Shape of things to comeMaking quantum cryptography's promise a reality
New research details how quantum communication can be made possible without having to use cryogenic cooling or complicated optical setups, making it much more likely to become commercially viable soon
Quantum cryptography, in theory, is a completely secure means of communication. It is now much closer to being used practically as researchers from Toshiba and Cambridge University’s Cavendish Laboratory have developed high speed detectors capable of receiving information with much higher key rates, thereby able to receive more information faster.
The journal paper, “Practical Gigahertz Quantum Key Distribution Based on Avalanche Photodiodes,” by Z. L. Yuan et al., published as part of New Journal of Physics’s “Focus Quantum Cryptography: Theory and Practice” issue, details how quantum communication can be made possible without having to use cryogenic cooling or complicated optical setups, making it much more likely to become commercially viable soon.
One of the first practical applications to emerge from advances in the study of quantum mechanics, quantum cryptography has become the soon-to-be-reached gold standard in secure communications (see, for example, “Quantum Calibration Shows Way for Super-Secure Communication,” 18 November 2008 HS Daily Wire). Quantum mechanics describes the fundamental nature of matter at the atomic level and offers very intriguing, often counter-intuitive, explanations to help us understand the building blocks that construct the world around us. Quantum cryptography uses the quantum mechanical behavior of photons, the fundamental particles of light, to enable highly secure transmission of data beyond that achievable by classical encryption.
The photons themselves are used to distribute keys that enable access to encrypted information, such as a confidential video file that, say, a bank wishes to keep completely confidential, which can be sent along practical communication lines, made of fiber optics. Quantum indeterminacy, the quantum mechanics dictum which states that measuring an unknown quantum state will change it, means that the key information cannot be accessed by a third party without corrupting it beyond recovery and therefore making the act of hacking futile.
Other detectors can offer a key rate close to that reported in Yuan’s paper, but the present advance only relies on practical components for high speed photon detection, which has previously required either cryogenic cooling or highly technical optical setups, to make quantum key distribution much more user-friendly. Using an attenuated (weakened) laser as a light source and a compact detector (semiconductor avalanche photodiodes), the researchers have introduced a decoy protocol for guarding against intruder attacks that would confuse with erroneous information all but the sophisticated, compact detector developed by the researchers.
As the researchers write, “With the present advances, we believe quantum key distribution is now practical for realizing high band-width information-theoretically secure communication.”
Governments, banks, and large businesses have reason to fear the leaking of sensitive information, and they will be watching closely.
-read more in Z. L. Yuan et al., “Practical Gigahertz Quantum Key Distribution Based on Avalanche Photodiodes,” New Journal of Physics 11 (30 April 2009) (doi: 10.1088/1367-2630/11/4/045019)
