DES (Data Encryption Standard) algorithm is explained in detail in Persian language. چگونگی کارکرد و ساختار الگوریتم DES

1. Data Encryption Standard
(DES)
M.Golyani
Tehran University – Kish campus
Fall 2013
Copyright ©GPL
Mohammad.golyani@gmail.com

2. S-Box P-Box
DES
DES
-

3. DES
NBS
NIST
NSA
-
-
NBS
-
IBM
-

4. DES
-
-
S-Box
NSA
DES
-
-

5. DES
-
-

6. -
XOR
-

7. k
f
-
k
0 1 1 0 0 1 0 1
1 0 0 1 1 0 1 0
K=2
F = mirror(each K bit of input)
1 0 0 1 1 0 1 0
K=2
F = mirror(each K bit of input)

8. -
•
•
•
•
(R)
•
(L)
XOR
•

9. m
0
0
1
1
1
1
0
0
0
1
0
0
1
1
0
f
1
-
R0
L0
K0
L1
R1
DES
K1
-
Kn
Kn-1
Rn
C
0
1
Ln XOR f(Kn,Rn)
1
0
0
1
1
0
C = (Rn+1,Ln+1)
Kn
Li+1 = Ri
Ri+1 = Li XOR f ( Ri , Ki )

10. c
Rn
0
0
1
1
1
1
0
0
0
1
0
0
1
1
0
Ln XOR f(Kn,Rn)
1
-
Kn
Ln-1
-
Rn-1
Kn-1
-
f
K0
Ri = Li+1
L0
m
0
1
R0
1
0
0
1
m = (L0 , R0)
1
0
Li = Ri+1 XOR f ( Li+1, Ki )

11. DES Feistel function
f
Backdoor
DES
-
P-Box S-Box
DES
-

12. P-Box S-Box
P-Box S-Box
-
S-Box
-
P-Box
Confusion
P-Box
S-Box
Diffusion

13. P-Box S-Box
P-Box
S-Box
BlowFish
S-Box
P-Box
-
-
DES
P-Box
S-Box
S-Box
-

14. P-Box S-Box
P-Box
Straight
P-Box
I0
O0
0
0
I1
O1
1
0
I2
O2
1
1
I3
O3
0
1
I4
O4
0
0
I5
O5
1
1
I6
O6
0
0
I7
O7
1
-

15. P-Box S-Box
P-Box
S-Box
-
y = 3x2 + 4x -1
S-Box
S-Box
-
-
-

16. P-Box S-Box
m0
m1
m2
m1
m0
m2
Lookup Table:
00
01
10
11
0
010
101
110
001
1
111
100
011
000
m0
n
m0
m1
0
m2
0
Straight
S-Box
1
1
n

17. DES
S-Box
S-Box
S-Box
-
S-Box
DES
-
S1
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0
14
4
13
1
2
15
11
8
3
10
6
12
5
9
0
7
1
0
15
7
4
14
2
13
1
10
6
12
11
9
5
3
8
2
4
1
14
8
13
6
2
11
15
12
9
7
3
10
5
0
3
15
12
8
2
4
9
1
7
5
11
3
14
10
0
6
13
m1,m2,m3,m4
m0,m5
S-Box
Diffusion

18. DES
S-Box
DES
S-
S-Box
backdoor
Box
IBM
S-Box
S-Box
NSA

19. DES
DES
-
DES
-
DES
XOR
-
-

20. DES
DES
Ri
f
XOR
Li
Ri

21. DES
P-Box
-
(Initial
Permutation)
58
50
42
34
26
18
60
52
44
36
28
62
54
46
38
64
56
48
57
49
59
IP
10
2
20
12
4
30
22
14
6
40
32
24
16
8
41
33
25
17
9
1
51
43
35
27
19
11
3
61
53
45
37
29
21
13
5
63
55
47
39
31
23
15
7
-

22. DES

23. DES
-
“_MAGMAG_”
IP
DES
M
77
01001101
A
65
01000001
G
71
01000111
_
95
01011111
-
0101111101001101010000010100011101001101010000010100011101011111

24. DES
IP
IP
–
58
50
42
34
26
18
10
2
60
52
44
36
28
20
12
4
62
54
46
38
30
22
14
6
64
56
48
40
32
24
16
8
57
49
41
33
25
17
9
1
59
51
43
35
27
19
11
3
61
53
45
37
29
21
13
5
63
55
47
39
31
23
15
7
IP
-

25. DES
R
L
P-Box
-
”4950515253545556”
P-Box
(L0)
(R0)

26. m
0
1
1
0
0
32 bit
1
0
DES
1
-
32 bit
R0
L0
K0
L1
f
R1
DES
-
K1
f
K16
Ri
XOR
-
Li
Ri+1
R14
L14 XOR f(K14,R14)
(L15)
C
0
1
(R15)
1
0
0
1
1
0
Ri
Li+1
-

