Kriptografi Metode FCB 8-bit

EKj

Pi Ci

Bit kunci kiri (20 bit) Bit kunci kiri (20 bit)

R1

R2

R3

R4

R5

L1

L2

L3

L4

L5

Bit kunci EKSTERNAL (40 bit)

K1 = R1 + L1

K2 = R2 + L2

K3 = R3 + L3

K4 = R4 + L4

K5 = R5 + L5

SL1

SL1

SL1

SL1

SL1

SL1

SL1 SL1

SL1

SL1

TUGAS KRIPTOGRAFI 2011 DWI KUSRIANTO PUTRO J2F008098

Diketahui suatu data akan dienkripsi dengan system berikut:

Metode yang digunakan adalah FCB dengan panjang blok 8-bit dengan panjang blok 40 bit (setiap blok akan mempunyai 5 blok kecil dengan panjang blok 8 bit) dengan mengunakan kunci yang dihasilkan oleh suatu keystream generator dan setiap blok kecil menggunakan kunci yang berbeda sesuai dengan indek blok kecil tersebut, Fungsi Enkripsi didefinisikan sebagai berikut:

1. Geser kiri antrian sejauh 22. (hasil langkah satu) XOR Kj3. Geser ke kanan (hasil langkah kedua) sejauh 14. (hasil langkah tiga) XOR Kj

IV yang digunakan adalah “HARUS”Adapun keystream generator yang digunakan adalah

Enkripsi kalimat “KERJAKAN DENGAN BENAR” dengan kata kunci eksternal “DWIKU” dengan asumsi spasi tidak diperhitungkan.

Tabel ASCII

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 51 52 53 54 55 56 57 58 59 5A


A 41 01000001 N 4E 01001110B 42 01000010 O 4F 01001111C 43 01000011 P 50 01010000D 44 01000100 Q 51 01010001E 45 01000101 R 52 01010010F 46 01000110 S 53 01010011G 47 01000111 T 54 01010100H 48 01001000 U 55 01010101I 49 01001001 V 56 01010110J 4A 01001010 W 57 01010111K 4B 01001011 X 58 01011000L 4C 01001100 Y 59 01011001M 4D 01001101 Z 5A 01011010

Diketahui:

P: KERJAKAN DENGAN BENAR Kj: DWIKU IV: HARUS Keystream generator

Ditanya : Hasil enkripsi

Jawab :

1. IV “HARUS”Alfabet ASCII (biner)

H,A,R,U,S 01001000, 01000001, 01010010, 01010101, 01010011 2. Kj = DWIKU

Alfabet ASCII (biner)D,W,I,K,U 01000100, 01010111, 01001001, 01001011, 01010101

Bit kunci kiri (20 bit)01000100010101110100

Bit kunci kiri (20 bit)10010100101101010101

10001000101011101000

00010001010111010001

00100010101110100010

01000101011101000100

10001010111010001000

00101001011010101011

01010010110101010110

10100101101010101100

01001011010101011001

10010110101010110010

1000100010101110100000101001011010101011

0001000101011101000101010010110101010110

0010001010111010001010100101101010101100

0100010101110100010001001011010101011001

1000101011101000100010010110101010110010

SL1

SL1

SL1

SL1

SL1

SL1

SL1 SL1

SL1

SL1


3. Proses Enkripsi Karakter ke-1 (K) IV= 0100100001000001010100100101010101010011 harus SL2 0010000100000101010010010101010101001101 sift left 2 XOR K1 1000100010101110100000101001011010101011 k1

1010100110101011110010111100001111100110 SR1 0101010011010101111001011110000111110011 sift right 2 XOR K1 1000100010101110100000101001011010101011

1101110001111011011001110111011101011000 XOR P1(K) 01001011 k

10010111 97

Proses Enkripsi Karakter ke-2 (E)

IV= 0100000101010010010101010101001110010111 SL2 0000010101001001010101010100111001011101 XOR K2 0001000101011101000101010010110101010110

0001010000010100010000000110001100001011 SR1 1000101000001010001000000011000110000101 XOR K2 0001000101011101000101010010110101010110

