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PL ToolsTools for a Smarter You

Protect PDF

Add an AES-256 password or restrictions

Your files are processed locally in your browser and never uploaded to our servers.

How to use Protect PDF

  1. 1

    Add your file

    Drag & drop, tap to browse, or paste from your clipboard.

  2. 2

    Choose your options

    Adjust the settings for exactly what you need.

  3. 3

    Download the result

    Ready instantly — no watermark, no waiting in a queue.

Supported formats

Input
PDF (including one that already has a password you know)
Output
PDF encrypted with AES-256 (or AES-128), checked before download

Frequently asked questions

Is Protect PDF free?

Yes — completely free, with no signup and no watermarks. PL Tools is supported by a small number of non-intrusive ads.

Are my files uploaded anywhere?

No. Protect PDF runs entirely in your browser, so your files never leave your device and are never sent to our servers.

Is there a file size limit?

Nothing is uploaded, so there's no upload limit — but very large files depend on your device's memory. Files up to about 100 MB work well on most computers; phones may struggle with much larger ones.

How strong is the protection?

The open password encrypts the whole file with AES-256, the strongest standard PDF encryption, supported by Adobe Reader, Chrome, Edge, Firefox, macOS Preview and most phone PDF apps. The real strength is your password: a long one with a mix of words, numbers and symbols is very hard to guess.

What do the restrictions do?

They ask PDF apps to block printing, copying or editing. Most apps respect them, but some ignore them, so treat restrictions as a polite request rather than security — use an open password for anything confidential.

How do you know it worked?

After encrypting, the tool re-opens the new file: it checks that it asks for a password, opens with yours, has every page, uses the encryption you picked and shows the restrictions you chose. If any check fails, you get an error instead of a download.

I forgot the password. Can you recover it?

No. The password isn't stored anywhere — keep it somewhere safe, like a password manager.

Which formats are supported?

Input: PDF (including one that already has a password you know). Output: PDF encrypted with AES-256 (or AES-128), checked before download.

Does it work on my phone?

Yes. PL Tools works in any modern browser on iPhone, Android, tablets and desktop — there's nothing to install.