Fig. 1. PSK-QNRC encrypted coded signal vector image

Fig. 2. Experimental structure of PSK-QNRC scheme

Fig. 3. Overall schematic of Y-00 encryption protocol

Fig. 4. Internal structure diagram of DPSK receiver

Fig. 5. Eye diagrams measured by B2B under different mechanisms. (a) M=8; (b) M=256

Fig. 6. Eye diagrams measured after 500-km fiber transmission under different mechanisms. (a) M=8; (b) M=256

Fig. 7. BER versus P_S0

Fig. 8. BER versus M

Fig. 9. BER versus P_recv