Quantum-chaotic key distribution in optical networks: from secrecy to implementation with logistic map

In a recent paper, the quantum-chaotic key distribution (QCKD) in optical networks was introduced. In the present work, we extend the QCKD theory in two ways: Firstly, we propose to use the dependent Bernoulli trials to model the key generation in QCKD. Using this model, we show that the key generated by QCKD is far from presenting the observed correlations in chaos-based cryptography, and it is very close to the maximum secrecy offered by ideal quantum cryptography. Secondly, we show a new optical scheme for QCKD in which the optical chaotic scheme using optoelectronic oscillators is substituted by nonlinear discrete equations running in computers and the information carrier used is the phase instead of the light polarization. These changes make much easier its implementation with today technology while keeping the same security level guaranteed by chaotic and quantum rules.