Plume
A Diary App With a Lock:
What Actually Keeps It Private
A lock on your diary app stops the person who picks up your phone. It does not, on its own, decide who else can read your words. Privacy comes in layers: the lock, where the entries live, how they sync, and what the app knows about you. Here is each one, in plain words.
Privacy comes in layers
Most people searching for a diary app with a lock want one thing: nobody else reads this. A lock is the first layer of that. It is not the only one. Here is what each layer does, in plain words.
The lock on the app
Face ID, Touch ID or a passcode on the app itself. It protects you from the person who picks up your unlocked phone: a partner, a child, a curious friend. It is the layer you see, and it matters. In most apps the fallback is your device passcode, so anyone who knows that passcode can usually get in.
Where your words are stored
Some journal apps keep entries on your device. Others keep them on the company's servers, tied to an account. On-device storage is also protected by your iPhone's own encryption, which relies on your device passcode. A long passcode helps every app on the phone.
How sync is protected
If your journal syncs between devices, ask who holds the key. With end-to-end encryption, entries are encrypted before they leave your device, and only your devices can read them. Without it, the service can technically read what it stores.
What the app collects about you
An account links your journal to your email. Analytics tools report how you use the app. Neither is sinister on its own, but a journal needs neither. The App Store privacy label shows what an app collects.
What to look for in a secure journal app
A real lock
Face ID or Touch ID on the app, with a passcode fallback. It should lock again when you leave the app.
No account, or a good reason for one
The fewer places your identity is stored next to your writing, the better.
Encrypted sync, or no sync
End-to-end encrypted sync, or a clear option to keep everything on one device.
A way out
Export to plain text or JSON. Privacy includes being able to take your words with you.
Private journal apps on iPhone with a lock
There is more than one good answer here. Three worth knowing:
Apple Journal
Free and built in. Can be locked with Face ID, Touch ID or your passcode. Entries stored in iCloud are end-to-end encrypted, according to Apple. A simple, solid choice.
Day One
The best-known journal app. It offers an app lock, and new journals use end-to-end encrypted sync by default. It uses an account, and syncing between devices needs a paid plan.
Plume
Face ID, Touch ID or passcode lock. No account, no analytics, no ads. Entries live on your device. Optional iCloud sync is encrypted before upload with ChaCha20-Poly1305, using a key derived from your sync passphrase. How it works.
Published by the makers of Plume, so read our view with that in mind. For a longer comparison, see our guides to the best private journaling app and private journaling apps for Mac.
A place for the things you will never send
A lot of people want a locked diary for one reason. They need somewhere to vent. The angry draft to a boss. The thing you can't say to your family yet. The feeling that doesn't have a name.
Honest writing needs a door that closes. When you trust that no one else will read it, you stop editing yourself, and that is where the clarity comes from.
A few ways to use that space:
Write the unsent letter
Address it to the person. Say all of it. Close the app. You don't have to reread it.
Name it, then leave it
One line: what happened, and how it felt. Sometimes naming a feeling is enough to set it down.
Come back tomorrow
Read yesterday's entry with a little distance. Often the most useful sentence is the calm one you write after.
If you are carrying something heavy, writing can help, and it works best alongside real support, not instead of it. Our piece on journaling for anxiety covers what the research says.
What a lock cannot do
No app can promise perfect privacy, and you should be wary of any that does. A lock will not help if someone knows your device passcode, reads over your shoulder, or finds an exported file you left in a shared folder. Exports are usually plain, unencrypted files.
The simple habits matter most. Use a long device passcode. Keep your phone's software up to date. Store exports somewhere private, and delete the ones you no longer need.
Frequently asked questions
Is there a diary app with a lock on iPhone?
Yes. Apple Journal, Day One and Plume can all be locked with Face ID, Touch ID or a passcode. Apple Journal is free and built in. Plume also works without an account and keeps entries on your device.
Can I put a password on Apple's Journal app?
Yes. Apple Journal can be locked so it asks for Face ID, Touch ID or your device passcode when you open it. Apple says entries stored in iCloud are end-to-end encrypted.
Is an app lock the same as encryption?
No. A lock stops someone who picks up your unlocked phone. Encryption protects the stored or synced data itself. A private journal app uses both, and end-to-end encrypted sync means only your devices can read the entries.
What is a good private journal app for venting?
Any journal app with a lock, no account requirement and encrypted or on-device storage works well. Apple Journal is a free option. Plume adds no account, no analytics and on-device storage with optional passphrase-encrypted sync.
Does Plume need an account?
No. Plume has no account, no analytics and no ads. Entries stay on your device, and iCloud sync is optional and encrypted with a key derived from your own passphrase.
Write it honestly.
Keep it yours.
Face ID lock. No account. Entries on your device. 21 writing days free, then read-only, never locked out.