If the option is to use GPG/PGP, or some form of encrypted chat to send the keys to be shared, wouldn't / shouldn't I just use GPG to encrypt the file im trying to share anyways, at which point i could use any syncing / sharing service. To sync with someone else requires that you share your key, and if you cant share that key securely .. then you can't sync securely. To say sharing your key is outside of Bt Syncs scope is to say that sharing your key so that you can Sync securely it outside of BT's scope and defeats it purpose. BT doesn't have to even develop a secure way to share keys or communicate, just implement already existing features, team up with up and coming services like heml.is, or at least inform users that your security is dependent on the secrecy of that key, and that sending keys via unencrypted chat or email like facebook, yahoo, aim, aol, gmail, google hangout, outlook, etc is insecure.