Password Protect a PDF Online
Add password protection to a PDF.
Choose a PDF to protect
Preview the document locally, then create and confirm the password before processing.
PDF files · 50 MB current per-file limit · keep the original until you verify the protected resultHow to password protect a PDF
Choose a PDF, preview it locally, then create and confirm a password before processing. PdfnMore requires at least 8 characters and recommends a longer unique password. The file is uploaded only after you explicitly press Protect PDF.
Select your file
Choose the supported file from your device or drag it into the upload area.
Set the action
Choose the pages or settings needed for this tool.
Download and check
Open the result and verify it before replacing your original file.
Choose a strong PDF password
The live Protect PDF renderer uses AES-256-R5 password encryption and returns a new encrypted PDF. Use a password you have not reused elsewhere, keep it in a secure password manager, and share the document password separately from the document when practical.
What PDF password protection does
After download, open the protected result and prove that it asks for the password and opens with the exact password you created. PdfnMore reports the measured browser request duration after completion; any remaining-time display during processing is an estimate that can recalibrate rather than a promise of an exact finish time.
Protect PDF currently accepts one PDF up to 50 MB and 1,000 pages. It controls document opening with AES-256-R5 password encryption, rejects already encrypted input until it is unlocked, and does not add certificate-based digital signatures, rights-management enforcement or password recovery. Anyone who knows the password can open the file, so broader access-control and safe sharing practices still matter.
Frequently asked questions about Protect PDF
What encryption does PdfnMore Protect PDF use?
The current production renderer uses AES-256-R5 password encryption. Release checks confirm that the output is encrypted, rejects a wrong password and opens with the password you supplied while preserving the source page geometry.
Why do I need to enter the password twice?
The confirmation field catches typing mistakes before the PDF is uploaded for protection. PdfnMore requires 8 to 128 characters and recommends a longer unique password for sensitive documents.
What are the current Protect PDF limits?
The current production limit is one PDF up to 50 MB and 1,000 pages. An already encrypted PDF must be unlocked first before a new password can be applied. PdfnMore does not provide password recovery, so save the password securely and verify the downloaded file before replacing your original.