Featured Research

from universities, journals, and other organizations

Major step taken towards 'unbreakable' message exchange

Date:
August 3, 2012
Source:
Institute of Physics (IOP)
Summary:
Single particles of light, also known as photons, have been produced and implemented into a quantum key distribution (QKD) link, paving the way for unbreakable communication networks.

Single particles of light, also known as photons, have been produced and implemented into a quantum key distribution (QKD) link, paving the way for unbreakable communication networks.

The results of the experiment, undertaken by a close collaboration of researchers based in Wuerzburg, Munich and Stuttgart, have been published August 2, in the Institute of Physics and German Physical Society's New Journal of Physics.

The single photons were produced using two devices made of semiconductor nanostructures that emitted a photon each time they were excited by an electrical pulse. The two devices were made up of different semiconductor materials so they emitted photons with different colours.

QKD is not a new phenomenon and has been in commercial use for several years; one of its first uses was to encode the national election ballot results in Switzerland in 2007. The techniques currently being used on a commercial scale rely on lasers to create the source of photons; however, researchers hope to further increase the efficiency of QKD by returning to the original concept of using single photons for generating a secure key.

One of the project coordinators, Dr Sven Hoefling, said: "The nature of light emitted by lasers is very different from light emitted by single photon sources. Whereas the emission events in lasers occur completely random in time, an ideal single photon source emits exactly one photon upon a trigger event, which in our case is an electrical pulse.

"The random nature of emission events from strongly attenuated lasers sometimes results in the emission of two photons very close to each other. Such multiple photon events can be utilized by an eavesdropper to extract information.

"Single photon sources, such as the ones used in our study, are predestined for use in the secure communication systems using quantum communication protocols."

QKD is a process that enables two parties, 'Alice' and 'Bob', to share a secret key that can then be used to protect data they want to send to each other. The secret key is made up of a stream of photons that 'spin' in different directions -- vertically, horizontally or diagonally -- according to the sender's preferences.

The laws of physics state that it is not possible to measure the state, or 'spin', of a particle like a photon without altering it, so if 'Eve' attempted to intercept the key that was sent between 'Alice' and 'Bob', it would become instantly noticeable.

In their experiment, the single photons were produced with high efficiency, then made into a key and successfully transmitted from the sender to the receiver across 40 cm of free space in the laboratory.

The researchers are aware that to make this experiment more practical and commercially viable, it needs to be scaled up so that quantum keys can be sent over larger distances. To do this, quantum repeater stations need to be incorporated into the network to 'amplify' the message.

"Meanwhile, quantum keys have been sent over 500 metres of free space on top of the roofs in the centre of Munich, Germany. Several projects have also been funded to develop this technology further," continued Hoefling.


Story Source:

The above story is based on materials provided by Institute of Physics (IOP). Note: Materials may be edited for content and length.


Journal Reference:

  1. Tobias Heindel, Christian A Kessler, Markus Rau, Christian Schneider, Martin Fürst, Fabian Hargart, Wolfgang-Michael Schulz, Marcus Eichfelder, Robert Roßbach, Sebastian Nauerth, Matthias Lermer, Henning Weier, Michael Jetter, Martin Kamp, Stephan Reitzenstein, Sven Höfling, Peter Michler, Harald Weinfurter, Alfred Forchel. Quantum key distribution using quantum dot single-photon emitting diodes in the red and near infrared spectral range. New Journal of Physics, 2012; 14 (8): 083001 DOI: 10.1088/1367-2630/14/8/083001

Cite This Page:

Institute of Physics (IOP). "Major step taken towards 'unbreakable' message exchange." ScienceDaily. ScienceDaily, 3 August 2012. <www.sciencedaily.com/releases/2012/08/120803082931.htm>.
Institute of Physics (IOP). (2012, August 3). Major step taken towards 'unbreakable' message exchange. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2012/08/120803082931.htm
Institute of Physics (IOP). "Major step taken towards 'unbreakable' message exchange." ScienceDaily. www.sciencedaily.com/releases/2012/08/120803082931.htm (accessed July 23, 2014).

Share This




More Matter & Energy News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) — 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
Powered by NewsLook.com
Boeing Ups Outlook on 52% Profit Jump

Boeing Ups Outlook on 52% Profit Jump

Reuters - Business Video Online (July 23, 2014) — Commercial aircraft deliveries rose seven percent at Boeing, prompting the aerospace company to boost full-year profit guidance- though quarterly revenues missed analyst estimates. Bobbi Rebell reports. Video provided by Reuters
Powered by NewsLook.com
Europe's Car Market on the Rebound?

Europe's Car Market on the Rebound?

Reuters - Business Video Online (July 23, 2014) — Daimler kicks off a round of second-quarter earnings results from Europe's top carmakers with a healthy set of numbers - prompting hopes that stronger sales in Europe will counter weakness in emerging markets. Hayley Platt reports. Video provided by Reuters
Powered by NewsLook.com
9/11 Commission Members Warn of Terror "fatigue" Among American Public

9/11 Commission Members Warn of Terror "fatigue" Among American Public

Reuters - US Online Video (July 22, 2014) — Ten years after releasing its initial report, members of the 9/11 Commission warn of the "waning sense of urgency" in combating terrorists attacks. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins