The document discusses requirements for a COVID-19 tracking mobile app, including that it be reliable, cost-effective, privacy-friendly, user-friendly, and have good performance worldwide. It asks for estimates of development time, monthly infrastructure costs, and what tools and languages would be used.

2. Hello,
Imagine, you have received requirements to build a Covid19 tracking
mobile app (both frontend and backend).
Should be reliable, cost-effective, privacy-friendly, user-friendly, works
worldwide and with a great performance.
Tell me: (1) how much time do you need for development, (2) monthly cost
for infrastructure, and (3) what tools/languages will you use.
roman@ralabs.orgwww.ralabs.org
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3. Looks like mobile app (?IoT device)
Probably will be using GPS sensor => Research phase for GPS/BLE
Will communicate with Backend through cryptography/HTTPS
Q: How many infected people? => 83 millions?
Q: how many coordinates will be stored? => BigData? Balancing?
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High-level planning
roman@ralabs.org

4. Native or ReactNative, GPS (?BLE), CI/CD
Hadoop/Apache Spark (batch processing)
Apache Kafka (streaming/piping; data ingestion)
AWS Redshift (data warehousing)
Serverless (AWS Lambda), AWS Route53
LaaS (Papertrail/DataDog)
...
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Architecture looks,
roman@ralabs.org

5. Sorry, but..
We have limited time
We have limited infrastructure budget
We have limited time for discovery phase
We have to support 1’000’000 intersections daily
We still should be very careful with false negatives & privacy
We’re open for any ideas..
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roman@ralabs.org

6. (x) Make you familiar with Contact Tracing and existing protocols, that can
be re-used for similar applications (not limited to COVID-19).
(x) Share our experience building Digital Contact Tracing application, so you
will be aware about technical limitations.
roman@ralabs.orgwww.ralabs.org
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Goal

7. IntroRoman Rodomansky
CTO at Ralabs
CTO at CURSOR Education
Organizer of NodeSchool Lviv
ex Co-organizer of Google Group Lviv
ex Fan of Hackathons
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8. roman@ralabs.orgwww.ralabs.org
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Digital Contact Tracing

9. Our experience building COVID-19 solution
for Germany and Switzerland government.
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10. User journey
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User shoud share medical
results photo with
medical stuff

11. User journey
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Daily history updates
every dat at midnight

12. roman@ralabs.orgwww.ralabs.org
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High-level technical workflow

13. Results
First COVID-19 tracking app on German & Swiss market
Implemented own centralized protocol & algorithm for matching intersections
Apple AppStore public release in 4 weeks after project started
Google PlayStore public release in 6 weeks
Reached over 1’000 downloads
Reached over 16’000’000 coordinates
Reached ~$200/mo infrastructure budget
Engaged 200 beta testers (load testing) world-wide
Overcame App Store’s restrictions for COVID-19 apps
roman@ralabs.orgwww.ralabs.org
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14. roman@ralabs.orgwww.ralabs.org
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COVID-19 algorigthm
It might take up to
couple hours

15. roman@ralabs.orgwww.ralabs.org
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Proposed desired architecture (idea)

16. roman@ralabs.orgwww.ralabs.org
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Implemented architecture, due to budget limitations

17. Compliences
What governments will ask you to follow?
GDPR-compliant for EU, CCPA, PIPEDA, LGPD, POPI, etc (protection of
personal data)
HIPAA-compliant (protecting medical data if app managing any PHI data)
ACLU-compliant
Privacy-preserving (privacy-friendly), Anonymous-based, Battery efficient,
Security rules (OWASP following, etc)
roman@ralabs.orgwww.ralabs.org
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18. Depends on GPS, Bluetooth (BLE), Beacons and Audio sensors.
What are issues?
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Tracing Methodologies

19. Geolocation
* Pure accuracy on big cities (i.e. NYC, Kyiv, Berlin, etc)
* Android background geolocation tracking
* Lower-power mode limitations (Significant change location)
* Background task updates frequency is every 10 minutes
* AppStore limitations
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20. Bluetooth
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* BLE distance limitations
* Wall between two devices
* iOS background scanning is not supported

21. Beacons
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* Require client, that broadcasting updates
* Supports iPhone 4S and higher
* Delays with notifications

22. Audio
* Using ultrasound (inaudible), issues on loud places
* Battery consuming
* Success case at Novid app (novid.org)
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That’s only as additional
sensor to increase
accuracy to GPS/BLE
sensors

23. Digital Tracing
Digital contact tracing protocols
* PEPP-PT
* DP-3T
* Google / Apple privacy-preserving tracing project
* BlueTrace
* PACT (MIT)
* NHS contact tracing protocol
* ...
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24. PEPP-PT proto
Pan-European Privacy-Preserving Proximity Tracing
* https://github.com/pepp-pt
* Centralized
* Human-in-the-loop checks
* Singapore, Australia, New Zeland, etc
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25. roman@ralabs.orgwww.ralabs.org
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PEPP-PT protocol (Pan-European Privacy-Preserving Proximity Tracing)

26. BlueTrace
* Singapore Government
* Is used by 20% of Singapore population
* 909 cases (Feb) => 74 cases (Mar)
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27. DP-3T proto
Decentralized Privacy-Preserving Proximity Tracing
* https://github.com/OpenCovidTrace
* https://github.com/DP-3T
* Switzerland, Austria and Estonia
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28. DP-3T, Decentralized Tracing protocol
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29. Apple/Google proto
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* Exposure Notification Technology
* Re-using DP-3T
* 10-minutes EphIDs
* Encryption changes

30. roman@ralabs.orgwww.ralabs.org
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How might look app’s architecture nowadays

31. bit.ly/R77832
Thank you!
This is Telegram channel
with a good stuff.
Open to join!
roman@ralabs.orgwww.ralabs.org
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