Quantum Cryptography: an overview of Quantum Key Distribution

This chapter highlights the transformation of secure communications through the incorporation of quantum mechanics. Over the past four decades, this groundbreaking theory has quietly revolutionized private communication. The chapter provides a concise historical overview of this field's inception, tracking the development of its pioneering protocol, BB84. It delves deeply into the protocol's evolution, spotlighting its milestones and challenges. Furthermore, it offers a panoramic view of the entire quantum key distribution landscape, encompassing continuous variable protocols designed to harness existing telecom technologies and device-independent quantum key distribution protocols aimed at achieving secure key exchange with minimal reliance on the experimental setup.