Sudeshna Bhattacharya and Pratyush Pandey and Pradeep Kumar K Decoypulse Protocol for Frequencycoded Quantum Key Distribution
297 - 301
2012
6
3
International Journal of Mathematical, Computational, Physical, Electrical and Computer Engineering http://waset.org/publications/9765
http://waset.org/publications/63
World Academy of Science, Engineering and Technology
We propose a decoypulse protocol for frequencycoded implementation of B92 quantum key distribution protocol. A direct extension of decoypulse method to frequencycoding scheme results in security loss as an eavesdropper can distinguish between signal and decoy pulses by measuring the carrier photon number without affecting other statistics. We overcome this problem by optimizing the ratio of carrier photon number of decoytosignal pulse to be as close to unity as possible. In our method the switching between signal and decoy pulses is achieved by changing the amplitude of RF signal as opposed to modulating the intensity of optical signal thus reducing system cost. We find an improvement by a factor of 100 approximately in the key generation rate using decoystate protocol. We also study the effect of source fluctuation on key rate. Our simulation results show a key generation rate of 1.5×104pulse for link lengths up to 70km. Finally, we discuss the optimum value of average photon number of signal pulse for a given key rate while also optimizing the carrier ratio.
International Science Index 63, 2012