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PDF Shield

Lock · Unlock · Watermark · Restrict Permissions
100% free — no upload, works in browser

Select a PDF File

Your file stays on your device — nothing is uploaded

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Choose a tool
🔒 Lock PDF
Allow Printing
Allow Copying
Allow Modifying
Allow Annotating
🔓 Unlock PDF
💧 Add Watermark
CONFIDENTIAL
🚫 Set Permissions

Turn off to restrict that action in the PDF

Printing
Copying
Modifying
Commenting
Form Filling
✅
Done!
Your PDF is ready

About PDF Shield

PDF Shield is a free, browser-based tool to fully secure your PDF files. Lock PDFs with strong passwords, remove existing protection, add visible text watermarks, or restrict printing and copying — all without uploading your files to any server.

Everything happens inside your browser. Your files never leave your device. No registration, no limits, no data collection — 100% private and free.

Password Lock

Remove Password

Text Watermark

Permissions Control

How to Use PDF Shield

1
Upload your PDF — tap "Choose PDF File" and select any PDF from your device.
2
Choose a tool — Lock, Unlock, Watermark, or Permissions.
3
Configure settings — set your password, watermark text, or permission toggles.
4
Download — your processed PDF downloads instantly to your device.

Frequently Asked Questions

Is PDF Shield really free?
Yes, 100% free. No subscription, no sign-up, no hidden charges. All features are available without any payment.
Are my PDF files uploaded to a server?
No. All processing happens inside your browser using JavaScript. Your PDF never leaves your device — it is completely private.
What happens if I forget the PDF password?
If you forget the password, you will not be able to unlock the PDF. Always save your password in a secure place. PDF encryption is designed to be irreversible without the correct password.
Does locking a PDF really protect it?
Yes. PDF Shield uses 128-bit RC4 encryption (PDF standard). The locked PDF cannot be opened without the correct password in any standard PDF reader like Adobe Acrobat, Chrome, or Android PDF viewers.
Can I remove a password from any PDF?
You can remove the password only if you know the correct password. PDF Shield cannot bypass encryption — you must enter the correct password to unlock it.
What is a watermark and why add one?
A watermark is a semi-transparent text (like "CONFIDENTIAL" or your name) added to every page. It helps identify the document owner and discourages unauthorized sharing or copying.
What do the PDF permissions do?
Permissions let you control what others can do with your PDF — you can prevent printing, copying text, modifying content, or adding comments. The PDF opens normally but those actions are restricted.
What file size limit is there?
PDF Shield supports files up to 50MB. For very large PDFs, processing may take a few seconds depending on your device speed.