Protect PDF
Add password protection to PDF files online for free. Encrypt PDF documents with AES-256 encryption to prevent unauthorized access. 100% browser-based, no upload required.
How do I add a password to a PDF?
Upload your PDF file, enter your desired password in the password field, and click the protect button. The tool encrypts your PDF with AES-256 encryption instantly in your browser.
Is this PDF password tool free to use?
Yes, this PDF protection tool is completely free. There are no file size limits, no watermarks, and no registration required.
Is my PDF data safe with this tool?
Absolutely. All processing happens locally in your browser using the MuPDF engine. Your PDF files and passwords never leave your device — no server uploads involved.
What encryption standard is used?
The tool uses AES-256 encryption, the same standard used by governments and security agencies worldwide. It is compatible with all major PDF readers including Adobe Acrobat.
Can I remove the password from a protected PDF?
Yes, you can use our PDF unlock tool to remove the password. You will need the original password to unlock the file.
Does the protected PDF work on all devices?
Yes. The encrypted PDF follows the standard PDF specification and can be opened on any device with a PDF reader that supports password-protected files.
Can I set different permissions for the PDF?
The tool applies open-password protection, which means the PDF requires a password to open. This prevents unauthorized viewing, printing, and copying.
What happens if I forget my PDF password?
Unfortunately, there is no way to recover a forgotten PDF password. The AES-256 encryption is designed to be unbreakable without the correct password. Please store your password safely.
Can I protect multiple PDF files at once?
You can protect one PDF at a time. Simply repeat the process for each file you want to secure.
Does this tool work offline?
Yes. Once the page loads, all encryption is performed locally in your browser. No internet connection is needed during the protection process.
How to Use Protect PDF
Encrypt a PDF with a password using AES-256 so only people who know it can open the file. Encryption runs in your browser and the document is never uploaded.
- Drop your file onto the “Click or drag PDF files here” area.
- Type your password in the Password field — it is the only lock on the document, so make it strong.
- Repeat the identical password in Confirm Password; encryption only proceeds when the two match.
- Press Protect PDFs and wait while the encryption engine runs locally on the file.
- Save the encrypted copy with Download and test it by opening with the password.
There is no password recovery: keep it in a password manager, because an AES-256 PDF whose password is lost stays unreadable for good.
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