Quantum Key Distribution is a cryptographic technique based on the laws ofquantum information. It enables secure key distribution
between two parties having a prior shared authenticated classical
channel. It guarantees unconditional security.
The word unconditional signifies that eavesdropper possesses
unlimited computational power, whether it be classical or quantum.
The security is ensured on the basis of null results of quantum
mechanics, which are non commutivity and non realism, signifying that any observation by eavesdropper will cause perturbation.
We are in an era of post quantum cryptography where study of QKD has acquired tremendous attention all over the world. The existence of the quantum
algorithms which can break the present cryptographic techniques like RSA,
Elliptic curve algorithms and the advent of a quantum computer which can pose
a threat to IPSec and TLS security models has caused lot of concern.
This has induced an urgency in government bodies, financial institutions and industries around the world to implement new age cryptographic techniques which will be resilient to a quantum computer. At present QKD is achieved in hundreds of kilometers in free space and in optical fibers. QKD networks have been demonstrated in Japan, Europe and China in recent past.
The importance of QKD has been further established as the European Telecommunications Standards Institute has published a white paper on Quantum Safe Cryptography and Security.
QKD is a technology for secure communication and its demand will be in Cryptography, government agency networks, defence, financial bodies and critical infrastructure as power plants, water and gas supply etc.