Password Protect PDF
Password protect a PDF for free. Add a password with 128-bit encryption in your browser so it can't be opened without it — your file is never uploaded.
Select a PDF file
or drop PDF here
Select PDF fileAbout PDF Password Protector
Our PDF Password Protector allows you to secure sensitive documents with RC4 128-bit encryption directly in your web browser. This ensures maximum privacy, as your files are never uploaded to any remote server.
Features
- Real RC4 128-bit encryption
- Prevents unauthorized viewing
- 100% local, client-side processing
- No file uploads required
- Fast, instant downloads
How to Use
- Select or drag-and-drop the PDF you want to protect
- Type a strong password in the sidebar input
- Click "Lock PDF" to apply the encryption
- Download the protected PDF document
Frequently Asked Questions
Can you recover my password if I forget it?
No. Because the encryption happens entirely in your browser and we never see or store your files or passwords, it is impossible for us to recover your password. Please keep it safe.
Are my files uploaded for encryption?
Never. Our PDF Password Protector uses JavaScript to encrypt your document directly within your device's memory. Your sensitive files remain 100% private.
Does this tool work offline?
Yes! Because the tool processes files entirely within your web browser using client-side technologies, it will continue to work even if you lose your internet connection after loading the page.
What encryption standard does this tool use?
We use the PDF Standard Security Handler with 128-bit RC4 encryption (PDF 1.4). It opens in every standard PDF reader, such as Adobe Acrobat, Chrome and Preview, and stops casual access. For highly sensitive documents, use a tool that supports AES-256.
Is there a file size limit for protecting PDFs?
Since all processing happens locally on your device, the file size limit depends entirely on your system's available memory (RAM). Most modern computers and smartphones can easily handle PDFs up to 50MB or more.