The Understanding of GOST Cryptography Technique
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Nowadays, it is often found a wide range of the securing information. The understanding that the author wants to design is about cryptography. Cryptography is the study of the security of data or information, commonly found in transferring data. One of them is the method of GOST, GOST is an abbreviation of "Gosudarstvennyi Standard" or "Government Standard." The algorithm is simple encryption algorithm which has some processes as many as 32 rounds and uses 64-bit block cipher with 256-bit key. GOST method also uses the S-Box 8 pieces of permanent and XOR operations and Rotate Left Shift. The author chose the GOST topic since the author wants to describe the understanding of the GOST method. The learning is presenting calculation of the encryption and decryption. The learning course is the study of cryptographic methods GOST. Learning software is also designed so that the method can be more easily understood GOST both algorithms and operations contained in this GOST method.
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![International Journal of Engineering Trends and Technology (IJETT) – Volume 39 Number 3- September 2016
ISSN: 2231-5381 http://www.ijettjournal.org Page 168
The Understanding of GOST Crytography
Technique
Muhammad Iqbal1
, Yudi Sahputra2
, Andysah Putera Utama Siahaan3
Faculty of Computer Science
Universitas Pembangunan Panca Budi
Jl. Jend. Gatot Subroto Km. 4,5 Sei Sikambing, 20122, Medan, Sumatera Utara, Indonesia
Abstract - Nowadays, it is often found a wide range of
the securing information. The understanding that the
author wants to design is about cryptography.
Cryptography is the study of the security of data or
information, commonly found in transferring data.
One of them is the method of GOST, GOST is an
abbreviation of "Gosudarstvennyi Standard" or
"Government Standard." The algorithm is simple
encryption algorithm which has some processes as
many as 32 rounds and uses 64-bit block cipher with
256-bit key. GOST method also uses the S-Box 8
pieces of permanent and XOR operations and Rotate
Left Shift. The author chose the GOST topic since the
author wants to describe the understanding of the
GOST method. The learning is presenting calculation
of the encryption and decryption. The learning course
is the study of cryptographic methods GOST. Learning
software is also designed so that the method can be
more easily understood GOST both algorithms and
operations contained in this GOST method.
Keywords – Cryptography, GOST, Encryption,
Decryption
I. INTRODUCTION
Encryption is the way to hide information from
being stolen [2][7][8]. GOST is a cryptography
algorithm made in Russia. This algorithm is a rival of
the DES algorithm created by the United States
[1][4][6]. Structurally, this algorithm is very similar to
the DES algorithm. As with algorithms DES, GOST
algorithm uses the structure Feistel network
encryption. This algorithm has a block size of the 64-
bit message. Unlike the AES, it has a block size of the
128-bit message. Every encryption and decryption
algorithms have a key [5]. This algorithm also has
some rounds more than AES-256, which is 32 rounds.
Each round uses eight key pieces scheduled internal
use. Functions used in each round in the GOST
algorithm is very simple. It just adds the subkey that
in-mod with 232. Then the results are put into the S-
box and rotate these results to the left as much as 11
bits. The results will be used in the next round. And so
on up to 32 rounds. Key scheduling done by GOST is
very simple. First, the primary key into eight pieces
measuring 32-bit subkey. Each subkey is used four
times in the algorithm. Twenty-four first round use
keywords in the order while eight last round uses the
key in the reverse order.
This understanding tries to describe the flow of the
GOST algorithm. It describes the basic rule of the key
generating. It also covers the round of the key. The
encryption and decryption will prove the GOST
method has been done.
II. THEORIES
A. Definition
GOST stands for "Gosudarstvennyi Standard" or
"Government Standard." Method GOST is a block
cipher algorithm developed by a national of the Soviet
Union. This method was developed by the Soviet
Union during the Cold War to hide data or information
that is confidential at the time of the communication
[3]. This algorithm is a simple encryption algorithm
which has some processes as much as 32 round (round)
and uses 64-bit block cipher with 256-bit key. GOST
method also uses the S-Box 8 pieces different and
XOR operations and Circular Shift Left. Weakness
GOST known until now is because its key schedule is
simply that in certain circumstances be the weak point
of the method of cryptanalysis as Related-key
cryptanalysis. However, this can be resolved by
passing the keys to a strong hash function in
cryptography such as SHA-1, and then use the results
to input initialization hash key. The advantage of this
method is the speed GOST pretty good, although not
as fast as Blowfish, faster than IDEA.
