http://www.assodigitale.it/content/view/5354/74/ Toshiba has demonstrated two ways of solving the multi-photon problem in the Quantum Key Distribution (QKD):
1) "decoy pulses". These decoy pulses are weaker on average and so very rarely contain two or more photons. If an eavesdropper attempts a pulse-splitting attack, she will transmit a lower fraction of these decoy pulses than signal pulses. Thus by monitoring the transmission of the decoy and signal pulses separately this type of intervention can be detected. 2) single photon diode based on nano-technology. Yes they have created a diode that is capable of emitting just a single photon. This will not only solve the multi-photon problem but will also improve the bit-rate drastically. Why are multi-photon pulses such a problem in QKD? The eavesdropper can split the multi-photon pulse, measuring one photon and letting the other one go. Thus the eavesdropper can determine part of the key. Even more, the attacker can stop all single photon pulses, and allow only multi-photon pulses, thus gaining access to the whole key. http://www.assodigitale.it/content/view/5354/74/ _______________________________________________ FDE mailing list [email protected] http://www.xml-dev.com/mailman/listinfo/fde
