quantum cryptography broken?

[travis+ml-cryptography at subspacefield.org]

http://www.kurzweilai.net/news/frame.html?main=/news/news_single.html? 
id%3D8471

Quantum cryptography broken
KurzweilAI.net, April 20, 2008

Two Swedish scientsts, Jorgen Cederlof, now of Google, and Jan-Ake
Larsson of Link In a paper published in IEEE Trans. Inf Theory, 54:
1735-1741 (2008), they point out that an eavesdropper could gain
partial knowledge on the key in quantum cryptography that may have an
effect on the security of the authentication in the later round.

By accessing the quantum channel used in quantum cryptography, the
attacker can change the message to be authenticated (since the message
is influenced by attacker-initiated events on the quantum
channel). This, combined with partial knowledge of the key
(transmitted on the quantum channel), creates a potential security
gap, they suggest.

Their proposed solution: simply transmit an extra exchange of a small
amount of random bits on the classical (Internet) channel.

FAQ:

http://www.mai.liu.se/~jalar/qkg/faq.html
-- 
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