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Encrypt DOTX Files via C#

Password-protect Word documents including DOTX format using .NET Library.

How to Protect DOTX File Using C#

In order to protect DOTX file, we’ll use

Aspose.Words for .NET

API which is a feature-rich, powerful and easy to use document protection API for C# platform. Open


package manager, search for Aspose.Words and install. You may also use the following command from the Package Manager Console.

Package Manager Console Command

PM> Install-Package Aspose.Words

Protect DOTX via C#

Developers can easily lock Microsoft Word DOTX files by following the workflow.

  1. Load DOTX file in an instance of Document class
  2. Call Document.Protect method with ProtectionType & password
  3. Save the result back in DOTX format with Doucment.Save method

System Requirements

Before integrating the code, make sure that you have the following prerequisites.

  • Microsoft Windows or a compatible OS with .NET Framework, .NET Core, Windows Azure, Mono or Xamarin Platforms
  • Development environment like Microsoft Visual Studio
  • Aspose.Words for .NET referenced in your project

C# example code to protect DOTX files with password

// load DOTX document
var doc = new Document("unlocked.dotx");
// protect with a protection type and password
doc.Protect(ProtectionType.ReadOnly, "password");
// save the protected DOTX file 
  • .NET Words API can be used to load, view and convert Microsoft Word and OpenDocument Formats like DOC, DOCX, ODT to PDF, XPS, HTML and various other formats. You can also create new documents from scratch and save them in the supported formats. It is a standalone API that is suitable for server side and backend systems where high performance is required. It does not depend on any software like Microsoft or OpenOffice. ‎

    Free App to Protect DOTX

    Other Supported Protection Formats

    Using C#, one can easily protect other formats including.

    DOC (Microsoft Word Binary Format)
    DOCX (Office 2007+ Words Document)
    DOT (Microsoft Word Template Files)
    ODT (OpenDocument Text File Format)
    OTT (OpenDocument Standard Format)