Password Protect PDF Free Online
Encrypt your PDF with strong AES passwords to prevent unauthorized viewing or editing.
How to Protect PDF
Upload Your PDF
Select the PDF document you want to protect with password encryption.
Set Password & Permissions
Choose a strong password and configure which actions (printing, copying, editing) to allow.
Download Protected PDF
Download your encrypted PDF that requires a password to open or modify.
Encrypt and protect PDFs with a strong password
Secure your sensitive files. Add user and owner passwords to your PDF and define custom permission flags (disallow printing, copying, or editing) to prevent unauthorized access.
Encryption is computed locally using client-side libraries. Your secure passwords are never transmitted over the internet.
Frequently Asked Questions
How secure is Protect PDF?
Protect PDF uses industry-standard algorithms processed entirely within your browser. No passwords, encryption keys, or file data are transmitted over the internet, making it as secure as offline desktop software.
Is it safe to use Protect PDF with confidential documents?
Absolutely. Protect PDF processes everything locally inside your web browser using JavaScript and WebAssembly. Your files are never uploaded to any external server. Sensitive documents, contracts, and personal files remain completely private on your device.
Is Protect PDF really free? Are there hidden limits?
Yes, Protect PDF is 100% free with no hidden costs. There are no file size limits, no daily usage caps, no watermarks on your output, and no account registration required. Use it as many times as you need.
What encryption standard is used?
PDFtoPixel uses AES-256 encryption, the same standard used by banks and government agencies, to secure your PDF with a strong password.