QUANTUM COMPUTING AND ITS IMPACT ON MODERN CRYPTOGRAPHY: A SIMULATION-BASED ANALYSIS OF SECURITY AND PERFORMANCE

Abstract

The rapid advancement of quantum computing poses a significant threat to modern cryptographic systems that rely on computational
hardness assumptions. This study investigates the impact of quantum computing on widely used classical cryptographic algorithms and evaluates
the effectiveness of post-quantum cryptographic (PQC) alternatives through a simulation-based approach. Specifically, the study analyzes the
vulnerability of RSA and AES under quantum attack models based on Shor’s and Grover’s algorithms, respectively, and compares their
performance with PQC algorithms such as CRYSTALS-Kyber and SPHINCS+. A quantitative experimental framework is employed using
Python-based simulation tools, integrating classical cryptographic libraries and quantum simulation environments. Key performance metrics,
including encryption time, decryption time, memory utilization, and resistance to quantum attacks, are evaluated across multiple iterations. The
results reveal that RSA is highly vulnerable to quantum attacks, while AES demonstrates partial resilience with reduced effective security. In
contrast, post-quantum algorithms exhibit strong resistance to quantum threats, albeit with increased computational overhead.
The study highlights a critical trade-off between performance efficiency and quantum security and identifies CRYSTALS-Kyber as a
balanced solution for practical implementation. Furthermore, a quantum-safe transition framework is proposed to guide the migration from
classical to post-quantum cryptographic systems. The findings contribute to the growing body of research on quantum-resistant security and
provide practical insights for developing future-proof cryptographic infrastructures.