Cryptography Assignment | Doc

Running head: CRYPTOGRAPHY
CRYPTOGRAPHY
Name of the Student
Name of the University
Author Note

CRYPTOGRAPHY 1
Question 1:
Encrypted text: KNTGETRZTXRUQFACTIOSJNZAGTQ
K1 = QWERTYUIOPLKJHGFDSAZXCVBNM
K N T G E T R Z T X R U Q F A C T I O S J N Z A G T Q
Q W E R T Y U I O P L K J H G F D S A Z X C V B N M
Output: LYEOCEDTEUDGAPSVEHIRMYTSOEA
1 L U I
2 Y D R
3 E G M
4 O A Y
5 C P T
6 E S S
7 D V O
8 T E E
9 E H A
K2 = 627158943
6 E S S
2 Y D R
7 D V O

2CRYPTOGRAPHY
1 L U I
5 C P T
8 T E E
9 E H A
4 O A Y
3 E G M
K2 = 627158943
Final output: VOILA YOU DECRYPTED THE MESSAGE.
Question 2:
1)
a)
[ 00 04 08 0 C
01 05 09 0 D
02 06 0 A 0 E
03 07 0 B 0 F ]
b)
Key =
[ 01 01 01 01
01 01 01 01
01 01 01 01
01 01 01 01 ]

3CRYPTOGRAPHY
[ 00 04 08 0 C
01 05 09 0 D
02 06 0 A 0 E
03 07 0 B 0 F ] (+)
[ 01 01 01 01
01 01 01 01
01 01 01 01
01 01 01 01 ] =
[ 01 05 09 0 D
00 04 08 0 C
03 07 0 B 0 F
02 06 0 A 0 E ]
c)
[ 01 05 09 0 D
00 04 08 0 C
03 07 0 B 0 F
02 06 0 A 0 E ] =
[ 7C 6 B 01 D 7
63 F 2 30 FE
7 B C 5 2 B 76
77 6 F 67 AB ]
d)
[ 7C 6 B 01 D 7
63 F 2 30 FE
7 B C 5 2 B 76
77 6 F 67 AB ] =
[ 7 C 6 B 01 D 7
F 2 30 FE 63
2 B 76 7 B C 5
AB 77 6 F 67 ]
2)
a)
p = 47, q = 53,
n = p*q = 2491 (12 Bit)
e = 19
φ(n) = (p − 1) × (q − 1) = 2392
gcd(e, φ(n)) = 1
e × d = 1 (mod φ(n))
For the chosen values of p, q, and e, we get d as:
d = 1259

4CRYPTOGRAPHY
b)
The message M = 03
The cipher text is 723.
3)
a)
e= 5, n = 1343
gcd(e, φ(n)) = 1
e × d = 1 (mod φ(n))
d = 749.
b)
The DES is basically a symmetric crypto-graphic related algorithm. On the other side the
RSA is basically an asymmetric crypto-graphic algorithm or public key. The decryption and
encryption is done with the single key that is DES. On the other side, the users can use
separate keys such as private and public in the RSA algorithm. The RSA algorithm uses 2600
bits keys and the DES algorithm uses 56 bits of key. The RSA algorithm is more secure than
the DES algorithm. The RSA algorithm is used widely in the electronic commerce protocols
as well as it is believed for being more security provided with sufficient long keys as well as
the utilization of up to date implementation.

5CRYPTOGRAPHY
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algorithms. International Journal of Security and Its Applications, 9(4), 289-306.
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Hybrid Technique using DES and RSA algorithms. In Computing for Sustainable
Global Development (INDIACom), 2017 4th International Conference on IEEE.
Gambhir, A., & Arya, R. (2016, December). Performance Analysis of DES Algorithm and
RSA Algorithm with Audio Steganography. In International Conference on
Communication and Signal Processing 2016 (ICCASP 2016). Atlantis Press.
Patil, P., Narayankar, P., Narayan, D. G., & Meena, S. M. (2016). A comprehensive
evaluation of cryptographic algorithms: DES, 3DES, AES, RSA and
Blowfish. Procedia Computer Science, 78, 617-624.
Rihan, S. D., Khalid, A., & Osman, S. E. F. (2015). A performance comparison of encryption
algorithms AES and DES. International Journal of Engineering Research &
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Wahid, M. N. A., Ali, A., Esparham, B., & Marwan, M. (2018). A Comparison of
Cryptographic Algorithms: DES, 3DES, AES, RSA and Blowfish for Guessing
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