27. DES
XOR
L0
f
K0 R0
-
L0
K0
R0
f
L1
R1
Li+1 = Ri
L1 = R0
Ri+1 = Li XOR f ( Ri , Ki )
R1 = L0 XOR f ( R0 , K0 )

28. DES
K0
XOR
K
K0
K0
-
-
K0 = 101100 001001 001011 001010 011100 001000 000101 000101
K8 = 001110 010001 101010 001010 010100 011100 001000 111000
K1 = 101100 000001 101011 010010 011101 101000 000001 001100
K9 = 001100 000011 100011 001100 000100 010001 110000 001100
K
“4950515253545556”= 000100 000110 110001 010100 100010 000011 000010 110100 -
K2 = 001101 000111 101001 010000 000000 001011 010111 001010
10
K3 = 000001 100111 010101 010100 001011 001011 010000 100001
K11= 010001 000110 110100 110100 001000 010110 101010 100101
K4 = 010011 100100 010101 010101 011010 100100 110001 100010
K12= 110001 101010 010100 100101 001100 100000 100010 010011
K5 = 010011 111100 000100 101001 000011 001100 100100 011010
K13= 110010 111000 011000 100011 100001 110000 000100 010111
K6 = 100010 111000 000110 101011 100001 010101 010001 010000
K14= 111010 011001 001010 101010 000001 110010 001111 000000
K7 = 101110 010000 101010 001011 110010 011000 001001 100000
K15= 101000 011001 001010 101010 010101 000010 001001 000011

29. DES
-
L0
f
L1
K0
R0
R1
f
DES

30. DES
XOR
-
XOR
f
-
S-Box
S-Box
P-Box
-

31. DES

32. DES
-
R0
E
48-bit
E(R0)

33. DES

34. DES
m
0
1
1
0
32 bit
0
1
0
1
32 bit
R0
L0
K0
L1
R1
K1
K16
R14
L14 XOR f(K14,R14)
(L15)
C
0
1
(R15)
1
0
0
1
1
0

35. DES
XOR
K0 E(R0)
0
0
0
0
1
0
1
1
1
1
1
1
1
1
1
0
0
0
1
0
1
1
1
48-bit
48-bit
48-bit
E(R0)
K0
E(R0) xor K0
S-Box
f

36. DES
S-Box
P-Box
f
0
0
0
0
S1
1
0
1
1
S2
S3
S4
S5
Straigh P-Box
1
S6
1
1
1
1
0
0
0
1
S7
1
0
1
S8
1
1

37. DES
S-Box
14 4 13 1
S1
0 15 7
4
2 15 11 8
3 10 6 12 5
9
0
7
15 1
4 14 2 13 1 10 6 12 11 9
5
3
8
3 13 4
3 10 5
0
1 14 8 13 6
15 12 8
2
4
9
2 11 15 12 9
1
3 15 4
1 13 12 7 11 4
2
8
7 13 14 3
0
8
5 14 12 11 15 1
13 8 11 5
6 15 0
2 12 5 10 14 7
9
3
4
13 6
4
9
8 15 3
0 11 1
1 10 13 0
6
7
2 12 4
S5
0
7 10 11 6
1
14 11 2 12 4
4
2
6 10 2
7 13 1
1 11 10 13 7
11 8 12 7
4 15 14 3 11 5
8
5
5
0 15 10 3
8 15 9 12 5
S7
1
9
5
3
0 14
9 10 4
6
S6
2
9 14 15 5
5
0 15 14 2
9
2
3 12
S8
7 11 4
2
5 14 9
2
8
5 11 12 4 15
7
2 12 1 10 14 9
1
1 14 7
4
2
1 13 14 0 11 3
8 12 3
7
0
4 12 5
9 12 14 2
0
5 11
8
4 10 1 13 11 6
5 15 10 11 14 1
7
4
2 14
6
6 15 11 1 10 9
4 14 7
8
5
1 15 13 8 10 3
4
9
2 15
7 12 9
6
0
3
0 13 3
5 12 2 15 8
8
4
7 12 0
9 11 5
8
2 12 9
8
3
9
5 10
6
2
2
13 2
7
3
8 12 6
2 11 6
9 10 1
1 10 6
5 11 12 7
12 1 10 15 9
10 15 4
5
2 13 12 0
6 10 1 13 8
1
7 14 10 15 6
4 10 7
8
7
3 14 5
5 10 6
1 10 14 3
6 11 13 8
3 15 0
9
0 12 11 7 13 15 1
4
13 0 11 7
4 11 13 12 3
6
9
9
3
8 13 3 12 9
1
2 12
10 6
6
5
4 11 2 14 15 0
9
S4
3 15 13 0 14 9
1 14 2 13 6 15 0
4
0 14 7 11 10 4 13 1
13 8 10 1
13 7
4
8 14 12 0
6 13
3 15 5
8
7 15 2
5 11 3 14 10 0
9 14 6
9
S2
8 14 6 11 3
7
10 0
S3
7
-
7
6
3 14 5
0
8 13
0 12 7
6 11 0 14 9
6 10 13 15 3
4 10 8 13 15 12 9
0
3
5
5
2
8
6 11

