The increasing complexity of cyber threats in the Information Age demands ground-breaking developments in security procedures. This chapter explores quantum cryptography, a paradigm change that has the potential to revolutionize cyber security. Quantum cryptography provides never-before-seen levels of security by taking advantage of superposition and entanglement, two key concepts in quantum mechanics. A key component of this field is quantum key distribution (QKD), which guarantees secure communication channels by using the inherent features of quantum states to detect any efforts at eavesdropping. We examine the fundamental ideas, useful applications, and present difficulties associated with incorporating quantum cryptography systems into the infrastructures that are already in place. The chapter also addresses possible future advancements and the wider effects of quantum technologies on international cyber security. This chapter seeks to clarify how quantum cryptography has the potential to transform the field of digital security and open the door to a more resilient and safe cyberspace through a thorough investigation.