A failure in implementation leads to the ability to eavesdrop on a quantum-secrecy based key exchange on 2/3 of the types of quantum equipment used.
From: <http://technology.newscientist.com/article/dn14866-laser-cracks-unbreakable-quantum-communications.html> Makarov and colleagues from Sweden and Russia have shown that Eve could control Bob's equipment, so that they both decode exactly the same digits from Alice's transmission...The method exploits the way a common type of photon counter can have its sensitivity reduced by a very bright flash of light. The attack begins when Eve fires a pulse of laser light to all four detectors in Bob's equipment...[Eve leverages this into getting the key] by sending on a sequence of encoded photons that are identical to the ones she receives from Alice, Eve can safely intercept a message without leaving the tell-tale quantum errors...Makarov and colleagues have now uncovered such vulnerabilities in two of the three types of quantum equipment commonly used. They are now investigating ways to solve the flaw without introducing more weaknesses. A paper, "Can Eve control PerkinElmer actively-quenched single-photon detector?" is available at <http://arxiv.org/ftp/arxiv/papers/0809/0809.3408.pdf>. -Michael Heyman --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]