Optimized Coherent State Based Quantum Cryptography With High Robust for Networks Deployment

Quantum cryptography enables unconditional security, which would be one of most promising techniques for the internet of things networks deployment. While backwards existing in the realistic systems may be explored by the eavesdroppers, thus threatening the information security. We present a coherent state based quantum cryptography protocol, which has capability of high robust. Concretely, real local oscillator and discrete modulation strategies are adopted for such purpose. The former circumvents the side-channel attack effectively, and the latter providers long transmission distance. Numerical simulations are performed, during which the optimized modulation variance is taken into account to achieve long transmission distance and high secrete key rate. The results reveal that phase mismatch and weak reference pulse resulting from the real local oscillator will degrade the performance, as well as voltage fluctuation from the modulator. Also, discrete modulation with more states may outperform over those less states in secret key rate for short transmission range.