Hidy VaultHow to password protect a PDF on iPhone
Open the PDF in the Files app, tap More (…), tap Lock, enter the password twice, then tap Apply. Keep an unlocked copy first, because the lock is meant to stop edits and deletion.
- Keep an unlocked copy: open the PDF, tap More (…) > Duplicate.
- Tap More (…) > Lock, enter the password twice, tap Apply.
- The lock is documented to stop editing and deleting, not opening.
What does the Files lock actually do?
Apple's Files instructions say the lock is there to prevent others from editing or deleting the PDF. They do not say it stops someone from opening or viewing the file. That is the honest limit, and it matters if your goal is privacy rather than tamper protection.
So: use the lock to protect a document from being changed or removed. Do not assume it turns the PDF into a sealed file that nobody can read.
Step by step: lock a PDF in Files
- Open the Files app and open the PDF.
- Tap More (…) and tap Duplicate. This keeps an unlocked copy before you lock anything.
- Tap More (…) next to the filename, then tap Lock.
- Enter the same password in Password and Verify. The Require Password toggle turns on automatically.
- Tap Apply (the checkmark) to lock the PDF, or Cancel (×) to discard the change.
Apple's page does not specify a minimum password length, a character set, a retry limit or a recovery option. Choose a long password you can remember, and store it somewhere separate from the PDF.
Hidy Vault keeps photos, videos and documents in encrypted vaults that open only with a pattern you draw. No account, no Hidy server. Free for 3 vaults.
Why keep an unlocked copy first?
Because the lock is easy to forget and Apple's instructions do not describe a recovery path. If you lock the only copy and lose the password, you may be stuck with a file you cannot edit or delete.
Duplicate the PDF before locking it, then move the unlocked copy somewhere you control. If you are keeping passport or ID scans, see keeping passport and ID scans on your iPhone.
How to unlock a PDF again
Apple's Files instructions do not describe a step for turning the lock off. That is why the unlocked copy you made before locking matters: it is your way back to an editable file.
Password-protecting a document in Pages
If the document is still in Pages, Apple documents a separate password option there. This is a different flow from locking a PDF in Files, and it applies to Pages documents rather than finished PDFs.
For a PDF you already exported, the Files lock above is the documented iPhone route.
What the Files lock does not cover
- Opening or viewing. Apple's instructions describe the lock as stopping edits and deletion, not reading.
- Other copies. A duplicate, an emailed copy or a copy in another app is not affected by the lock on this file.
- The rest of your iPhone. The lock protects one PDF. It does not lock the Files app, your photo library or your notes.
- Password recovery. Apple's page does not describe one.
When a Files lock is not enough
If the PDF contains something you would not want read at all, a lock that is documented to stop editing is the wrong tool. You want the file kept somewhere that needs a secret to open.
Hidy Vault is an encrypted vault for iPhone. You can import any file from Files, and Hidy encrypts file contents and file names with AES-256-GCM. A vault opens only when you draw its pattern on a 5×5 grid. There is no list of vaults and no wrong-pattern message, so an unused pattern opens a new, empty vault.
Documents preview inside Hidy. Each vault can have its own 12-word recovery phrase, shown once, which reopens the vault if you forget the pattern. Hidy is coming to the App Store; there is no store link yet.
Limits you should know
- Hidy has no Face ID or Touch ID unlock for the app itself. You draw the pattern.
- An open vault is readable on screen. Hidy locks when the app goes to the background and covers the app switcher, but someone holding your unlocked phone while a document is open can read it.
- Hidy has not had an independent cryptographic audit yet.
- Do not uninstall Hidy to troubleshoot. Local vaults and the Keychain secret can be lost.
- Sharing a file out of Hidy gives the recipient a readable copy.
For a PDF you only need to protect from edits, the Files lock is quick and built in. For a PDF you do not want read, put it in an encrypted vault and keep the password or pattern to yourself.
Frequently asked questions
Does locking a PDF stop someone from opening it?
Apple's Files instructions describe the lock as preventing others from editing or deleting the PDF. They do not say it stops someone from opening or viewing it.
Can I undo the lock?
Apple's Files instructions do not describe a step for turning the lock off. Keep the unlocked copy you made before locking.
What if I forget the PDF password?
Apple's page does not describe a recovery option. Keep the unlocked copy you made before locking.
Is the password stored in iCloud?
Apple's Files instructions do not say where the password is stored. Treat it as something only you should know.
