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from the Or-fher-gb-qevax-lbhe-Binygvar dept.
Researchers of the UT[*] found a new way to protect data from attacks with quantum computers. As they published today in New Journal of Physics. With quantum computers on the rise, we can no longer exclude the possibility that a quantum computer will become so powerful it can break existing cryptography. Single particles of light are already being used to protect data but the transmission of one bit per photon is slow. Pepijn Pinkse led the experiment to increase the transmission speed up to seven bits per photon.
[...] Standard QKD [(Quantum Key Distribution)] systems use single particles of light—photons—that are in one of two possible states, for instance horizontally or vertically polarized. This limits the transmission to one bit per photon. In a sense, the photons are encoded in an alphabet of just two letters: a and b.
Researchers from the UT now increased this number with more than a thousand letters. This increases the resistance against noise and potentially increases the data rate. They achieved this by encoding the quantum information in 1024 possible locations of the used photons. To make it hard for an attacker to see what was sent, they randomly switch the encoding between two different alphabets.
[...] Employing this technique together with very weak light, a video projector chip and modern single-photon detecting camera, the researchers demonstrated that they could transmit up to seven secure bits per quantum key distribution using spatially encoded light."
[*] UT - University of Twente, The Netherlands. More information: T B H Tentrup et al. Large-alphabet quantum key distribution using spatially encoded light, New Journal of Physics (2019). DOI: 10.1088/1367-2630/ab5cbe
(Score: 3, Touché) by RedGreen on Saturday December 21 2019, @05:13AM (1 child)
"In a sense, the photons are encoded in an alphabet of just two letters: a and b."
if we thought about in terms of numbers say a 0 and a 1 it could a binary method of computing... Christ.
"I modded down, down, down, and the flames went higher." -- Sven Olsen
(Score: 2, Informative) by pTamok on Saturday December 21 2019, @12:48PM
Possibly not.
The presence or absence of a photon can be regarded as binary 1 and 0. If the photon can have different states, then you can have three possible options [absent photon, present photon in state 'a', present photon in state 'b']*, so you have a ternary system.
An alphabet implies the existence of a medium that the alphabet is conveyed on. This is normally assumed, so you talk about the number of symbols expressible on the medium.
A related issue is assigning meanings to strings: for example, what meanings should be ascribed to an empty string "", a string that isn't there, and a value of NULL. How such things are represented and manipulated is an interesting problem, especially when dealing with free text produced by humans.
*It is difficult to determine the difference between "absent photon in state 'a'" and "absent photon in state 'b'".