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Protect PDF

Protect PDF files with a password. Encrypt PDF documents to prevent unauthorized access.

Drop your PDF here or click to browse

PDF or image files supported

Protect a PDF with a password

Encrypt any PDF so it can't be opened without your password.

Protect PDF applies standard AES-128 or AES-256 encryption (whichever the underlying pypdf library picks for the version you upload) with a user password. Anyone opening the file will need to type the password before they can read it.

This is a document-open password, the strongest common form of PDF password. It is different from a permissions password (which only limits printing/copying and can often be bypassed).

How to use it

  1. 1Upload the PDF.
  2. 2Type the password you want to set. Choose something you can share with the intended reader — the tool cannot recover it.
  3. 3Press Protect PDF.
  4. 4Share the encrypted PDF and the password through separate channels.

Real-world use cases

  • Send a contract or salary letter that only the recipient should open.
  • Store sensitive financial statements before uploading to cloud storage.
  • Add a password to invoices before emailing them.
  • Share medical or legal documents with a specific individual.

Supported formats & limits

Input: any unencrypted PDF. Minimum password length: 4 characters (longer is strongly recommended). Output: encrypted PDF.

Privacy

Your uploaded file is written to a temporary folder on our server, processed, and deleted by the operating system as soon as the request finishes — typically within seconds. Nothing is stored in our database. Traffic is encrypted over HTTPS. We do not store or log your password anywhere — the encryption happens in memory and the password is dropped as soon as the encrypted file is written.

Full details in the Privacy Policy.

Frequently asked questions

Can I recover the password later?▾

No. PDF Hub does not store your password — if you forget it, the file is effectively lost. Save the password in a password manager.

How strong is the encryption?▾

The underlying pypdf library uses AES encryption per PDF standard — practically uncrackable for a good password. The password strength is your responsibility.

Can the recipient open the file without special software?▾

Yes — every PDF viewer (Adobe Reader, browsers, macOS Preview, mobile viewers) supports opening password-protected PDFs.

Should I send the password in the same email?▾

No — send it separately (SMS, WhatsApp, phone call). Sending both in the same email defeats the purpose.

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