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About PDF Lock Online
This tool adds password protection to a PDF document. You can set a user password (required to open the file) and optionally restrict permissions such as printing, copying text, and editing.
Password-protecting PDFs is useful for confidential reports, legal documents, contracts, and any file that should only be accessible to specific recipients.
Encryption and decryption happen on Toolsina's servers for this request only. The protected file is returned as a download immediately after processing.
How to use this tool
How to password-protect a PDF
Upload the PDF
Drop the .pdf into the "PDF file" field. The file must not be encrypted already — the tool refuses to re-encrypt a locked PDF.
Set the open password
"Open password" (≥ 4 characters after trimming) is required to open the PDF in any viewer. Pick something you can remember — we do not store it and cannot recover it.
Optional owner password
"Owner password" controls edit/print rights in strict viewers. Leave blank to reuse the open password as the owner password. The same caveat applies: not recoverable.
Press Run
The PDF is encrypted server-side. Output is base64 PDF you can download as locked.pdf — every viewer will prompt for the open password before showing pages.