Protect a PDF with a password
NetroDoc adds password protection to a PDF so the new file requires the password before it can be opened.
The protected copy uses AES-256 encryption. Enter the password twice to prevent typing mistakes, then download the encrypted PDF.
How to protect a PDF
Upload your PDF
Choose an unprotected PDF that you want to secure.
Enter and confirm a password
Use the same password in both fields. Keep it somewhere safe because NetroDoc cannot recover it.
Protect and download
Start Protect PDF and download the new encrypted copy.
What happens when a PDF is protected?
The source PDF is validated before processing. PDFs that already require a password are not accepted by this tool.
NetroDoc rewrites the file with AES-256 PDF encryption and an open password. The page count is verified after encryption before the download is returned.
The tool is designed to require a password to open the document. It does not rely on print or copy restrictions, which PDF viewers may enforce differently.
Rewriting a PDF can invalidate existing digital signatures and may affect unusual advanced PDF features.
When is Protect PDF useful?
Sensitive documents
Add an opening password before sending a PDF that contains private information.
Shared files
Protect a document before placing it in a shared folder or sending it through another service.
Client documents
Add access protection to reports, forms, or records before distribution.
Personal archives
Create an encrypted copy before storing a PDF in an archive.
Temporary processing and password handling
The PDF is processed in a temporary working directory on the NetroDoc server and is not intentionally sent to a third-party conversion API.
The password is used only for the protection operation and is not intentionally stored or written to the output metadata. Temporary files are removed after the response is sent or when processing fails.
NetroDoc cannot recover a forgotten password. Keep your password in a safe place.
Privacy →Protect PDF FAQ
Which encryption does NetroDoc use?
Protect PDF uses AES-256 PDF encryption.
Can I protect a PDF that already has a password?
No. The source PDF must be unprotected for this tool.
Can NetroDoc recover my password later?
No. If you lose the password, NetroDoc cannot recover it.
Does the protected PDF keep the same number of pages?
Yes. The output page count is verified against the source file.
Does Protect PDF block printing or copying?
The tool focuses on requiring a password to open the file and does not add print or copy restrictions.