A team of scientists from the Quantum ICT Research Institute of Tamagawa University in Japan has reported that the researchers have demonstrated the limit and incompleteness of the security theory in quantum cryptography or quantum key distribution.
The research team proved that the existing theory is not capable of ensuring unconditional security. The researchers will describe their findings at the SPIE conference on Quantum Communication and Quantum Imaging, which will be conducted on August 15, 2012 in San Diego. The title of the presentation is ‘Incompleteness and Limit of Quantum Key Distribution Theory.’
Hitherto, most of the scientists in quantum information science have assumed that quantum cryptography is capable of providing unconditional security. The assurance of its unconditional security is provided by the trace distance, a quantum translation of the assessment of a mathematical cipher. Nevertheless, since 2006, new advancements in the realm have raised disapproval against the meaningful security of quantum key distribution guaranteed only by the trace distance. In spite of these criticisms, several papers have continued to state that the trace distance ensures unconditional security in quantum cryptography.
Now, scientists at the Quantum ICT Research Institute of Tamagawa University have successfully explained a logical path between the existing hypothesis and its criticisms. As a result, they have confirmed that the existing hypothesis fails to quantify security and is not capable of providing the unconditional security as described in Shannon’s theory, which describes the security for an unbreakable cipher.
Source: http://www.tamagawa.jp