Known limits
Security limits we know about today.
We'd rather you know these now than find out later.
No independent review yet
OpenBeacon's encryption hasn't been independently reviewed. Our own tests check that keys and plaintext are never sent to the server, but tests aren't a security review.
Phones trust the server for other people's keys
When your phone encrypts a group key for other members, it uses public keys the server gives it. A server that had been deliberately altered could hand out its own keys and receive new locations. The server also decides which phones are set up on an account, though a phone you link by scanning its code only hands your history keys to the phone that showed the code. We plan to add key verification so phones don't have to trust the server for this. Recovery data is already protected: a phone only accepts recovery data made with your phrase.
Removing a phone can't take back what it's seen
When you remove a phone, it's signed out, left out of new group keys, and deletes its keys and data the next time it connects. Until then, it can still read what it already holds. If it never connects again, its copy stays on it.
Metadata isn't hidden
The server can see who is in which group and when each phone sends data, even though it can't read what's sent. See What the server can see.
Pictures aren't encrypted
Profile and group pictures are stored unencrypted, and anyone with a picture's address may be able to view it.
What someone has seen stays seen
Removing someone from a group stops them reading anything new, but can't take back what their phone already received.
No email when you first set up a phrase
We email you when your phrase is changed or reset, but not when it's first set up.