Another app may bind the Tor ports
Another app may bind the ports that Briar uses for communicating with Tor. If Briar finds that the control port is already bound at startup it will assume Tor is already running and not start its own Tor process.
Briar will pass confidential data over the control port, including the Tor authentication cookie and the hidden service private key.
Briar will also pass confidential data over the proxy port, including the hidden service addresses of contacts and encrypted BTP streams and crash reports.