How to password-protect a PDF on your phone (AES-256)
Sending a contract or a scanned ID? Protect it with a password so only the intended person can open it.
Encryption that never leaves your device
PDF Master uses AES-256 — the same encryption standard banks and governments use — and performs it entirely on your phone. Your password is used only in memory and is never stored.
Protect a PDF in three taps
- Open the PDF and choose Protect.
- Type a password (letters and numbers).
- Save — the file is now encrypted.
To remove protection later, open it with the password and choose Remove password.
Tip: use a password you can remember. Because encryption is on-device, no one — including us — can recover it for you.
Free, offline, and private.