About the Protect & Unlock PDF
This tool adds an open password to PDFs that shouldn’t be read by just anyone — contracts, payslips, documents with personal data. If you like, you can also set permission restrictions that block printing, copying or editing.
It also works the other way: enter the password of a protected PDF to save an unlocked copy, so you don’t have to type it every time. Encryption is done by qpdf, the standard PDF toolkit, running inside your browser, so neither the file nor the password leaves your device.
How to use
- Tap the box above and choose a PDF. The tool tells you whether it is already password-protected.
- For an unprotected PDF, type the password twice. To block printing, copying or editing, open Restrict permissions and untick those actions.
- For a protected PDF, enter its password.
- Press the button to download the result. Your original file is not changed.
Open password vs. permissions password
| Type | What it does | Strength |
|---|---|---|
| Open password (user password) | The file can’t be opened at all without it | The whole content is AES-256 encrypted and can’t be read without the password |
| Permissions password (owner password) | Needed to change the print/copy/edit restrictions | Restrictions are honored by PDF viewers; some programs ignore them |
For documents that really need protection, always set an open password. Permission restrictions alone don’t protect the content.
Choosing a strong password
- Use at least 8 characters and mix upper- and lower-case letters, digits and symbols. Longer is harder to guess.
- Avoid easy guesses such as birthdays, phone numbers or 1234.
- Send the PDF and the password through different channels (e.g. the file by email, the password by text message).
- If you forget the password, no tool — including this one — can open the file normally. Keep the original somewhere safe.
Need a random password? Try the Password Generator.
FAQ
Are my file or password sent to a server?
No. The encryption engine (qpdf) is downloaded to your browser and runs on your device, so the file and password are never transmitted.
Can I unlock a PDF if I forgot the password?
No. The tool only removes the password when you enter the correct one. It does not recover, crack or guess passwords.
Which encryption is used?
AES-256 as defined in the PDF 2.0 standard. The file opens with its password in Adobe Acrobat (X or later), macOS Preview, Chrome, Edge and current mobile PDF apps.
Does it work on a phone?
Yes, in iPhone and Android browsers too. The encryption engine (about 0.5 MB) is downloaded the first time you use it.