Quantum Key Distribution Protocols: A Survey

Most cryptographic mechanisms, such as symmetric and asymmetric cryptography, often involve the use of cryptographic keys. However, all cryptographic techniques will be ineffective if the key distribution mechanism is weak. The security of most modern cryptographic systems of key distribution mechanism is based on computational complexity and the extraordinary time needed to break the code. Quantum Key Distribution (QKD) or Quantum Cryptography is attracting much attention as a solution of the problem of key distribution; QKD offers unconditionally secure communication based on quantum mechanics. In this article we survey the most popular QKD protocols. Also, we give a short state of the art of Quantum Cryptography.