1001101101010111001101010001110011010011 XOR P2(E) 01000101

11011110 DE

Bit kunci EKSTERNAL (40 bit)0100010001010111010010010100101101010101


Proses Enkripsi Karakter ke-3 (R)

IV= 0101001001010101010100111001011111011110 SL2 0100100101010101010011100101111101111001 XOR K3 0010001010111010001010100101101010101100

0110101111101111011001000000010111010101 SR1 1011010111110111101100100000001011101010 XOR K3 0010001010111010001010100101101010101100

1001011101001101100110000101100001000110 XOR P3(R) 01010010

11000101 C5

Proses Enkripsi Karakter ke-4 (J)

IV= 0101010101010011100101111101111011000101 SL2 0101010101001110010111110111101100010101 XOR K4 0100010101110100010001001011010101011001

0001000000111010000110111100111001001100 SR1 0000100000011101000011011110011100100110 XOR K4 0100010101110100010001001011010101011001

0100110101101001010010010101001001111111 XOR P4(J) 01001010

00000111 07

Proses Enkripsi Karakter ke-5 (A)

IV= 0101001110010111110111101100010100000111 SL2 0100111001011111011110110001010000011101 XOR K5 1000101011101000100010010110101010110010

1100010010110111111100100111111010101111 SR1 1110001001011011111110010011111101010111 XOR K5 1000101011101000100010010110101010110010

0110100010110011011100000101010111100101 XOR P4(A) 01000001

00101001 29

Proses Enkripsi Karakter ke-6 (K)

IV= 1001011111011110110001010000011100101001 SL2 0101111101111011000101000001110010100110 XOR K1 1000100010101110100000101001011010101011

1101011111010101100101101000101000001101 SR1 1110101111101010110010110100010100000110 XOR K1 1000100010101110100000101001011010101011

0110001101000100010010011101001110101101 XOR P6 (K) 01001011

00101000 28



IV= 1101111011000101000001110010100100101000 SL2 0111101100010100000111001010010010100011 XOR K2 0001000101011101000101010010110101010110

0110101001001001000010011000100111110101 SR1 1011010100100100100001001100010011111010 XOR K2 0001000101011101000101010010110101010110

1010010001111001100100011110100110101100 XOR P7(A) 01000001

11100101 E5

Proses Enkripsi Karakter ke-8 (N)

IV= 1100010100000111001010010010100011100101 SL2 0001010000011100101001001010001110010111 XOR K3 0010001010111010001010100101101010101100

0011011010100110100011101111100100111011 SR1 1001101101010011010001110111110010011101 XOR K3 0010001010111010001010100101101010101100

1011100111101001011011010010011000110001 XOR P8(N) 01001110

11110111 F7

Proses Enkripsi Karakter ke-9 (D)

IV= 0000011100101001001010001110010111110111 SL2 0001110010100100101000111001011111011100 XOR K4 0100010101110100010001001011010101011001

0101100111010000111001110010001010000101 SR1 1010110011101000011100111001000101000010 XOR K4 0100010101110100010001001011010101011001

1110100110011100001101110010010000011011 XOR P9(D) 01000100

10101101 AD


IV= 0010100100101000111001011111011110101101 SL2 1010010010100011100101111101111010110100 XOR K5 1000101011101000100010010110101010110010

0010111001001011000111101011010000000110 SR1 0001011100100101100011110101101000000011 XOR K5 1000101011101000100010010110101010110010

1001110111001101000001100011000010110001 XOR P10 (E) 01000101

11011000 D8



IV= 0010100011100101111101111010110111011000 SL2 1010001110010111110111101011011101100000 XOR K1 1000100010101110100000101001011010101011

0010101100111001010111000010000111001011 SR1 1001010110011100101011100001000011100101 XOR K1 1000100010101110100000101001011010101011

0001110100110010001011001000011001001110 XOR P11 (N) 01001110

01010011 53

Proses Enkripsi Karakter ke-12 (G)

IV= 1110010111110111101011011101100001010011 SL2 1001011111011110101101110110000101001111 XOR K2 0001000101011101000101010010110101010110

