Protect PDF

Password-protect a PDF without uploading it.

Add 256-bit AES encryption to any PDF right in your browser. Your file and your password never leave your device, because there's no server for them to be uploaded to, retained on, or breached.

Protect a PDF free How it works

Don't upload the file you're trying to secure.

The whole point of a password is to keep a sensitive document out of the wrong hands. Most online tools make you hand over the unprotected version first.

The difference in one sentence

To protect a sensitive file, you shouldn't have to send the unprotected version to a stranger's server first.

Most "protect PDF online" tools upload your unencrypted document, add the password on their servers, and stream it back. For the window in between, the very file you're trying to secure is sitting on someone else's infrastructure. KeptPDF does the encryption in your browser, so the unprotected file is never uploaded anywhere. You can verify it yourself in the network tab.

How to password-protect a PDF

Three steps, entirely on your device. No account needed, nothing uploaded, and no watermark.

1. Open your PDF

Drop your file onto the page or pick it from your device. It loads straight into your browser, and nothing is sent anywhere.

2. Set a password

Choose the password people will need to open the file. KeptPDF encrypts it with 256-bit AES, the same standard banks and governments rely on.

3. Download the protected PDF

Save the encrypted copy. From now on it can't be opened without the password, on any device, in any PDF reader.

Real encryption, nothing uploaded.

256-bit AES

The PDF is encrypted with AES-256: strong, modern, standards-based encryption that any compliant reader will honor.

Never uploaded

There is no upload endpoint. The file is processed in your browser, so there's nothing on a server to leak, subpoena, or retain.

Free, no account

Protect PDFs free, no sign-up, no daily limit. Pro supports larger files (hundreds of MB practical limit if you need it, browser memory dependent), with the same on-device privacy either way.

Lossless quality

The PDF is rewritten, not flattened to images. Text stays selectable, vectors stay crisp, and the file size barely moves.

Working with protected PDFs

Two sides of the same job, and both run entirely on your device.

Remove a password Redact sensitive text

Questions, answered.

How do I password-protect a PDF for free?

Open KeptPDF's Protect tool, drop in your PDF, type the password you want it to open with, and download the encrypted copy. It's free, needs no account, and the file never leaves your browser.

What kind of encryption does KeptPDF use?

256-bit AES, the modern PDF encryption standard. The encryption runs entirely in your browser, and the file is rebuilt losslessly, so text stays selectable and quality is untouched.

Is it safe to password-protect a PDF online?

With most tools the risk is that you upload the unprotected file to their servers first. KeptPDF never uploads it, because the encryption happens on your device. You can confirm it: open your browser's developer tools, watch the Network tab, and protect a file. Your file never appears in a single request.

Can I remove the password again later?

Yes, as long as you know the password. Use the Unlock a PDF tool to remove it. KeptPDF is not a password cracker, so it can't open a file you don't have the password for.

Do I need to create an account?

No. Protecting PDFs is free with no sign-up, no daily limit. Pro ($29/month) supports larger files (hundreds of MB practical limit, browser memory dependent). You only make an account if you upgrade.

Does it work on my phone?

Yes. KeptPDF runs in mobile browsers too, with the same on-device encryption, and nothing is uploaded from your phone either.

Protect a PDF. Free, in your browser.

Open Protect PDF