Method of Security Evaluation of the LBlock-like Ciphers against Differential Cryptanalysis
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Дата
2025
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Видавець
Igor Sikorsky Kyiv Polytechnic Institute
Анотація
This paper considers the problem of estimating the security of the lightweight block cipher LBlockagainst differential cryptanalysis. We formalize the process and present two algorithms of computingupper bounds for differential probabilities. The baseline algorithm provides approximate estimatesbased on the number of active𝑆-boxes, while the refined algorithm incorporates the full probabilitydistributions of𝑆-box differentials, yielding significantly better bounds.To illustrate the efficiency of the proposed methodology, we introduce a modified version of LBlockwith8×8𝑆-boxes, which has lower computational complexity and allows experimental evaluationon our resources. We consider different linear permutations of encryption round, analyzing affect theestimates produced by both algorithms. The results demonstrate that the refined algorithm achievesmuch smaller maximum bounds (below2−40in the best cases) compared to the baseline approach andprovides a more accurate characterization of security against differential cryptanalysis.Overall, the proposed algorithms make it possible to efficiently evaluate the provable security ofLBlock-like ciphers against differential cryptanalysis
Опис
Ключові слова
symmetric cryptography, block cipher, differential cryptanalysis, LBlock
Бібліографічний опис
Yakymchuk, O. Method of Security Evaluation of the LBlock-like Ciphers against Differential Cryptanalysis / Oleksii Yakymchuk, Mykhailo Lopatetskyi // Theoretical and Applied Cybersecurity: scientific journal. – 2025. – Vol. 7, No. 2. – P. 13-23. – Bibliogr.: 17 ref.