GOST structure such as:
1. Key Store Unit (KSU) stores 256-bit string
by 32-bit register (K0, K1, …, K7).
2. Twoof 32 bit register (R1, R2)
3. 32 bit adder modulo 232 (CM1)
4. Bitwise Adder XOR (CM2)
5. Substitusion block (S), an eight of 64 bit S-
Box.
6. Left rotation shift register (R),11 bit.
B. Key Structure
The key structure process is the technique to compose
the password to encrypt the plaintext. This process can
be seen as follow.](https://cdn.statically.io/img/image.slidesharecdn.com/ijett-v39p229-160928010843/85/The-Understanding-of-GOST-Cryptography-Technique-1-320.jpg)
![International Journal of Engineering Trends and Technology (IJETT) – Volume 39 Number 3- September 2016
ISSN: 2231-5381 http://www.ijettjournal.org Page 169
1. Input key, 256-bit key (k1, k2, k3, k4, …,
k256)
2. Generating of eight KSU
K0 = (k32, …, k1)
K1 = (k64, …, k33)
K2 = (k96, …, k65)
K3 = (k128, …, k97)
K4 = (k160, …, k129)
K5 = (k192, …, k161)
K6 = (k224, …, k193)
K7 = (k256, …, k225)
III. Result and Discussion
A. Key Generator
The process of formation of this key requires data
input with the key length of 256 bits or 64
hexadecimal digits or 32 pieces of character. This
process can be seen in the following example:
Suppose key: “Kriptografi Metode GOST, Andysah”,
then the process of formation of the key above the key
is in the following table.
TABLE I
KEY GENERATOR
No. Coordinate X Y
1 K 75 01001011
2 r 114 01110010
3 i 105 01101001
4 p 112 01110000
5 t 116 01110100
6 o 111 01101111
7 g 103 01100111
8 r 114 01110010
9 a 97 01100001
10 f 102 01100110
11 i 105 01101001
12 32 00100000
13 M 77 01001101
14 e 101 01100101
15 t 116 01110100
16 o 111 01101111
17 d 100 01100100
18 e 101 01100101
19 32 00100000
20 G 71 01000111
21 O 79 01001111
22 S 83 01010011
23 T 84 01010100
24 , 44 00101100
25 32 00100000
26 A 65 01000001
27 n 110 01101110
28 d 100 01100100
29 y 121 01111001
30 s 115 01110011
31 a 97 01100001
32 h 104 01101000
In Table 1, there are 32 pieces of characters which
are converted to the binary digit. It is used as a key to
process the encryption in GOST algorithm. The
conversion to the binary key of the 256-bit is as follow.
010010110111001001101001011100000111
010001101111011001110111001001100001
011001100110100100100000010011010110
010101110100011011110110010001100101
001000000100011101001111010100110101
010000101100001000000100000101101110
011001000111100101110011011000010110
1000
The key will be categorized to eight parts.
K[0] :
0100101101110010011010010111000
0
K[1] :
0111010001101111011001110111001
0
K[2] :
0110000101100110011010010010000
0
K[3] :
0100110101100101011101000110111
1
K[4] :
0110010001100101001000000100011
1
K[5] :
0100111101010011010101000010110
0
K[6] :
0010000001000001011011100110010
0
K[7] :
0111100101110011011000010110100
0](https://cdn.statically.io/img/www.slideshare.net/data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
The Understanding of GOST Cryptography Technique
- 1. International Journal of Engineering Trends and Technology (IJETT) – Volume 39 Number 3- September 2016 ISSN: 2231-5381 http://www.ijettjournal.org Page 168 The Understanding of GOST Crytography Technique Muhammad Iqbal1 , Yudi Sahputra2 , Andysah Putera Utama Siahaan3 Faculty of Computer Science Universitas Pembangunan Panca Budi Jl. Jend. Gatot Subroto Km. 4,5 Sei Sikambing, 20122, Medan, Sumatera Utara, Indonesia Abstract - Nowadays, it is often found a wide range of the securing information. The understanding that the author wants to design is about cryptography. Cryptography is the study of the security of data or information, commonly found in transferring data. One of them is the method of GOST, GOST is an