An explanation of quantum cryptography
In this video, Informa TechTarget product marketing associate Katie Donegan explains what quantum cryptography is, how it differs from classical cryptography and how it works.
Math might not offer the security you need ... but physics might.
Classical cryptography that encrypts messages with mathematical equations is secure enough for classical computing -- but with the emergence of quantum computing, it might not be enough protection. That's where quantum cryptography comes in: It uses physics instead of math.
Here, we'll talk about why quantum cryptography is so secure. However, despite the advantages, there are still limits and challenges to quantum cryptography and quantum key distribution (QKD).
Quantum cryptography uses particles of light, or photons, to transmit cryptographic keys over fiber optic wire. The photons represent binary bits, meaning 0s and 1s. It's a completely secure system because of these properties of quantum mechanics:
- Particles can exist in more than one place or state at a time.
- A quantum property cannot be observed without changing or disturbing it.
- Whole particles cannot be copied.
Quantum cryptography follows a model developed in 1984 that goes like this:
Alice wishes to send Bob a message. Alice initiates the message, sending Bob a key or stream of photons. But the photons first pass through a polarizer, polarizing each photon in a certain state -- horizontal, vertical, diagonal to the right or diagonal to the left.
As Bob receives the photons, he doesn't know the correct polarization of the photons, so he randomly uses one of two beam splitters to read each photon's polarization and decipher the key. Alice and Bob can then compare the splitter they used; the photons read with the wrong splitter are discarded, and the remaining sequence is the key.
If there is an eavesdropper present who has the same tools as Bob, they would not only have the disadvantage of not being able to compare their results with Alice, but their presence would also change the photon positions that Alice and Bob expect to see. This would blow their cover.
It's impossible to measure the quantum state of a system without disturbing it. So, in theory, QKD is unhackable. After keys are exchanged between the involved parties, there is little concern that a malicious actor could decode the data without the key.
What do you think? Is quantum cryptography the answer to the quantum computing threat? Share your thoughts in the comments.
Sabrina Polin is a managing editor of video content for the Learning Content team. She plans and develops video content for Informa TechTarget's editorial YouTube channel, Eye on Tech. Previously, Polin was a reporter for the Products Content team.