Protect PDF with a password
Add a password so the file can only be opened by people who know the password. Uses AES encryption in your browser — the document never leaves your device.
Drop a PDF here
or click to choose a file
Accepted: PDF · No upload
How to protect a PDF with a password
- Add a PDF file.
- Choose a strong password. Write it down — it cannot be recovered.
- Optionally set an owner password and adjust permissions.
- Click Protect PDF to download the encrypted file.
What is preserved
Pages, text, images, bookmarks and form fields stay exactly as they are. Only the ability to open the file changes.
Privacy
Encryption happens in your browser using AES. The password and the document never leave your device.
Known limitations
- If you forget the password, the file cannot be opened. OmniPDF has no way to recover it.
- Encryption uses standard AES compatible with Acrobat and modern readers.
- Unusual PDFs with broken structures may not encrypt reliably.
Frequently asked questions
Is browser encryption as safe as desktop software?
AES encryption is the same algorithm used by desktop tools. The output is a standard encrypted PDF that opens in any modern reader. Safety comes down to choosing a strong password.
Can OmniPDF recover a lost password?
No. Once encrypted, only the password can open the file. We cannot recover a forgotten password.
Can I protect multiple PDFs at once?
Not yet. Protect one file, then repeat for the others.