University of Isfahan & Iranian Society of Cryptology Journal of Computing and Security 2322-4460 13 2 2026 07 01 Boomeyong Cryptanalysis of Reduced-Round mCrypton 75 83 30616 10.22108/jcs.2026.147711.1189 EN Parsa Yousefpour Department of Electrical Engineering, Sharif University of Technology, Tehran, Iran. Atiyeh Mirzaie Information Systems and Security Lab (ISSL), Department of Electrical Engineering, Sharif University of Technology, Tehran, Iran. Siavash Ahmadi Electronics Research Institute, Sharif University of Technology, Tehran, Iran. Mohammad Reza Aref Information Systems and Security Lab (ISSL), Department of Electrical Engineering, Sharif University of Technology, Tehran, Iran. Journal Article 2025 12 06 Given the growing demand for secure yet lightweight encryption in constrained environments such as RFID tags and wireless sensor networks, resource-constrained devices are increasingly relying on lightweight block ciphers to protect sensitive data while meeting strict power, area, and latency requirements. In response to the challenge of designing such block ciphers, several lightweight block ciphers, such as the mCrypton, have been proposed. However, a thorough security evaluation of such ciphers is crucial, since their vulnerabilities can threaten the entire security architecture of systems. In this paper, we present the first application of the boomeyong attack—a hybrid technique combining boomerang and yoyo frameworks—on the reduced-round mCrypton block cipher. We formulate a novel 5-round distinguisher and demonstrate a key recovery attack that improves upon all previously known results. By refining structural definitions and adapting the boomeyong framework to the SPN-based design of mCrypton, our attack achieves a data complexity of 2²⁶, a time complexity of 2^23.02En. +2²⁵XOR, and a memory complexity of 2¹² blocks. https://jcomsec.ui.ac.ir/article_30616_003839389a8d52cd4ada2a5357d8a885.pdf