Just noticed that when setting up camera backup in the iOS app, if you don't have a mail account setup you can't email the secret and there doesn't appear to be any other way to get the secret. I'm using the gmail app for my email and would like to avoid setting up a mail account just to enable camera backup.
The Off-the-Record messaging protocol provides a mechanism for verifying a 3rd party by giving a simple question with an answer which only the sender and recipient should know. It might be useful to have a mechanism like this in BTSync. Particularly, generating a secret which when entered by the recipient prompts them to answer the given question. Answering correctly would allow syncing as usual. Any input on this feature request is welcome.