Quantum Cryptography and Quantum Key Distribution Protocols: A Survey on the Concepts, Protocols, Current Trends and Open Challenges

Abstract

Secure communication in the modern day is made possible by cryptography. With advances in the field of quantum mechanics, classical cryptosystems have become vulnerable to quantum algorithms. Quantum cryptography is being touted as a replacement to its classical counterpart in the near future. Although one can assume classical cryptosystems safe for now due to the maturity in quantum computing still required, it is best to prepare ourselves for the future threat. Quantum Key Distribution, an application of quantum cryptography, is the method of using quantum mechanics to exchange encryption keys securely between communicating parties. Numerous protocols, exploiting different principles of quantum mechanics, have been proposed to perform this key exchange. This paper reviews multiple such protocols, while also offering a general overview of quantum cryptography.

Keywords: Quantum Cryptography, Photon polarisation, Qubit, QKD, Entanglement, QBER, Privacy Amplification