Fig. 1. Diagram of ISK Y-00 protocol encryption process

Fig. 2. Encryption principle of ISK Y-00. (a) Y-00 protocol encoding rule; (b) Bob; (c) Eve

Fig. 3. Mapping relationship of ISK Y-00. (a) Mapping relationship between plaintext and ciphertext; (b) mapping relationship between basis and threshold

Fig. 4. Diagram of ISK-QNRC realization scheme

Fig. 5. Simulation diagram of parallel ISK-QNRC system

Fig. 6. Waveforms and eye diagrams of signal before and after decryption. (a) Waveform of signal before decryption; (b) eye diagram of signal before decryption; (c) waveform of signal after decryption; (d) eye diagram of signal after decryption

Fig. 7. BER versus received power

Fig. 8. BER versus power of mesoscopic state

Fig. 9. BER versus length