PDF Tool
Protect PDF
Add password protection to your PDF
Drop a PDF here or browse
One PDF · 10 MB max · PDF only
How to Protect PDF
1
Upload
Select or drag and drop your PDF file(s) into the upload area above.
2
Process
Click the process button. Our server handles your file instantly and securely.
3
Download
Download your processed file. Files are available for 1 hour before auto-deletion.
Why Use PaperFlow Protect PDF
✓
Completely Free
No subscription, no hidden fees. Use the tool as many times as you need.
✓
No Registration Required
Start using the tool immediately without creating an account.
✓
Bank-Level Security
All files are encrypted in transit and deleted automatically after processing.
✓
High Quality Output
Our algorithms maintain original document quality and formatting.
Frequently Asked Questions
How does Protect PDF work?
Upload a PDF, set a password, and we encrypt the file with strong AES-256 encryption. Anyone opening the protected PDF will be prompted for the password.
What encryption is used?
AES-256 — the same industry-standard encryption trusted for sensitive documents. Without the correct password, the PDF contents cannot be read.
Do you store or see my password?
No. Your password is used only to encrypt the file during processing and is never stored or logged. If you lose it, the PDF cannot be recovered — so keep it safe.
Can I protect an already password-protected PDF?
No. Remove the existing password first (using an Unlock PDF tool with the current password), then apply a new one.
Is my file secure?
Yes. Files are processed on secure servers over an encrypted connection and automatically deleted within 1 hour. We never store or share your documents.
Is it free?
Yes, with daily limits. Free/guest outputs include a watermark; upgrade to Pro for clean, watermark-free protected PDFs and higher limits.