Enhancing Privacy of Chaotic Communications by Double Masking

In this paper, we numerically demonstrate that the
performances of private transmission using chaotic lasers can be
substantially improved by double masking the message by a suitable
scheme. In addition to standard optical chaos, our method
makes use of the chaotic voltage waveform available across the
transmitter laser junction.With respect to the standard setup, the
new one requires only one more electrical amplifier and a passive
adder at the transmitter, while the receiver remains unchanged.
It has been found that with this new scheme, synchronization
quality is significantly improved for the twin lasers, while this
is not the case for an unmatched laser pair. This results in an
increased bit error rate differential between the authorized user
and an eavesdropper, thus enhancing privacy. Simulations have
been performed with the Lang–Kobayashi model.