Abstract
The exponential increase in data transmission and the rise of quantum computing threaten classical encryption systems, necessitating a paradigm shift in secure communication. Quantum cryptography, particularly Quantum Key Distribution (QKD), exploits the principles of quantum mechanics to enable theoretically unbreakable security. This paper explores the foundational theories, key technologies, real-world implementations, current challenges, and future trajectories of quantum cryptography. Emphasis is placed on QKD protocols, entanglement-based communication, and integration with existing infrastructure. The study also evaluates potential vulnerabilities and the global movement toward quantum-resilient security systems.

This work is licensed under a Creative Commons Attribution 4.0 International License.
Copyright (c) 2021 Dr. Emma Reinhardt (Author)