5 ms·
DTKs are derived rather than random so that the device doesn't have to store its own keys or identifiers, saving both space and flash wear. It can start with th
by sowbug 7y ago
DTKs are derived rather than random so that the device doesn't have to store its own keys or identifiers, saving both space and flash wear. It can start with the initial seed and re-derive all the rest as needed.
- awinter-py 7y agowhy does the device need to know its own key history?
- drrotmos 7y agoBecause the idea is that when you test positive, you upload DTKs for all days you could have been contagious, so that includes historical keys.
- awinter-py 7y agoohhhh makes sense. I'll update the post
- gruez 7y agoWhy not randomly generate a key for each day and store the keys for the last n days? 16 byte keys for 60 days is less than a kilobyte.
- tehlike 7y agoYou phone already stores lots of data every 10minutes, I am not sure if flash wear is a problem. Same with storage space. A guid is 16 bytes per key * 6 keys per hour 24 hours per day 365 days makes less than a megabyte. Even accounting for additional data stored where guid is the key it feels not a big concern. I imagine data stored like: Key: guid Contacts made: <timestamp, guid>[]
- gorgoiler 7y agoBecause you want to use the same protocol for 89¢ devices?