In the rapidly evolving realm of digital technology, quantum computing (QC) represents a groundbreaking advancement, fundamentally transforming the approach to computation and communication. By leveraging quantum mechanics principles—specifically superposition and entanglement—QC achieves computational power that surpasses classical computers. This chapter explores the core concepts of QC, including quantum circuits, gates, and algorithms, and demonstrates how these principles enable unprecedented problem-solving efficiency. This chapter also discusses quantum cryptography, a key application of quantum technologies (QT), which secures communication channels through Quantum Key Distribution (QKD). As quantum computers evolve, the chapter addresses the development of post-quantum cryptographic algorithms designed to safeguard data against quantum attacks, ensuring that future encryption methods remain robust. Offering an in-depth exploration of these transformative technologies, this chapter underscores their critical role in shaping the future of secure digital communication.