Secret key-based Authentication with a Privacy Constraint

TL;DR

This paper analyzes the tradeoffs in secret key-based authentication systems under privacy constraints, balancing data compression, privacy leakage, and security against adversaries with correlated side information.

Contribution

It characterizes the optimal tradeoffs among compression rate, privacy leakage, and security metrics, linking secret key rate to authentication security.

Findings

Optimal tradeoff between compression and leakage rates

Characterization of false acceptance probability exponent

Connection between secret key rate and authentication security

Abstract

We consider problems of authentication using secret key generation under a privacy constraint on the enrolled source data. An adversary who has access to the stored description and correlated side information tries to deceive the authentication as well as learn about the source. We characterize the optimal tradeoff between the compression rate of the stored description, the leakage rate of the source data, and the exponent of the adversary's maximum false acceptance probability. The related problem of secret key generation with a privacy constraint is also studied where the optimal tradeoff between the compression rate, leakage rate, and secret key rate is characterized. It reveals a connection between the optimal secret key rate and security of the authentication system.