Signal keeps your messages private in transit. All messages are stored on your phone. If you lock Signal your messages are stored encrypted at rest. You can lock Signal by enabling a passcode. Additionally, many privacy conscious users add a passcode to their phone and do not leave it unlocked in other people's hands.
To enable a passphrase
- Open Signal.
- Tap on the Menu or .
- Choose Settings.
- Choose Privacy.
- Enable/Change passphrase
- To Enable: Tap Enable passphrase until it slides and shows a blue color.
- To Change: Choose Change Passphrase.
If you've enabled a passphrase then choose to lock Signal
- manually through Signal > Menu or > Lock
- by auto-lock after an inactivity timeout
Signal > Menu or > Settings > Privacy > check on Inactivity timeout passphrase and adjust the Inactivity timeout interval.