When to protect a PDF
Use Protect PDF when a document should require an open password before casual viewing. The tool creates a new password-protected PDF in the browser, which can help add a basic access layer before sending a file through email or storage.
Password responsibility
Choose a password with at least four characters and store it safely. 100PDF cannot recover forgotten passwords because supported processing happens locally and no account or password recovery service is attached to the tool.
Privacy and limits
PDF protection runs in the browser without uploading the source file or password to 100PDF. This tool is not a legal compliance system, does not redact content, and does not guarantee protection against every PDF attack or specialized cracking workflow.
What the password does not restrict
The result uses an open password: a reader must enter it to view the document. It does not add separate controls for printing, copying, or editing, and it does not hide or remove sensitive content. Redact information in the source PDF before applying a password when disclosure would be harmful.
Test the protected result
Open the downloaded -protected.pdf in a PDF reader and confirm that a wrong password is rejected and the correct password opens every page. Keep the unprotected original somewhere appropriate until this test is complete, and share the password through a separate channel when practical.