How to Protect PDF Files with Passwords and Permissions in C#

Chipego Kalinda

Updated:July 12, 2025

Unlock the secrets to safeguarding your PDF files with IronPDF in C#, as this tutorial empowers developers with step-by-step guidance on setting robust security measures, ensuring your documents remain protected and accessible only to those you choose.

In this tutorial, we explore the process of securing PDF files using IronPDF in C#. Starting with a new PDF document created from HTML using Chrome PDF R, we demonstrate setting owner and user passwords. The owner password restricts document editing, while the user password prevents unauthorized viewing. The protected PDF is saved as 'protected.PDF' on the C drive.

Next, we work with existing encrypted files by opening 'protected.PDF', editing its metadata, and updating security settings. This includes removing previous passwords and making the PDF read-only with a new owner password. We disable annotations, copying, pasting, and form data, while allowing full printing rights. Finally, we change the owner and user passwords, saving the updated document as 'secure.PDF'.

Upon execution, the program allows file access with the user password, while editing requires the owner password. This comprehensive guide offers valuable insights into using IronPDF to enhance document security, making it an essential resource for developers looking to protect their PDF files effectively.