Encrypt your PDF with an opening password.
Uses AES-256 encryption. Keep your password safe: it is not stored and cannot be recovered by PDFBuddy.
Choose your PDF, set the options and click Protect PDF with Password. Download the result when processing finishes.
Your PDF is processed on your device. Passwords stay in memory for this operation and are cleared when it finishes. Editing a digitally signed PDF can invalidate its existing signatures.
Protect uses AES-256 encryption and requires a password to open the saved PDF. Keep the password separately and share it through a suitable channel. PDFBuddy does not offer password recovery. Test the protected file in your intended PDF reader.
Related tool: Unlock PDF.