The BBC reports…

The technique uses photons of light as decoys

British scientists have found a way to fix a vulnerability in quantum cryptographic systems.

If left unpatched the flaw would make it possible to grab information about the keys used to scramble information without being detected.

The flaw emerges because of the way that laser diodes emit the photons of light used to carry quantum key data.

Using decoy photons the researchers can spot when attackers are eavesdropping on secure communication channels.

One thing that will go wrong and unsettle everybone is broken crypto: the cracking of more and more complex keys. There are two strange aspects for me. One is that I just dont begin for the life of me to understand the cryptography on which the safety of my on-line business life depends. The second is that only a small proportion of the people who crack these security systems are good enough to say so (eg Ben Laurie on PGP) and we have have to assume that those who are secretive about it (of whatever variety) are more numerous, more highly motivated and generally ahead of the honest hobbyists to whom I can more easily relate.