How to Password-Protect a PDF (and When You Shouldn't)
Whether it's a contract, a bank statement, or an HR document, some PDFs simply shouldn't be readable by anyone who gets the file. Password-protecting a PDF encrypts it so only people with the password can open it. Here's how to do it properly — and a couple of mistakes that quietly defeat the purpose.
Two kinds of PDF passwords
PDF security actually offers two distinct protections, and mixing them up is the most common error:
- Open password (user password): required to open and view the document at all. This is real encryption — without it, the content is unreadable.
- Permissions password (owner password): the file opens freely, but certain actions — printing, copying text, editing — are restricted unless you have this password.
For genuinely confidential files, you want the open password. Permissions restrictions are more of a polite "please don't" than a hard lock.
How to password-protect a PDF
- Open Protect PDF and upload your document.
- Enter a strong open password — long, unique, and not reused from another account.
- Optionally restrict printing or copying for an extra layer.
- Download the encrypted PDF and share the password through a separate channel (don't email the file and the password together).
Encryption is not redaction
This is the trap that catches people: a password controls access to the file, but anyone who opens it sees everything inside. If your goal is to share a document while hiding specific sensitive details — a salary, an account number, a name — a password won't do that. You need to permanently remove that content with Redact PDF, which deletes the underlying text, not just covers it visually.
Also beware of "black box" redaction in basic editors: drawing a black rectangle over text often leaves the text selectable underneath. Proper redaction removes the bytes.
Removing a password you own
If you have a protected PDF you're authorized to access and want a convenient unlocked copy (for example, to merge or compress it), use Unlock PDF with the correct password. Tools should only ever help you unlock documents you own or have permission to open.
Good password hygiene for documents
- Use a long passphrase, not a single word.
- Never send the password in the same message as the file.
- Don't reuse a password you use for important accounts.
- Remember: if you lose an open password, the file may be unrecoverable — that's the point of strong encryption.
The takeaway
Use an open password via Protect PDF to keep a whole document private, use Redact PDF to permanently remove specific sensitive content, and only unlock files you're authorized to access. Encryption and redaction solve different problems — strong security usually means using both.