ACM Asia Conference on Computer and Communications Security (ASIA CCS)
Physical-Layer Public Key Encryption Through Massive MIMO
Senlin Liu, Tianshun Gao, Yijian Liu, Xianhui Lu
Abstract
We propose a new physical-layer public key encryption scheme and establish a trapdoor one-way function through Massive MIMO techniques and precoding designs. Under standard arguments, we show that the eavesdropper's decoding complexity grows exponentially with the number of antennas, while the legitimate receiver's decoding complexity grows only quadratically. The proposed scheme builds a bridge between information-theoretic security and cryptographic security. Compared to the traditional physical-layer security, the proposed scheme is secure when the number of the eavesdropper's antennas is infinite or much larger than the number of transmitter/receiver antennas, provided that the eavesdropper's distance from the legitimate receiver is less than one-half of the wavelength, or that the channel estimation process between the sender-receiver pair is broken by the eavesdropper. Because the scheme is based on lattice, not on channel reciprocity, it can be applied to both time-division duplex and frequency-division duplex channels, and utilizes the simple physical layer characteristics of Massive MIMO to resist the currently known quantum attacks. The proposed scheme is adapted to the future requirements of 6G for the security of communication, and provides a new idea for the post-quantum cryptosystem. The simulation results show that the proposed scheme has a decoding bit error rate (BER) close to 0.5 at the eavesdropper and almost 0 at the legitimate receiver.