AES Simplified algorithm in English .pdf

خوارزمية aes

1. AESExample-Input(128bitkeyandmessage)
KeyinEnglish:
ThatsmyKungFu
(16ASCIIcharacters,1byteeach)
TranslationintoHex:
T
h
a
t
s
m
y
K
u
n
g
F
u
54
68
61
74
73
20
6D
79
20
4B
75
6E
67
20
46
75
KeyinHex(128bits):
5468617473206D79204B756E67204675
PlaintextinEnglish:
TwoOneNineTwo
(16ASCIIcharacters,1byteeach)
TranslationintoHex:
T
w
o
O
n
e
N
i
n
e
T
w
o
54
77
6F
20
4F
6E
65
20
4E
69
6E
65
20
54
77
6F
PlaintextinHex(128bits):
54776F204F6E65204E696E652054776F
1

2. AESExample-TherstRoundkey

KeyinHex(128bits):
5468617473206D79204B756E67204675

w[0]=(54;68;61;74);w[1]=(73;20;6D;79);w[2]=(20;4B;75;6E);w[3]=(67;20;46;75)

g(w[3]):

circularbyteleftshiftofw[3]:(20;46;75;67)

ByteSubstitution(S-Box):(B7;5A;9D;85)

Addingroundconstant(01;00;00;00)gives:g(w[3])=(B6;5A;9D;85)

w[4]=w[0]g(w[3])=(E2;32;FC;F1):
01010100
01101000
01100001
01110100
10110110
01011010
10011101
10000101
11100010
00110010
11111100
11110001
E2
32
FC
F1

w[5]=w[4]w[1]=(91;12;91;88),w[6]=w[5]w[2]=(B1;59;E4;E6),
w[7]=w[6]w[3]=(D6;79;A2;93)

rstroundkey:
E232FCF191129188B159E4E6D679A293
2

3. AESExample-AllRoundKeys

Round0:5468617473206D79204B756E67204675

Round1:E232FCF191129188B159E4E6D679A293

Round2:56082007C71AB18F76435569A03AF7FA

Round3:D2600DE7157ABC686339E901C3031EFB

Round4:A11202C9B468BEA1D75157A01452495B

Round5:B1293B3305418592D210D232C6429B69

Round6:BD3DC2B7B87C47156A6C9527AC2E0E4E

Round7:CC96ED1674EAAA031E863F24B2A8316A

Round8:8E51EF21FABB4522E43D7A0656954B6C

Round9:BFE2BF904559FAB2A16480B4F7F1CBD8

Round10:28FDDEF86DA4244ACCC0A4FE3B316F26
3

4. AESExample-AddRoundkey,Round0

StateMatrixandRoundkeyNo.0Matrix:
0
B
B
@
544F4E20
776E6954
6F656E77
2020656F
1
C
C
A
0
B
B
@
54732067
68204B20
616D7546
74796E75
1
C
C
A

XORthecorrespondingentries,e.g.,694B=22
01101001
01001011
00100010

thenewStateMatrixis
0
B
B
@
003C6E47
1F4E2274
0E081B31
54590B1A
1
C
C
A
4

5. AESExample-Round1,SubstitutionBytes

currentStateMatrixis
0
B
B
@
003C6E47
1F4E2274
0E081B31
54590B1A
1
C
C
A

substituteeachentry(byte)ofcurrentstatematrixbycorrespondingentryinAES
S-Box

forinstance:byte6EissubstitutedbyentryofS-Boxinrow6andcolumnE,i.e.,
by9F

thisleadstonewStateMatrix
0
B
B
@
63EB9FA0
C02F9392
AB30AFC7
20CB2BA2
1
C
C
A

thisnon-linearlayerisforresistancetodierentialandlinearcryptanalysisattacks
5

6. AESExample-Round1,ShiftRow

thecurrentStateMatrixis
0
B
B
@
63EB9FA0
C02F9392
AB30AFC7
20CB2BA2
1
C
C
A

fourrowsareshiftedcyclicallytotheleftbyosetsof0,1,2,and3

thenewStateMatrixis
0
B
B
@
63EB9FA0
2F9392C0
AFC7AB30
A220CB2B
1
C
C
A

thislinearmixingstepcausesdiusionofthebitsovermultiplerounds
6

7. AESExample-Round1,MixColumn

MixColumnmultipliesxedmatrixagainstcurrentStateMatrix:
0
B
B
@
02030101
01020301
01010203
03010102
1
C
C
A
0
B
B
@
63EB9FA0
2F9392C0
AFC7AB30
A220CB2B
1
C
C
A
=
0
B
B
@
BA84E81B
75A48D40
F48D067D
7A320E5D
1
C
C
A

entryBAisresultof(0263)(032F)(01AF)(01A2):

0263=0000001001100011=11000110

032F=(022F)2F=(0000001000101111)00101111=01110001

01AF=AF=10101111and01A2=A2=10100010

hence
11000110
01110001
10101111
10100010
10111010
7

8. AESExample-AddRoundkey,Round1

StateMatrixandRoundkeyNo.1Matrix:
0
B
B
@
BA84E81B
75A48D40
F48D067D
7A320E5D
1
C
C
A
0
B
B
@
E291B1D6
32125979
FC91E4A2
F188E693
1
C
C
A

