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Protect PDF with a password

Add a password to a PDF so only people who know it can open it, and block printing, copying or editing if you like. AES-256, and nothing is uploaded.

  • Runs in your browser
  • Nothing is uploaded
  • Free, no sign-up

or drop it here. Up to 100 MB. Nothing is uploaded.

How it works

Choose a PDF and type the password that should open it, twice so a typing mistake can't lock you out. If you like, also block printing, copying or editing for people who open it with that password; a separate permissions password, which you can set or leave random, is the only one that lifts those restrictions.

Your browser then encrypts the whole PDF with AES-256, the standard security of PDF 2.0: every page, image, font and the document's title. Before the download is offered, the protected PDF is opened again with a second PDF reader to check that it asks for a password and that yours opens every page. Neither the PDF nor the password leaves your device, and the password is never put in the address bar or anywhere it could be saved.

To lock several PDFs as one file, use Merge PDF first. To send a big PDF by email, make it smaller with Compress PDF before protecting it: compressing a protected PDF removes its password.

Questions

How do I password protect a PDF for free?

Choose the PDF, type the password twice and press Protect PDF, then download it. From then on every PDF reader asks for that password before showing the PDF. There is no account, and neither the PDF nor the password is uploaded.

How secure is the password protection?

The PDF is encrypted with AES-256, the strongest method PDFs have, so without the password its pages can't be read. Its safety then rests on the password: a short or common one can be guessed by password-cracking programs, so use a long one, like three or four unrelated words.

Can I stop people printing or copying my PDF?

You can ask PDF readers to block printing, copying and editing for anyone who opens it with the password. Adobe Reader, browsers and most apps respect this, but some ignore it, and anything shown on a screen can be photographed, so treat it as a polite lock, not a guarantee.

What if I forget the password?

Then the PDF can't be opened, by you or by anyone else: the password isn't stored anywhere, and this site never sees it. Keep the original PDF, or put the password in a password manager, before you send the protected copy.

Limits

Opens one PDF of up to 100 MB at a time. Large PDFs take a while on phones, since every part of the file is encrypted. A PDF that already has a password asks for it first; the new password replaces it. Restrictions the original PDF had are kept.

AES-256 PDFs open in Adobe Acrobat and Reader X (2010) or later, every current browser and current PDF apps; older readers can't open them. Passwords can be up to 127 characters, fewer with accented letters. A password made of letters, digits and symbols on a standard keyboard types the same on every device.

Restrictions on printing, copying and editing are respected by PDF readers but can't be enforced: some apps ignore them. A digital signature in the PDF shows as no longer valid after it is protected; the page warns you when it finds one.

Privacy

This tool runs entirely in your browser. The files you open and what you type are never sent to a server, and nothing is stored after you close the page. See the privacy page.

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