This tool encrypts a PDF with a password using AES-256, the same encryption standard used for genuinely sensitive data, not a cosmetic "lock" that just hides a file behind an app-level password check. Once encrypted, any PDF reader (not just this site) will refuse to open the file without the correct password, because the encryption is baked into the PDF format itself.
You set a password with a confirm field and a strength hint, and can optionally restrict permissions, for instance, allowing someone to view a document without being able to print or copy text out of it. Encryption happens entirely in your browser: your file, and the password you choose, are never transmitted anywhere, which matters given the sensitivity of anything worth password-protecting in the first place.
It's worth being clear about what this does and doesn't protect against: it stops someone from opening the file without the password, which is real, meaningful protection for a document sent over email or stored on a shared drive. It isn't a substitute for physical device security or account security, if someone has both your device and the password, the encryption isn't doing any more work at that point.
This is the right tool for anything genuinely sensitive that has to travel somewhere less trusted than your own inbox, tax documents shared with an accountant, a contract sent through a work channel you don't fully control, financial statements attached to an email. Because the strength hint reacts as you type, it's easy to tell at a glance whether a password is likely to actually resist a guessing attempt, rather than assuming any password is equally protective.
Restricting printing or copying separately from the open password is also useful when a document should be readable but not easily redistributed further, such as a proprietary report shared for review only.
How to Password Protect
- Upload the PDF you want to protect.
- Enter and confirm a password: check the strength hint as you type.
- Optionally restrict permissions, like disallowing printing or copying.
- Tap "Protect PDF" and download the encrypted file.
Frequently asked questions
Is this real encryption, or just a password prompt?
It's genuine AES-256 encryption applied to the PDF file itself, any standard PDF reader will require the correct password to open it, not just this site.
Is my password sent anywhere?
No. Encryption happens entirely in your browser, so neither your file nor the password you set ever leaves your device.
Can I restrict printing or copying separately from the open password?
Yes, you can set permissions to allow opening the file while restricting actions like printing or copying text.
What happens if I forget the password?
There's no way to recover it, encryption is real, so a lost password means the file genuinely can't be opened. Store it somewhere safe.
Does this work on any PDF, or only ones created here?
It works on any standard PDF you upload, regardless of where it came from.
Related tools
- Unlock PDF: Remove a known password from a protected PDF.
- Redact PDF: Permanently black out sensitive text or areas.
- eSign PDF: Draw your signature and place it anywhere on a page.
- Compress PDF: Shrink file size with five presets, or target an exact size.