A new type of optical fiber filled with nothing but thin air has been found to be particularly effective for carrying out quantum key distribution (QKD), a security protocol that is in principle un-hackable and could play a key role in protecting sensitive data against ever-more sophisticated cyberattacks.
BT experimented with QKD over a six-kilometer-long cable of hollow core fiber, a technology that it has been working on for the past few months as an alternative to traditional fiber optic cables.
Optical fiber is typically made of solid strands of glass that carry information by channeling light signals emitted by laser transmitters. Hollow core fiber, on the other hand, has a hollow center filled with air, which runs the entire length of the cable and is encased in a ring of glass.
It turns out that this configuration is better suited to QKD, because it reduces the possibility that different signals interfere with each other and spoil the whole process.
QKD works in a similar way to traditional cryptography: data is encoded into an unreadable message thanks to a cryptography key that the recipient needs to decrypt the information. The method works by encoding the cryptography key onto a quantum particle (or qubit) that is sent to the other person, who measures the qubit in order to obtain the key value.
Image Source: Extremetech