Rethinking Security: Cryptography in the Age of Quantum Computing
John Olusegun Fajinmi · 2025
The advent of quantum computing poses a paradigm-shifting threat to classical cryptographic systems that underpin global digital security. As quantum processors advance towards practical scalability, previously secure encryption schemesparticularly those based on integer factorization (e.g., RSA) and discrete logarithm problems (e.g., ECC and DH)-are rendered vulnerable due to quantum algorithms like Shor's and Grover's. This paper critically examines the implications of quantum computing for contemporary cryptographic frameworks and explores the urgent need to transition toward quantum-resistant alternatives. We begin by analyzing the computational capabilities of quantum systems and their impact on symmetric and asymmetric cryptographic algorithms. The study delves into the principles of postquantum cryptography (PQC), including lattice-based, hash-based, code-based, multivariate polynomial, and supersingular isogeny cryptography, evaluating their strengths, implementation challenges, and resistance to quantum attacks. Additionally, we assess ongoing global initiatives such as NIST's post-quantum cryptography standardization project, highlighting their role in shaping future security infrastructures. The paper also considers hybrid cryptographic models and quantum key distribution (QKD) as transitional and long-term security strategies. By rethinking security from both theoretical and practical standpoints, this study emphasizes the need for immediate and collaborative action across academia, industry, and government sectors to future-proof digital communication systems against the looming quantum threat.