Protect PDF

Add a real password to a PDF using industry-standard 256-bit encryption.

Free — sign in to use it. Your file is handled securely at every step — it is encrypted and never stored or seen.

Select a PDF to protect

or drop it here.

How to password-protect a PDF

  1. Sign in to your free Quikbench account.
  2. Choose your PDF and type the password you want people to use to open it.
  3. Click Protect PDF. The file is encrypted with 256-bit encryption.
  4. Download the protected copy. Your original file is unchanged.

Choosing a good password

  • Use at least 12 characters. A few random words ("harbor-violet-ladder-47") are strong and easier to remember than a short string of symbols.
  • Don't reuse a password from your email, bank or social media.
  • Write it down somewhere safe. A forgotten PDF password can't be recovered by us or by anyone else — that is the point of real encryption.
  • Send the password separately from the file, using a different channel (for example, the file by email and the password by SMS or a call).

What protection does — and doesn't — do

A protected PDF can't be opened without the password, and its contents are scrambled so they can't be read from the file itself. It does not hide the file's name, and it can't stop someone who has the password from copying the content or sharing the unlocked version. Think of the password as the key to a locked box, not a guarantee about what happens once it is open.

How your file is handled

Unlike our browser-only tools, encryption is done on our server using qpdf, a widely used open-source PDF tool. Your file travels over an encrypted connection, is protected, and is not stored afterwards. That is why this tool needs a (free) account.

Frequently asked questions

Is this really encrypted, or just a flag?

It is real encryption. The PDF's contents are encrypted with a 256-bit key derived from your password, so the file can't simply be opened by ignoring a setting.

What if I forget the password?

It can't be recovered. Keep an unprotected original, or store the password in a password manager.

Can I remove the password later?

Yes — with the password, use Unlock PDF to make an unprotected copy.

Why do I need an account?

Because the work happens on our server rather than in your browser, this tool needs a (free) account.

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