Email attachments get forwarded, cloud links get shared, and laptops get lost. If a PDF contains salaries, ID numbers, medical details or a contract, a password means only the people you choose can open it.
What PDF protection does
A protected PDF has two kinds of settings:
- An open password. Without it, the file can't be opened — the content is encrypted, not just hidden.
- Permissions. Once someone opens it, you can allow or block printing, copying text and editing.
Our tool uses AES-256, the strongest standard PDF encryption, supported by Adobe Acrobat, web browsers, macOS Preview and other PDF readers.
How to password-protect a PDF
- Open the free Protect PDF tool and choose your file.
- Enter a password and type it again to confirm.
- Choose what people can do after opening it: Print, Copy text and images, Edit the document.
- Click Protect PDF and download the encrypted copy.
The encryption runs in your browser — neither the file nor the password is sent anywhere.
Choosing a good password
The encryption is only as strong as the password. A short or guessable one can be cracked by trying combinations.
- Make it long — 12+ characters, or a phrase of four or more random words.
- Don't reuse your email or banking password.
- Generate one with the Password Generator if you don't need to type it from memory.
See How to Create a Strong Password You Can Remember for more.
Share the password separately
Never put the password in the same email as the PDF. Send it by text message, phone call or a different messaging app, so someone who intercepts one doesn't get both.
A note on permissions
Print and copy permissions are respected by mainstream PDF readers, but they are a deterrent rather than a guarantee: someone who can open the file can still photograph the screen. For truly sensitive content, rely on the open password and share it only with people you trust.
FAQ
What if I forget the password? It can't be recovered — not by us or anyone else. Keep the original file or store the password in a password manager.
Can I protect a PDF that already has a password? Remove the old one with Unlock PDF first, then add the new password.
Does protection change the content or quality? No. Pages look exactly the same once opened.
Try it now
Lock your file with the free Protect PDF tool.
Related reading
See How to Remove a Password From a PDF You Own and How Strong Is Your Password?. Browse the full blog for more guides.