1000011010000011101000100100110000011001 SR1 1100001101000001110100010010011000001100 XOR K2 0001000101011101000101010010110101010110

1101001000011100110001000000101101011010 XOR P12(G) 01000111

10010101 95


IV= 1111011110101101110110000101001110010101 SL2 1101111010110111011000010100111001010111 XOR K3 0010001010111010001010100101101010101100

1111110000001101010010110001010011111011 SR1 1111111000000110101001011000101001111101 XOR K3 0010001010111010001010100101101010101100

1101110010111100100011111101000011010001 XOR P13(A) 01000001

10011101 9D


IV= 1010110111011000010100111001010110011101 SL2 1011011101100001010011100101011001110110 XOR K4 0100010101110100010001001011010101011001

1111001000010101000010101110001100101111 SR1 1111100100001010100001010111000110010111 XOR K4 0100010101110100010001001011010101011001

1011110001111110110000011100010011001110 XOR P14(N) 01001110

11110010 F2

Proses Enkripsi Karakter ke-15 (B)


IV= 1101100001010011100101011001110111110010 SL2 0110000101001110010101100111011111001011 XOR K5 1000101011101000100010010110101010110010

1110101110100110110111110001110101111001 SR1 1111010111010011011011111000111010111100 XOR K5 1000101011101000100010010110101010110010

0111111100111011111001101110010000001110 XOR P15 (B) 01000010

00111101 3D


IV= 0101001110010101100111011111001000111101 SL2 0100111001010110011101111100100011110101 XOR K1 1000100010101110100000101001011010101011

1100011011111000111101010101111001011110 SR1 0110001101111100011110101010111100101111 XOR K1 1000100010101110100000101001011010101011

1110101111010010111110000011100110000100 XOR P16 (E) 01000101

10101110 AE


IV= 1001010110011101111100100011110110101110 SL2 0101011001110111110010001111011010111010 XOR K2 0001000101011101000101010010110101010110

0100011100101010110111011101101111101100 SR1 0010001110010101011011101110110111110110 XOR K2 0001000101011101000101010010110101010110

0011001011001000011110111100000010100000 XOR P17(N) 01001110

01111100 7C


IV= 1001110111110010001111011010111001111100 SL2 0111011111001000111101101011100111110010 XOR K3 0010001010111010001010100101101010101100

0101010101110010110111001110001101011110 SR1 0010101010111001011011100111000110101111 XOR K3 0010001010111010001010100101101010101100

0000100000000011010001000010101100000011 XOR P18(A) 01000001

01001001 49

Proses Enkripsi Karakter ke-19 (R)

IV= 1111001000111101101011100111110001001001


SL2 1100100011110110101110011111000100100111 XOR K4 0100010101110100010001001011010101011001

1000110110000010111111010100010001111110 SR1 0100011011000001011111101010001000111111 XOR K4 0100010101110100010001001011010101011001

0000001110110101001110100001011101100110 XOR P19(R) 01010010

01010001 51

Proses Enkripsi Karakter ke-20 ( )

IV= 0011110110101110011111000100100101010010 SL2 1111011010111001111100010010010101001000 XOR K5 1000101011101000100010010110101010110010

0111110001010001011110000100111111111010 SR1 0011111000101000101111000010011111111101 XOR K5 0100010101110100010001001011010101011001

0111101101011100111110001001001010100100 XOR P20( ) 00000000

01111011 7b

Pi K E R J A K A N D E N G A N B E N A RASCII 4B 45 52 4A 41 4B 41 4

E44 45 4E 47 41 4E 42 45 4E 41 52 0

ENKRIPSIASCII 97 D

EC5 07 29 28 E5 F7 AD D8 53 95 9

DF2 3

DAE 7C 49 51 7B

Ci — Þ Å BEL ) ( å ÷ Ø S • ò = ® | I Q {

P: KERJAKAN DENGAN BENAR C: — Þ ÅBEL) (å÷ Ø S• ò=®| I Q {

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Kriptografi Metode FCB 8-bit