Password Protect PDF Online Free

Add strong RC4 128-bit encryption to any PDF with customizable permissions — 100% private, no uploads required.

Try PDF Protector

Why Use QuickPDFify to Protect PDFs?

Most online PDF protection tools require uploading your document to a remote server, exposing sensitive information. QuickPDFify is different — it uses pdf-lib with an inlined RC4 128-bit encryption engine to process everything locally in your browser. Your files never leave your device, guaranteeing 100% privacy and security.

Strong Password Protection

Set a password that must be entered to open the PDF. The built-in strength meter helps you choose a secure password (Weak to Very Strong).

Restrict Permissions

Choose what readers can do: disable printing, prevent content copying, and block modifications. All restrictions are enforced by the PDF reader.

Password Confirmation

Re-enter your password to confirm it's correct. Real-time match feedback prevents typos that could lock you out of your own file.

Custom Filename

Name your protected document anything you like before downloading. Defaults to "protected" for convenience.

Use Cases for Password-Protecting PDFs

QuickPDFify is ideal for many scenarios: secure confidential contracts before emailing clients, protect NDAs and legal documents, encrypt financial reports and tax forms, safeguard medical records and personal information, lock business proposals with sensitive pricing, or add security to invoice attachments. The encryption is built on the same RC4 128-bit engine that powers PDFSmaller.com — battle-tested on thousands of PDFs daily.

How It Works

  1. Upload — Select a PDF file from your device or drag and drop it into the upload area (max 50 MB).
  2. Set a password — Enter a strong password and confirm it. Check the strength meter to ensure your password is secure.
  3. Choose restrictions — Optionally uncheck Printing, Copying, or Modifications to limit what readers can do.
  4. Protect — Click "Protect PDF" and your encrypted file downloads automatically. Everything stays on your device.

Frequently Asked Questions

Is my data safe?

Absolutely. Your PDF is encrypted entirely in your browser using pdf-lib with an inlined RC4 128-bit encryption engine. No files are uploaded to any server. This means complete privacy by design — your data never leaves your computer.

What encryption does QuickPDFify use?

QuickPDFify uses RC4 128-bit encryption following the PDF specification (ISO 32000). The encryption engine is based on pdf-encrypt-lite, the same technology powering PDFSmaller.com's encryption tool. It's the same standard used by most desktop PDF editors.

Can I restrict printing and copying?

Yes. You can individually toggle Printing, Copying, and Modifications permissions. When a permission is disabled, the PDF reader will enforce that restriction when the file is opened with the user password.

How large can my PDF be?

You can protect PDF files up to 50 MB in size.

Do I need to create an account?

No. QuickPDFify is completely free and requires no registration, no sign-up, and no personal information.

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