)[3]) On 10 April 2020, Google and Apple jointly announced that they would integrate functionality to support such Bluetooth-based apps directly into their Android and iOS operating systems.

India's COVID-19 tracking app Aarogya Setu became the world's fastest growing application—beating Pokémon Go—with 50 million users in the first 13 days of its release.

[6] In a March 2020 model by the University of Oxford Big Data Institute's Christophe Fraser's team, a coronavirus outbreak in a city of one million people is halted if 80% of all smartphone users take part in a tracking system; in the model, the elderly are still expected to self-isolate en masse, but individuals who are neither symptomatic nor elderly are exempt from isolation unless they receive an alert that they are at risk of carrying the disease.

[citation needed] Proportionality refers to the concept that a contact tracing app's potential negative impact on a person's rights should be justifiable by the severity of the health risks that are being addressed.

[24] Some argue that contact-tracing apps should be considered societal experimental trials where results and adverse effects are evaluated according to the stringent guidelines of social experiments.

[26] Time boundedness describe the need for establishing legal and technical sunset clauses so that they are only allowed to operate as long as necessary to address the pandemic situation.

[27] The American Civil Liberties Union (ACLU) has published a set of principles for technology-assisted contact tracing and[28] Amnesty International and over 100 other organizations issued a statement[29] calling for limits on this kind of surveillance.

[30] The organisations declared eight conditions on governmental projects:[29] The German Chaos Computer Club (CCC)[31] and Reporters Without Borders[32] also issued checklists.

The Exposure Notification service intends to address the problem of persistent surveillance by removing the tracing mechanism from their device operating systems once it is no longer needed.

Vladimir Putin signed laws introducing criminal penalties, including up to seven years imprisonment, for quarantine violations that led to others being infected.

The dubious behavioral interpretations recorded by the social monitoring tracking application led to the mistaken fining of hundreds of people in Moscow.

Initial releases were found to come with incongruent privacy policies, hidden built-in surveillance and location-tracing functions, and generally contained few cues about a proper specification and quality assurance process.

[42] GPS-based proximity detection can also be unreliable: according to the United States' GPS.gov, "GPS-enabled smartphones are typically accurate to within a 4.9 meter (16 ft.) radius under open sky", with accuracy decreasing further in the presence of signal blockage.

[43][44] In the Google/Apple mechanism, a log entry is only added on the phone if Bluetooth proximity persists for five minutes (or possibly longer, depending on app configuration).

[59][60][61] Covid Watch was the first organization to develop[62] and open source[63][64] an anonymous, decentralized Bluetooth digital contact tracing protocol, publishing their white paper on the subject in March 2020.

[73][74][75] As of 1 April 2020, a group of European researchers, including from the Fraunhofer Heinrich Hertz Institute and École Polytechnique Fédérale de Lausanne (EPFL), were under the umbrella of the Pan-European Privacy-Preserving Proximity Tracing (PEPP-PT) project,[76] developing a BLE-based app to serve this purpose that is designed to avoid the need for intrusive surveillance by the state.

[80] As of 7 April 2020, over a dozen expert groups were working on privacy-friendly solutions, such as using Bluetooth Low Energy (BLE) to log a user's proximity to other cellphones.

[81][82] As of 23 March 2020, Mary-Louise McLaws, professor at the University of New South Wales' School of Public Health and Community Medicine in Australia, a technical adviser to the World Health Organization's Infection Prevention and Control Global Unit and a member of European, US and UK epidemiology and infection control bodies recommended the idea for wider adoption.

[85] Later it was reported that KU Leuven, the CISPA Helmholz Center for Information Security, the European Laboratory for Learning and Intelligent Systems and the Technical University of Denmark, also withdrew from the project.

The COCOVID app is Open Source and the backend is based on a highly scalable solution that is already used by several of the largest financial institutions in Europe.

The team working on the project includes persons from Orange, Ericsson, Proventa AG, Stratio, TH Köln and Charta digitale Vernetzung.

[citation needed] On 10 April 2020, Google and Apple, the companies that control the Android and iOS mobile platforms, announced an initiative for contact tracing, which they stated would preserve privacy, based on a combination of Bluetooth Low Energy technology and privacy-preserving cryptography.

"[108] for Mobile Contact Tracing (PACT) / CovidSafe [118][119] [121] [122] [123] Stefano Piotto, Luigi Di Biasi,[126] Softmining, Minervas, PushApp, NexusTlc, University of Salerno, dibiasi.it Materiale Electrico,[127] BiTS Community beta volunteers In the United Kingdom, Matthew Gould, chief executive of NHSX, the government body responsible for policy regarding technology in the NHS, said in late March 2020 that the organisation was looking seriously at an app that would alert people if they had recently been in contact with someone testing positive for the virus after scientists advising the government suggested it "could play a critical role" in limiting lockdowns.

[234] Russia introduced a geofencing app, Social Monitoring, for patients diagnosed with COVID-19 living in Moscow, designed to ensure they do not leave home.