abbreviation of "Gosudarstvennyi Standard" or "Government Standard." The algorithm is simple encryption algorithm which has some processes as many as 32 rounds and uses 64-bit block cipher with 256-bit key. GOST method also uses the S-Box 8 pieces of permanent and XOR operations and Rotate Left Shift. The author chose the GOST topic since the author wants to describe the understanding of the GOST method. The learning is presenting calculation of the encryption and decryption. The learning course is the study of cryptographic methods GOST. Learning software is also designed so that the method can be more easily understood GOST both algorithms and operations contained in this GOST method. Keywords – Cryptography, GOST, Encryption, Decryption I. INTRODUCTION Encryption is the way to hide information from being stolen [2][7][8]. GOST is a cryptography algorithm made in Russia. This algorithm is a rival of the DES algorithm created by the United States [1][4][6]. Structurally, this algorithm is very similar to the DES algorithm. As with algorithms DES, GOST algorithm uses the structure Feistel network encryption. This algorithm has a block size of the 64- bit message. Unlike the AES, it has a block size of the 128-bit message. Every encryption and decryption algorithms have a key [5]. This algorithm also has some rounds more than AES-256, which is 32 rounds. Each round uses eight key pieces scheduled internal use. Functions used in each round in the GOST algorithm is very simple. It just adds the subkey that in-mod with 232. Then the results are put into the S- box and rotate these results to the left as much as 11 bits. The results will be used in the next round. And so on up to 32 rounds. Key scheduling done by GOST is very simple. First, the primary key into eight pieces measuring 32-bit subkey. Each subkey is used four times in the algorithm. Twenty-four first round use keywords in the order while eight last round uses the key in the reverse order. This understanding tries to describe the flow of the GOST algorithm. It describes the basic rule of the key generating. It also covers the round of the key. The encryption and decryption will prove the GOST method has been done. II. THEORIES A. Definition GOST stands for "Gosudarstvennyi Standard" or "Government Standard." Method GOST is a block cipher algorithm developed by a national of the Soviet Union. This method was developed by the Soviet Union during the Cold War to hide data or information that is confidential at the time of the communication [3]. This algorithm is a simple encryption algorithm which has some processes as much as 32 round (round) and uses 64-bit block cipher with 256-bit key. GOST method also uses the S-Box 8 pieces different and XOR operations and Circular Shift Left. Weakness GOST known until now is because its key schedule is simply that in certain circumstances be the weak point of the method of cryptanalysis as Related-key cryptanalysis. However, this can be resolved by passing the keys to a strong hash function in cryptography such as SHA-1, and then use the results to input initialization hash key. The advantage of this method is the speed GOST pretty good, although not as fast as Blowfish, faster than IDEA. GOST structure such as: 1. Key Store Unit (KSU) stores 256-bit string by 32-bit register (K0, K1, …, K7). 2. Twoof 32 bit register (R1, R2) 3. 32 bit adder modulo 232 (CM1) 4. Bitwise Adder XOR (CM2) 5. Substitusion block (S), an eight of 64 bit S- Box. 6. Left rotation shift register (R),11 bit. B. Key Structure The key structure process is the technique to compose the password to encrypt the plaintext. This process can be seen as follow.
