Comparison of Encryption Algorithms: AES, Blowfish and Twofish for Security of Wireless Networks

Abstract

Encryption is the process of encoding data to prevent unauthorized access. Cyber security is the need of the hour which ensures transfer of data across the internet with confidentiality and integrity, and provides protection against malicious attacks. In this research paper, comparison between the encryption algorithms, viz. AES (Advanced Encryption Standard), Blowfish, and Twofish is done in terms of time of encryption and decryption, and their throughput, and the results are analysed indicating the superiority of Twofish over AES and Blowfish as a viable algorithm for data encryption in wireless networks.

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International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 07 Issue: 06 | June 2020 www.irjet.net p-ISSN: 2395-0072
© 2020, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 4656
Comparison of Encryption Algorithms: AES, Blowfish and Twofish for
Security of Wireless Networks
Archisman Ghosh
Department of Computer Science & Engineering, National Institute of Technology, Durgapur, West Bengal, India
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Abstract - Encryption is the process of encoding data to
prevent unauthorized access. Cyber security is the need of
the hour which ensures transfer of data across the internet
with confidentiality and integrity, and provides protection
against malicious attacks. In this research paper,
comparison between the encryption algorithms, viz. AES
(Advanced Encryption Standard), Blowfish, and Twofish is
done in terms of time of encryption and decryption, and
their throughput, and the results are analysed indicating the
superiority of Twofish over AES and Blowfish as a viable
algorithm for data encryption in wireless networks.
Keywords: Cryptography, Network security, AES,
Blowfish, Twofish, Secure communication.
1. Introduction
Owing to the advancement in internet accessibility and
networking, most of the security sensitive stuff like
internet banking, online shopping and bill payments is
done through wireless networks. Therefore, such
transactions demand to be end-to-end encrypted and
should be purely private so as to ensure data
confidentiality, integrity and availability, also known as the
CIA triad [1].
In order to increase the efficiency of implementation of
data security according to the CIA triad, the algorithms
(like DES, 3DES, AES, RSA, Blowfish,Twofish) should be
used alongside Hash-based Message Authentication Code
(HMAC) for authentication purposes to ensure a safe WiFi
design [2].
The process of encryption translates the data to a code to
ensure the security of the data. Encryption algorithms
perform various substitutions and transformations on the
plaintext (original message before encryption) and
transforms it into ciphertext (scrambled message after
encryption). These are classified into two groups:
Symmetric Key (also known as secret-key) and
Asymmetric Key (also known as public-key) encryption
[3].
A secure WiFi system uses algorithms such as DES, RSA,
AES, Blowfish and Twofish to secure the communication
over seemingly unsecured Internet channels. In addition,
the existing cryptographic algorithm is based on an
encryption model designed by Horst Feistel of IBM [4].
In this paper, a comparative study of the cryptographic
algorithms: AES, Blowfish and Twofish has been done and
the results have been analysed in order to find the
algorithm most suitable for encrypting data in wireless
networks.
2. Overview of the algorithms
2.1 AES
The Advanced Encryption Standard (AES) is a
cryptographic algorithm for encryption of electronic data
established by the U.S. National Institute of Standards and
Technology (NIST) [5]. NIST selected different key sizes of
128, 192 or 256 bits for which there would be 10, 12 or 14
rounds of encryption respectively to encrypt a block of 128
bit plaintext to a 128 bit ciphertext or decrypt a block of
128 bit ciphertext to a 128 bit plaintext. It is the successor
to the DES which was published in 1977 [6]. It follows an
algorithm which is symmetric-key in nature.
AES operates on a 4 by 4 column-major order matrix of 8-
bit bytes which is known as the State array which is
modified at each stage of encryption. In the first N-1 (N
depends on the length of the key used for encryption)
rounds the matrix undergoes 4 different transformation
functions, viz. SubBytes, ShiftRows, MixColumns and
AddRoundKey. The matrix undergoes an AddRoundKey
function before being entered in the rounds and the last
round has only three transformation functions. The Key
expansion function generates N+1 round keys, each of
which is a distinct 4 by 4 column-major order matrix. Each
round key serves as one of the inputs to the AddRoundKey
transformation in each round [3].
The SubBytes step involves the replacement of each byte
of the State array with a SubByte using a 8-bit substitution
box (the S-box). The S-box is derived from the
multiplicative inverse over Galois Field of GF (28) in order
to make the cipher non-linear [7]. In the ShiftRows step
the first row of the State array is kept unchanged and the

