Korzh, Nikita2026-02-252026-02-252025Korzh, N. Some Properties of RX-Differential Probabilities for an Operation that Approximates Modular Addition / Nikita Korzh // Theoretical and Applied Cybersecurity: scientific journal. – 2025. – Vol. 7, No. 2. – P. 31-37. – Bibliogr.: 12 ref.https://ela.kpi.ua/handle/123456789/79046In this paper, we consider RX-analysis for the NORX mixing operation, a logic-only surrogate for mod-ular addition used in ARX/LRX designs. Given established closed-form RX-probability expressions andfeasibility conditions, we characterize the distribution ofRX-probabilitiesover randomRX-differentials,provide a constructive algorithm that, for fixed input differences and rotation value, enumerates theadmissible output differences and simultaneously yields their cardinality, together with a maximizationmethod for identical-input cases.ensymmetric cryptographydifferential cryptanalysisrotational cryptanalysisRX-analysisARXNORXArticleP. 31-37https://doi.org/10.20535/tacs.2664-29132025.2.342753004.056.53:512.60009-0009-8794-8788