Janus: Safe Biometric Deduplication for Humanitarian Aid Distribution

TL;DR

Janus is a privacy-preserving biometric deduplication system designed for humanitarian aid registration, preventing double registration without exposing sensitive biometric data, and supporting practical deployment with various secure technologies.

Contribution

Janus introduces a novel approach combining privacy-enhancing technologies with biometrics to securely prevent duplicate aid registrations in humanitarian contexts.

Findings

Supports privacy, accuracy, and performance requirements of aid organizations.

First system to balance biometric accuracy with strong privacy protections.

Effective implementation using secure multiparty computation, homomorphic encryption, and trusted execution environments.

Abstract

Humanitarian organizations provide aid to people in need. To use their limited budget efficiently, their distribution processes must ensure that legitimate recipients cannot receive more aid than they are entitled to. Thus, it is essential that recipients can register at most once per aid program. Taking the International Committee of the Red Cross's aid distribution registration process as a use case, we identify the requirements to detect double registration without creating new risks for aid recipients. We then design Janus, which combines privacy-enhancing technologies with biometrics to prevent double registration in a safe manner. Janus does not create plaintext biometric databases and reveals only one bit of information at registration time (whether the user registering is present in the database or not). We implement and evaluate three instantiations of Janus based on secure multiparty computation, somewhat homomorphic encryption, and trusted execution environments. We demonstrate that they support the privacy, accuracy, and performance needs of humanitarian organizations. We compare Janus with existing alternatives and show it is the first system that provides the accuracy our scenario requires while providing strong protection.