🔒 Protect PDF – Add Password Encryption
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📘 Protect PDF: Complete Guide & Best Practices
Our free PDF password protector adds strong encryption to your PDF files. Protect sensitive documents, financial reports, or personal information with a user password. The tool uses 128-bit AES encryption (standard PDF encryption) and works entirely offline – your files and password never leave your computer.
✨ How It Works
Upload your PDF, enter a password (and confirm it). The tool uses pdf-lib to load the PDF and then re-save it with AES-128 encryption using the provided password. The encrypted PDF is downloaded to your device. Only those with the correct password will be able to open and view the document. No server interaction, no data leaks.
🚀 Key Features
✅ Add user/open password to any PDF.
✅ 128-bit AES encryption (industry standard).
✅ Password confirmation to avoid typos.
✅ Preview the original PDF before encryption.
✅ 100% client-side – zero upload, private.
✅ No watermarks, no registration.
✅ Fast and unlimited usage.
⚠️ Important: Lost passwords cannot be recovered. Store your password safely. This tool encrypts the entire PDF – once protected, anyone without the password cannot open the file.
❓ Frequently Asked Questions
It uses 128-bit AES encryption (PDF 2.0 standard) with the user password. This is the same level used by Adobe Acrobat.
This tool sets the user password (required to open the document). Owner permissions remain unrestricted (printing/copying) because the main goal is access control.
Yes. The original file remains unchanged on your device. The tool creates a new encrypted copy for download.
Yes, using our "Unlock PDF" tool (separate page) with the correct password.
Password recovery is not possible. Keep your password in a secure place. There is no backdoor.
Yes, up to your device's memory. For very large files (100+ MB), processing may take a few seconds.