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Password Protect PDF

Create a Protect PDF in your browser, free and instantly.

Drop a PDF here, or click to choose
Encrypted in your browser · never uploaded
Drop a PDF and set a password — the file is encrypted with 256-bit AES so it can only be opened by someone who knows the password. The encryption runs entirely in your browser using qpdf (WebAssembly); your PDF and password are never uploaded. Keep the password safe — it cannot be recovered.

About password-protecting PDFs

This tool adds a password to a PDF, encrypting it with 256-bit AES so it can only be opened by someone who knows the password. The encryption is done in your browser using qpdf compiled to WebAssembly, so your PDF and password are never uploaded. It is the secure way to share confidential documents.

How Protect PDF works

How to use it

  1. Drop or choose a PDF.
  2. Enter a password and confirm it.
  3. Click Protect & download to save the encrypted PDF.

How it works

The tool runs qpdf in your browser to encrypt the file with AES-256. The password becomes the key: anyone opening the PDF in a reader will be asked for it, and the content stays unreadable without it. Because everything happens locally, neither the file nor the password leaves your device.

Important

Keep the password somewhere safe — there is no way to recover or reset it, and a strong password cannot be bypassed. To password-protect a file that is already encrypted, remove the existing password first.

Common uses

  • Password-protect a PDF
  • Encrypt a confidential document
  • Secure a PDF before emailing it
  • Lock a contract or statement
  • Protect personal records
  • Add AES-256 encryption to a PDF
  • Restrict who can open a file
  • Share a document securely

Frequently asked questions

How do I password protect a PDF?
Drop the PDF, set a password and download the encrypted file.
What encryption is used?
256-bit AES, the strong standard supported by modern PDF readers.
Is my PDF uploaded?
No — encryption runs in your browser with qpdf WebAssembly.
Can the password be recovered?
No — if you lose it, the PDF cannot be opened, so store it safely.
Will it open in any reader?
Yes — standard readers will prompt for the password to open it.
Can I protect an already-encrypted PDF?
Remove the existing password first, then protect it again.
Does it change the content?
No — it only encrypts the file; the pages are unchanged.
Is it free?
Yes — completely free with no sign-up.