Password protect is a free tool that runs entirely in your browser. Encrypt a PDF with a password (standard AES-256). Marking and protecting documents helps you control how they’re shared, printed and reused. Because everything happens locally with pdf-lib and pdf.js, your files are never uploaded to a server — Password protect works instantly, even offline, and keeps every document completely private, with no account, no watermarks and no file-size limits.
How to use Password protect
- 1Open the Password protect tool and drop in your PDF, or click to choose it.
- 2Set your options — Password — then press Run.
- 3Download your result. The whole thing happens on your device, so your PDF never leave your browser.
100% private — nothing is uploaded
Unlike most online PDF tools, Password protect never sends your PDF to a server. Everything is computed locally in your browser with JavaScript, so your documents stay on your device. There's no account, no watermark and no file-size limit — and it even keeps working with your Wi-Fi switched off.