Signal provides end-to-end encrypted messages and calls between Signal users. Encryption protects message content while it travels, but it cannot protect an unlocked or compromised device, prevent the recipient from saving content, or prove that a profile name belongs to a particular person.
Install from the official source
Use Signal’s official website or the verified Apple or Google app-store listing. Keep Signal and the device operating system updated.
Signal Desktop must be linked from a registered phone. Treat every linked computer as another place where messages may be stored and read.
Review linked devices
On the phone, open Signal Settings → Linked devices. Remove anything you do not recognise. When in doubt, unlink every desktop or tablet and add back only the devices you control.
Protect registration
Set a strong Signal PIN and enable registration lock in Settings → Account.
The Signal PIN is not a chat backup or the phone’s screen-lock code. Signal cannot recover it for you. With registration lock enabled, forgetting the PIN can prevent account access for up to seven days, so store it securely before enabling the setting.
Never share an SMS verification code, PIN, backup recovery key or password with someone who messages or calls you. Signal support does not contact users inside Signal chats.
Reduce lock-screen exposure
Configure notification previews so sensitive message text is not displayed on the lock screen. In Signal’s privacy settings, enable screen lock if you want the app to require the device authentication method after a period of inactivity.
Screen-security settings can reduce previews in the application switcher or operating-system capture features. They cannot prevent another participant from photographing or capturing a conversation on their device.
Verify important contacts
Signal profile names are not verified identities. For a sensitive conversation:
- Confirm the person through another trusted channel.
- Open the conversation details and view the safety number.
- Compare the number in person or through an already trusted channel.
- Mark the contact verified only after it matches.
Treat an unexpected safety-number change as a reason to verify again, not automatic proof of an attack; legitimate device changes also create new safety numbers.
Use disappearing messages carefully
Disappearing messages reduce the amount of conversation history retained on participating devices. They do not prevent screenshots, photographs, copying, backups outside Signal or a compromised recipient device.
Choose a timer appropriate to the conversation and make sure participants understand it.
Plan for loss and recovery
Review Signal’s current backup or device-transfer options for your platform before replacing or resetting a phone. A PIN alone does not restore message history.
If a phone is lost, use the device maker’s remote-lock or erase service. Registering Signal on a replacement phone stops new messages and calls reaching the old phone, but existing history may remain on it.
