How secure is PDF password protection?

noll encrypts with AES-256, the strongest standard PDF encryption. The protection is only as strong as the password, so use a long, unique one and send it through a different channel than the file.

What is the difference between the open password and the owner password?

The open (user) password is needed to view the document. The owner password controls permissions such as printing, copying and editing. If you leave the owner password empty, the open password is used for both, so anyone who can open the file can also change its permissions.

What's the difference between an open password and a permissions password?

They serve different purposes. An open password (also called a user password) is required just to view the PDF at all—without it, the document won't open. A permissions password (also called an owner password) allows the document to be viewed but restricts specific actions like printing, copying text, or editing. You can use both together: require a password to open, then have a separate password that controls whether someone can print or copy from the document.

How secure is PDF password protection?

When using AES-256 encryption with a strong password (12+ characters mixing letters, numbers, and symbols), PDF protection provides robust security suitable for most confidential documents. However, no protection is absolute—given enough time and computing power, any encryption can theoretically be broken. For highly sensitive material, consider whether PDF protection alone meets your security requirements. The encryption itself is industry-standard; the main vulnerability is weak passwords.

Can I remove the protection later if I know the password?

Yes. Use our Unlock PDF tool with your original password to remove protection and create an unrestricted copy. This is useful when you need to edit a document you previously protected or when sharing with someone who needs full access. Keep your passwords secure, as they're required for removal.

Will protected PDFs work on all devices and PDF readers?

Yes. We use standard PDF encryption that's compatible with Adobe Acrobat, Apple Preview, Chrome's built-in PDF viewer, and virtually all other PDF software. Recipients will be prompted for the password regardless of which application they use to open the file.

Protect PDF

Powerful Protect PDF Features

Password Protection

Require a password to open documents or restrict what recipients can do. Full control over document access.

AES Encryption

Industry-standard AES-128 or AES-256 encryption protects your documents with proven cryptographic security.

Granular Permission Control

Individually enable or disable printing, text copying, editing, form filling, and annotation capabilities.

How To Protect PDF Online for Free

Upload Your PDF

Drag and drop your document or browse to select it. The tool loads your PDF and prepares it for encryption.

Configure Protection

Set an open password and/or permissions password. Choose which actions to allow or restrict: printing, copying, editing, form filling.

Download Protected PDF

Click protect and download your encrypted document. It's now secured and ready to share safely.

Secure your PDF documents with password protection and encryption before sharing sensitive information. Add an open password that recipients must enter to view the document, set a permissions password to control what they can do with it (printing, copying, editing), or both. Whether you're protecting confidential contracts, financial statements, medical records, or any sensitive documents, our protection tool uses AES encryption to secure your files. The entire encryption process runs locally in your browser using WebAssembly—your sensitive documents and passwords never leave your device, making this the most private way to protect PDFs.

Everything You Need in a Protect PDF

Open Password Protection

Require a password before anyone can view the PDF. Prevents unauthorized access to document contents entirely.

Permissions Password

Control what viewers can do even if they can open the document. Separate from the open password for flexible access control.

Print Control

Allow or prevent printing. Choose between no printing, low-quality printing, or full-quality printing permissions.

Copy Protection

Restrict or allow copying text, images, and other content from the document to the clipboard.

Edit and Annotation Control

Prevent modifications to the document including form filling, commenting, and page manipulation.

Private Local Encryption

All encryption happens in your browser. Your documents and passwords never leave your device.

How it works locally

Encryption happens in your browser with PyMuPDF compiled to WebAssembly. The PDF is saved with AES-256, an open password and the permissions you choose. Your password and your document never leave your device, so noll can't recover either.

Legal & compliance toolkit

More tools for preparing confidential and legal PDFs, all running in your browser.

View Metadata
Check what a PDF reveals: properties, XMP, forms and restrictions.
Remove Metadata
Delete author, software, dates and XMP history from a PDF.
Sanitize PDF
Strip metadata, scripts, attachments, comments and form data before sharing.
Redact PDF
Permanently remove confidential text, not just cover it.
Edit Metadata
Set a clean title, author and subject on a PDF.
Flatten PDF
Turn form fields and comments into fixed page content.
Bates Numbering
Number every page for discovery, e.g. ACME000001.
Header & Footer
Put case numbers or confidentiality notices on every page.
Add Stamps
Mark pages CONFIDENTIAL, DRAFT, APPROVED or your own text.
Sign PDF
Add a visible signature to a contract or form.
Change Permissions
Allow or block printing, copying, editing and comments.
Remove Restrictions
Lift printing, copying and editing restrictions you're entitled to.
Validate Signature
Check the digital signatures in a signed PDF.

All secure PDF tools for legal work

Frequently Asked Questions

Document Work Made Easy

Process your PDFs with our collection of free, privacy-first tools. No uploads to servers, no registration required. Everything runs directly in your browser.