Quantum Key Distribution in practice: The state of art

Since it was noted that quantum computers could break public key cryptosystems based on number theory, extensive studies have been undertaken on Quantum Key Distribution (QKD). QKD or Quantum Cryptography solves the key distribution problem by allowing the exchange of a cryptographic key between two remote parties with absolute security, guaranteed by the laws of physics. Actually, the progress of research in this field allows the implementation of Quantum Cryptography outside of laboratories. Efforts are made to exploit this technology in the existing communication networks and to improve the performance and reliability of the implemented technologies. The cryptosystems based on QKD are very promising and also the technology is improving more and more to fulfill requirements. In this paper, we provide a state-of-the-art of practical Quantum Cryptography by exposing the popular works and projects on QKD implementation.