1. GIẤU TIN TRONG ẢNH, PHÁT HIỆN ẢNH CÓ
GIẤU TIN VÀ CÁC NGHIÊN CỨU LIÊN QUAN

 
 
 
,   cho 


1.1. GIẤU TIN TRONG ẢNH VÀ NGHIÊN CỨU LIÊN QUAN
1.1.1. Khái niệm
 (image steganography) 
   (cover image)   

 
 [18, 27, 32].
 tin hai 
    
   [27, 45,
74] 
  tin .





Hình 1.1: Sơ đồ quá trình giấu tin trong ảnh [84].





-1
(
 c
(Cover) C

tin s


22





Hình 1.2: Sơ đồ quá trình tách tin trong ảnh.
.1    trong

-1
cosine, wavelet,
  (image difference). 

- 


cosine [43 
23, 25,
69, 70, 92, 94, 104].
- 
72, 99


 HL 

42, 73, 91, 99]. 



-              

ij
 -
1,  - 
    D ={d
ij
}   d
ij
=


 tin

(Stego) s
(Cover) C


23

x
i,2j+1
 x
i,2j
/2  1  d
ij
= x
i,j-1
 x

i,j

i  m  1, 0   2
[48, 49, 52, 53, 90, 97].
1.1.2. Phương pháp giấu tin và nghiên cứu liên quan


               
replacement  LSB hiding)           n
trong ].
 tin  tin 
 . Trong  -bit  

11101100) bit 
bit 1110110) MSBs (Most Significant Bit) 
 ,    bit LSB 
 LSB 0
sang 1 1 sang 0
.
LSB 
    
tin tin 
tin  
  8  bit 
,   

={x
ij
 m,
 n, x

ij
 . tin B
l
= {b
i
l,
b
i
 
i
 
ij
theo
  

={s
ij
 
24

n, s
ij
    theo 
1.3 (gi  117).


Hình 1.3. Minh họa giấu thông tin trong LSB của ảnh cấp xám 8 - bit [84].
tin 
24 -   bit)
 

 bit .

 xoay, 

cosine [3, 7, 23, 25, 94, 104], wavelet [91, 99]
 [49, 53, 90, 97].
Bit LSB  hay    
 theo thứ tự tuần tự ], Jstego
[104 ], DE [91 theo thứ tự ngẫu nhiên    
OutGuess [71], F5 [94], Hide
and Seek [69)

Phương pháp tăng giảm LSB (

1 embedding), btin 

  
25

tin 

tin. 78, 49
Phương pháp đồng chẵn lẻ, c
k tin 
1 
LSB tin 1
0
 . 

. K


             
       l c phng ph      
  (phương pháp tuần tự, phương pháp ngẫu nhiên, phương pháp
tăng giảm, phương pháp đồng chẵn lẻ) nh 


chèn nhiễu SS hay điều chỉnh hệ số lượng tử QIM 
Kỹ thuật giấu tin theo hình thức chèn nhiễu SS: 
tin 

3, 4, 26, 27, 32, 60
Cox [26x
k

tin 
d
k
tin x
k

s
k
= x
k
d
k
, s
k
= x

k
x
k
) d
k
= x
k
d
k
s
k
= x
k

e
d
k
. 
tron  
26

Kỹ thuật giấu tin điều chỉnh hệ số lượng tử QIM: 


h  
 
n
}
N
n=1


n
}
N
n=1
, M 
tin )=q
M
 bao

tin  bao

 M) = q(X + D(M))  D(M
M

 
5, 23, 42, 65, 79].
: 
 
tin  V
      t 
[39]  T
   21, 24, 25, 35, 41,
45, 48, 49, 52, 53, 58, 90, 91, 93, 98, 99]t

KDE (Difference Expansion) (2002)
[90],  
 1.1),  
 . 
 [91]. 2008, 

 [93]  

DE.
27

N, 
62 
dDIH [49] (2004) 
), HKC [41] , 
IWH [99]  
98


  Multiple-Base Notational System) [101]:   
    
 c   
  [25
     RVH [45]         
M
1
M
2



1.1.3. Phương pháp đánh giá độ an toàn của một lược đồ giấu tin
        
 hay    Cachin
15].
u s c s dt

lut  hip tt c nh gc C,  tin mt
M,  K giu tin,  p tt c nh stego S. M giu
tin (thut cp (S
E
, S
X
), vi S
E
:      
S
X
:     S
E
to ra mng S 
 t mi C , M   K  
X
 M S
K.
28

Gi s P
C
 t ca C  . NK   M  

E
, S
X

P
C

s  t P
S
ng ca S  
15
Định nghĩa 1.1  Một lược đồ (thuật toán) giấu tin được gọi là an toàn nếu sai phân
Kullback – Leibler giữa hàm mật độ xác suất của P
C
và P
S
theo (1.1) là bằng 0
D
KL
(P
C
|| P
S
) =















(1.1)
Khi D
KL
(P
C
|| P
S
) < ε

thì

lược đồ giấu tin có độ an toàn

ε (ε - secure), trong
đó ε là một số thực dương đủ nhỏ tùy ý cho trước.

D
KL
(P
C
|| P
S
) 
, t l P
C
= P
S
(theo b  c b trong
L thuy thng tin) - secure


[25, 45, 49, 52, 62, 90, 91, 93, 99] 

89]. PSNR 


PSNR
 
 MOS (Mean Opinion Score) .1.
Bảng 1.1. 
PSNR [dB]
MOS
> 37

31 -37

25  31

20  25

< 20
