Diagnosis Key Distribution

API Pattern: Distribution

HTTP Request and Response

Daily ZIP of diagnosis keys: GET https://<FQDN>/distribution/daily/yyyyMMdd00.zip
Two-hourly ZIP of diagnosis keys: GET https://<FQDN>/distribution/two-hourly/yyyyMMddhh.zip

FQDN: One (CDN) hostname for all distributed APIs
Authorization NOT required and signatures provided - see API security
yyyyMMdd00 (formatted UTC timestamp): 14 valid values (the last 14 days < today)
yyyyMMddhh (formatted UTC timestamp, hh = hour of day - hour of day % 2): 14*12 valid values (the last 14*12 two-hour periods < current two-hour period)

Content-Type: application/zip
The file format ("the ZIPs" in the scenario below) is described here: https://developers.google.com/android/exposure-notifications/exposure-key-file-format

The client downloads diagnosis keys periodically (newly available keys since the last successful download)
If the downloads fails, the client will try again in the next download cycle

Sequential downloads (assumption: full history is not required):

GET https://distribution-<host>/distribution/two-hourly/2020062608.zip

After successful download of all ZIPs, the mobile app will store 2020062608 as "last download timestamp"

Sequential downloads:

GET https://distribution-<host>/distribution/two-hourly/2020062610.zip

After successful download of the ZIP, the mobile app will store 2020062610 as "last download timestamp"

Sequential downloads:

GET https://distribution-<host>/distribution/two-hourly/2020062612.zip
GET https://distribution-<host>/distribution/two-hourly/2020062614.zip

Mobile will store 2020062614 as "last downloaded" after successful download of the ZIP