Featured Research

from universities, journals, and other organizations

Quantum Cryptography: Researchers Break 'Unbreakable' Crypto

Date:
May 11, 2008
Source:
Linköping University
Summary:
Quantum cryptography has been regarded as 100-percent protection against attacks on sensitive data traffic. But now a research team in Sweden has found a hole in this advanced technology. The risk of illegal accessing of information, for example in money transactions, is necessitating more and more advanced cryptographic techniques.

Quantum cryptography has been regarded as 100-percent protection against attacks on sensitive data traffic. But now a research team at Linköping University in Sweden has found a hole in this advanced technology. The risk of illegal accessing of information, for example in money transactions, is necessitating more and more advanced cryptographic techniques.

When you send an encrypted message via the computer network, one of the most difficult problems to solve is how the key should be transmitted. One way is to send it by courier (either by regular mail or, as in spy movies, a person with a briefcase attached to his wrist). Another way is a "public key," which is used for online banking and security functions in Web browsers (https://).

A courier must of course be reliable, otherwise there is a risk that the key will be secretly copied on the way. A public key is regarded as secure, since enormous calculations are required to break the long strings of data bits - some 2,000 - that make up the key.

But a new technology called quantum cryptography is supposed to be absolutely secure. Thus far, however, very few people have made use of it. It requires special hardware, for example with a type of laser that emits polarized light particles (photons) via optic fiber or through the air. Some companies and banks in Austria are testing the system, and trials are underway with satellite-TV transmission.

The security is guaranteed by the laws of quantum mechanics. Quantum-mechanical objects have the peculiar property that they cannot be measured upon or manipulated without being disturbed. If somebody tries to copy a quantum-cryptographic key in transit, this will be noticeable as extra noise. An eavesdropper can cause problems, but not extract usable information.

But Jan-Åke Larsson, associate professor of applied mathematics at Linköping University, working with his student Jörgen Cederlöf, has shown that not even quantum cryptography is 100-percent secure. There is a theoretical possibility that an unauthorized person can extract the key without being discovered, by simultaneously manipulating both the quantum-mechanical and the regular communication needed in quantum cryptography.

"The concern involves authentication, intended to secure that the message arriving is the same as the one that was sent. We have scrutinized the system as a whole and found that authentication does not work as intended. The security of the current technology is not sufficient," says Jan-Åke Larsson.

In the article, published in the journal IEEE Transactions on Information Theory, the authors propose a change that solves the problem.

"We weren't expecting to find a problem in quantum cryptography, of course, but it is a really complicated system. With our alteration, quantum cryptography will be a secure technology," says Jan-Åke Larsson.


Story Source:

The above story is based on materials provided by Linköping University. Note: Materials may be edited for content and length.


Cite This Page:

Linköping University. "Quantum Cryptography: Researchers Break 'Unbreakable' Crypto." ScienceDaily. ScienceDaily, 11 May 2008. <www.sciencedaily.com/releases/2008/05/080508143107.htm>.
Linköping University. (2008, May 11). Quantum Cryptography: Researchers Break 'Unbreakable' Crypto. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2008/05/080508143107.htm
Linköping University. "Quantum Cryptography: Researchers Break 'Unbreakable' Crypto." ScienceDaily. www.sciencedaily.com/releases/2008/05/080508143107.htm (accessed October 20, 2014).

Share This



More Computers & Math News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Japanese Scientists Unveil Floating 3D Projection

Japanese Scientists Unveil Floating 3D Projection

Reuters - Innovations Video Online (Oct. 20, 2014) — Scientists in Tokyo have demonstrated what they say is the world's first 3D projection that floats in mid air. A laser that fires a pulse up to a thousand times a second superheats molecules in the air, creating a spark which can be guided to certain points in the air to shape what the human eye perceives as an image. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Google To Protect Against Piracy ... At A Cost

Google To Protect Against Piracy ... At A Cost

Newsy (Oct. 20, 2014) — Google is changing its search-engine results to protect content producers from piracy — for a price. Video provided by Newsy
Powered by NewsLook.com
What We Know About Microsoft's Rumored Smartwatch

What We Know About Microsoft's Rumored Smartwatch

Newsy (Oct. 20, 2014) — Microsoft will reportedly release a smartwatch that works across different mobile platforms, has a two-day battery life and tracks heart rate. Video provided by Newsy
Powered by NewsLook.com
Is Spotify Family A Great Deal Or Catching Up?

Is Spotify Family A Great Deal Or Catching Up?

Newsy (Oct. 20, 2014) — Spotify Family lets you add a family member to your account for half price. Although users are excited, it's a move competitors have already made. Video provided by Newsy
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:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

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