Page - 269 - in VULNERABLE - The Law, Policy and Ethics of COVID-19

269Privacy, Ethics, and Contact-Tracing Apps interoperability.5 Apps are adopted by specific national or regional governments. As restrictions lift and people begin once again to cross borders, interoperability of different apps across jurisdictions becomes important.6 Centralized vs Decentralized Data Storage Apple and Google have sought to address both privacy and interoper- ability by collaborating on an exposure notification system that could be used as a foundation for Bluetooth-enabled contact-tracing apps.7 With input from privacy scholars and advocates,8 this system was designed for decentralized data storage. A decentralized data storage approach keeps information about contacts stored locally on a user’s phone, rather than automatically uploading it to a central database.9 A person who tests positive for COVID-19 can enable public health authorities to notify significant contacts without actually identifying them. Some governments were unwilling to adopt a fully decentral- ized contact-tracing app, preferring a centralized model in which data about users and/or contacts is stored on a central server acces- sible to public authorities. Centralized data solutions have the benefit of allowing governments (or app developers) to access de-identified data about proximity and infection that might be useful in modelling and analytics to better understand the disease and its spread. Some governments have sought a compromise solution that allows for decentralized storage of contact data only up until the point of a user’s 5. Leila Abboud, Joe Miller & Javier Espinoza, “How Europe Splintered over Contact Tracing Apps”, Financial Times (10 May 2020), online: <www.ft.com/ content/7416269b-0477-4a29-815d-7e4ee8100c10>. 6. Teresa Scassa, “One App per Province? How Canada’s Federalism Complicates Digital Contact Tracing”, Heinrich  Böll  Stiftung (13 May 2020), online: <us.boell. org/en/2020/05/13/one-app-province-how-canadas-federalism-complicates-digi- tal-contact-tracing>. 7. Apple/Google, “Privacy-Preserving Contact Tracing” (last visited 11 May 2020), online: <www.apple.com/covid19/contacttracing/>; Andy Greenberg, “Google and Apple Reveal How Covid-19 Alert Apps Might Look”, Wired (4 May 2020), online: <www.wired.com/story/apple-google-covid-19-contact-tracing-interface/>. 8. DP-3T, “Decentralized Privacy-Preserving Proximity Tracing—Documents”, GitHub (last visited 11 May 2020), online: <github.com/DP-3T/documents>. 9. Carmela Troncoso et al, “Decentralized Privacy-Preserving Proximity Tracing— White Paper” (12 April 2020), online (pdf): <github.com/DP-3T/documents/blob/ master/DP3T%20White%20Paper.pdf>.