Protect PDF
Add a password with AES-256 encryption and choose what readers may do with the file.
Protect PDF in 4 steps
- Open the PDF.
- Enter the password needed to open it, and optionally a separate owner password.
- Choose permissions such as printing, copying and editing.
- Encrypt and save the protected PDF.
Questions and limits
No. PDF Studio has no upload server. Your files are opened, changed and saved inside this browser tab by JavaScript and WebAssembly running on your device. You can check it yourself: open your browser's developer tools, watch the Network tab while you use the tool, and you will see that no request carries your file.
Files are encrypted with AES-256 (PDF 2.0 security handler revision 6) by qpdf, the strongest standard PDF encryption. A long, unique password matters more than anything else.
A random owner password is generated, so the open password alone cannot be used to lift the restrictions you set.
Permissions such as no printing or no copying are honoured by standard PDF readers, but they are a request, not a hard lock: anyone who can open the file could use software that ignores them. Only the open password actually protects the content.
No. Changing a PDF writes a new file, and that invalidates any digital signature it had. Sign the document again after editing it.
Yes, after the first visit. The app and the processing engines are stored in your browser's cache, so the core tools keep working without a connection once they have loaded once.