How to password-protect a PDF
- Select the PDF you want to protect.
- Type a strong password and repeat it to confirm.
- Optionally set restrictions such as printing, copying or editing, protected by an owner password.
- Click protect and download the encrypted PDF.
Strong, standard encryption
The PDF is encrypted with AES-256, the strongest encryption method defined in the PDF standard, using the open-source qpdf engine running in your browser. Without the password, the document's content cannot be read. Encrypted files open in Adobe Acrobat and Reader, browser PDF viewers, macOS Preview and other modern PDF apps, which ask for the password.
Choosing a good password
- Use at least 12 characters, or a passphrase of several unrelated words.
- Avoid names, birthdays and words that appear in the document.
- Share the password through a different channel than the file, for example by phone or text message rather than in the same email.
- Store it safely. We never see or store your password, so it cannot be recovered if you forget it.
Open password versus restrictions
The open password controls who can read the file. Restrictions on printing, copying and editing are a separate layer controlled by an owner password; they are respected by standard PDF software but are not as strong as the open password, so don't rely on them alone to protect secrets. For restrictions without an open password, use Restrict PDF Permissions. To also clear the document's author and title information before sharing, run Remove PDF Metadata first.
Frequently asked questions
How secure is the encryption?
The file is encrypted with AES-256, the strongest standard PDF encryption. Security ultimately depends on choosing a strong password.
Can you recover my password if I forget it?
No. The password never leaves your browser and is not stored anywhere, so keep a copy in a safe place.
Will the protected PDF open on phones?
Yes. Modern PDF apps on iOS and Android support AES-256 encrypted PDFs and ask for the password.
Is the file uploaded for encryption?
No. Encryption runs locally in your browser, so the unprotected document never leaves your device.
How do I remove the password later?
Use Unlock PDF and enter the password to save an unprotected copy.