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 07 Issue: 06 | June 2020 www.irjet.net p-ISSN: 2395-0072
© 2020, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 4657
bytes of the following rows are shifted by offsets of 1, 2
and 3 respectively. In the MixColumns function the four
bytes of each column of the State array are combined using
linear transformation using 8-bit bytes as the coefficients
of a polynomial of order . In the final AddRoundKey
step the State array is combined with the subkey
generated by a main key. The combination is done by
performing XOR between every byte of the subkey and the
State array [8].
2.2 Blowfish
Bruce Schneier designed the Blowfish algorithm to be a
symmetric-key block cipher in 1993. A few of the striking
features of the Blowfish algorithm are the complicated key
schedule and the key-dependant substitution boxes [9].
The algorithm has a block size of 64 bits and the key size
ranging from 32 to 448 bits [9]. It is a 16-round Feistel
Cipher with subkey-arrays, viz. the P-array and the 4 S-
boxes. Each round of the Blowfish algorithm undergoes
four steps. In the nth round, the left part of the block is
XORed with the nth P-array followed by inputting it in the
F function of the Blowfish algorithm. The output of the F
function is XORed with the right half of the initial block
and then swapped [9].
2.3 Twofish
When NIST called for a block cipher, Twofish was
submitted alongside AES and it went on to be one of the
finalists of the contest but was never considered for
standardization.
The building blocks of Twofish are 16 rounds of Feistel
networks, four different key-dependent 8 by 8 bit S-boxes,
Maximum Distance Separable (MDS) matrices, and the idea
of key whitening and key scheduling. The design
parameters include a 128-bit symmetric block cipher, key
lengths of 128, 192 and 256 bits, and the absence of weak
keys.
Twofish was designed based on simplicity of the algorithm.
However, the performance of Twofish is heavily dependent
on hardware (in terms of the power of CPU and/or the
VLSI hardware) [10].
3. Evaluation metrics
● Encryption Time: The time taken by an
encryption algorithm to convert plaintext data to
ciphertext refers to encryption time. It is an
indicator of the efficiency of the algorithm. In the
following analysis the encryption time is
measured in milliseconds and is considered a
factor determining the speed of encryption in
wireless networks.
● Decryption Time: The time taken by an
encryption algorithm to convert ciphertext data to
plaintext data refers to decryption time. Lesser the
decryption speed, more is the efficiency of the
algorithm. In the following analysis decryption
time is measured in milliseconds and it also is
used to determine speed of the wireless network.
● Throughput: The throughput of a cryptosystem is
the megabytes of plaintext encrypted per
millisecond by the algorithm. A greater
throughput is indicative of a more efficient
system. The unit of measurement is MBps.
4. Experimental Design
The analysis has been performed using the encryption
algorithms, viz. AES, Blowfish and Twofish implemented in
python 3.6.9 on a Laptop having 3.8GHz Intel i5-9300H
processor with 8GB RAM on Ubuntu 18.04, Linux kernel
5.3.0-53. The algorithms are tested on a text file of size 1.1
MB.
5. Results and Discussion
The analysed data are presented in Table 1, 2 & 3 and
Figure 1 & 2, and discussed accordingly.
Table 1: Comparison of Encryption time (in ms) of the
Algorithms
Algorithm
Encryption time (in
ms)
AES
8.9
Twofish
3.1
Blowfish
4.2
Table 2: Comparison of Decryption time(in ms) of the
Algorithms
Algorithm
Decryption time (in
ms)
AES
7.4
Twofish
4.1
Blowfish
4.9

