Lock PDF
Password-protect your PDF to prevent unauthorized access. Free and private.
How to use Lock PDF
Using Lock PDF is quick and simple. Upload your file using the upload zone above — drag and drop it directly or click to browse your files. The tool works entirely in your browser, so your files never leave your device and nothing is uploaded to any server. Once you have your file loaded, adjust the settings to your preference and click the process button. Your result will be ready to download in seconds. All processing happens client-side using modern browser APIs, ensuring complete privacy and fast performance even for large files.
Frequently Asked Questions
What kind of encryption is used? +
The PDF is encrypted with AES-256 (when supported) or RC4-128 bit encryption, which is the standard PDF security method.
Can I set different user and owner passwords? +
Yes. The user password is required to open the PDF. The owner password allows full control including removing the password.
What permissions can I restrict? +
You can restrict printing, copying text, and editing. The user can open and read the PDF but cannot perform restricted actions.
Will the password protect against all threats? +
PDF password protection is standard security, not unbreakable encryption. It deters casual access but is not a substitute for strong security measures.
Are my files private? +
Yes. All locking happens in your browser with pdf-lib. Your PDF and password never leave your device.
Your files never leave your device. All processing happens in your browser. No data is sent to any server.