Iranian Society of Cryptology The ISC International Journal of Information Security 2008-2045 17 2 2025 07 01 A Lightweight General Modular Multiplier for Kyber PQC 243 249 217886 10.22042/isecure.2025.217886 EN Hossein Naderi Varandi Faculty of Computer Science and Engineering, Shahid Beheshti University, Tehran, Iran Raziye Salarifard Faculty of Computer Science and Engineering, Shahid Beheshti University, Tehran, Iran Journal Article 2025 03 26 Kyber, a key encapsulation mechanism (KEM), plays a pivotal role in post-quantum cryptography. As a finalist in the NIST project, Kyber is gaining traction in industry libraries and systems. The heart of the Kyber algorithm lies in the Number Theoretic Transform (NTT), where modular multiplication is the most intricate operation. In this paper, we propose a novel general modular multiplier that reduces both time and area requirements compared to prior methods. Our key innovation lies in the novel reduction algorithm, which avoids fixed values for coefficients A or B (i.e., C = A × B mod q) used in NTT, Inverse NTT (INTT), and PWM (Point-Wise Multiplication). Additionally we introduce two pipeline architectures for modular multiplication within Kyber, emphasizing low area usage and high frequency. These architectures demonstrate 8% and 31% better frequency, while our work achieves the lowest slice usage and AT (Area × Time) among all previous work. https://www.isecure-journal.com/article_217886_71f00fb72800dcf2d6418b4a242fa701.pdf