- 2. International Journal of Engineering Trends and Technology (IJETT) – Volume 39 Number 3- September 2016 ISSN: 2231-5381 http://www.ijettjournal.org Page 169 1. Input key, 256-bit key (k1, k2, k3, k4, …, k256) 2. Generating of eight KSU K0 = (k32, …, k1) K1 = (k64, …, k33) K2 = (k96, …, k65) K3 = (k128, …, k97) K4 = (k160, …, k129) K5 = (k192, …, k161) K6 = (k224, …, k193) K7 = (k256, …, k225) III. Result and Discussion A. Key Generator The process of formation of this key requires data input with the key length of 256 bits or 64 hexadecimal digits or 32 pieces of character. This process can be seen in the following example: Suppose key: “Kriptografi Metode GOST, Andysah”, then the process of formation of the key above the key is in the following table. TABLE I KEY GENERATOR No. Coordinate X Y 1 K 75 01001011 2 r 114 01110010 3 i 105 01101001 4 p 112 01110000 5 t 116 01110100 6 o 111 01101111 7 g 103 01100111 8 r 114 01110010 9 a 97 01100001 10 f 102 01100110 11 i 105 01101001 12 32 00100000 13 M 77 01001101 14 e 101 01100101 15 t 116 01110100 16 o 111 01101111 17 d 100 01100100 18 e 101 01100101 19 32 00100000 20 G 71 01000111 21 O 79 01001111 22 S 83 01010011 23 T 84 01010100 24 , 44 00101100 25 32 00100000 26 A 65 01000001 27 n 110 01101110 28 d 100 01100100 29 y 121 01111001 30 s 115 01110011 31 a 97 01100001 32 h 104 01101000 In Table 1, there are 32 pieces of characters which are converted to the binary digit. It is used as a key to process the encryption in GOST algorithm. The conversion to the binary key of the 256-bit is as follow. 010010110111001001101001011100000111 010001101111011001110111001001100001 011001100110100100100000010011010110 010101110100011011110110010001100101 001000000100011101001111010100110101 010000101100001000000100000101101110 011001000111100101110011011000010110 1000 The key will be categorized to eight parts. K[0] : 0100101101110010011010010111000 0 K[1] : 0111010001101111011001110111001 0 K[2] : 0110000101100110011010010010000 0 K[3] : 0100110101100101011101000110111 1 K[4] : 0110010001100101001000000100011 1 K[5] : 0100111101010011010101000010110 0 K[6] : 0010000001000001011011100110010 0 K[7] : 0111100101110011011000010110100 0
- 3. International Journal of Engineering Trends and Technology (IJETT) – Volume 39 Number 3- September 2016 ISSN: 2231-5381 http://www.ijettjournal.org Page 170 B. Encryption Process GOST encryption process of the method of processing the input plaintext data 64-bit or 16 hexadecimal digits or characters 8 through 32 stages of iterations (rounds). Suppose picking up the key on the formation and plaintext "ENKRIPSI", then the encryption process is as follows: ENCRYPTION, ROUND 0 (1) PLAIN TEXT = ENKRIPSI Convert to Binary= 0100010101001110010010110101001001001001010 100000101001101001001 L(0) = 10010010110010100000101010010010 R(0) = 01001010110100100111001010100010 (2) R(0) + K(0) mod 232 R( 0) = 1255305890 K( 0) = 244731602 -------------------------------- + R = 1500037492 mod 232 = 1500037492 = 01011001011010001100000101110100 (3) Split to 8 part and put to SBox. 0101 = 5 = SBOX(0) = 8 = 1000 1001 = 9 = SBOX(1) = 3 = 0011 0110 = 6 = SBOX(2) = 4 = 0100 1000 = 8 = SBOX(3) = 14 = 1110 1100 = 12 = SBOX(4) = 0 = 0000 0001 = 1 = SBOX(5) = 11 = 1011 0111 = 7 = SBOX(6) = 9 = 1001 0100 = 4 = SBOX(7) = 5 = 0101 (4) Concatenate and Rotate Left Shift 11 times. RLS(11)=0111000001011100101011000001101 0 (5) R(1) = R(0) XOR L(0) R( 0) = 01110000010111001010110000011010 L( 0) = 10010010110010100000101010010010 -------------------------------------------------- XOR R( 1) = 11100010100101101010011010001000 (6) L(1) = R(0) before process. L(1) = 01001010110100100111001010100010 ENCRYPTION, ROUND 1 (1) L(1) = 01001010110100100111001010100010 