🔒 Protect PDF Add password encryption

Add a password to your PDF to prevent unauthorized access. Encryption uses AES‑128.
or drag & drop a PDF file here
How to Protect PDF – Add Password – Free & Private Guide

Our PDF Protector adds a user password to your PDFs, encrypting them with AES‑128. Only people who know the password can open the document. All processing happens locally – your file never leaves your device.

🔒 100% Local

No upload – your PDF and password stay private.

⚡ Strong Encryption

Uses AES‑128 encryption (PDF 2.0 standard).

📄 Preserves Content

Images, text, formatting remain unchanged.

⚠️ Important: Choose a strong password and store it safely. If you lose the password, the file cannot be opened. There is no password recovery.

📌 How to use this tool

  1. Upload your PDF – Click “Select PDF” or drag & drop.
  2. Set a password – Enter and confirm a strong password.
  3. Click “Encrypt & Download” – The tool encrypts the PDF.
  4. Download the protected PDF – Now password‑protected.

❓ Frequently Asked Questions

🔹 Is my PDF uploaded to a server?
No. Encryption happens entirely in your browser using PDF-Lib. Your file and password remain private.
🔹 What encryption is used?
AES‑128 (with revision 6), the standard PDF 2.0 encryption. It provides strong protection against unauthorized access.
🔹 Can I add both user and owner passwords?
This tool sets a user password (required to open the PDF). Owner permissions (printing, copying) are set to full by default.
🔹 Is there a file size limit?
PDFs up to 100 MB work reliably. Very large files may take longer due to encryption processing.
🔹 What if I lose the password?
The PDF cannot be opened without the password – there is no backdoor. Store your password securely.
🔹 Is this tool free?
Yes, completely free for personal and commercial use, no watermarks or registration.
⚡ Powered by PDF-Lib • Client‑side encryption • No tracking • Works offline after first load