Quantum noise stream cipher based on optical digital to analog conversion

Abstract

An implementation method of quantum noise stream cipher with optical digital to analog converter is proposed and demonstrated. The proof-of-principle experiment for quantum noise stream cipher system has been designed to transmit 16-level signal with the baud rate of 10 Gbps by means of 4-bit port. So, the encrypted signal is obtained by weighting the intensities of multiple optical wavelengths and summing them according to plaintext signal and secret key, that makes the adjacent level of the signals are covered with the fluctuation of quantum noise. Experimental results show that the legitimate user can successfully recover the QNSC signal by the decryption with a very low probability of error with 2.19×10–11. However, the eavesdropper cannot distinguish the distinct bits due to the disturbance of quantum noise, which it is giving a very high probability of error with 0.425 due to the disturbance of quantum noise.