ImagePDF.Tools
PDF Tool

Password protect your PDF. No upload ever.

Add AES-256 encryption to any PDF in seconds. Your file is processed entirely in your browser and never sent to a server.

Processing securely on your device, no data sent to any server

Drop your PDF here

PDF files only, processed entirely in your browser

Privacy Note: We use your browser's hardware to process this file. Your PDF stays on your computer throughout the entire process, nothing is transmitted.
No upload·100% private·Instant
How it works

Three steps. Secured in your browser.

Drop your PDF

Drag any PDF onto the upload zone or click to browse. No file size limit, everything is local.

Enter a password

Type and confirm the password you want to set. The password never leaves your device.

Save your protected PDF

Click Protect PDF. AES-256 encryption runs in your browser and the secured file is ready to save.

Use cases

When should you protect a PDF?

Any document containing confidential data benefits from a password. Here are the most common scenarios where encryption matters.

Legal and contract documents

Protect signed contracts, NDAs, and legal filings so only the intended recipient can open them.

Financial reports

Encrypt salary sheets, tax returns, and invoices before sending them over email or messaging apps.

Medical and personal records

Add a password layer to health records, test results, or any document containing sensitive personal data.

Client deliverables

Share proposals, reports, and designs with clients while ensuring only they can access the contents.

Academic submissions

Lock thesis drafts, research papers, and exam materials so early access is controlled before submission.

Internal company policies

Distribute HR documents, employee handbooks, and policy PDFs that should only be read by authorised staff.

How encryption works under the hood.

When you click Protect PDF, the tool uses pdf-lib to load your file entirely in browser memory and apply AES-256 encryption, the same cipher used by governments and financial institutions. The password you set becomes the key required to open the file in any PDF viewer.

Your PDF and your password never leave your device. There is no upload, no server, and no risk of your confidential documents being intercepted or stored by anyone else.

Common questions

Everything you need to know about PDF protection.

Is my PDF uploaded to a server?
No. All encryption happens locally in your browser using pdf-lib. Your file never leaves your device at any point.
What type of encryption is used?
pdf-lib applies AES-256 encryption, the same standard used by governments and financial institutions. Compatible with Adobe Acrobat, macOS Preview, and iOS Files.
Will the protected PDF open in Adobe Acrobat?
Yes. AES-256 encrypted PDFs are fully compatible with Adobe Acrobat, macOS Preview, iOS Files, and all other standard PDF viewers.
Can I set an owner password to restrict editing or printing?
The tool sets a user password that is required to open the file. Owner-password permission restrictions (controlling editing and printing) are on our roadmap.
Does encryption change the file content or layout?
No. Encryption wraps the entire file so it cannot be read without the correct password. The text, images, formatting, and page layout are completely unchanged.
What if I forget the password?
There is no way to recover the file contents without the password. Always store your password in a safe place before protecting the file.
Is this different from a digital signature?
Yes. Password protection controls who can open the file. Digital signatures verify the identity of the signer and detect tampering. This tool handles password protection only.
How strong is AES-256 protection?
AES-256 is computationally infeasible to brute-force with a strong, unique password. Using a long passphrase with mixed characters makes the protection extremely robust.
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