Linkoping University Researchers Break 'Unbreakable' Crypto

Researchers at Linkoping University in Sweden have discovered that quantum computing is not 100 percent secure. Quantum computing was considered unbreakable because quantum-mechanical objects cannot be measured or manipulated without being disturbed, and an attempt to copy a quantum-cryptographic key in transit would lead to extra noise that is noticeable and would not yield any usable information. However, Jan-Ake Larsson, associate professor of applied mathematics, and his student Jorgen Cederlof have found that it is theoretically possible for an unauthorized person to extract the key and hide their activities by simultaneously manipulating the quantum-mechanical and regular communication needed for quantum cryptography. "The concern involves authentication, intended to secure that the message arriving is the same as the one that was sent," Larsson says. In an article in the journal IEEE Transactions on Information Theory, Larsson and Cederlof also describe a solution that would secure quantum cryptography.http://www.liu.se/en/news-and-events/startpage?newsitem=18074