Protect PDF

Add a password and encryption to secure your PDF.

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Processed on your device. This tool runs entirely in your browser, your file is never uploaded, so nothing is stored, logged or transmitted.

About the Protect PDF

Encrypting a document before it leaves your control is one of the clearest technical safeguards you can apply to it. Both UK GDPR and the EU GDPR name encryption explicitly in Article 32 as an example of an appropriate technical measure, and US frameworks including HIPAA treat it as a recognised way to reduce the impact of a document going astray.

This tool applies AES-256 encryption with an open password using qpdf compiled to WebAssembly. The encryption runs inside your browser, so the document and the password you choose are both handled locally. The resulting file requires the password in any standards-compliant PDF reader.

It's part of the PDF collection on Toolzy, a growing platform of 135+ free, privacy-first tools built for speed and a great experience on every device.

Also known as: encrypt, pdf, password, lock.

Why use the Protect PDF?

  • No watermarks on your output
  • Handles multi-page and large PDFs
  • Keeps your original formatting and quality
  • Works on Windows, Mac, Linux, Android and iPhone

When to use it

  • Preparing documents for email or printing
  • Combining scanned pages or invoices
  • Reducing file size to meet upload limits

How to use the Protect PDF

  1. Open the Protect PDF. Open the Protect PDF on this page, there is nothing to install and no account needed.
  2. Add your input. Add your file by clicking the upload area or dragging it in. It is read on your device, not uploaded.
  3. Adjust options. Choose any options you need, the Protect PDF updates instantly.
  4. Get your result. Click the action button to download or copy your result. It is 100% free.

Frequently Asked Questions

What encryption strength is used?
AES-256, the strongest encryption defined by the PDF specification and the standard expected for documents containing personal or financial data.
Does encrypting a PDF satisfy GDPR requirements?
Encryption is specifically cited in Article 32 of the UK and EU GDPR as an example of an appropriate technical measure, and encrypting attachments before emailing them is widely treated as good practice. It is one control among several, not blanket compliance, so it should sit within your organisation’s wider data-protection approach.
Is my password sent anywhere?
No. Encryption happens in your browser through WebAssembly. The document and the password never leave your device, so we could not recover the password for you even if asked.
What happens if I forget the password?
The file cannot be opened. AES-256 has no backdoor and there is no reset. Record the password somewhere safe before you send the document, and share it with the recipient through a different channel than the file itself.
Is my data private?
The Protect PDF runs entirely inside your browser. Your file is never uploaded, so there is nothing for us to store, log or delete, your data stays on your device from start to finish.
Is the Protect PDF free?
Yes, the Protect PDF is 100% free with no watermarks, no limits and no account needed.
Does it work on mobile?
Yes. The Protect PDF works on any modern browser across desktop, tablet and mobile.

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