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Password protect a PDF

Add a password that's needed to open your PDF.

Updated

How to password protect a PDF

  1. Drop a PDF into the box above, or choose one.
  2. Type a password and type it again to confirm.
  3. Optionally, turn on restrictions and choose what people may do, with a separate permissions password.
  4. Select Protect PDF and download the protected copy.

Open password and permissions password

PasswordWhat it doesHow strong it is
Open passwordNeeded to open and read the file at allThe content is encrypted with AES-256 and can't be read without it
Permissions passwordLifts limits on printing, copying and editingRespected by mainstream PDF apps, but some apps ignore it

Choosing a good password

  • Length matters most: aim for at least 12 characters, or four or five unrelated words.
  • Avoid names, birthdays and common words with a number added.
  • Send the password separately from the file, for example by phone or text message.
  • Store it in a password manager. A lost password can't be recovered.

Common uses

  • Emailing personal documents. Protect a payslip, tax return or medical report before attaching it, and share the password by phone or message rather than in the same email.
  • Sending documents to clients. Accountants and lawyers can lock statements and agreements so only the client who has the password can open them.
  • Storing records in the cloud. Add a password to scans of ID cards, property papers or certificates before saving them to a shared drive or backup.
  • Handouts that shouldn't be edited. Turn on the restrictions to stop casual printing, copying or editing of a price list or exam paper, while still letting people read it.

Questions

How strong is the protection?

The file is encrypted with AES-256, the strongest method the PDF standard offers. Its real strength comes from your password: a long passphrase of several unrelated words is far harder to guess than a short word with a number on the end.

What if I forget the password?

The file can't be opened without it, and there's no way for us or anyone else to recover it. Keep the password in a password manager, and keep an unprotected copy somewhere safe if you might need it later.

What does restricting printing and copying do?

It sets permissions that PDF apps such as Acrobat, Preview and browsers respect: people who open the file can't print it, copy its text or edit it unless you allow it. A separate permissions password lifts the restrictions. Some apps ignore permissions, so rely on the open password to keep the content private.

Will the PDF open in every reader?

AES-256 is part of the PDF standard and works in Adobe Acrobat and Reader, Apple Preview, Chrome, Edge, Firefox and current phone apps. Very old readers from before about 2010 may not open it.

How do I remove the password later?

Open the file with Unlock PDF, enter the password, and download a copy that opens without one.

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