R(1) = 11100010100101101010011010001000 (2) R(1) + K(1) mod 232 R( 1) = 3801523848 K( 1) = 1323759150 -------------------------------- + R = 5125282998 mod 232 = 830315702 = 00110001011111011001110010110110 (3) Split to 8 part and put to SBox. 0011 = 3 = SBOX(0) = 2 = 0010 0001 = 1 = SBOX(1) = 11 = 1011 0111 = 7 = SBOX(2) = 2 = 0010 1101 = 13 = SBOX(3) = 2 = 0010 1001 = 9 = SBOX(4) = 10 = 1010 1100 = 12 = SBOX(5) = 9 = 1001 1011 = 11 = SBOX(6) = 7 = 0111 0110 = 6 = SBOX(7) = 10 = 1010 (4) Concatenate and Rotate Left Shift 11 times. RLS(11)=0001010101001011110100010101100 1 (5) R(2) = R(1) XOR L(1) R( 1) = 00010101010010111101000101011001 L( 1) = 01001010110100100111001010100010 --------------------------------------------------- XOR R( 2) = 01011111100110011010001111111011 (6) L(2) = R(1) before process. L(2) = 11100010100101101010011010001000 o o The process will continue until Round 31. ENCRYPTION, ROUND 31 (1) L(31) = 10110101101111001100010101011110 R(31) = 10011000110000000111100010010101 (2) R(31) + K(0) mod 232 R(31) = 2562750613 K( 0) = 244731602 -------------------------------- + R = 2807482215 mod 232 = 2807482215 = 10100111010101101100011101100111 (3) Split to 8 part and put to SBox. 1010 = 10 = SBOX(0) = 1 = 0001 0111 = 7 = SBOX(1) = 10 = 1010 0101 = 5 = SBOX(2) = 3 = 0011 0110 = 6 = SBOX(3) = 9 = 1001 1100 = 12 = SBOX(4) = 0 = 0000 0111 = 7 = SBOX(5) = 13 = 1101 0110 = 6 = SBOX(6) = 5 = 0101 0111 = 7 = SBOX(7) = 4 = 0100 (4) Concatenate and Rotate Left Shift 11 times. RLS(11)=1100100001101010101000001101000 1 (5) R(32) = R(31) before process. R(32) = 10011000110000000111100010010101
- 4. International Journal of Engineering Trends and Technology (IJETT) – Volume 39 Number 3- September 2016 ISSN: 2231-5381 http://www.ijettjournal.org Page 171 (6) L(32) = R(31) XOR L(31) R(31) = 11001000011010101010000011010001 L(31) = 10110101101111001100010101011110 ------------------------------------------------------ XOR L(32) = 01111101110101100110010110001111 (7) L(32) = b(32), b(31), ... b(1) R(32) = a(32), a(31), ... a(1) R = a(1), ... a(32), b(1), ... b(32) Rin binary = 10101001000111100000 0011000110011111000110100110011010111011 1110 = convert to text CIPHER TEXT = © ñ¦k¾ C. Decryption Process The decryption process is the reverse of the encryption process. GOST decryption process of the method of using the same algorithm with the encryption process. Suppose picking up the key establishment and ciphertext above, the decryption process is as follows: DECRYPTION, ROUND 0 (1) CIPHER TEXT = © ñ¦k¾ Convert to binary = 1010100100011110000000110001100111110001101 001100110101110111110 L(0) = 01111101110101100110010110001111 R(0) = 10011000110000000111100010010101 (2) R(0) + K(0) mod 232 R( 0) = 2562750613 K( 0) = 244731602 -------------------------------- + R = 2807482215 mod 232 = 2807482215 = 10100111010101101100011101100111 (3) Split to 8 part and put to SBox. 1010 = 10 = SBOX(0) = 1 = 0001 0111 = 7 = SBOX(1) = 10 = 1010 0101 = 5 = SBOX(2) = 3 = 0011 0110 = 6 = SBOX(3) = 9 = 1001 1100 = 12 = SBOX(4) = 0 = 0000 0111 = 7 = SBOX(5) = 13 = 1101 0110 = 6 = SBOX(6) = 5 = 0101 0111 = 7 = SBOX(7) = 4 = 0100 (4) Concatenate and Rotate Left Shift 11 times. RLS(11)=11001000011010101010000011010001 (5) R(1) = R(0) XOR L(0) R( 0) = 11001000011010101010000011010001 L( 0) = 01111101110101100110010110001111 ---------------------------------------------------- XOR R( 1) = 10110101101111001100010101011110 (6) L(1) = R(0) before process. L(1) = 10011000110000000111100010010101 DECRYPTION, ROUND 1 (1) L(1) = 10011000110000000111100010010101 R(1) = 10110101101111001100010101011110 (2) R(1) + K(1) mod 232 R( 1) = 3049047390 K( 1) = 1323759150 -------------------------------- + R = 4372806540 mod 232 = 77839244 = 