TraceTogether is an app released by the Singaporean Government that allows for digital contact tracing using the custom BlueTrace protocol. The app was developed by the Government Technology Agency and released on 20 March 2020. Since the release of the app, 17% of the population have downloaded it, meaning over 900,000 downloads. Downloading, installing and activating the app has been made mandatory for a significant part of the population by the government, and government employees have been pressed into installing the app, with some agencies making it mandatory. The app and protocol were also open sourced as OpenTrace and BlueTrace respectively.
Description
TraceTogether adopts a distributed approach where participating devices exchange proximity information whenever an app detects another device with the TraceTogether app installed. To trace users the Ministry of Health issues time sensitive anonymous temporary IDs that are used to identify the patient to all third parties. When two users of the app pass by, it uses the Bluetooth Relative Signal Strength Indicator readings between devices across time to approximate the proximity and duration of an encounter between two users. This proximity and duration information is stored on one's phone for 21 days on a rolling basis. Once a user tests positive for infection, the MOH works with them to map out their activity for past 14 days and requests the contact log. The user cannot legally refuse to share it.
Effectiveness of the app
However in May 2020, there are only 17% of the population who have installed the application, which limited the usefulness of the application. The usage of the app is limited by technical limitations such as needing to have the application to run in the foreground on iOS devices, and battery drain, but had been fixed in the 2.1 version of the app released on 3 July 2020. The authorities are issuing wearable devices, TraceTogether Token, as a complementary addition to the application end of June 2020.
Usage
TraceTogether is convenient and easy-to-use. Simply download the app, enter the phone number, grant the app permissions, turn on Bluetooth and leave the app running.
Privacy and Data
TraceTogether is explicitly designed to preserve the privacy of users from each other, but in contrast to alternative approaches favoured in other countries, is not anonymous as participants have to register the app using their phone number and national registration number. In order to safeguard participant's mutual privacy and ensuring their control over the data Trace Together:
Stores limited data. When signing up, a random User ID is generated and associated with the mobile number. Both the mobile number and User ID are stored in a secure server, and never shown to the public. The data will never be accessed, unless the user has been in close contact with a COVID-19 case and is contacted by the contact tracing team.
Does not collect data about GPS location. TraceTogether uses Bluetooth to approximate your distance to other phones running the same app.
Creates temporary IDs that change regularly. The lack of a persistent identifier means it is impossible for third parties to identify or track users.
Allows consent revoking at any time. If a user opts out, their contact information is deleted from the MOH, meaning any log entries they appear in can no longer be matched with them. Users are only able to request opt-out via an email to a government agency.
Prompts disabling TraceTogether's functionality once contact tracing ceases.
