PDFVoid LogoPDFVoid

Protect PDF

Encrypt your PDF document with a password using strong client-side encryption. Secure your file instantly.

Drag & drop your PDF here, or click to browse
Supported formats: .pdf (Max size: no limit, executed 100% locally)

Executed 100% locally on your browser

When you upload files, they are read as binary arrays in your browser's sandboxed RAM. We use high-performance WebAssembly engines and Client APIs to execute all processing locally. No files are sent to our servers, keeping your documents 100% confidential and secure.


Proteja su privacidad y asegure las propiedades de sus documentos. Nuestra herramienta Protect PDF le ayuda a controlar el acceso, eliminar metadatos o inspeccionar archivos localmente sin riesgos de seguridad.

How to use our free Protect PDF tool

1

Select PDF document

Select the PDF file you wish to secure by browsing your folders or dragging it in.

2

Set a strong password

Type your desired password in the security panel. Choose a combination of letters, numbers, and symbols.

3

Encrypt locally

Click the 'Encrypt PDF' button. The WebAssembly engine compiles the PDF with local cipher encryption.

4

Download locked PDF

Save the protected PDF file. It will require the password before any PDF reader will open it.

Why Use PDFVoid Protect PDF?

100% Local y Seguro

Todas las operaciones se ejecutan en tu navegador. Los archivos nunca se suben.

Sin límites de uso

Procesa todos los documentos que necesites. Sin registro, pagos ni marcas de agua.

Velocidad instantánea

Utiliza la potencia de tu CPU para procesar archivos al instante, eliminando esperas.

Frequently Asked Questions

What happens to the password I type?

Your password stays strictly inside your browser's execution stack. It is used to generate the cryptographic keys to encrypt the PDF array, and is never logged or sent to any server.

Can anyone open my protected PDF without the password?

No. The PDF will be locked using standard compliance algorithms. Standard PDF software will refuse to decrypt the document streams without the correct password.

Is this tool free to use?

Yes, like all PDFVoid tools, securing your PDFs is completely free, unlimited, and runs client-side.