According to New Scientist, Laszlo Kish at Texas A&M University in College Station has come up with a cunning plan that uses the thermal properties of a simple wire to create a secure communications channel which outperforms quantum cryptography keys. His invention uses thermal noise which is generated by the natural agitation of electrons within a conductor.

Kish and fellow boffins at the University of Szeged in Hungary say this noise can be used to securely pass information, or an encryption key, down any wire, including a telephone line or network cable.

The idea is based on using two resistors. One high resister sends a greater thermal noise and the other ends a low one. Half the time they produce either too much or too little noise on the line and will ignore any communication. The rest of the time they will produce a little bit of noise and send some real data. It takes an "educated eavesdropper" to even realise information is being sent when there seems to be just low-level noise on the line.

If hackers do realise they are listening to a message then they cannot tell what it is because it's impossible to tell whether a person has a high or low resistor turned on. Listening will alter the level of thermal noise so that the parties will know someone is trying to hear their conversation.