Journeying Through Securing Digital Communication: A Comparative Analysis from Classical to Post-Quantum Cryptography

Classical cryptography faces significant challenges from quantum computing, particularly due to the power of Shor’s and Grover’s algorithms, which threaten widely used encryption methods. This study examines a range of post-quantum cryptography (PQC) schemes designed to withstand quantum attacks, including lattice-based, isogeny-based, hash-based, code-based, and multivariate approaches. It also explores Quantum Key Distribution (QKD) protocols, highlighting both prepare-and-measure and entanglement-based techniques. A detailed comparison of PQC algorithms is presented, evaluating their security, efficiency, and practicality for implementation. The findings offer strategies to future-proof digital communications against quantum threats, while addressing the key challenges quantum computing introduces to cryptographic systems.