# Channel Impulse Response-based Physical Layer Authentication in a Diffusion-based Molecular Communication System

## TL;DR

This paper proposes a physical layer authentication method for diffusion-based molecular communication systems using 3D channel impulse response as a device fingerprint to detect impersonation attacks.

## Contribution

It introduces a novel authentication scheme leveraging CIR for nano transmitter verification, addressing impersonation attack challenges in DbMC systems.

## Key findings

- Impersonation attacks significantly challenge system security.
- Trade-off exists between false acceptance and false rejection errors.
- Simulation demonstrates the effectiveness of CIR-based authentication.

## Abstract

Consider impersonation attack by an active malicious nano node (Eve) on a diffusion based molecular communication (DbMC) system---Eve transmits during the idle slots to deceive the nano receiver (Bob) that she is indeed the legitimate nano transmitter (Alice). To this end, this work exploits the 3-dimensional (3D) channel impulse response (CIR) with $L$ taps as device fingerprint for authentication of the nano transmitter during each slot. Specifically, Bob utilizes the Alice's CIR as ground truth to construct a binary hypothesis test to systematically accept/reject the data received in each slot. Simulation results highlight the great challenge posed by impersonation attack--i.e., it is not possible to simultaneously minimize the two error probabilities. In other words, one needs to tolerate on one error type in order to minimize the other error type.