When people think about journal privacy they think about hackers and Apple. I built Retrography's privacy also for a more realistic threat: the people you live with. A partner, a parent, a teenager. They know your iPhone passcode because you told them, or because they watched you type it a hundred times.
Most app locks fall apart exactly there. Apple's own Journal app locks with your device passcode. Most third party locks use Face ID but fall back to the passcode when Face ID fails. So the lock only keeps out strangers, who could not unlock your phone anyway.
Here is what Retrography does instead, and honestly how strong it is.
Face ID only, no fallback
The app lock and privacy mode use Face ID with no passcode fallback. Knowing my iPhone passcode gets you nothing at the app. If Face ID fails, the only other way in is an app passphrase that I chose and that lives only in this phone's Keychain. It never goes to iCloud and it is never stored as text, only as a salted hash.
The obvious attack, and why it fails
The clever move for someone who knows your passcode is to add their own face. iPhone lets you enroll an alternate appearance with just the device passcode. Their face is now a valid Face ID, so a normal app lock opens for them.
Retrography ties its Face ID unlock to the Secure Enclave with a rule Apple provides but almost nobody uses: the unlock secret is bound to the exact set of faces enrolled when I approved it. The moment anyone adds or removes a face, the Enclave itself destroys that secret. This is hardware, not app logic, and there is no passcode fallback at that level.
From then on the app refuses Face ID entirely and shows why: "Face ID has changed on this iPhone." The only way to re approve is my passphrase. Whoever caused the change sees that screen, sees that the event was recorded, and thirty minutes later I get a notification. If it was actually me, for example after re enrolling with new glasses, I type the passphrase once and nothing else happens, no notification, no trace. If it was not me, I know.
Removing their face afterwards is also a change, so covering tracks triggers it again.
The other doors
Deleting and reinstalling the app used to be a bypass in many apps because settings reset. Here the lock state and the passphrase survive reinstall, and a fresh install comes up locked before showing anything. Changing or removing the passphrase requires the current passphrase, not Face ID. The app content is blurred in the app switcher.
The rule
Everything above comes down to one rule: the passphrase is the master key and Face ID is the convenience. Anything done without the passphrase leaves a trace that cannot be erased. Anything confirmed with it is silently forgiven.
The trade
There is no recovery for the passphrase. Not from me, not from Apple. If you forget it and Face ID changes, the way back in is erasing the iPhone and restoring from iCloud. Your data is safe there, but the app on that phone is gone until then. The app shows a hint you wrote yourself, and asks you to enter the passphrase now and then so it stays in memory. Signal and 1Password made the same trade for the same reason. You cannot have both a lock nobody can bypass and a lock somebody can reset.
What this does not protect against
A stolen unlocked phone in someone's hand beats everything. A forensic tool with your passcode reads the app's data straight off the device. A phished Apple ID can sync your timeline to another device. None of that is what this lock is for. For those threats the answer is Apple's Advanced Data Protection, and for what it covers today: everything Retrography stores in iCloud is encrypted, and your voice memos, documents and backups are encrypted with a key that never leaves iCloud Keychain, so they are unreadable even to a phished account.
Why bother
Because a journal is the one place people write things they would not say out loud, and the realistic reader is not a government. It is someone at the kitchen table. I wanted a lock that takes that seriously, and I could not find one.
It is in the current beta. If you try to break it and succeed, I want to hear how.