Add an owner marker and restrict a PDF, then re-save it securely.
Browsers cannot apply AES encryption to a PDF without a server. This tool stamps a confidential notice and locks document metadata; for true password encryption use a desktop tool.
Drag & drop files here
or use the button below · processed locally on your device
Output settings
Free file tool
Free PDF Protect online
Add an owner marker and restrict a PDF, then re-save it securely. Use the tool directly in your browser with no sign-up. It supports multiple source files in the same session, so it also works as a free batch tool when you have more than one file.
Free to use
No payment required for this tool.
Batch conversion
Queue multiple source files in one session.
Browser-based
The conversion workflow runs from the web page on your device.
No sign-up
Start the file workflow without creating an account.
What PDF Protect is useful for
✓Converting a supported source into the required output
✓Preparing files for sharing or upload
✓Creating a new downloadable copy without replacing the original
Input and output checks
Accepted input: pdf.
✓Open the downloaded output before deleting or replacing the source file.
✓Check the details that matter for your use: page count, dimensions, orientation, text, duration or metadata.
✓For batch jobs, confirm every queued file produced the expected output.
✓If quality or size matters, compare more than one settings combination before choosing the final copy.
How to use this calculator: PDF Protect
1Upload the PDF you want to prepare for controlled sharing.
2Enter an owner or author name if needed.
3Set the confidential notice text.
4Run PDF Protect to rebuild the document with the configured metadata and notice.
5Download the protected output PDF.
Worked conversion example
Example: protect a PDF with a strong unique password, download it, close the preview and reopen the file in a separate reader. Keep an unencrypted original—forgotten passwords may make the protected copy unusable.
Accepted input
pdf
Batch behaviour
Multiple files supported
Output settings
Setting
Example/default
Effect
Owner / author name
Changes how the output is encoded or arranged; preview the result before relying on it.
Confidential notice
CONFIDENTIAL — do not distribute
Changes how the output is encoded or arranged; preview the result before relying on it.
How the browser process works
Add an owner marker and restrict a PDF, then re-save it securely. The page sends the selected file and settings to its pdf-protect browser engine, creates a new output and downloads it without overwriting the source.
Browsers cannot apply AES encryption to a PDF without a server. This tool stamps a confidential notice and locks document metadata; for true password encryption use a desktop tool.
Privacy, quality checks and limitations
Keep the original file until the downloaded output has been opened and checked.
Verify page count, orientation, dimensions, text legibility, audio/video duration and metadata relevant to your use.
Browser-local processing reduces routine upload exposure, but your device, browser extensions and download location still matter.
A converted preview is not proof of legal authenticity, archival compliance, accessibility or digital-signature validity.
Prepare a PDF for controlled sharing by adding an owner or author marker and a configurable confidential notice. The current browser implementation does not provide modern AES PDF encryption.
What does PDF Protect do?
Adds the configured owner or author information.
Adds a configurable confidential notice to PDF pages.
Rebuilds the document through the existing browser PDF workflow.
PDF protection vs encryption
The current tool is not a replacement for strong password-based PDF encryption. For highly sensitive documents, use a PDF security solution that supports modern encryption and access controls.
Related PDF Tools
Continue with a related PDF task using another OneCalcApp tool.
