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Free Protect PDF
Password-protect PDF files with AES-256.
Encrypt a PDF so viewers need a password to open it. Uses AES-256 encryption and keeps processing on your device.
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How to use Protect PDF
- Upload a PDF.
- Choose and confirm a password.
- Download the protected PDF.
Features
- AES-256 encryption
- Open password
- Browser-based
Why use this tool
- Require a password before anyone can open a sensitive PDF.
- Use modern AES-256 encryption instead of weak legacy protection.
- Encrypt locally so the unprotected file never leaves your device.
Common use cases
- Secure HR or payroll PDFs before emailing
- Protect client contracts shared over chat
- Lock personal scanned documents on shared drives
What is Protect PDF?
Protect PDF is a free online tool on Free Quick Tools. Password-protect PDF files with AES-256. Processing stays in your browser whenever this tool runs locally.
Privacy
Your files never leave your device. All processing happens in your browser.
Frequently Asked Questions
What encryption is used?
AES-256 (PDF 2.0 standard security handler). Modern Acrobat, Preview, and browsers can open the file with the password.
Do you store my password?
No. Encryption runs in your browser. We never see your password or PDF.
Can I unlock it later?
Yes — use Unlock PDF with the same password when you need an unprotected copy.
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