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.
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 prestigious 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.
Contact: Jan-Åke Larsson, phone: +46 (0)13-281468; e-mail: firstname.lastname@example.org
Åke Hjelm | alfa
Marine Skin dives deeper for better monitoring
23.04.2019 | King Abdullah University of Science & Technology (KAUST)
CubeSats prove their worth for scientific missions
17.04.2019 | American Physical Society
Researchers led by Francesca Ferlaino from the University of Innsbruck and the Austrian Academy of Sciences report in Physical Review X on the observation of supersolid behavior in dipolar quantum gases of erbium and dysprosium. In the dysprosium gas these properties are unprecedentedly long-lived. This sets the stage for future investigations into the nature of this exotic phase of matter.
Supersolidity is a paradoxical state where the matter is both crystallized and superfluid. Predicted 50 years ago, such a counter-intuitive phase, featuring...
A stellar flare 10 times more powerful than anything seen on our sun has burst from an ultracool star almost the same size as Jupiter
A localization phenomenon boosts the accuracy of solving quantum many-body problems with quantum computers which are otherwise challenging for conventional computers. This brings such digital quantum simulation within reach on quantum devices available today.
Quantum computers promise to solve certain computational problems exponentially faster than any classical machine. “A particularly promising application is the...
The technology could revolutionize how information travels through data centers and artificial intelligence networks
Engineers at the University of California, Berkeley have built a new photonic switch that can control the direction of light passing through optical fibers...
Physicists observe how electron-hole pairs drift apart at ultrafast speed, but still remain strongly bound.
Modern electronics relies on ultrafast charge motion on ever shorter length scales. Physicists from Regensburg and Gothenburg have now succeeded in resolving a...
17.04.2019 | Event News
15.04.2019 | Event News
09.04.2019 | Event News
23.04.2019 | Information Technology
23.04.2019 | Earth Sciences
23.04.2019 | Life Sciences