Internal Re-keying Based Modified AES

• Published in: Indian journal of science and technology Vol. 18; no. 1; pp. 85 - 94
• Main Authors: Rathod, Amit, Patel, Kajal
• Format: Journal Article
• Language: English
• Published: 22.01.2025
• ISSN: 0974-6846; 0974-5645; 0974-5645
• DOI: 10.17485/IJST/v18i1.2012

Objectives: Masking and re-keying are two major countermeasures against the Power Side Channel Analysis attacks. Re-keying has either secret sharing overhead or needs to be used in synchronization. The Advanced Encryption System (AES) has been modified in the proposed scheme and uses re-keying without the need for secret random sharing or need for synchronized communication. The research proposed a modified AES scheme and validated its effectiveness with the AES. Methods: This study proposes modifying AES and then implementing it as software encryption using Python. As the AES has been modified, the proposed scheme should also match its strength to be further used against the Power Analysis Attack. Avalanche parameter is used to check the proposed solution strength. A data set of 10000, 50000, and 100000 records were generated to test the avalanche effect. The avalanche of existing AES and modified AES are then compared. Findings: The results indicate that the avalanche effect for both AES and the modified AES remains equivalent for the supplied dataset. To analyze further, the avalanche distribution is analyzed and randomness is checked using the Shannon entropy and found that the modified AES provides 0.5% more randomness against the AES. Hence, the modified AES fulfills the benchmark criteria to further check its strength against the Power Side Channel Analysis attacks. Novelty: The algorithm uses a part of the plain text to generate the round key making the resultant key unique and as it can be re-generated from the ciphertext and original key schedule on the decryption side, the random sharing is not needed. Keywords: Masking, Random Sharing Overhead, Differential Power Analysis (DPA), AES, Avalanche Effect, Re-keying