tracetogether tracetogether tracetogether is a digital system implemented by the government of singapore to facilitate contact tracing efforts in response to the covid-19 pandemic in singapore. the main goal is quick identification of persons who may have come into close contact with anyone who has tested positive for covid-19. the system helps in identifying contacts such as strangers encountered in public one would not otherwise be able to identify or remember. together with safeentry, it allows the identification of specific locations where a spread between close contacts may occur. tracetogetherdeveloper(s)government technology agencystable release2.14.2 / 31 may 2022 repositorygithub.com/opentrace-community written inkotlin (android)swift (ios)operating systemandroid, iosavailable inbengali, burmese, chinese, english, hindi, malay, tamil, thaitypedigital contact tracingcovid-19 appslicencegpl-3.0websitewww.tracetogether.gov.sg released on 20 march 2020, the system initially consisted only of an app by the same name. however, this was later supplemented by a physical token mainly intended for elderly and children who may not own a smartphone, or those who prefer not to use the app. the app was the first main covid-19 tracking app released in the world and its development encouraged the development of similar apps in other countries. the app has raised significant concerns about the privacy of those who use the app, especially due to a lack of decentralised report processing and access to the data by police. however, the app states it has several features to ensure users' privacy, such as regularly rotating users' ids and storing limited data. despite the concerns over privacy, the app was slowly adopted by the population of the singapore, eventually reaching a 92% adoption rate in may 2021. the app was now mandated for specific groups of people and those attempting to enter certain venues and events. on 9 february 2023, the system was deactivated after the authorities determined that the system was no longer required. tracetogether app technology the app utilises a custom protocol, bluetrace, which allows for a distributed approach whereby participating devices exchange proximity information whenever an app detects another device with the tracetogether app installed. the protocol, and reference app implementations of it, were also open sourced as bluetrace and opentrace respectively. initial versions of the app required users to register using only their mobile number., with subsequent versions from june 2020 onwards requiring users' nric or passport numbers. the website states that the nric number is required in order to allow moh to reach the right person when they need to give important health advice on covid-19, and is stored in a secure server, never accessed unless needed for contact tracing, and never shared with other app users. further iterations of the app added support for safeentry, a national digital check-in system that logs the national identification and mobile numbers of individuals visiting hotspots, workplaces of permitted enterprises, as well as selected public venues. the main goal of safeentry helps covid-19 cases remember the places that they've visited. this helps moh to identify potential infection clusters and perform cluster covid-19 testing. following installation, the user is requested to grant relevant permissions such as bluetooth. android users are additionally required to grant location permission as bluetooth can be used to derive location information when combined with beacons in fixed locations. to trace users the ministry of health (moh) 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 (rssi) 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 25 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. to facilitate the conduct of contact tracing measure to prevent further outbreak of any infectious disease, the user cannot withhold their contact information log under the infectious diseases act (chapter 137). the usage of the app had been limited by the technical limitations of needing to have the application to run in the foreground on ios devices, and battery drain, but these problems had been reportedly addressed in the 2.1 version of the app released on 3 july 2020, and version 2.1.3 of 5 aug added informational, work pass and safeentry qr features. release timeline the app was released on 20 march 2020, following 8 weeks of development by singapore's government technology agency in collaboration with ministry of health (moh). on 10 april 2020, following the lifting of the embargo on the google-apple exposure notification (gaen) system, the developers announced that they had been working with apple and google on specifications which would allow for cross-border inter-operability, and had begun to incorporate these new apis into tracetogether. the developers envisaged this as a way to overcome the app's inability to access full background bluetooth scanning functionality on ios devices (which led to the app being active only when it ran in the foreground), and increase the pool of interoperable devices, both of which could have increased the contact tracing utility. on 5 june 2020, the minister-in-charge of the smart nation initiative vivian balakrishnan acknowledged in parliament the inability of the tracetogether app to work well particularly on ios or apple devices, and that these had not been overcome despite discussions at the technical and policy level with apple. he subsequently explained that the government had decided against using the google-apple exposure notification (gaen) system, citing its inability to "identify how, when and whom the person was infected by or passed the infection to" and "the 'graph' not being available to the contact tracers". instead, a new portable, wearable device, called the tracetogether token would be issued to all 5.7 million residents in order to increase the pool of participants. on 7 december 2020, market research firm gartner crowned tracetogether as the asia-pacific winner for its 2020 government eye on innovation award, after the firm had conducted a poll among various government organisations around the world. uptake during the release of the app, minister for national development lawrence wong, a co-chair of the multi-ministry covid task force, explained that for