Quantum Computing and its Implications for Cryptographic Security

Abstract

: Quantum computing, leveraging principles like superposition and entanglement, challenges classical cryptography by enabling efficient algorithms—Shor’s and Grover’s—that undermine widely used encryption methods. This study analyzes the impact of quantum algorithms on both asymmetric (e.g., RSA, ECC) and symmetric (e.g., AES, hash functions) cryptographic schemes, evaluating the scale of threat using theoretical and resource-based assessments. It also surveys quantum cryptographic protocols (e.g., BB84-based QKD) and post-quantum cryptography (PQC) approaches including lattice-, code-, hash-, and multivariate-based methods. Our methodology involves systematic literature review, algorithmic threat modeling, and comparison of cryptographic resilience. Key findings illustrate that Shor’s algorithm threatens RSA, Diffie–Hellman, and ECC, while Grover’s algorithm effectively halves symmetric key strength—mitigated by doubling key sizes. QKD offers information-theoretic security but is limited by practical implementation vulnerabilities. PQC shows promise in thwarting quantum attacks, with NIST initiating standardization as early as 2019. We propose a structured migration workflow: threat assessment → data lifespan analysis → QKD and PQC evaluation → hybrid deployments → pilot testing → full migration. The benefits include anticipatory defense, future-proofing, and maintaining confidentiality; drawbacks encompass increased complexity, performance costs, and infrastructural upheaval. The discussion underscores the urgency of transitioning to quantum-resistant cryptography before quantum capabilities materialize. We conclude that proactive preparation is essential to ensure cryptographic security and privacy continuity. Future work should address efficient PQC integration, key lifecycle management under quantum threat, and robust, low-overhead implementations suitable for resource-constrained systems.