DES walkthrough

DES Walk Through
Kathryn Neugent
April 16, 2011
Here I show the actual encryption example used in my animation and presented on the webpage. 1

Input
1. Get Text = “Hello World!”
2. Convert to Binary
H
e l l o =
=
=
=
=
=

01001000
01100101
01101100
01101100
01101111
00100000

W o r l d
!

=
=
=
=
=
=

01010111
01101111
01110010
01101100
01100100
00100001

3. Break into 64-bit blocks block 0 1 0
0 1 1
0 1 1
0 1 1
0 1 1
0 0 1
0 1 0
0 1 1

2

1:
0 1
0 0
0 1
0 1
0 1
0 0
1 0
0 1

0
1
1
1
1
0
1
1

0
0
0
0
1
0
1
1

0
1
0
0
1
0
1
1

block 2:
0 1 1 1 0
0 1 1 0 1
0 1 1 0 0
0 0 1 0 0 padding padding padding padding

Example Key

0 0 1 1 0 1 0 0
0 0 1 0 1 1 0 1
1 0 1 1 0 1 0 1
1

0
1
1
0

1
0
0
0

0
0
0
1

1
0
1
1
0

3

0
0
1
0
0

1
0
0
0
0

0
1
1
1
0

0
1
0
0
1

0
0
1
0
0

0
1
1
0
0

IP

input:
0 1 0 0
0 1 1 0
0 1 1 0
0 1 1 0
0 1 1 0
0 0 1 0
0 1 0 1
0 1 1 0

4

1
1
1
0
0

1
0
1
1
1
0
0
1

0
1
1
1
1
0
1
1

0
0
0
0
1
0
1
1

0
1
0
0
1
0
1
1

IP:
58
60
62
64
57
59
61
63

50
52
54
56
49
51
53
55

42
44
46
48
41
43
45
47

34
36
38
40
33
35
37
39

26
28
30
32
25
27
29
31

18
20
22
24
17
19
21
23

10
12
14
16
9
11
13
15

0
1
1
0
1
1
0
0

PC-1:
57 49
1 58
10
2
19 11
63 55
7 62
14
6
21 13

41
50
59
3
47
54
61
5

33
42
51
60
39
46
53
28

25
34
43
52
31
38
45
20

17
26
35
44
23
30
37
12

9
18
27
36
15
22
29
4

result:
1 1 0 1
0 1 0 0
1 1 0 1
1 1 0 1
0 0 0 0
1 0 1 1
1 0 0 1
1 1 0 1

2
4
6
8
1
3
5
7

1
0
1
0
0
1
1
0

PC-1

key:
0 0 1
0 0 1
1 0 1
1 0 1
0 0 0
1 1 0
1 0 0
0 0 0

1
0
1
0
1
1
1
0

0
1
0
1
1
1
0
0

1
1
1
0
1
0
0
1

0
0
0
0
0
1
0
0

2

C:

D:

0
0
0
1
0
0
1
0

1
0
0
1
0
1
1
1

1
0
0
1
1
0
0
0

0
1
0
0
0
0
0
0

1
0
0
1
0
1
1
1

1
0
0
1
0
0
1
0

0
0
1
1
0
1
1
1

1
0
1
0
0
1
1
0

1
0
1
1
0
1
0
0

1
0
0
0
0
0
1
0

5

Key Scheduler
1. Left Circular Shift
Round
1

shift #
1

2

1

3

2

4

2

5

2

6

2

7

2

8

2

C
1101100
0010000
0000011
1101110
1101100
0100000
0000111
1011101
0110001
0000000
0011110
1110111
1000100
0000000
1111011
1011101
0010000
0000011
1101110
1110110