Secure Transmission with One-Time Pad Encryption Using FDM-Based CV-QKD in VLC System

This work presents the implementation of one-time padding (OTP) encryption in intensity modulation/direct detection-based (IM/DD)-based visible light communication (VLC) systems using a discrete modulation continuous-variable quantum key distribution (QKD) protocol. The proposed system uses a QKD-based quadrature phase shift keying protocol to prepare and share the secret key and employs binary phase shift keying modulation to transfer the encrypted information simultaneously via frequency division multiplexing. In the proposed system, OTP encryption is applied to each frame using secret keys generated during the preceding frame. To analyze the system's performance, bit error rate (BER) and transmission efficiency of the overall system are derived and verified using Monte Carlo simulation. It is found that the overall BER of Bob decreases with the increase in transmitted power (P<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</inf>), however, the BER of Eve remains constant throughout the considered range of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$P_{\mathrm{t}}$</tex>. This shows the effectiveness of the proposed strategy as a practical quantum cryptographic method in IM/DD VLC system.