Protect PDF
Encrypt your PDF with a password. Control who can open and edit your document.
Drag your PDF here or click to choose
Single file, up to 100MB
When to Use This Tool
Add password protection to your PDF documents. Encrypt files so only people with the password can open them. Processing runs entirely in your browser.
PDF encryption is essential when sharing confidential documents via email or cloud storage. Legal agreements, financial statements, medical records, and personal identification documents all benefit from password protection. Without the password, the file cannot be opened, copied, or printed.
The tool uses AES-256 encryption, which is the same standard used by banks and government agencies. You set a password, and the tool applies it to the PDF. The original file is not modified — a new encrypted copy is created.
Use cases include protecting client documents before emailing them, securing tax returns and financial records stored in the cloud, adding passwords to HR documents containing personal data, and encrypting business proposals shared with external partners.
How to Protect PDF
- Upload your PDF file (drag & drop)
- Enter a password to open the PDF
- Optionally set an owner password for permissions control
- Click Protect PDF and download your encrypted file
Features
- RC4 128-bit encryption for strong security
- Separate user and owner passwords
- Owner password controls printing, editing permissions
- 100% browser-based processing (no uploads to servers)
- Your password never leaves your device
Things to Know
Choose a strong password (8+ characters, mixed case, numbers). Lost passwords cannot be recovered — there is no backdoor. Some older PDF readers may not support AES-256 encryption. The file size increases slightly due to encryption overhead. You cannot password-protect a file that is already encrypted — unlock it first.
Frequently Asked Questions
What encryption does this use?
The tool applies RC4 128-bit encryption, which is widely supported by PDF readers including Adobe Acrobat, Preview, and Chrome's built-in viewer.
Can I set permissions (print, edit, copy)?
Yes. You can set an owner password that controls whether recipients can print, edit, or copy content from the PDF.
What if I forget the password?
There is no password recovery mechanism. Make sure to store your password somewhere safe. We cannot recover it because all processing happens locally in your browser.
Is my password sent to any server?
No. The password and encryption process happen entirely in your browser. Your password never leaves your device.
Built for locking sensitive documents, controlling access to contracts, and securing confidential files. Continue with Merge PDF or Watermark PDF.
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