Exposure Notification - Cryptography Specification

Preliminary — Subject to Modification and Extension April 2020 v1.1

Table of Content

• Overview

• External Functions

• Key Schedule for Exposure Notification

• Positive Diagnosis

• Value Matching of Positive Users

• Privacy Considerations

• Test Vectors

• Revision History

Contents Overview

This document provides the detailed technical specification for cryptographic key scheduling for a new privacy-preserving Bluetooth protocol to support Exposure Notification.

Exposure Notification makes it possible to combat the spread of the coronavirus — the pathogen that causes COVID-19 — by alerting participants about possible exposure, through someone they have recently been in contact with who has subsequently been positively diagnosed. This specification complements the Bluetooth specification, which contains further information about the scheduling of broadcasts and the higher-level life cycle of the Bluetooth protocol.