On April 16, 2020, Nodle released The Whisper Tracing Protocol white paper and the Coalition App on Android. The protocol is intended to be a privacy first

Digital contact tracing Digital contact tracing is a method of contact tracing relying on tracking systems, most often based on mobile devices, to determine contact between an infected patient and a user. It came to public prominence in the form of COVID-19 apps durin ...

tool developed for the 2020

COVID-19 pandemic The COVID-19 pandemic (also known as the coronavirus pandemic and COVID pandemic), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), began with an disease outbreak, outbreak of COVID-19 in Wuhan, China, in December ...

. The project has been spun off into The Coalition Foundation. The protocol is being used for the

Government of Senegal The Government of Senegal (French language, French: ''Gouvernement du Sénégal'') is the union government created by the constitution of Senegal, consisting of the executive, parliament, and judiciary. The Seat of the Government is located in D ...

's Daancovid19 mobile contact tracing app initiative. Daancovid19 is the Senegalese digital response against the coronavirus. It was started by a handful of digital professionals and subsequently brought together nearly 500 volunteer experts from the private, public, and civil society. The respective Coalition App has been promoted by the City of

Berkeley, California Berkeley ( ) is a city on the eastern shore of San Francisco Bay in northern Alameda County, California, United States. It is named after the 18th-century Anglo-Irish bishop and philosopher George Berkeley. It borders the cities of Oakland, Cali ...

to their residents. __TOC__

Technical specification

The deployed system uses

Bluetooth LE Bluetooth Low Energy (Bluetooth LE, colloquially BLE, formerly marketed as Bluetooth Smart) is a wireless personal area network technology designed and marketed by the Bluetooth Special Interest Group (Bluetooth SIG) aimed at novel applications i ...

to exchange rotating public keys between two users. If a key is marked “infected” by the Network, users who have come into contact with the keys are notified. The protocol leverages a keyed hash function using 160 Bit BLAKE 2 (hash function) to generate user keys: Seed: Generated and stored locally on the

smartphone A smartphone is a mobile phone with advanced computing capabilities. It typically has a touchscreen interface, allowing users to access a wide range of applications and services, such as web browsing, email, and social media, as well as multi ...

or user hardware. Session Key: Generated weekly from the seed. This key is uploaded if a user declares they are infected. Temporary ID: Generated Hourly (or less) from the session Key. This key is included in the

bluetooth Bluetooth is a short-range wireless technology standard that is used for exchanging data between fixed and mobile devices over short distances and building personal area networks (PANs). In the most widely used mode, transmission power is li ...

data packet. Whisper Tracing Protocol Bluetooth Packet Format

Smartphone A smartphone is a mobile phone with advanced computing capabilities. It typically has a touchscreen interface, allowing users to access a wide range of applications and services, such as web browsing, email, and social media, as well as multi ...

s running the protocol record "proximity events" which may include the Temporary ID of the user in contact, time, signal strength, location, and other metadata. A key difference with other Digital contact tracing tools is that the Contacttracing happens locally on the phone, meaning that the system does not need to transmit location, or all of the user's proximity events to a server.

Adoption by Region

References

{{Reflist Mobile applications Software associated with the COVID-19 pandemic Scientific and technical responses to the COVID-19 pandemic Digital contact tracing protocols Digital contact tracing protocols with decentralized reporting