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Free PDF Password Protect

Add real password encryption to a PDF file, right in your browser. Set a user password (and optional owner password), then download the protected file.

✅ Free🔐 Real Encryption⚡ Instant

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Drop a PDF here or click to browse

Max 20MB

Frequently Asked Questions

What encryption does this tool use?

This tool uses RC4 128-bit encryption, a standard PDF security method supported by virtually all PDF readers, applied entirely in your browser.

Can I set a separate owner password?

Yes. You can optionally set a separate owner password in addition to the user password required to open the document.

Will my PDF be uploaded to a server?

No, encryption happens entirely in your browser using JavaScript. Your PDF and password are never sent to any server.

What if I forget the password?

There is no recovery option — keep your password saved somewhere safe, since a forgotten password will make the PDF permanently inaccessible.

Password Protect a PDF Online — Free and Private

This tool encrypts a PDF file with a real password, using RC4 128-bit encryption applied entirely in your browser via open-source encryption libraries. Once protected, the PDF will require the password to open in any standard PDF reader — Adobe Acrobat, browser PDF viewers, and most other software.

User Password vs. Owner Password

PDF encryption supports two distinct password roles. The user password is required simply to open and view the document — without it, the PDF cannot be read at all. The owner password is a separate, optional password that governs permissions like printing, copying, or editing; a PDF reader that already has the user password can typically open the document regardless of the owner password. If you leave the owner password blank, this tool uses the user password for both roles, which is the most common setup for simple "keep this document private" use cases.

When to Password Protect a PDF

Keep in mind that PDF password protection, while a real and useful security layer, is not unbreakable — it protects against casual, unauthorized access rather than determined, resourced attackers. For highly sensitive data, additional security measures beyond PDF password protection are recommended.

How This Tool Works

This tool uses an open-source RC4 128-bit PDF encryption library running entirely in your browser via JavaScript. When you provide a password, the tool encrypts the PDF's content streams according to the standard PDF encryption specification, producing a new file that any compliant PDF reader will recognize as password-protected and prompt for the password before opening.

Privacy and Local Processing

Your PDF file and the password you set are processed entirely in your browser — nothing is uploaded to, or stored on, any server. This is especially important for a password-protection tool, since sending an unprotected document (or its password) to a third-party server would defeat the purpose of protecting it in the first place.

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