XORyieldsnewStateMatrix
0
B
B
@
581559CD
47B6D439
081CE2DF
8BBAE8CE
1
C
C
A

AESoutputafterRound1:
5847088B15B61CBA59D4E2E8CD39DFCE
8

9. AESExample-Round2

afterSubstituteByteandafterShiftRows:
0
B
B
@
6A59CBBD
A04E4812
309C989E
3DF49B8B
1
C
C
A
0
B
B
@
6A59CBBD
4E4812A0
989E309B
8B3DF49B
1
C
C
A

afterMixcolumnsandafterRoundkey:
0
B
B
@
15C97F9D
CE4D4BC2
8971BE88
654797CD
1
C
C
A
0
B
B
@
430E093D
C65708F8
A9C0EB7F
62C8FE37
1
C
C
A
9

10. AESExample-Round3

afterSubstituteByteandafterShiftRows:
0
B
B
@
1AAB0127
B45B3041
D3BAE9D2
AAE8BB9A
1
C
C
A
0
B
B
@
1AAB0127
5B3041B4
E9D2D3BA
A9AAE8BB
1
C
C
A

afterMixcolumnsandafterRoundkey:
0
B
B
@
AA65FA88
160C053A
3DC1DE2A
B34B5A0A
1
C
C
A
0
B
B
@
7870994B
76763C39
307D3734
54235BF1
1
C
C
A
10

11. AESExample-Round4

afterSubstituteByteandafterShiftRows:
0
B
B
@
BC51EEB3
3838EB12
04FF9A18
202639A1
1
C
C
A
0
B
B
@
BC51EEB3
38EB1238
9A1804FF
A1202639
1
C
C
A

afterMixcolumnsandafterRoundkey:
0
B
B
@
10BCD3F3
D894E0E0
53EA9E25
2440737B
1
C
C
A
0
B
B
@
B10804E7
CAFCB1B2
5154C96C
EDE1D320
1
C
C
A
11

12. AESExample-Round5

afterSubstituteByteandafterShiftRows:
0
B
B
@
C830F294
74B0C837
D120DD50
55F866B7
1
C
C
A
0
B
B
@
C830F294
B0C83774
DD50D120
B755F866
1
C
C
A

afterMixcolumnsandafterRoundkey:
0
B
B
@
2A268FE9
781E0C7A
1BA76F0A
5B62003F
1
C
C
A
0
B
B
@
9B235D2F
515F1C38
2022BD91
68F03256
1
C
C
A
12

13. AESExample-Round6

afterSubstituteByteandafterShiftRows:
0
B
B
@
14264C15
D1CF9C07
B7937A81
458C23B1
1
C
C
A
0
B
B
@
14264C15
CF9C07D1
7A81B793
B1458C23
1
C
C
A

afterMixcolumnsandafterRoundkey:
0
B
B
@
A937AAF2
AED80C21
E76CB19C
F0FD673B
1
C
C
A
0
B
B
@
148FC05E
93A4600F
252B2492
77E84075
1
C
C
A
13

14. AESExample-Round7

afterSubstituteByteandafterShiftRows:
0
B
B
@
FA73BA58
DC49D076
3FF1364F
F59B099D
1
C
C
A
0
B
B
@
FA73BA58
49D076DC
364F3FF1
9DF59B09
1
C
C
A

afterMixcolumnsandafterRoundkey:
0
B
B
@
9F375137
AFEC8CFA
63390466
4BFBB1D7
1
C
C
A
0
B
B
@
53434F85
39060A52
8E933B57
5DF895BD
1
C
C
A
14

15. AESExample-Round8

afterSubstituteByteandafterShiftRows:
0
B
B
@
ED1A8497
126F6700
19DCE25B
4C412A7A
1
C
C
A
0
B
B
@
ED1A8497
6F670012
E25B19DC
7A4C412A
1
C
C
A

afterMixcolumnsandafterRoundkey:
0
B
B
@
E88A4BF5
7475EEE6
D31F7558
558A0C38
1
C
C
A
0
B
B
@
6670AFA3
25CED373
3C5A0F13
74A80A54
1
C
C
A
15

16. AESExample-Round9

afterSubstituteByteandafterShiftRows:
0
B
B
@
3351790A
3F8B668F
EBBE767D
92C26720
1
C
C
A
0
B
B
@
3351790A
8B668F3F
767DEBBE
2092C267
1
C
C
A

afterMixcolumnsandafterRoundkey:
0
B
B
@
B6E7518C
848898CA
346066FB
E8D77051
1
C
C
A
0
B
B
@
09A2F07B
66D1FC3B
8B9AE630
7865C489
1
C
C
A
16

17. AESExample-Round10

afterSubstituteByteandafterShiftRows:
0
B
B
@
013A8C21
333EB0E2
3DB88E04
BC4D1CA7
1
C
C
A
0
B
B
@
013A8C21
3EB0E233
8E043DB8
A7BC4D1C
1
C
C
A

afterRoundkey(Attention:noMixcolumnsinlastround):
0
B
B
@
2957401A
C3142202
502099D7
5FF6B33A
1
C
C
A

ciphertext:
29C3505F571420F6402299B31A02D73A
17