Protect PDF with Password
Runs entirely in your browser
Add a password to a PDF so only people who know it can open it. Your file is encrypted with AES-256 entirely in your browser — it's never uploaded to our servers, and we never see or store your password.
Drag & drop a PDF file here
or
Up to 50MB.
File
This password can't be recovered if you lose it — nobody, including us, ever sees or stores it.
What is Protect PDF?
Protect PDF adds password encryption to a PDF so it can't be opened without the password you choose. It uses AES-256 encryption, the current PDF standard for strong protection, applied entirely on your device. Because the password is never transmitted or stored anywhere, it's essential to remember it — there's no recovery option.
How to use Protect PDF
- Choose a PDF file, or drag and drop it into the tool.
- Enter a password and confirm it.
- Click Protect PDF and download the encrypted file.
Features
- Strong AES-256 encryption, with automatic fallback if your browser can't use it in the current context.
- Password confirmation field to help avoid typos.
- Show password toggle so you can double-check what you typed.
- 100% client-side — your PDF and password never leave your browser.
Frequently Asked Questions
Is my PDF or password uploaded to a server?
No. Protect PDF encrypts your file entirely in your browser. Neither the PDF nor the password you choose is ever sent to our servers, and we never store your password.
What happens if I forget the password?
There is no way to recover it. Since the password is never stored anywhere, including by us, a lost password means the protected PDF can no longer be opened. Keep it somewhere safe.
What encryption does this use?
AES-256 (PDF 2.0 standard), the strongest widely supported PDF encryption. If your browser can't use AES-256 in your current context, a legacy RC4 mode is used instead so the tool still works, and the result page tells you which one was used.
Does this stop people from printing or editing the PDF?
Setting a password also declares the PDF's permissions to compliant readers. However, PDF permissions are advisory — they're honored by well-behaved PDF software but aren't a cryptographic guarantee against a determined tool. For true confidentiality, rely on the open password itself.
Can this remove a password from a PDF instead?
No, this tool only adds a password. To remove one, use Unlock PDF instead.