This brief tutorial elaborates the details on how to protect PDF file with password in C#. While using C# PDF password protect feature can be implemented with the help of the following steps and a runnable sample code having a couple of API calls. Moreover, you can specify the encryption algorithm like RC4 or AES with 128 or 256-bit keys for maximum security as per your requirements.

Steps to Protect PDF File with Password in C#

1. Add the reference to Aspose.PDF for .NET library in the project for protecting a PDF file
2. Load the input PDF file with confidential data using the Document class
3. Encrypt the PDF file while specifying a password and required parameters for the Encrypt method
4. Save the password-protected PDF file after encrypting it

These steps precisely explain how using C# password protect PDF functionality can be used to secure any confidential or sensitive data from unauthorized access. It simply states that load the source PDF file, encrypt it with custom settings, and save it back on the disk. Moreover, we can choose the security level of the document as well, for instance, setting a user password will prompt for a password every time a PDF file will be opened, whereas, the permission password will be required only for modifying the PDF contents.

Code to Create Password Protected PDF File in C#

To password protect PDF C# code is demonstrated here that can be used to secure PDF documents with reliable security. We can control access permissions like allowing or forbidding extraction of contents and annotations. Similarly, you can set different document privileges including print, fill, or copy privileges to secure the data of your PDF files.

In this article, we have learned how to create password protected PDF file in C#. However, if you want to learn to split PDF pages, refer to the article on how to split PDF files by pages in C#.