Password Protect PDF

Secure PDF files with password protection and encryption online. Protect sensitive documents instantly without registration.

Add password protection and AES-256 encryption to PDF files online for free. Set an owner password, restrict printing, copying, and editing, and choose your encryption strength - all processing runs in your browser, nothing is uploaded to any server.

Upload your PDF to get started — no sign-up required.

How to Password Protect a PDF Online

  1. Upload the PDF you want to secure - drag and drop or click Choose PDF File.
  2. Set an owner password and optionally a user (open) password in the sidebar.
  3. Configure permission controls to allow or restrict printing, copying, annotations, and editing.
  4. Click Protect PDF to encrypt locally in your browser, then download the secured document.

Why Use PDFCrush?

  • AES-256 or RC4-128 encryption - processed entirely in your browser without any server upload
  • Fine-grained permission controls: independently restrict printing, copying, annotations, and editing
  • Protected PDFs open in any standard viewer - Adobe Acrobat, Preview, Chrome, and Edge
  • Ideal for contracts, confidential reports, HR documents, financial records, and legal files

Your Privacy & Security

Encryption runs entirely in your browser using @pdfsmaller/pdf-encrypt. Your PDF and password are never transmitted to any server. When you close the tab, all data is gone.

Frequently Asked Questions

What encryption standards are used to lock my sensitive files?

Our security framework applies industry standard 128 ext{-bit AES} encryption protocols directly to the output binary stream, restricting permissions for viewing, printing, or copying text elements globally.

Will adding a password modify the underlying document formatting?

No. Password protection secures the file container by encrypting its internal dictionary structure, leaving your layout, vector artwork, and embedded text layers completely unchanged.

Can I restrict text copying and printing while allowing users to view the document?

Yes. You can configure custom user permission flags to prevent unauthorized text extraction and printing, while leaving the document accessible for viewing without a password.

Is my new password transmitted or logged on an external database?

No. The encryption process runs locally inside your browser session using WebAssembly scripts. Your password never leaves your device and is never stored on an external server.

Can I clear or change encryption rules if I know the master key?

Yes. If you have the current owner password, you can load the file, decrypt the stream, and apply completely new permission settings.

Will the encryption work across all standard external PDF reading apps?

Yes. The encryption uses standard PDF specification protocols, ensuring it is recognized correctly across apps like Adobe Reader, Apple Preview, and browsers.

What is the primary difference between a User Password and an Owner Password?

A User Password restricts access to opening and viewing the file, while an Owner Password secures permissions like printing and editing.

Can PDFCrush help me recover a password if I forget it?

No. Because our toolkit is serverless and never uploads or stores your passwords, we cannot recover or trace forgotten keys.