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
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Table 3: Comparison of Throughput (in MBps) of the
Algorithms
Algorithm
Throughput (in
MBps)
AES
1236
Twofish
3548
Blowfish
2619
Fig. 1: Time analysis of the algorithms: AES, Twofish and
Blowfish
Fig. 2: Comparison between the throughput of the
algorithms: AES, Twofish and Blowfish
The algorithms, viz. AES, Blowfish and Twofish have been
implemented and the encryption time and decryption time
have been noted, and the throughput calculated separately
for each algorithm. The result indicates that Twofish has
the best performance followed by Blowfish and AES owing
to its least encryption and decryption time (Table 1 & 2
and Fig.1) and the maximum throughput (Table 3 and
Fig.2).
The superiority of Blowfish over AES in prevention of
guessing attacks was reported by Wahid et al. (2018) [11],
and in another experiment, the superiority of Twofish over
Blowfish was reported earlier by Rane (2016) [12]. These
findings are in agreement with the present result.
6. Conclusion
Twofish has a clear advantage over AES and Blowfish in
terms of the evaluation metrics studied, viz., encryption
time, decryption time and throughput. Hence, Twofish can
be implemented alongside HMAC in the security of all
networking protocols owing to its low encryption and
decryption time, and high throughput.
7. References
1. Bono, S.C., Green, M., Stubblefield, A., Juels, A.,
Rubin, A.D., Szydlo, M. (2005) Security analysis of
a cryptographically-enabled RFID device. In:
SSYM’05: Proceedings of the 14th Conference on
USENIX Security Symposium, August 1-5, 2005,
Baltimore, USA.
2. Bellare, M., Canetti, R. and Krawczyk, H. (1996)
Message Authentication using Hash functions-The
HMAC Construction. RSA Laboratories’
CryptoBytes, Vol 2, No. 1.
3. Stallings, W. (2017) Cryptography and Network
Security: Principles and Practice, 7th Edition,
Pearson India Education Services Pvt.Ltd., Noida,
Uttar Pradesh, pp. 89, 172-190.
4. Polimon, J., Hernandez-Castro, J.C., Estevez-
Tapiador, J.M., Ribagorda, A. (2008) Automated
design of a lightweight block cipher with genetic
programming. Int. J. Know-Based Intell Eng.
Syst.,12(1):3-14.
5. NIST (2001) Announcing the Advanced
Encryption Standard (AES). Federal Information
Processing Standards Publication 197. United
States National Institute of Standards and
Technology (NIST).
6. Nechvatal, J.,Barker, E., Bassham, L., Burr, W.,
Dworkin, M., Foti, J. and Roback, E. (2001) Report
on the Development of the Advanced Encryption
Standard (AES). Journal of Research of the
National Institute of Standards and Technology,
106(3):511-577.
7. Nyberg, K. (1991) Perfect nonlinear S-boxes. In:
Davies, D. W. (eds) Advances in Cryptology —
EUROCRYPT. Lecture Notes in Computer Science,
vol 547. Springer, Berlin, Germany.

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 07 Issue: 06 | June 2020 www.irjet.net p-ISSN: 2395-0072
© 2020, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 4659
8. NIST (2001) Federal Information Processing
Standards Publication 197, Announcing the
Advanced Encryption Standard (AES).
9. Schneier, B. (1993) Description of a New Variable-
Length Key, 64-Bit Block Cipher (Blowfish). Fast
Software Encryption, Cambridge Security
Workshop Proceedings. Springer-Verlag, pp. 191–
204.
10. Schneier, B., Kelsey, J., Whiting, D., Wagner, D.,
Hall, C. and Ferguson, N. (1998) Twofish: A 128-
bit block cipher, pp.1-68.
11. Wahid, M.N.A., Ali, A., Esparham, B. and Marwan,
M. (2018) A Comparison of Cryptographic
Algorithms: DES, 3DES, AES, RSA and Blowfish for
Guessing Attacks Prevention. Journal of Computer
Science Applications and Information Technology,
3(2); 1-7.
12. Rane, D. D. (2016) Superiority of Twofish over
Blowfish. International Journal of Scientific
Research and Management, 4(11): 4744-4746.
Biography
Archisman Ghosh is
currently pursuing B.
Tech. in Computer
Science & Engineering
(Batch 2019-23) at
National Institute of
Technology, Durgapur,
an institute of national
importance in India.
His area of interest
includes algorithms,
cryptography,
network security, and
machine learning.