2.2 KiB
2.2 KiB
Original NHSx app vs Post-may Apple/Google API-based app
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NHSx app builds a database of significant contacts (<2 metres for at least 15 mins) who can be alerted if the user reports symptoms (presumably a positive test, too) (from independent)
- Users could be notified of false positive if this was found out later
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NHSx uses a centralised model (FIXME: Find decent source and explanation!)
- A centralised server figures out the matching process
- Phone has a unique key thats sent to other devices that come in contact
- If the user logs positive, device tells server their key is positive
- Other device asks NHS server if any device keys it's received are positive (here, the server checks for matches)
- If the key is found to have logged positive, the user is alerted
- The server knowing if your key has come into contact with someone could pose a risk of tracking by gov/hackers
- Could make tracking outbreaks on a national scale easier
- App connected to NHS account
- Battery-saving features on phones (especially iPhones) could pose a challenge to keeping the service running 24/7 on the device
- Even if not, Apple claimed NHSx solution would be less power-efficient
- A centralised server figures out the matching process
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Apple/Google uses a semi-decentralized model (good ass diagram here)
- Uses BLE to reduce power usage
- No NHS account, name or details need to be given
- When two phones meet, a unique key is created and exhanged between them
- When one logs a positive, the user agrees to upload the key to a central database
- All other phones regularly download the central database, and then check (matches are searched for on-device) for any keys they have received from other devices
- If the key is in the db, the user is alerted, but the central server does not know about the match.
Similar between the two
- Risk of high false-positives/Self-certification being used maliciously
- This was more of a concern when the apps were in development, as conveninent testing (LFD) was not easily available so self-cert was the most likely way to log "positive" on the app