Previews leak without anyone unlocking anything
A notification banner renders message content on a locked screen, which means it is readable by anyone near the phone. That includes verification codes, conversation excerpts, and image thumbnails.
It is one exposure path among several. Preview settings reduce that path, while other notification, sharing, and device surfaces need separate review.
Preview settings have three useful levels
Previews can be shown always, only when the device is unlocked, or never. The middle option is the pragmatic default: you see content when you are already looking at an authenticated device, and a passer-by sees only that a message arrived.
Per-conversation settings allow tightening specific threads without changing the global behaviour.
The other screens
A paired Apple Watch and CarPlay each render notifications with their own settings, and both are frequently visible to other people. Changing the phone does not change them.
Notification history and the Shared with You feature, which injects received photos into other apps, are two further surfaces worth reviewing.
Setting it up
- Set Show Previews to When Unlocked, or Never for higher sensitivity.
- Use per-conversation settings for specific threads.
- Review Apple Watch and CarPlay notification behaviour separately.
- Audit Shared with You photo injection.
- Check whether message attachments are being saved into Photos automatically.
Two misconceptions
- Assuming muting notifications encrypts a conversation.
- Leaving message attachments saved into the photo library.
A fictional example
Maya starts with a non-sensitive test: “Set Show Previews to a level matching your threat model.” Next, Maya follows the second check: “Review Apple Watch and CarPlay notification behavior.” This fictional scenario demonstrates the decision process; it is not a report of product testing.
Common mistakes
- Assuming muted notifications encrypt a conversation
- Leaving attachments saved in Photos
What this workflow does not change
- Assuming muted notifications encrypt a conversation
- Leaving attachments saved in Photos
Questions people ask
Can iMessage lock one conversation with a unique password?
The ordinary Messages interface does not provide a separate password per conversation.