38. DES
S-Box
0
-
0
0
S1 0
S1
1
2
3
0 14 4 13 1
1
0 15 7
2
4
4
5
7
2 15 11 8
8
9 10 11 12 13 14 15
3 10 6 12 5
9
0
7
4 14 2 13 1 10 6 12 11 9
5
3
8
3 10 5
0
1 14 8 13 6
3 15 12 8
6
2
4
9
2 11 15 12 9
1
7
7
5 11 3 14 10 0
6 13
S-Box
P-Box
S-Box
1 0 1 1 1 0 0 1 1 0 1 0 0 1 1 0 1 1 1 1 0 1 0 0 1 1 1 1 1 0 1 1

39. DES
m
0
1
1
0
32 bit
0
1
0
1
32 bit
R0
L0
K0
L1
R1
K1
K16
R14
L14 XOR f(K14,R14)
(L15)
C
0
1
(R15)
1
0
0
1
1
0

40. DES
P-Box
1
-
7
20
21
1
1
0
1
29
12
28
17
1
0
1
0
1
15
23
26
1
1
1
0
5
18
31
10
1
1
1
1
2
8
24
14
0
1
0
1
32
27
3
9
1
0
1
0
19
13
30
6
1
1
0
1
22
S-Box
16
11
4
25
0
0
1
1
P-Box
f

41. DES

42. DES
L0
K0
R0
f
L1
R1
Li+1 = Ri
L1 = R0
Ri+1 = Li XOR f ( Ri , Ki )
R1 = L0 XOR f ( R0 , K0 )

43. DES
XOR
L0
R1
1
1
0
1
1
0
1
0
1
1
1
0
1
1
1
1
0
1
0
1
1
0
1
0
1
1
0
1
0
0
1
1
0
=
0
1
1
1
0
1
1
1
0
1
0
1
0
0
0
0
1
0
1
0
1
f(K0,R0)
1
0
XOR
0
0
L0
1
0
=
0
1
0
0
R1

44. DES
m
0
1
1
0
32 bit
0
1
0
1
32 bit
DES
R0
L0
K0
L1
K16
R14
L14 XOR f(K14,R14)
(L15)
0
1
P-Box
R1
K1
C
-
(R15)
1
0
0
1
1
0
IP
P-Box
-

45. DES
0
1
0
1
0
0
1
0
0
0
1
1
0
1
1
1
0
0
0
0
0
0
0
0
0
0
1
1
0
0
1
1
0
0
0
0
1
1
0
0
1
1
0
0
0
1
1
0
0
1
0
0
1
1
R15 =
0
1
L15 =
1
0
1
0
1
1
1
1
0
1
0
1
0
1
0
0
1
1
0
0
0
1
1
0
1
1
1
0
0
0
0
0
0
0
0
0
0
1
1
0
0
1
1
0
0
0
0
1
1
0
0
1
1
0
0
0
1
1
0
0
1
0
0
1
1
0
1
0
1
1
1
1
0
1
0
1
0
1
0
0
40
8
48
16
56
24
64
32
1
1
0
0
0
1
1
0
39
7
47
15
55
23
63
31
1
1
1
0
0
0
0
0
38
6
46
14
54
22
62
30
0
0
0
0
0
1
1
0
37
5
45
13
53
21
61
29
0
1
1
0
0
0
0
1
36
4
44
12
52
20
60
28
1
0
0
1
1
0
0
0
35
3
43
11
51
19
59
27
1
1
0
0
1
0
0
1
34
2
42
10
50
18
58
26
1
0
1
0
1
1
1
1
33
1
41
9
49
17
57
25
f
IP-1
64 bit

46. DES

47. DES
DES
“_MAGMAG_”
“4950515253545556”
01000101 00100011 10100011 00010101 10010000 01001001 11101100 00111101
“4523a3159049ec3d”
_MAGMAG_
5f4d41474d41475f
4950515253545556
IPQRSTUV
4523a3159049ec3d

48. DES
DES
-
RSA
-
DES
RSA
DES
DESCHALL
-

49. DES
DES
DESCHALL
-
-
Usenix

50. DES
DES
RSA
Distributed.net
DES
-
DES
RSA
EFF
Deepcrack
-
-

51. DES
DES
DES
-

52. DES
DES
cryptome
PicoComputing
FPGA
-
DES
FPGA
AES
3DES
-
DES
DES
ARM

53. Secure MCU with 32-bit ARM SC300 CPU, SWP interface, NESCRYPT cryptoprocessor and high-density Flash memory

54. DES
-
XOR
Electronic Code Book
ECB
DES
CBC, CFB, OFB, CTR
DES
DES
DES
-
-

55. -
Introduction to modern cryptography, Jonathan Katz, Yehuda Lindell
-
The Day DES Died, SANS Institute InfoSec Reading Room
-
Practically secure Feistel ciphers, Lars R. Knudsen, Arhus University, Denmark
-
Implementation of Data Encryption Standard Using Reversible Gate Logic, Nuthan.A.C
-
DES, CSIS 5857: Encoding and Encryption
-
DES Walk Through, Kathryn Neugent, April 16, 2011
-
United States Patent, 3,798,359 Mar.19,1974
-
Cryptography and Network Security, Behruz Forouzan
-
,…