Protect & Unlock PDF

Add AES-256 password protection, set permissions, and encrypt your PDFs — or remove passwords and unlock restrictions.

🔐

Drop your PDF here

Drag & drop, or select from your device or cloud

Add from:
📄
document.pdf

Password Protection

Required

Encryption Level

Required
Recommended
AES-256
PDF 1.7+
Strongest
AES-128
PDF 1.4+
Compatible
RC4-128
PDF 1.3+
Legacy

Permission Controls

Optional

Security Options

Optional

Output Options

Optional
Leave blank to auto-name

🛡 Protection Summary

Live preview of your security settings

EncryptionAES-256
Open passwordNot set
Owner passwordNot set
Strength
PDF version1.7
Files1 PDF
Permissions
Protecting PDF…
Applying AES-256 encryption
0%
Uploading file…

Protect PDF — free online Secure PDF tool

Protect PDF is a free online tool from HuntPDF. Add password protection and AES-256 encryption to your PDF. Control printing, copying, editing permissions. Free, secure, browser-based. You work straight from your browser — there is nothing to install, no account to create and no watermark on the result. Upload a file up to 250MB, the processing happens on our secure servers, and your document is deleted automatically once you have your result.

How to Protect PDF

  1. Upload your PDF

    Drop in the PDF you want to secure. Files are sent over an encrypted connection.

  2. Set your protection

    Choose the password, permissions or content you want handled, then confirm.

  3. Download the secured PDF

    Save the protected file. Your upload is wiped from the server automatically.

Why use HuntPDF?

Completely free

No signup, no watermark and no daily cap. Use it as often as you need.

Private by default

Files travel over an encrypted connection and are deleted the moment your download finishes.

Works everywhere

Runs in any modern browser on Windows, macOS, Linux, Android and iOS.

Fast and accurate

Most files are processed in a few seconds on our servers, not your laptop.

Frequently asked questions

What is Protect PDF and how does it work?

Protect PDF adds a password to a PDF so it can't be opened without it. You can also restrict printing, copying and editing, so the document can be read but not reused.

How do I use Protect PDF online?

Upload your file using the box above — drag it in, browse for it, or bring it in from your cloud storage. A preview appears so you can check you've picked the right file. Run Protect PDF, then download the result. You can rename it before you save it.

Is my file secure when I use Protect PDF?

Yes. The file you send to Protect PDF travels over an encrypted HTTPS connection and is processed automatically on our servers. It is never made public, never shared with anyone, and nobody reads it.

Does HuntPDF store my files after Protect PDF has run?

No. Your upload is deleted the moment Protect PDF finishes with it, and the file it produces is removed as soon as you have downloaded it, or when you upload another file, or when you close the page. Nothing is kept, and nothing is used to train anything.

Will the original quality and formatting be maintained?

Yes. Adding a password doesn't alter a single page — the content is identical, it's just locked.

Can I use Protect PDF on mobile?

Yes. Protect PDF runs entirely in your browser, so it works on any modern phone or tablet — iPhone, iPad or Android — with nothing to install. You can upload straight from your device or from your cloud storage.

Can I rename my file before downloading it from Protect PDF?

Yes. The file Protect PDF gives you back keeps the name of the file you uploaded by default. If you'd rather call it something else, edit the name in the field next to the download button before you save it.

Do I need to install any software to use Protect PDF?

No. There is nothing to download, install or sign up for — Protect PDF runs in your browser and does the work on our servers, so it behaves the same on Windows, macOS, Linux, Android and iOS.

How long does Protect PDF take?

Most files are finished in a few seconds. A large or page-heavy file takes a little longer, because Protect PDF runs on our servers rather than on your device — but you won't be waiting around. You can upload files up to 250MB.

Is Protect PDF free to use?

Yes. Protect PDF is free, with no signup, no watermark on the result and no daily limit for normal use.