Quantum cryptography allows users to distribute a cryptographic key across an optical network by exploiting the laws of quantum physics to guarantee its secrecy.

However, the Norwegian University of Science and Technology (NTNU) and the University of Erlangen-Nürnberg together with the Max Planck Institute for the Science of Light in Erlangen have developed and tested a technique they claim exploits imperfections in quantum cryptography systems to implement an attack.

The research project, in collaboration with manufacturer ID Quantique, found a loophole in the implementation of quantum cryptography. "The security of quantum cryptography relies on quantum physics but not only. It must also be properly implemented. This fact was often overlooked in the past", said Gerd Leuchs, a professor at the University of Erlangen-Nürnberg.

This story was first published by Computer Weekly