# Password Protect PDF - Encrypt a PDF Online

> Free online PDF encryption: set an open password and restrict printing, copying, editing and annotating with AES-256. Everything runs on your device.

- URL: https://qilingtools.com/en/pdf/encrypt
- Category: PDF Tools (https://qilingtools.com/en/pdf)
- Tags: [PDF](https://qilingtools.com/en/tags/pdf), [Privacy & Security](https://qilingtools.com/en/tags/privacy)
- Last updated: 2026-10-26
- Price: Free, no sign-up
- Privacy: Runs locally in the browser; files are never uploaded

Put an open password on a PDF so nobody can read it without the password. You can also set a separate permissions password that restricts printing, copying text, changing the content and adding annotations. AES-256 is used by default — the only cipher ISO 32000-2 still recommends — and AES-128 is available for older readers. Encryption happens entirely in your browser: neither the file nor the password is uploaded, which beats sending a confidential contract to someone else’s server.

## How to use

1. Upload a PDF file
2. Type the open password twice, then set a permissions password and allowed actions if you need them
3. Click Encrypt & download to get the protected PDF

## Features

- AES-256 or AES-128 encryption
- Separate open and permissions passwords
- Restrict printing, copying, editing and annotating
- Passwords never leave your browser

## FAQ

### What is the difference between the two passwords?

The open password is needed to open the file at all. The permissions password lifts the restrictions, so whoever knows it can print, copy and edit. Leave it empty and it defaults to the open password.

### Can a forgotten password be recovered?

No. Encryption happens on your machine — we never have your file or your password, and AES-256 cannot be bypassed. Keep the password somewhere safe.

### Can I encrypt a PDF that already has a password?

Remove the existing password first with our Unlock PDF tool (you will need to know it), then encrypt it again.

### Are my files or data uploaded?

No. Everything runs locally in your browser with no network upload, and is discarded when you close the page.

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