Fesenko, Andrii2026-03-022026-03-022025Fesenko, A. Quantum cryptanalysis of ciphers based on generalized Feistel and Lai-Massey schemes / Andrii Fesenko // Theoretical and Applied Cybersecurity: scientific journal. – 2025. – Vol. 7, No. 3. – P. 60-66. – Bibliogr.: 11 ref.https://ela.kpi.ua/handle/123456789/79154This paper investigates generalizations of the Lai-Massey scheme, including unified constructionscombining it with the Feistel scheme (MD GLM, UFLM, L-Feistel, and quasi-Feistel). New reductionsto the quasi-Feistel scheme are provided. Known efficient quantum attacks are analyzed, includingchosen-plaintext attacks on 3 rounds and chosen-ciphertext attacks on 4 rounds for a special case of thequasi-Feistel cipher using Simon’s algorithm. It is demonstrated that restrictions in that work led to thedegeneration of the quasi-Feistel scheme into the standard Feistel scheme, replicating known quantumattacks on the Feistel scheme. New two-round distinguishing attacks are presented for the L-Feistel andMD-1 GLM schemes, enabling round key recoveryenLa-Massey schemequasi-Feistel cipherL-Feistel schemequantum cryptanalysisArticleP. 60-66https://doi.org/10.20535/tacs.2664-29132025.3.347525004.056.550000-0002-4489-3256