Edit PDF

Protect PDF (Password)

Add a password so a PDF can only be opened by people who know it — encrypted in your browser with 256-bit AES.

PDF file

Choose a file to convert. It's processed locally — never uploaded. Tip: add several files to convert them all at once.

Settings

Output

Result appears here after you select

{ } How to use

  1. Upload your PDF and choose a password.
  2. Process, then download the encrypted copy.
  3. Keep the password safe — it can’t be recovered.

{ } What kind of protection this is

The PDF is encrypted with AES-256, and the password you type becomes both the user (open) password and the owner password. Anyone with the password can open, print, copy and edit the document. There is no way to set “print but not copy” permissions here, and no separate owner password.

{ } Where the work happens

Encryption runs inside your browser using qpdf built for WebAssembly (about 1.3 MB, downloaded on first use and then cached). The password is handed to the engine in memory and is never logged or sent anywhere — there is no server that could receive it.

{ } Password rules and recovery

  • At least 4 characters; there is no upper limit, and any characters are allowed.
  • Nobody can recover a lost password — not us, and not this tool. Keep it somewhere safe.
  • An already-encrypted PDF cannot be re-encrypted directly: unlock it with its current password first, then protect it again.

{ } Compatibility

The output needs a viewer that supports AES-256 — every current browser, Adobe Reader, Preview and mobile viewer does. A very old viewer limited to 128-bit encryption will refuse the file.

{ } How it works

Protect PDF (Password) works on the file you upload. Adjust the options, then select Process ▸ and it runs entirely in your browser — nothing is uploaded to a server — then shows the result in the Output panel.

Inputs

  • PDF file — upload a file (.pdf); it is read locally in your browser
  • Password — a value

Output

A downloadable PDF file — use the Download button in the Output panel.

{ } Common uses

  • Password-protect a confidential document before sharing.
  • Encrypt a PDF you’re storing or emailing.

{ } Limitations

  • This sets an open password only. There are no permission flags — no allow-printing-but-not-copying — so anyone with the password has the whole document.
  • The password can’t be recovered if you lose it — there is no back door.
  • The encryption engine (~1.3 MB) downloads the first time you use this tool, then is cached.

{ } FAQ

Is my data uploaded to a server?

No. Everything runs locally in your browser — your files never leave your device.

Can I process more than one file at once?

Yes — add several files and they’re all processed and downloaded together as a ZIP.

Is this tool free?

Yes — it’s completely free and needs no sign-up.

Is my file or password uploaded?

No. Encryption runs entirely in your browser; neither the PDF nor the password ever leaves your device.

What if the PDF is already encrypted?

Unlock it first with the current password, then protect it again.

{ } Guides