Ask for a password whenever the PDF is opened. It's locked with AES-256 on this device, so the file never leaves it.
PDF
How to use Protect
What it does
Locks a PDF so it asks for a password whenever it is opened, and saves it as a new PDF. The password is applied with AES-256. Only someone who knows the password can open the file.
Step by step
Drop a PDF onto the screen, or click to choose one.
Type the password you want in “Password”, then type the same one again in “Confirm password”. The button works only when both match.
If you also want to stop printing and copying, turn on “Block printing and copying” under “Options”. It starts off.
Click “Protect PDF”.
Click “Save”. The file name is the original name with “-protected” added.
Good to know
If you forget the password, the file cannot be opened and there is no way to recover it. A password can be up to 127 characters in English (about 42 in Korean). If the two fields differ, you see “The passwords don’t match”.
With “Block printing and copying” on, people who open the file cannot print it or copy its text. Some viewers ignore these limits.
A PDF that already has a password cannot get a new one. Unlock it first. A PDF that cannot be read can be rewritten with Repair first.
A password-protected PDF cannot be opened in other tools, so there is no “Keep going” button. Do any other changes before you add the password.
The file is processed in your browser and is not uploaded to a server.
Frequently asked questions
Can I open the file again if I forget the password?
No. There is no way to recover it. Without the password the file cannot be opened, so write the password down somewhere.
How is the password applied?
With AES-256, using qpdf in your browser. You set one password on the screen.
Does it change my original PDF?
No. The protected PDF is saved as a new file, and the original stays as it is.