# Private Authentication with Physical Identifiers Through Broadcast Channel Measurements

## TL;DR

This paper extends key agreement models using physical identifiers by incorporating broadcast channel measurements, providing bounds on secrecy, key rate, privacy leakage, and storage, with tight bounds for specific channel types.

## Contribution

It introduces an inner bound for key agreement using broadcast channel measurements, applicable to biometric and physical identifiers, and proves tightness for certain channel classes.

## Key findings

- Inner bound for strong secrecy and key rate established.
- Bound tightness demonstrated for physically-degraded and less-noisy broadcast channels.
- Framework enhances physical identifier-based security models.

## Abstract

A basic model for key agreement with biometric or physical identifiers is extended to include measurements of a hidden source through a general broadcast channel (BC). An inner bound for strong secrecy, maximum key rate, and minimum privacy-leakage and database-storage rates is proposed. The inner bound is shown to be tight for physically-degraded and less-noisy BCs.