What is Quantum Key Distribution (QKD): Significance, uses and challenges
What is Quantum Key Distribution?
The theory of quantum key distribution was first proposed in the 1970s. It came to light in the 1980s. The digital society is highly dependent on security data. It may either be during communication or in e-banking, e-business etc. QKD is the technology that actually addresses the issue of long-term security. With nowadays Whatsapp and Facebook's compromised security issues, the term QKD is back in action.
What is the significance of QKD?
- Quantum Key Distribution (QKD) is nowadays getting much attention, basically among cybersecurity experts.
- As traditional encryption processes are threatened by various quantum computers, we need a far more secure means of encryption.
How does QKD work?
- QKD functions by transmitting hundreds of thousands of polarized light particles called photons through a fibre optic cable from one entity to another.
- Every single photon has a random quantized state while all photons collectively create a bitstream of ones and zeros.
- It is when the photons reach the endpoint, receivers use beam splitters in any direction-horizontal/vertical and diagonal, to read every photon’s polarization.
- The receivers hardly know about the beam splitter to be used for each photon. One has to guess which one to use.
- It is after the receiver informs the sender about the beam splitter used for each photon in the sequence, the sender compares it with the sequence of polarizers that were used to send the photons. All photons read using wrong beam splitter are discarded, making the resulting sequence of bits into a unique optical useful in encrypting the data.
Why is QKD secure?
- The ability to detect any intrusion in QKD transmission brings its unique security into the picture.
- The unique and fragile properties of photons or any third party intruder like eavesdroppers, who tries to go through or copy the photons in any way would bring a change to the photons’ state.
- This change would then be detectable by the endpoints. It would alert them about the key being tampered with and requirement of it being discarded.
- A new key is transmitted post this. However, since the keys generated are random, they remain protected from future attempts of being hacked.
Challenges in Quantum Key Distribution and future trends
Although quantum key distribution has evolved from the 1980s, its usage in computers and networks has gained momentum in past 5-10 years only.
The fragility of the quantum particles brings in some inherent challenges for this technology to grow. Scientists, however, are working to overcome this and are also making progress.
The challenges within this technology and its slow growth curtail the uptake of these technologies by governments.
The integration of these QKD systems into the existing network infrastructure is the current challenge.
One of the major challenges for QKD is the distance that the photons can cover at a time which is around 100km.
As technology improves, progress will continue towards overcoming the challenges posed by QKD, increasing the prospects for making QKD mainstream and available to those who need it, where they need it.