How do I encrypt and password-protect a PDF document?

Set a strong user password (required to open the file) and owner permissions password, selecting 128-bit or 256-bit AES encryption to lock the document byte stream.

What is the difference between a User Password and an Owner Password in PDF?

A User (Open) Password is required to open and view the PDF. An Owner (Permissions) Password restricts specific actions such as printing, editing, copying text, or extracting pages.

How secure is AES-256 encryption on a PDF document?

256-bit Advanced Encryption Standard (AES) is the military-grade encryption standard approved by NIST and ISO 32000. It is computationally infeasible to break without the correct password.

Can I restrict recipients from copying text or printing the PDF?

Yes. Configure permissions flags to disable text copying, high-resolution printing, annotation editing, and form modifications.

Will a password-protected PDF open across all desktop and mobile readers?

Yes. Standard AES-encrypted PDFs open in Adobe Acrobat, Apple Preview, Google Chrome, Edge, iOS Files, and Android PDF readers upon entering the password.

Password Protect PDF Online · Encrypt PDF with AES-256