PDFHope
All tools/Secure

Protect PDF

Encrypt a PDF locally with an opening password using modern 256-bit PDF encryption.

Drop a file here

or choose a file from your device

Processed on your device
About this tool

Create a new password-protected PDF without uploading the document.

An opening password encrypts the PDF with AES-256 so a compatible viewer asks for the password before showing its contents. PDFHope creates the protected copy in your browser.

Keep the password in a safe place: PDFHope does not receive it and cannot recover it. Password protection is not DRM.

How it works

How to use this PDF tool

  1. 1

    Choose a PDF.

  2. 2

    Enter and confirm an opening password.

  3. 3

    Create and download the protected copy.

Features

  • AES-256 encryption
  • Local processing
  • Password confirmation
  • Output validation

Output and quality

Encryption does not intentionally rasterize pages or reduce visual quality. Compatible viewers are needed for modern AES-256 PDF encryption.

Limitations

Password protection helps control access but is not DRM. PDFHope cannot recover a forgotten password. Rewriting may invalidate digital signatures.

Tips for better results

  • Use a unique password of 12 or more characters.
  • Share the password through a separate trusted channel.
  • Keep the original file.
Help

Troubleshooting

Why does a viewer reject the file?

Older PDF viewers may not support modern AES-256 encryption. Try an updated reader.

Why can’t I protect this PDF?

A damaged or already encrypted input may need repair or authorized unlocking first.

Frequently asked questions

Is my password uploaded?

No. Passwords are used only during local processing in this browser tab.

Which encryption is used?

QPDF creates an AES-256 encrypted PDF.

Can PDFHope recover my password?

No. PDFHope does not receive or store it.

Does protection change PDF quality?

The pages are not intentionally rasterized.

Will digital signatures remain valid?

Creating an encrypted copy may invalidate existing certificate-based signatures.

Can every PDF viewer open it?

Older viewers may not support AES-256; use a current compatible reader.

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