Quantum hacking is the latest fear in the world of information security. Not so long ago, physicists were claiming that they could send information with perfect security using a technique known as quantum key distribution.
This uses the laws of quantum mechanics to guarantee perfectly secure communication. And perfectly secure communication is what you get, at least in theory.
The trouble is that in practice the equipment used to carry out quantum key distribution has a number of weaknesses that an eavesdropper can exploit to gain information about the messages being sent. Various groups have demonstrated how quantum hacking presents a real threat to “perfectly secure” communication.
So in the cat and mouse game of information security, physicists have been fighting back by designing equipment that is more secure. Today, Nitin Jain at the Max Planck Institute for the Science of Light in Erlangen, Germany, and a few pals show how the changes still leave the equipment open to attack but at the same time reveal how the next generation of quantum cryptography could be made better.