tracetogether to be effective, at least three-quarters – if not everyone – of the population had to install it, and had to turn on their bluetooth function to ensure the app was running. on 10 april 2020, approximately 3 weeks after its release, about one million people had downloaded the app, which translated to about one in six of the resident population at the time. this percentage increased to 17% of the population in may 2020. on 5 june 2020, the minister-in-charge of the smart nation initiative announced in parliament that the tracetogether has been downloaded on a voluntary basis by 1.5 million users, which worked out to only 25 per cent of the population. by 4 september 2020, about 2.4 million users had downloaded the app, with 1.4 million active users in august. as of 14 december 2020, following the release of the token, adoption rate of the app and token combined exceeded 60% of singapore's resident population. despite falling short of the 70% adoption target that the government had set loosen restrictions, the government later announced on the same day the loosening of restrictions to start from 28 december 2020. on 23 december 2020, balakrishnan revealed that the adoption rate had exceeded 70%. on 11 may 2021, balakrishnan revealed that the adoption rate had exceeded 92%, with 4,923,054 individuals aged above six. on 19 january 2022, the smart nation and digital government office indicated that "almost all of singapore's population above the age of six" are using the system. there were about 3,000 users, or 0.056% of the registered users, who deregistered for reasons such as expats leaving the country, people who have died, or people opting out over data security reasons. effectiveness with tracetogether complementing manual contact tracing effort, the contact tracing teams has improved their efficiency by reducing the time taken to identify and quarantine a close contact from four days to less than two days. more than 10% of close contacts identified by tracetogether turned positive during quarantine period, the percentage may be low due to singapore mandating mask-wearing since 14 april 2020. it was reported on 22 april 2021 that tracetogether system had identified at least 75 persons who had to be placed under quarantine, but would likely not have been picked up through a manual contact tracing process. tracetogether token a tracetogether token on 7 june 2020, minister-in-charge of the smart nation initiative vivian balakrishnan announced that the government would be distributing a physical device, named tracetogether token, to augment the app. the tracetogether token is designed primarily to support singapore residents who do not own a smartphone, mainly some elderly, children aged seven and above or residents with workplace restriction. the physical token helps to increase the optimal number of users required for the contact tracing system to work well, which was 75% of the population. with the issuance of the device, the government aimed to achieve at least 70% of the population using either the tracetogether token or app. upon the announcement of the physical device, there was a public backlash against the physical device initiative, with a petition launched to protest against the development of the device over concerns about potential privacy issues. the singapore people's party also released a statement regarding the privacy concerns and about the potential abuse of the data. similar to the app, the tracetogether token utilises bluetooth to exchange signals with other tracetogether tokens or the mobile app. after encrypting the data of what devices or apps are near by, the device stores up to 25 days of information before deletion. the device is designed for those who have no smartphone, which consisted of about 5% of the population. it is designed to be waterproof and its battery life is about six months. there are no physical buttons on the device, and it has a green/red light indicator for battery life and/or to indicate a fault. the device does not have gps functionality, and access to the data remains restricted among the civil service. a tracetogether token vending machine at kitchener complex the physical device was made available for collection from 14 september 2020. a 26 october 2020 report indicated that there was a higher than expected demand after the news of mandatory usage of tracetogether was released. authorities also did not expect that residents would travel to different distribution points island-wide to collect the tokens and had suspended collection for a day on 28 october 2020 to rework the distribution strategy. the collection of the token at the community centres could only be made by residents in the respective constituencies, and distribution was done on a rolling basis at the constituency level, with the last remaining community centres reopened for collection only on 23 december 2020. a straits times editor, irene tham advocated on 30 october 2020 for the tokens to be distributed first and mandate the usage later. tham also suggested a similar queue system to that of telcos registering customers and assigning time slots could be adopted to avoid overcrowding at the collection points as it was noted that a crowd formed and lasted for a couple of hours at marsiling community centre for a couple of hours even after that distribution strategy was reworked. the distribution strategy would subsequently be changed from manned counter operations to token dispensing vending machines from 31 august 2021 onwards. mandatory usage of tracetogether an automatic self-check-in station at paya lebar square requiring the use of tracetogether downloading, installing, registering the tracetogether app and scanning in/out using the tracetogether-only safeentry (tt-only se) has been made mandatory for all singaporeans and at all places such as cinemas, restaurants, workplaces, schools and shopping malls for contact tracing purposes. these includes the device called safeentry gateway (check in and check out) to enable users to scan in and out. in addition, tracetogether also shows vaccination status and pre-event testing (pet) status whether the person test positive or negative for covid-19. all other methods of checking in through safeentry such as either the phone camera, nric or singpass app are all removed since the second lockdown