What is the difference between open and owner password?

The open password is required to view the PDF. The owner password controls permissions like printing and copying. If you only set an open password, it is used for both.

Is my PDF uploaded to a server?

No. All processing happens in your browser using pdf-lib. Your files never leave your device.

What restrictions are applied?

The protected PDF will restrict copying text/images, modifying content, and filling forms. Low-resolution printing is allowed.

Can I protect an already-protected PDF?

You would need to unlock it first using the PDF Unlock tool, then re-protect it with a new password.

What type of encryption is used?

The tool uses AES-128 encryption, which is the standard for PDF password protection.

Will my PDF content be visible to anyone else?

No. @pdfsmaller/pdf-encrypt applies encryption entirely within your browser. The password you set and the resulting encrypted PDF are never sent to any external server.

PDF Protect — Add Password to PDF Free Online

Add password protection to PDF files. Set an open password and restrict copying and editing. Free PDF protector — no upload required.

Click to upload or drag & drop

PDF files up to 50MB

100% Private

No Upload

Instant

What is PDF Protect — Add Password to PDF Free Online?

A PDF protector adds password encryption to a PDF file, preventing unauthorized access. You can set an open password (required to view the file) and restrict permissions like copying and editing. Our PDF Protect tool uses the @pdfsmaller/pdf-encrypt library running in your browser.

How to Use PDF Protect — Add Password to PDF Free Online

1Upload your PDF file.
2Enter the password you want to set.
3Optionally restrict copying and editing permissions.
4Click Protect.
5Download the password-protected PDF.

Key Features

Set open password
Restrict copying and editing
Runs in your browser
No file upload to server

Benefits

Protect confidential documents
Prevent unauthorized editing of contracts
Secure sensitive PDFs before sharing

Use Cases

Protect PDF with password PDF Password vs Encryption Remove PDF Password Add Page Numbers

Why Use Irreva for PDF Protect — Add Password to PDF Free Online?

Protect confidential documents

Prevent unauthorized editing of contracts

Secure sensitive PDFs before sharing

Runs 100% in your browser — files never leave your device.

No account, no sign-up, no subscription — free forever.

Works on any device: desktop, tablet, or mobile.

Frequently Asked Questions

PDF conversion guide

More PDF Tools

Add Page Numbers to PDF Add Signature to PDF Add Watermark to PDF Compare PDF Files Compress PDF Delete PDF Pages