Secure Over-the-Air Computation using Zero-Forced Artificial Noise

TL;DR

This paper introduces a secure over-the-air computation scheme that uses zero-forced artificial noise to protect against eavesdropping without external helpers, maintaining low distortion for legitimate receivers.

Contribution

It presents a novel artificial noise design for secure over-the-air computation that works with known or unknown eavesdropper channels, outperforming existing methods.

Findings

The proposed scheme achieves MSE-security against eavesdroppers.

Simulation results show the noise design outperforms other security methods.

The system parameters are thoroughly optimized for both known and unknown eavesdropper channels.

Abstract

Over-the-air computation has the potential to increase the communication-efficiency of data-dependent distributed wireless systems, but is vulnerable to eavesdropping. We consider over-the-air computation over block-fading additive white Gaussian noise channels in the presence of a passive eavesdropper. The goal is to design a secure over-the-air computation scheme. We propose a scheme that achieves MSE-security against the eavesdropper by employing zero-forced artificial noise, while keeping the distortion at the legitimate receiver small. In contrast to former approaches, the security does not depend on external helper nodes to jam the eavesdropper's received signal. We thoroughly design the system parameters of the scheme, propose an artificial noise design that harnesses unused transmit power for security, and give an explicit construction rule. Our design approach is applicable in both cases, if the eavesdropper's channel coefficients are known and if they are unknown in the signal design. Simulations demonstrate the performance, and show that our noise design outperforms other methods.