How to Password-Protect a PDF
Lock any PDF with strong 256-bit AES encryption — free, private, and nothing ever leaves your browser.
Why password-protect a PDF?
Adding a password to a PDF restricts who can open it. This is useful when:
- Emailing confidential documents (contracts, invoices, tax forms)
- Sharing patient or legal records electronically
- Storing sensitive files in shared cloud storage
- Requiring recipients to prove they're authorised before viewing
What type of encryption does PrivaPDF use?
PrivaPDF uses AES-256 encryption — the same standard used in banking and government systems. This is the strongest encryption available for PDF files per the PDF specification.
Step-by-step: lock a PDF with PrivaPDF
Go to PrivaPDF's Lock PDF tool.
Drag and drop the PDF you want to encrypt, or click to browse. The file loads into your browser's memory — nothing is uploaded.
Type your password in both fields. Use a mix of letters, numbers, and symbols. The longer the password, the harder it is to crack.
Hit Lock PDF. Your encrypted file downloads immediately. Anyone who opens it will be prompted for the password.
Tips for strong PDF passwords
- Use at least 12 characters.
- Mix uppercase, lowercase, numbers, and symbols.
- Avoid dictionary words or anything related to the document content.
- Share the password via a separate channel — never in the same email as the PDF itself.
- Store the password in a password manager so you don't lose access to your own file.
Frequently asked questions
Can I also restrict printing or copying of the text?
The Lock PDF tool currently applies an open password. Permission restrictions (copy, print, edit) are on the roadmap for the Business plan.
What if I forget the password?
There is no recovery mechanism for a forgotten password — that's the point of strong encryption. Store your password securely before locking.
Can I remove the password later?
Yes. Use the Unlock PDF tool on PrivaPDF. Enter the correct password and the tool will produce an unlocked version.