Free PDF tool
Password Protect a PDF Online
Encrypt a PDF with a password before sharing it. The tool uses AES-256 protection and runs in your browser.
Use Protect PDF free →No signup required · Everyday files are processed in your browserSimple and focused
Protect PDF without installing software
Add a password to sensitive reports, statements, forms, and attachments. Keep the password somewhere safe because recipients will need it to open the file.
Create a password-encrypted copy when recipients must know a password to open the document. This differs from adding a Confidential watermark, which only changes appearance.
Before you start
Choose a strong unique password and store it securely. The interface requires at least four characters, but that minimum is not a recommendation for a secure password. Decide how to share it separately from the PDF.
How it works
Finish in three steps
Choose one PDF file.
Enter and securely record a new password.
Protect the PDF and download the encrypted copy.
Built for everyday PDFs
What this tool gives you
- ✓AES-256 PDF encryption
- ✓Creates a separately protected copy
- ✓No account needed
Practical example
Share a protected report
- Enter the password and download the encrypted output.
- Close it and reopen the downloaded file in a PDF reader to test the password prompt.
- Send the file and the password through separate agreed channels.
The new PDF uses AES-256 encryption and requires its user password. Your original unencrypted file remains on your device.
Capabilities and limits
- FreePDFchanger cannot recover a forgotten password for you.
- Encryption does not prevent an authorized recipient from copying or redistributing information they can view, and it does not establish the author's identity.
When the result is unexpected
The recipient cannot open it
Check that they received the encrypted output and the exact password, then test a current compatible PDF reader.
I can still open my original without a password
Protection creates a separate download. It does not replace, delete, or encrypt the source file on your device.
Check the downloaded file
Test that the output asks for a password after closing the reader. Keep the password securely and review whether unencrypted originals or editor drafts remain on a shared device.
Questions
Protect PDF FAQ
What encryption does the tool use?
The Protect PDF tool uses AES-256 encryption.
Can FreePDFchanger recover a forgotten password?
No. Store the password safely; it is required to open the protected document.
Ready to work on your PDF?
Open Protect PDF, choose your file, and download the result.
Open Protect PDF →