Giáo trình AN TOÀN VÀ BẢO MẬT THÔNG TIN

4. William Stallings. Cryptography and Network Security Principles and Practices,
Fourth Edition. Prentice Hall. 2005.
5. MichaelWelschenbach. Cryptography in C and C++. Apress. 2005.

Hình thức và tiêu chuẩn đánh giá sinh viên:
- Sinh viên ph làm các bài ki tra trong quá trình h và th hành. Th
- 

Thang điểm : Thang điểm 10.
 = 0,3 X + 0,7 Y.




  

 1
:   2
1. 







 2
2.  







  2
3.  2
4.  3
5. 

(cryptology) 4
6. (CryptoSystem) 4
7. 









 5
8.   



 6
9. 





 8
10.  





 8
CHII: 

 10
1.  10
1.1. Entropy 10
1.2.  



. (Rate of Language) 11
1.3.  11
1.4. 





(Confusion and Diffusion) 12
2.  13
 14
 14
 16
3.  17
3.1.   17
3.2.   17
3.3.  17
3.4. 
N
() 18
3.5.  

 

 18
3.6.  19
3.7.  19
3.8. 





 20
3.9. 



 21
3.10. 

  1  22
3.11.  

 . 22
4. . 23
4.1.  



 23
4.2. 

-Strassen 25
4.3. 

-Miller 26
4.4. 

. 26
5.  26
:  28
1.  28
1.1. 



 (substitution cipher) 28
1.2. 

 28
1.3. 

 29
1.4. 

 30
1.5. 

 30
1.6. 



(transposition cipher) 32
2.  34
 34
 35
 51


2.4. Triple DES (3DES) 52
2.5. 





  54
 68
3.  72
:  77
1.  77
2.   







 78
3.  



 78
3.1. 

 78
3.2. 

 79
3.3. 

 Gamal 83
3.4.  85
4.  96
   

   101
1. 





101
 101
 102
 103
 106
1.5. 











108
 109
 109
 109
2.3. Birthday attack 110
 111
2.5. 



 118
3.  119
:  120
1. 

 120
khoá 120
 120
 122
2.3. 

-Hellman 123
 124
-Hellman 124
- 125
-Takashima-Imai 126
 127
4. 128
:   130
 130
 130
 131
 132
 132
 133
4.3. 

134
5. Các  134
 136
Danh m hình v


 5
3.1: 







 35
3.2:  38
3.3:  39
3.4: 

 41
 43
 44
3.7: Triple DES 53
3.8:  56
3.9:  59
3.10: ifftRows() 62
3.11:  63
3.12:  63
3.13: ()  66
3.14:   69
3.15:   70
 71
4.1: 



1  78
4.2: 



2  78
4.3: 











  83
4.4:  87
4.5: 
2
4
(g
4
, 1) 92
4.6: 





- 94
5.1: 











108
 109
 112
 113
 117

Danh m b




 2.1: 
*
21
19
2.2: 
13
20
3.1:  

 





  29
3.2:  32
3.3:  32
3.4:  33
3.5:  33
3.6:  39
3.7: 
-1
39
3.8: -1 41
3.9:  42
3.10: -2 42
3.11:  44

1
45

2
45

3
45

4
46

5
46

6
46

7
46

8
46
3.20:  47
3.21:  50
3.22:  51
3.23:  51
3.24: 

 

  





 54
3.25: 4 bit 56
3.26:  57
3.27: -

 61
3.28: B() 66
4.1:  



-Pollard 81
4.2: 



23(1, 1) 89
4.3:  95





1
  



, 
, . Ngày n
c 
, 
  ,  ngày càng

 
thông tin. Tài li



,  
   
p, các em sinh viên,   
 

 này.
 , 



 


 ,  . Xi












, 









 , 
 







. 





 


, 













  


 .  









  
, 

 

   ch, 
luôn    ,  

 

Hải phòng, tháng 12 năm 2007



N

: 



2
:  
1. 








(protocol) (mechanism)








 



 



 






( , , ). 














 

 










,   





 














  . 














   . 










  ( ) 








 : 

 




 





 







 

 . 
 

 nh 


, 

  





 

  


.
 









 








gian.  , 


  





 

 


  . 





 














. 











 g nhau
 . 












  



  . 
 





 



















. 







 , 



 

 


 







,  ,  .
2. 
 :  







 



 n
 

,   











.
:
  


   
 


 
 




 


3.   

 






3 :
: 



3
 : 
 .
 



:   







.  






 









. 





 ,
 



 





 


.
 p:  . 
   , 



.





 

 .  3  :
(insider), 







 


 

  , 

 

  (hacker, cracker),




 

 



  

 


, (

, ) 
 .
:
Th3 

:
  

   : 



 






  ( 

), 
  

 

 :  ,  

  













 : 



 






 











 .






 


, .
4. 






:
 : 
 .  : (reading), xem (viewing),  (printing), 




, 

   

 



c.










 ( 



 ) 












.  











 
 



.  
















.
 : 
.
 : 














 .
 





:
: 



4
 

  

 





 



 





  ,
.
 .
5. 

(cryptology)


 

 :  (cryptography) 
(cryptanalysis-codebreaking) 

:
 : 






















 (















 ). 














 , ,  





, 
  , .
 : 













. 
 ,  



, 


 











.










 







  
, , , c.
M ha (cryptography) là một ngành khoa học của các phương pháp truyền tin bảo
mật. Trong tiếng Hy Lạp, “Crypto” (krypte) c nghĩa là che dấu hay đảo lộn, còn “Graphy”
(grafik) c nghĩa là từ. [3]
, 


P-Plaintext), 

















C-Ciphertext).

 


 





 





.
6.  (CryptoSystem)
Một hệ m mật là bộ 5 (P, C, K, E, D) thoả mn các điều kiện sau:
1) P là không gian bản rõ: là tập hữu hạn các bản rõ c thể c.
2) C là không gian bản m: là tập hữu hạn các bản m c thể c.
3) K là kkhông gian khoá: là tập hữu hạn các khoá c thể c.
4) Đối với mỗi k

K, c một quy tắc m hoá e
k

E và một quy tắc giải m
tương ứng d
k

D. Với mỗi e
k
: P →C và d
k
: C →P là những hàm mà d
k
(e
k
(x)) = x cho mọi
bản rõ x

P. Hàm giải m d
k
chnh là ánh xạ ngưc của hàm m ha e
k
[5]
: 



5

























 A . 











  Anh, 

SCII, 
0 1.


k


d
k


k


1
và x
2
sao cho y = e
k
(x
1
) =
e
k
(x
2

1
hay x
2
.
 |CP| 
Khi |C| = |P| 
7. 

  





 


 

 : 

  thông 


 (

) 





 




(



) 



.
 



:


1.1: 

 (E-Enemy), các khoá mã hoá và




 .






 S (Sender) (Message  




) 

 (Insecured

E-Encryption) lê
 

 mã hoá Y (C-Ciphertext) 

 






 
1
(Key), khoá K
1







 mã Y (các bên
 

 



)D-Decryption) là quá trình




2
( 








).
 
 (Cryptosytem) .

X Y Y X
Sender
Encrypt
Insecured
Channel
Decrypt
Receiver
K
1
K
2
Enemy

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