Today, we are on the edge of a quantum revolution. The advent of quantum computers in the next decade will give mankind access to unparalleled processing power with all of the advantages that this brings. However, this will also create huge challenges in the sphere of privacy protection as quantum computers will render much of today’s encryption unsafe.
What is Quantum Cryptography?
Quantum cryptography is a technology that uses quantum physics to secure the distribution of symmetric encryption keys. A more accurate name for it is quantum key distribution (QKD). It works by sending photons across an optical link. The uncertainty principle stipulates that in quantum physics observation causes perturbation. This is used to verify the security of the distributed keys.
In theory, QKD should be combined to One-Time Pad (OTP) encryption to achieve provable security. However in practice, this would impose strong limitations on the available bandwidth due to the fact that the key distribution rate of QKD is typically 1’000 to 10’000 times lower than conventional optical communications.
In practice, QKD is combined with conventional symmetric encryption, such as AES, and used to frequently refresh encryption keys.
How does QKD improve traditional cryptography implementations?
A security solution is as secure as its weakest link and in network encryption, the current weakest link is the key distribution based on public key cryptography. As its name says, QKD is used to distribute encryption keys, whose security is based on quantum physics and is thus guaranteed for the long-term.