🔐 PDF Protector

Protect PDF

Add password encryption to your PDF. Set open password and restrict printing/copying.

Last Updated: August 2026Written by Ayaz Dilawar

Drop your PDF here

or click to browse

Choose File

⚠️ Remember your password! There is no way to recover a lost password from an encrypted PDF. Store it in a safe place.

Protect PDF

Add password protection to PDF online for free. Encrypt your PDF with a user password and owner password. Stays 100% on your device, fully private.

Stays in your browser

Processing runs on your own device. Your files are not uploaded to a server, so private documents stay private.

Adds a password so the PDF cannot be opened without it, and lets you switch off printing, copying and editing in readers that respect those permissions. PDFly uses the standard PDF security handler (RC4, 40-bit), which almost every reader supports, including older ones. That is enough to keep a file from casual readers, but it is not a substitute for modern AES encryption on highly sensitive documents.

How to password protect a PDF

  1. 1Drop your PDF into the tool above, or click to browse your device.
  2. 2Enter a password and confirm it. Choose your permissions — allow printing, copying, or modifying.
  3. 3Click "Protect PDF" and download your encrypted document. Everything runs in your browser — nothing is uploaded.

How PDFly protects your PDF

PDFly uses the pdf-lib library to apply standard PDF password encryption to your PDF. Here's how it works:

  • Standard PDF encryption: Your PDF is encrypted using the PDF Standard Security Handler (RC4, 40-bit), the same encryption format built into the PDF specification since version 1.1 and supported by virtually every PDF reader, including older ones.
  • User password: The password you set is required to open the document. Without it, the file is unreadable.
  • Owner password: An additional owner password is generated automatically to manage permissions like printing, copying, and editing.
  • Permission controls: You can restrict printing (low or high quality), copying text, and modifying the document.

The encryption happens entirely in your browser — your password and file data never leave your device.

Understanding permissions

  • Allow printing: When checked, users can print the document. If unchecked, most PDF readers will disable the print function.
  • Allow copying text: When unchecked, text selection and copying are disabled in compatible PDF readers.
  • Allow modifying: When unchecked, most PDF readers restrict editing, adding annotations, or filling forms.

Important: Permission restrictions depend on the PDF reader being used. Some readers may not enforce all permissions, so treat them as a helpful deterrent rather than absolute protection.

Choosing a strong password

  • Length matters: Use at least 12 characters. Longer passwords are harder to crack.
  • Mix character types: Combine uppercase and lowercase letters, numbers, and symbols (e.g., MyS3cur3P@ssw0rd!).
  • Avoid common words: Don't use "password," "123456," or easily guessable phrases.
  • Use a password manager: Consider using a password manager to generate and store strong, unique passwords.

Troubleshooting

  • The protected PDF won't open: Double-check that you're entering the correct password. Passwords are case-sensitive.
  • Permissions aren't being enforced: Some PDF readers (especially older ones) may not respect permission settings. Try opening in a modern reader like Adobe Acrobat or Chrome.
  • I forgot my password: PDFly cannot recover lost passwords. If you need the content, you'll need to find the original unprotected file.
  • The file is very large after protection: Encryption adds minimal overhead — any size increase is usually negligible.

Frequently asked questions

It encrypts your PDF and requires a password before the document can be opened in compatible PDF readers. The content is scrambled using the standard PDF encryption format (RC4, 40-bit).
No. PDFly's PDF Protector runs entirely in your browser using the pdf-lib library. Your file is read, encrypted, and made available for download without ever being sent anywhere. Your password and data are never sent anywhere — everything happens locally in your browser.
Yes. If you know the current password, you can use a PDF unlock tool like Unlock PDF to remove protection from the document.
Depending on the permissions you set and the PDF reader being used, editing, printing, or copying may be restricted. Most modern PDF readers respect these settings, but some older or basic readers may not enforce them.
The password cannot be recovered by PDFly. Be sure to save it somewhere secure before sharing the protected PDF. There is no backdoor or recovery mechanism in the encryption standard.
No. Your original document remains untouched. PDFly creates a separate password-protected copy and leaves your original file unchanged.
Yes. The tool works in modern mobile browsers on Android, iPhone, and tablets without requiring an app. Just visit the page and upload your PDF.

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