Encrypt Online
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Encrypt PDF

Password-protect PDF files

Choose + encryptFixed profile: AES-128, PDF security revision 4
Compatibility profile: output uses PDF 1.7, AES-128, Standard Security Handler V=4/R=4. For AES-256 revision 6, use a current qpdf release locally.
Only PDF files are supported.
Large files may take longer to process. Keep this tab open until the download starts.
Use a long passphrase and keep a recoverable copy. Encrypt Online does not store it or provide password recovery.
Encrypt PDF Tool

Add an open password to a supported PDF, then download and test the encrypted copy. The tool enforces AES-128 with PDF Standard Security Handler V=4/R=4 instead of selecting an algorithm from the source PDF version.

How to Password Protect a PDF
  1. Choose the PDF file from your device.
  2. Enter the password required to open the output.
  3. Click Encrypt PDF to download the protected file.
Why Encrypt PDFs?
  • Require a password before a compatible reader opens the PDF.
  • Keep the password separate from the PDF during a handoff.
  • Use a format that common PDF readers can open directly.
Tool Features
  • Fixed AES-128, V=4/R=4 output profile.
  • No application-server file upload in this workflow.
  • Download the encrypted PDF and test it before sharing.

PDF permission flags are reader-enforced preferences, not access controls. This tool allows normal printing, copying, annotation, form filling, assembly, accessibility, and modification after the open password is accepted.

Do This Locally (CLI)
# Encrypt a PDF with qpdf
qpdf --encrypt "$USER_PASSWORD" "$OWNER_PASSWORD" 256 -- input.pdf output.pdf
FAQ
Can I remove the password from an encrypted PDF?

Yes, if you know the password, you can remove it with a PDF password remover tool.

What does this tool protect?

A compatible reader asks for the open password before displaying the PDF. Protection still depends on password strength, how the password is shared, the reader implementation, and what happens after the file is opened.

What types of PDFs can I encrypt?

The tool accepts supported, unencrypted PDF files. PDFs with existing encryption or unsupported structures may fail.