Exposure Notification

Exposure Notification
Developed by
IntroducedApril 10, 2020 (2020-04-10)
IndustryDigital contact tracing
Compatible hardwareAndroid & iOS smartphones
Physical range~10 m (33 ft)[1]

The (Google/Apple) Exposure Notification System (GAEN)[2][3][a] is a framework and protocol specification developed by Apple Inc. and Google to facilitate digital contact tracing during the COVID-19 pandemic. When used by health authorities, it augments more traditional contact tracing techniques by automatically logging close approaches among notification system users using Android or iOS smartphones. Exposure Notification is a decentralized reporting protocol built on a combination of Bluetooth Low Energy technology and privacy-preserving cryptography. It is an opt-in feature within COVID-19 apps developed and published by authorized health authorities.[10][11] Unveiled on April 10, 2020, it was made available on iOS on May 20, 2020 as part of the iOS 13.5 update[12] and on December 14, 2020 as part of the iOS 12.5 update for older iPhones.[13] On Android, it was added to devices via a Google Play Services update, supporting all versions since Android Marshmallow.

The Apple/Google protocol is similar to the Decentralized Privacy-Preserving Proximity Tracing (DP-3T) protocol created by the European DP-3T consortium and the Temporary Contact Number (TCN) protocol by Covid Watch, but is implemented at the operating system level, which allows for more efficient operation as a background process.[14][15][16] Since May 2020, a variant of the DP-3T protocol is supported by the Exposure Notification Interface.[17] Other protocols are constrained in operation because they are not privileged over normal apps. This leads to issues, particularly on iOS devices where digital contact tracing apps running in the background experience significantly degraded performance.[18][19][20] The joint approach is also designed to maintain interoperability between Android and iOS devices, which constitute nearly all of the market.

The ACLU stated the approach "appears to mitigate the worst privacy and centralization risks, but there is still room for improvement".[21] In late April, Google and Apple shifted the emphasis of the naming of the system, describing it as an "exposure notification service", rather than "contact tracing" system.[22]

  1. ^ Sponås, Jon Gunnar. "Things You Should Know About Bluetooth Range". blog.nordicsemi.com. Retrieved 2020-04-12.
  2. ^ "Google | Apple Exposure Notifications". WeHealth.
  3. ^ Nebeker, C.; Kareem, D.; Yong, A.; Kunowski, R.; Malekinejad, M.; Aronoff-Spencer, E. (2023). "Digital exposure notification tools: A global landscape analysis". PLOS Digital Health. 2 (9): e0000287. doi:10.1371/journal.pdig.0000287. PMC 10473497. PMID 37656671.
  4. ^ "Exposure Notification". Apple Developer. Archived from the original on July 23, 2020. Retrieved February 19, 2024.
  5. ^ "Exposure Notification | Apple Developer Documentation". developer.apple.com. Retrieved 2020-05-21.
  6. ^ Burke, Dave (July 31, 2020). "An update on Exposure Notifications". The Keyword. Archived from the original on July 31, 2020. Retrieved February 19, 2020.
  7. ^ "Exposure Notifications: Helping fight COVID-19 - Google". Exposure Notifications: Helping fight COVID-19 - Google. Retrieved 2020-07-31.
  8. ^ "Privacy-Preserving Contact Tracing". Apple. 10 April 2020.
  9. ^ "Contact Tracing – Bluetooth Specification" (PDF) (Preliminary ed.). 2020-04-10. Archived from the original (PDF) on 2020-04-10. Retrieved 2020-04-10.
  10. ^ "Apple and Google are launching a joint COVID-19 tracing tool for iOS and Android". TechCrunch. 10 April 2020. Archived from the original on 2020-05-22. Retrieved 2020-04-10.
  11. ^ Sherr, Ian; Nieva, Richard (2020-04-10). "Apple and Google are building coronavirus tracking tech into iOS and Android". CNET. Archived from the original on 2020-04-10. Retrieved 2020-04-10.
  12. ^ "COVID-19 exposure notification settings begin to go live for iOS users with new update". TechCrunch. Retrieved 2024-04-17.
  13. ^ Miller, Chance (2020-12-14). "Apple releases iOS 12.5 for older iPhones with support for COVID-19 exposure notifications". 9to5Mac. Retrieved 2021-01-05.
  14. ^ "Apple and Google update joint coronavirus tracing tech to improve user privacy and developer flexibility". TechCrunch. 24 April 2020. Archived from the original on 2021-06-04. Retrieved 2020-04-26.
  15. ^ Farr, Christina (2020-04-28). "How a handful of Apple and Google employees came together to help health officials trace coronavirus". CNBC. Retrieved 2020-04-29.
  16. ^ "Private Contact Tracing Protocols Compared: DP-3T and CEN". Zcash Foundation. 2020-04-06.
  17. ^ "Coronalert: A Distributed Privacy-Friendly Contact Tracing App for Belgium : Corona App Task Force Version 1.2" (PDF). Esat.kuleuven.be. 5 August 2020. Retrieved 27 June 2022.
  18. ^ Bogle, technology reporter Ariel (2020-04-26). "Want the COVID-19 tracing app to work properly? Keep your iPhone charged". ABC News. Retrieved 2020-04-26.
  19. ^ Jason Bay, Joel Kek, Alvin Tan, Chai Sheng Hau, Lai Yongquan, Janice Tan, Tang Anh Quy. "BlueTrace: A privacy-preserving protocol for community-driven contact tracing across borders" (PDF). Government Technology Agency. Retrieved 12 April 2020.{{cite web}}: CS1 maint: multiple names: authors list (link)
  20. ^ "How COVIDsafe app tracks people 1.5m from you". Chronicle. Archived from the original on 2020-05-03. Retrieved 2020-04-26.
  21. ^ "ACLU Comment On Apple/Google COVID-19 Contact Tracing Effort". ACLU. 2020. Retrieved 2020-04-22.
  22. ^ Morrison, Sara (2020-04-24). "Apple and Google's new contact tracing tool is almost ready. Just don't call it a contact tracing tool". Vox. Retrieved 2020-04-27.


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