AES-256 encryption
Your PDF is locked with AES-256 password encryption, so it asks for the password when opened.
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Protect PDF
Lock a PDF with a password (AES-256 encryption) before you send it out.
🔒 Enterprise privacy — 100% client-side, no server uploads
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Drop a PDF here, or click to browse
🔒 Processed on your device — never uploaded, never stored.
What is Protect PDF?
Protect PDF is a free online tool that lets you lock a PDF with a password (AES-256 encryption) before you send it out. Add your PDF, choose your options and download the result. Your files stay on your device and are never uploaded.
Also searched as: password protect a PDF, encrypt a PDF, lock a PDF, add a password to a PDF.
Protect PDF at a glance
- Price
- Free, with no paid plans
- Account
- No signup or login needed
- Where it runs
- In your web browser
- Your data
- Files are not uploaded to a server
- Works on
- Any modern browser, on desktop and mobile
- Category
- Document & PDF Suite
When to use Protect PDF
- →Protect a contract or payslip before emailing it
- →Lock a private document kept on a shared drive
- →Share a file only with people who know the password
How to use Protect PDF
- 1
Open the Protect PDF page and drop your PDF into the upload box, or click it to browse your device.
- 2
Adjust any options this tool needs — page numbers, rotation angle, or watermark text, depending on the tool.
- 3
Click the process button and watch the on-screen progress as your file is handled entirely in your browser.
- 4
Download the finished PDF straight to your device — nothing is kept on a server afterward.
Why use Protect PDF
- ✓Runs entirely in your browser — your file is never uploaded to a server.
- ✓No account, signup, or email address required to use it.
- ✓Completely free, with no daily limit and no signup.
- ✓Works the same on Windows, Mac, Linux, and Chromebooks — anything with a modern browser.
Protect PDF
Lock a PDF with a password
Add a password to a PDF before you send it. It is protected with AES-256 encryption and processed on your own device.
Type it twice
You enter the password two times, and the tool warns you if they do not match, so a typo does not lock you out.
A new, protected copy
You download a new protected PDF and your original file is not changed.
Private by design
The password and the file never leave your browser.
Any device
Protect a document from your phone before you email it.
Free, no signup
No account and no limit.
Everything you need in Protect PDF
- AES-256 password encryption
- Password entered twice to avoid typos
- Creates a new protected copy
- Your original stays unchanged
- Runs in your browser
- Works on phone and computer
- No account needed
- Free to use
Tips for better results
- 1
Use a strong password
Make one with the Password Generator, and save it in a password manager.
- 2
Send the password separately
Share the password by a different route than the file, for example by message, not in the same email.
- 3
Keep the original and the password
Toolkitties never receives your password, so it cannot recover it. If you lose it, the protected file cannot be opened.
0files uploaded
0signups needed
0cost to use
Tutorials on Protect PDF
Short, practical guides that go with this tool.
🔒 Your privacy with Protect PDF
Protect PDF runs as client-side JavaScript inside your own browser tab. Your file or text is read, processed, and turned into a result on your device — it is never sent to, stored on, or seen by Toolkitties' servers. Closing or refreshing the page clears everything.
Frequently asked questions
What kind of encryption does Protect PDF use?
It locks the PDF with AES-256 password encryption.
Can I recover a password I forgot?
No. Toolkitties never sees your password or your file, so there is nothing to recover. Keep the password somewhere safe.
Will the protected PDF open in normal PDF readers?
Most modern PDF readers can open password-protected PDFs and will ask for the password.
Is my password or file uploaded?
No. The protection is applied in your browser.
Can I remove the password later?
Yes, if you know the password. Use the Unlock PDF tool, which saves a copy without a password.
Is my original file changed?
No. You download a new protected file and your original stays as it was.
Is Protect PDF free to use?
Yes. Protect PDF is 100% free, with no signup, no daily limit and no paid plans.
Do I need to create an account to use Protect PDF?
No signup or login is required. Open the page and start using Protect PDF immediately.
Is it safe to use Protect PDF with private or sensitive files?
Yes. Protect PDF processes your file locally in your browser using client-side code. The file itself is never uploaded to Toolkitties' servers.
Will Protect PDF work on a large PDF?
Most PDFs process in a few seconds. Very large files (100+ MB) depend on your device's memory, since everything happens in your browser rather than on a remote server.