Quantum Cryptography and Post-Quantum Security: Current State, Challenges, and Strategic Directions

Abstract

Quantum cryptography is a new field of research that tries to resolve the critical security concerns brought by quantum computing. There is an increasing effort to construct quantum-safe cryptographic solutions due to the threat that quantum algorithms, especially Shor’s and Grover’s, pose to popular cryptographic systems. Traditional cryptographic methods like RSA and ECC are based on problems that will be efficiently tackled by quantum computers, putting them at risk in a post-quantum world. Also, symmetric cryptography, despite being stronger against that threat, faces its own challenges as well, especially from Grover’s algorithm, which effectively slashes the key length by half, increasing the necessary key size for maintaining security. The rise of quantum technologies has come with additional risks such as cyber threats and security vulnerabilities, therefore creating a need for research in quantum as well as post-quantum cryptography. Quantum cryptography particularly Quantum Key Distribution (QKD) exploits quantum mechanical phenomena to safeguard the exchange of cryptographic keys with information-theoretic security. Eavesdropping in QKD is always detectable. However, due to stringent hardware requirements, QKD is limited for broader practical use. Meanwhile, post-quantum cryptography (PQC) seeks to devise traditional algorithms for cryptography which will continue to remain secure under attacks from quantum computers. Such algorithms include lattice-based cryptography and code-based cryptography which, among others, are being standardized by NIST. This paper examines the current status of quantum cryptography alongside the vulnerabilities present in traditional systems as well as the efforts dedicated to implementing post-quantum algorithms. It covers the standardization and implementation challenges while also outlining prospective future research avenues aimed at reinforcing the cryptographic infrastructure in the era of quantum computing. UDC: 004.056.55:530.145; JEL: O33, D80, G23.