Modified Blowfish Algorithm

Quilala, Theda Flare Ginoy; Sison, Ariel M.; Medina, Ruji P.

doi:10.11591/ijeecs.v12.i1.pp38-45

Cited by 14 publications

(9 citation statements)

References 20 publications

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“…Moreover, the modified AES has an improvement of 14.79% and 13.87% in round 2 and round 3 respectively. Consequently, an increase in the average results of the avalanche effect of the modified AES rivaled with the standard AES is evidently shown in Figure 6, the increase in avalanche effect also indicates an increase in security compared to the standard AES [21], [22]. The overall improvement of the modified AES in the avalanche effect over the standard AES is about 7%.…”

Section: Results and Analysismentioning

confidence: 90%

Modified AES Cipher Round and Key Schedule

Reyes¹,

Sison²,

Medina³

2019

IJEEI

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In this paper, Advanced Encryption Standard was modified to address the low diffusion rate at the early rounds by adding additional primitive operations such as exclusive OR and modulo arithmetic in the cipher round. Furthermore, byte substitution and round constant addition were appended to the key schedule algorithm. The modified AES was tested against the standard AES by means of avalanche effect and frequency test to measure the diffusion and confusion characteristics respectively. The results of the avalanche effect evaluation show that there was an average increase in diffusion of 61.98% in round 1, 14.79% in round 2 and 13.87% in round 3. Consequently, the results of the frequency test demonstrated an improvement in the randomness of the ciphertext since the average difference between the number of ones to zeros is reduced from 11.6 to 6.4 along with better-computed p-values. The results clearly show that the modified AES has improved diffusion and confusion properties and the ciphertext can still be successfully decrypted and recover back the original plaintext.

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Section: Results and Analysismentioning

confidence: 90%

Modified AES Cipher Round and Key Schedule

Reyes¹,

Sison²,

Medina³

2019

IJEEI

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“…The modification using multiple S-boxes indicated that it is the fastest among the algorithms, but suffered greatly in the avalanche effect test where it did not meet the mean value of 50% for all the plaintexts used. A very low value for the avalanche effect compromises the security of the encryption algorithm [24].…”

Section: Avalanche Effectmentioning

confidence: 99%

Implementation of a bit permutation-based advanced encryption standard for securing text and image files

Gamido

2020

IJEECS

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<span>The paper proposes a modification of the Advanced Encryption Standard (AES) to address its high computational requirement steaming from the complex mathematical operations in the MixColumns Transformation which makes the encryption process slow. Bit Permutation was used instead of the MixColumns Transformation since the use of bit permutation in an encryption algorithm achieves efficiency by providing minimum encryption time and memory requirement. Results of the study showed that the modified AES algorithm exhibited faster encryption by 18.47% and faster decryption by 18.77% for text files. The modified AES algorithm also resulted to 16.53% higher avalanche effect compared with the standard AES thus improving the security performance. Application of the modified AES in encrypting images in Cipher Block Chaining mode showed that the modified algorithm also exhibited 16.88% faster encryption and 11.96% decryption compared with the standard AES. Likewise, modifying the algorithm achieved the ideal result in the histogram analysis, information entropy, the correlation coefficient of adjacent pixels to resist statistical attack. The ideal value in number of pixels change rate and unified average change intensity were also achieved making the modified algorithm resistant to differential attack. These results show that modifying AES by using bit permutation to replace MixColumns Transformation was able to address the high computational requirement of the algorithm resulting in a faster and more secure encryption algorithm for text files and images</span><span>.</span>

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“…g) Approximate Entropy Test (AET) -The test compares the frequency of overlapping blocks of two adjacent lengths against the expected result for a random sequence. The performance of the file cryptographic transformation is analyzed using the metrics time and throughput [31]. The evaluation parameters are as follows: a) Encryption Time -The required time to process the transformation from plaintext to its equivalent ciphertext and measured in milliseconds.…”

Section: Metricsmentioning

confidence: 99%

File encryption based on reduced-round AES with revised round keys and key schedule

Reyes

Sison

Medina

2019

IJEECS

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The continuing advancement of technology had provided security issues in protecting the confidentiality of information. The need to protect unauthorized access of a third party is warranted. In this paper, the reduced-round modified AES with revised round keys and key schedule is proposed to ensure file confidentiality. The modifications to the AES cipher round was the reduction of the round iterations from 10 to 6, and additional key permutations were added in between states; while in the key schedule, additional byte substitution process was appended. Time and throughput were utilized to measure the performance of the application's encryption/decryption process; while the avalanche effect and randomness tests were used to measure the security of the modified AES algorithm. The results of evaluations have shown that the encryption and decryption time have improved by 1.27% and 1.21% respectively while the throughput has similarly improved by 1.29% and 3.19% for both encryption and decryption respectively. Whereas the avalanche effect of the modified AES was 50.06% which was more than the ideal value of 50% and it was also better than the standard AES which was 49.94% using the sample dataset. Finally, all the ciphertext outputs of the modified AES passed the randomness tests.

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Modified Blowfish Algorithm

Cited by 14 publications

References 20 publications

Modified AES Cipher Round and Key Schedule

Modified AES Cipher Round and Key Schedule

Implementation of a bit permutation-based advanced encryption standard for securing text and image files

File encryption based on reduced-round AES with revised round keys and key schedule

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