00000100101000111011101110001100 (3) Split to 8 part and put to SBox. 0000 = 0 = SBOX(0) = 4 = 0100 0100 = 4 = SBOX(1) = 6 = 0110 1010 = 10 = SBOX(2) = 12 = 1100 0011 = 3 = SBOX(3) = 1 = 0001 1011 = 11 = SBOX(4) = 14 = 1110 1011 = 11 = SBOX(5) = 5 = 0101 1000 = 8 = SBOX(6) = 0 = 0000 1100 = 12 = SBOX(7) = 6 = 0110 (4) Concatenate and Rotate Left Shift 11 times. RLS(11)=0000111100101000001100100011011 0 (5) R(2) = R(1) XOR L(1) R( 1) = 00001111001010000011001000110110 L( 1) = 10011000110000000111100010010101 ---------------------------------------------------- XOR R( 2) = 10010111111010000100101010100011 (6) L(2) = R(1) before process. L(2) = 10110101101111001100010101011110 o o The process continues until Round 31. DECRYPTION, ROUND 31 (1) L(31) = 11100010100101101010011010001000 R(31) = 01001010110100100111001010100010 (2) R(31) + K(0) mod 232 R(31) = 1255305890 K( 0) = 244731602 -------------------------------- + R = 1500037492 mod 232 = 1500037492 = 01011001011010001100000101110100 (3) Split to 8 part and put to SBox. 0101 = 5 = SBOX(0) = 8 = 1000
- 5. International Journal of Engineering Trends and Technology (IJETT) – Volume 39 Number 3- September 2016 ISSN: 2231-5381 http://www.ijettjournal.org Page 172 1001 = 9 = SBOX(1) = 3 = 0011 0110 = 6 = SBOX(2) = 4 = 0100 1000 = 8 = SBOX(3) = 14 = 1110 1100 = 12 = SBOX(4) = 0 = 0000 0001 = 1 = SBOX(5) = 11 = 1011 0111 = 7 = SBOX(6) = 9 = 1001 0100 = 4 = SBOX(7) = 5 = 0101 (4) Concatenate and Rotate Left Shift 11 times. RLS(11)=01110000010111001010110000011010 (5) R(32) = R(31) before process. R(32) = 01001010110100100111001010100010 (6) L(32) = R(31) XOR L(31) R(31) = 01110000010111001010110000011010 L(31) = 11100010100101101010011010001000 ------------------------------------------------------- XOR L(32) = 10010010110010100000101010010010 (7) L(32) = b(32), b(31), ... b(1) R(32) = a(32), a(31), ... a(1) R = a(1), ... a(32), b(1), ... b(32) R in binary = 01000101010011100100 1011010100100100100101010000010100110100 1001 = change to Text PLAIN TEXT = ENKRIPSI IV. CONCLUSION The downside of the GOST algorithm is a simple key schedule so that in certain circumstances be the weak point of the method of cryptanalysis as Related- key cryptanalysis. However, this can be resolved by passing the keys to a strong hash function in cryptography such as SHA-1, and then use the results to input initialization hash key. The advantage of this method is the speed GOST is pretty good.Although not as fast as Blowfish, it is faster than IDEA. REFERENCES [1] M. Varnamkhasti, “Overview of the Algorithms for Solving the Multidimensional Knapsack Problems,” Advanced Studies in Biology, vol. 4, no. 1, pp. 37-47, 2012. [2] N. Courtois dan G. V. Bard, “Algebraic Cryptanalysis of the Data Encryption Standard, In Cryptography and Coding,” dalam 11-th IMA Conference, 2007. [3] L. Babenko dan E. Maro, “Algebraic Cryptanalysis of GOST Encryption Algorithm,” Journal of Computer and Communications, vol. 2, no. 1, pp. 10-17, 2014. [4] C. E. Shannon, “Communication Theory of Secrecy Systems,” Bell System Technical Journal, vol. 28, no. 1, pp. 656-715, 1949. [5] N. T. Courtois, “Cryptanalysis of GOST In The Multiple-Key Scenario,” Tatra Mountains Mathematical Publication, vol. 57, no. 1, pp. 45-63, 2013. [6] E. Biham dan A. Shamir, “Differential Cryptanalysis of DES- like Cryptosystems,” Journal of Cryptology, vol. 4, no. 1, pp. 3- 72, 1991. [7] A. P. U. Siahaan dan R. Rahim, “Dynamic Key Matrix of Hill Cipher Using Genetic Algorithm,” International Journal of Security and Its Applications, vol. 10, no. 8, pp. 173-180, 2016. [8] A. P. U. Siahaan, “Factorization Hack of RSA Secret Numbers,” International Journal of Engineering Trends and Technology, vol. 37, no. 1, pp. 15-18, 2016.